Quincy

Meteorologist
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  1. Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. Light snow overspread the state from southwest to northeast shortly after midnight on February 5th. This was ahead of a low pressure system that was moving into the eastern Ohio Valley. The snow quickly became heavy at times around daybreak, with snowfall rates of 1 to 3 inches per hour. A gradual change to sleet and freezing rain also took place through the morning from south to north. Warmer air flooded in aloft, although there was a cold layer that was very slow to erode near the surface. Around midday, there was a break in the action with just some spotty drizzle and light mixed precipitation. The shoreline and parts of eastern Connecticut did briefly rise above freezing. A glaze of ice was observed between I-95 and I-84, with the most significant icing across the climatologically favored sheltered areas of Fairfield and New Haven Counties in the vicinity of Route 15. An inch of sleet was reported in many areas and the size and intensity of sleet that I observed was the most impressive I can ever recall. During the afternoon, colder air moved in as a secondary low developed just south of Long Island. Precipitation ended as a few snow showers on the night of the 5th, with a few flurries into the early morning hours on the 6th across eastern Connecticut. Snowfall totals between 8 and 10 inches were common. Somewhat less snow fell along the immediate shoreline and in eastern Connecticut. The higher totals were around a foot across central and northwest portions of the state. Here is a black and white version of the map with filtered reports:
  2. Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. Flurries began to move into Connecticut shortly after daybreak on January 21st. The snow gradually overspread the state from southwest to northeast and light accumulations were noted across southwestern Connecticut by midday. As an area of low pressure developed off the mid-Atlantic coast during the afternoon, a band of heavy snow developed along a SW to NE axis from Philadelphia into Long Island. This band of heavy snow lifted northward and made it about as far as I-84 in Connecticut. Drier air won out on the northwest side of the storm as snowfall totals across Litchfield and Hartford Counties were generally lower than forecast. Areas southeast of the I-95 corridor from Bridgeport to the Rhode Island border also saw less snow, as the heaviest band of snow lifted inland. The below radar image demonstrates where the heavy band of snow maxed out. Most of the higher-end snowfall totals were observed in the green shading: With low pressure moving eastward early on January 22nd, snow tapered off from west to east during the pre-dawn hours. By daybreak, the accumulating snow was over and air temperatures had dropped into the single digits above, and in some cases, below zero. Liquid-to-snow ratios with this storm were fairly impressive. Ratios were commonly in the 20-25:1 range, although some locations observed even greater ratios. Here is a sampling of some of the ratios that were reported: North Grosvenordale: 30:1, Oakdale: 26:1, Stratford, 26:1, Portland: 20:1, Essex: 19:1, West Hartford: 18:1. The result was a very light and fluffy snow that was very easy to move and shovel. The fluffy nature of the snow also resulted in settling and compaction. Here in New Haven, the final snowfall was 8.0". Most of the snow fell before 10 p.m. Snowfall rates averaged around 1" per hour from about 4 p.m. to 7 p.m. when the band of heavy snow moved through the area. The depth of snow as of the afternoon on January 22nd was approximately 6". Liquid equivalent precipitation amounts were generally less than modeled across Connecticut. Common values were near 0.2 to 0.3", with lower amounts across north-central and northwestern parts of the state. The SREF data did an excellent job at nailing down a region for heavy snow from the northern half of New Jersey into southwestern Connecticut. It was here that the model showed strong frontogenetical forcing and was eluding to a snowfall maxima. With that said, the SREF and many other models were too generous on the northwest side of the storm for precipitation amounts. Here is a black and white version of the map with filtered reports:
  3. Here's a recap of the 2013 tornado season across the Northeast. Connecticut had four reports of tornadoes during 2013, which is roughly twice the average amount of about two. Keep in mind that 2012 had no tornadoes in the state, so one could argue that this was nature's way of balancing itself out. Elsewhere, New Jersey was the only other state in the Northeast with above average tornado reports. (They average two per year, but had three in 2013) Maine is not pictured here, but Maine had at least two tornado reports. Since they average two per year, that's right at average. Massachusetts also saw an average year with one tornado report. Vermont and New Hampshire typically average about one tornado per year, but both states saw no tornadoes this year. New York was well below average with just four tornadoes. The average there is 10 per year. Pennsylvania reported nine tornadoes, also well below their average of 16 per year. Averages based off of 1991-2010 reports, per NCDC. April 19th: An EF-1 tornado touched down near Bainbridge, N.Y. and was on the ground for 3.2 miles. (link) May 9th: A weak EF-0 tornado touched down near Stoughton, Mass., but the length of damage was less than 0.5 miles. This was a cold air funnel case and not a "classic" tornado. (link) May 28th: There were four tornado reports across northwestern Pennsylvania. Three of the tornadoes were rated EF-1s and one was an EF-0. The longest tracking tornado was an EF-1 that touched down near Edinboro and had a damage path of 18 miles long. May 29th: Two tornadoes were reported in eastern New York State. One was a significant, long-track tornado (EF-2). It was on the ground for 17 miles and the damage path was up to 1 mile wide. Another tornado, a weaker EF-1, was reported just to the southwest of that storm. (link) June 2nd: Two brief and weak EF-0 tornadoes were reported in Maine. June 27th: Two EF-1 tornadoes were reported in central Pennsylvania. July 1st: A somewhat unusual morning tornado (EF-1) was reported in extreme northeastern New Jersey. The same storm that was responsible for that tornado resulted in three tornado reports across Connecticut from late morning into early afternoon. The first report was an EF-0 that touched down in Greenwich. The most notable tornado was the second one, which was an EF-1 in the Windsor and Windsor Locks areas. A weak, brief EF-0 tornado was the third report in Enfield. (link) July 10th: A brief EF-1 tornado was reported near Moravia, Penn. during the afternoon. Less than an hour later, an intermittent EF-1 tornado was reported in Connecticut between Andover and Mansfield. The damage path of that tornado was 11.2 miles long. July 27th: An EF-1 tornado was reported in north-central Pennsylvania near Borie. That same storm dropped another EF-1 tornado in adjacent New York State about an hour later. The second of those two tornadoes was on the ground for 14 miles. August 7th: A minor EF-0 tornado was reported in southwestern Pennsylvania near Ralphton. August 13th: A weak EF-0 tornado was reported near Manahawkin, N.J. October 7th: An EF-1 tornado was reported near Paramus, N.J. The tornadoes pictured above across Delaware, Maryland and Ohio were not included in the above time-line. As might be expected, the strongest and longest-tracking tornadoes across the Northeast this year were across New York and northwestern Pennsylvania. Those areas are climatologically favored for significant tornadoes, at least when compared to areas further east. With that said, there have certainly been cases of strong tornadoes in southern New England. The most recent case was the deadly EF-3 tornado that tracked across south-central Massachusetts on June 1st of 2011. The above image is a composite that is not perfectly to scale. United States tornado seasons: Through then winter, the Gulf States are favored for tornado development. There was a minor event this past Sunday, on January 12th, that featured a few EF-0 tornado reports in extreme southeastern Virginia. Into spring, the focus shifts toward the Midwest and late spring into early summer is when the Northeast most commonly sees tornadoes.
  4. Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. Blowing and drifting snow made it difficult to obtain an accurate measurement. Some towns had multiple reports and totals that appeared to be too high based off of surrounding reports were not used. Some warm-advection snow lifted into Connecticut as early as the night of January 1st, the vast majority of the accumulating snow began on January 2nd. From morning through afternoon, flurries and periods of light snow moved from south to north across the state. By afternoon, some areas, mainly across the northern half of the state, reported an inch or two of snowfall. The 12z sounding from January 2nd at OKX indicated somewhat of a dry layer aloft, while ALY was more saturated. The best snows early on were measured from central New York into portions of interior Massachusetts. During the evening, low pressure eventually developed off of the mid-Atlantic coast and an area of snow filled in across Connecticut. It was from about 9 p.m. to 4 a.m. that the heaviest snow fell. The bands of heaviest snow wound up remaining south of Connecticut and there were even more impressive snowfall totals across eastern Massachusetts. There, ocean-enhancement was a key role in significantly higher snowfall amounts. In Connecticut, accumulating snow ended by mid-morning on January 3rd, with most areas receiving anywhere from 4 to 7 inches of snow. There was a narrow band of 7 to 7.5 inches across the northern part of the state, where additional snow during the beginning of the event increased overall totals. Close to the coast, there were also a few totals of 7 to 7.5 inches, where some towns were grazed by heavier snow toward the end of the event. While there were a few snowfall totals reported in the range of 8 to 9+ inches, those did not line up with other totals in the same or neighboring towns. Strong winds caused blowing and drifting snow, which was the most likely cause for the totals that were assumed to be erroneously high. One variable that was generally missed by the computer forecast models was lower liquid-to-snow ratios. While these ratios are generally close to 10:1, model forecasts predicted anywhere from 15-20:1 ratios, or even higher. If higher ratios had been observed, snowfall totals across Connecticut would have been higher. In the end, ratios were fairly close to 10:1. It was quite cold during the storm with temperatures falling into the lower 10s and single digits by the morning of January 3rd. Although there is a loose correlation between surface temperatures and snow ratios (colder yielding higher ratios), it was the snow growth above the surface that did not promote higher ratios. Surface temperatures alone have no impact on snow ratios, unless the temperatures are near or above freezing, then they can actually lower the ratios. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:
  5. Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. A clipper system that gave way to a coastal low just south of Long Island resulted in generally 2 to 4 inches of snow across the state. There were a few localized totals of just over 4 inches, but there were no reports over 5.0 inches. The highest totals were across the higher terrain, where some modest orographic enhancement and/or higher snowfall ratios may have come into play. There was a "snow hole" in southeastern Connecticut where generally 2 inches or less was measured. A few of the higher resolution models hinted at this area of localized lower amounts, but most data pinned that area further north. Snow flurries developed around daybreak on December 17th and periods of light snow continued through midday. After a break in the action, an area of moderate to locally heavy snow formed by mid-afternoon as low pressure intensified just to the south. Snowfall rates approached one inch per hour for a time. Some warmer air worked north and there was a change to sleet and freezing rain cross portions of lower Fairfield County. Snow tapered to flurries during the evening hours. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:
  6. Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. It should be noted that some of the reports include sleet. A general 4 to 8 inch snowfall blanketed the state before a changeover to sleet and in some cases freezing rain/rain. Very few totals deviated from that range, except for a few 8"+ reports in northwestern Connecticut and totals less than 4" across coastal New London County. Precipitation came in multiple waves between December 14th and 15th. Periods of light snow fell from morning through early afternoon. Radar imagery showed pronounced dryslots and breaks in the snow shield through much of the afternoon and early evening hours before a slug of heavier precipitation moved back in. This lack of steady snow likely cut down on some of the snowfall totals. Warmer air began to work north overnight as low pressure developed along the New Jersey coast. It took quite some time to erode the cold air that was in place prior to the event. Even though areas such as KGON and KIJD changed to rain, KHVN never rose above freezing during the steady precipitation. There, there was even a pronounced temperature drop of 7 degrees within an hour around midnight as the wind shifted to the north, allowing for colder air to drain into the city. As a result, New Haven and nearby North Haven reported an ice accretion of 0.3 inches. Other areas between I-95 and I-84 saw some icing, but most of the freezing rain was confined to lower Fairfield and lower New Haven Counties. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:
  7. An upper level trough across the Great Lakes is associated with areas of surface low pressure in and around New York State. Bands of showers and thunderstorms have been pinwheeling through the eastern United States as a result. By afternoon, more organized thunderstorm development is expected and some storms could become severe. Isolated severe thunderstorm threat... Low pressure is spinning across New York State. An area of increased wind shear is in place along the east of the Appalachians. Satellite imagery has indicated that much of the region has broken out to at least partial sunshine. This is creating moderately steep lapse rates and with cooler temperatures aloft associated with a 500mb trough, that steepness continues into the mid-levels. A rich southerly flow continues to keep dew-points on the higher side with most stations in the upper 60's to lower 60's. As far as forcing goes, there there is a weak frontal boundary movingly slowly eastward across the Appalachians. The higher resolution models couple that disturbance with an unstable air-mass and develop isolated thunderstorms and broken line segments across the Northeast by mid-afternoon. Some of the obstacles include a marine influence and some shower activity across southern New England, which may limit just how much the atmosphere can destabilize. However, elevated amounts of wind shear can promote updraft formation and some strong to severe thunderstorms. The coverage of these storms is not anticipated to be widespread in New York and New England. With cooler 500mb temperatures, there is a marginal hail threat with some of the stronger updrafts. Damaging winds seems to be the biggest concern with a relatively low, but still mention-able tornado threat, especially given the relatively low ML LCL's. Climo would not favor widespread severe activity given a south wind, but a coastal front could have some interaction with the upper level setup, which may slightly enhance convective activity. Convection is trying to initiate as of midday, but the focus is from early to mid afternoon across the Appalachians and late afternoon in southern New England for any strong to potentially severe storms. Numerous severe thunderstorm threat... Further south, stronger wind shear combines with more impressive daytime heating to warrant a threat of numerous strong to severe thunderstorms. The focus for this extends from southeastern Pennsylvania and western New Jersey and points southwest. Here there is a threat of large hail, damaging winds and also isolated tornadoes, especially given bulk shear values near or possibly above 50kts this afternoon.
  8. Low pressure develops across Pennsylvania later today and I am expecting at least some isolated severe thunderstorms across the region. Isolated thunderstorm threat... Satellite imagery shows mostly clear skies with just some high clouds across eastern Pennsylvania and New Jersey. Daytime heating is expected to push surface temperatures well into the 80's along with dew-points that are already in the upper 60's to lower 70's. In the warm sector well ahead of a cold front (east of the Appalachians in the mid-Atlantic states), a few thunderstorm cells or clusters could develop and become marginally severe this afternoon. As the cold front approaches, a squall line is depicted on the higher resolution models. This may cause isolated wind damage, especially across eastern Pennsylvania and western New Jersey. NAM forecast MLCAPE values are modest at best, near 1000 J/kg in spots. Some hail is possible in the stronger storms, but large hail is not a major threat. Due to the relatively late timing, the severe threat is a bit more unclear across portions of New York State. Even with a loss of daytime heating, proximity to deepening low pressure may cause strong to isolated severe thunderstorms to continue into the overnight period and through the pre-dawn hours of Friday. Although the threat is relatively low due to a lack of directional wind shear, the northern portion of this isolated threat zone will see increased shear after sunset as low pressure amplifies. The late timing does not climatologically favor nighttime tornadic development, but a quick spin-up could be possible, mainly in northeastern Pennsylvania, northwestern New Jersey and portions of southern New York State. In Connecticut... Although skies are breaking for sunshine across southwest portions of the state, there is a lack of a trigger mechanism to fire off any storms. MLCAPE values may increase to near 500 J/kg in parts of the state. SBCAPE looks more impressive, but with poor mid-level lapse rates, severe thunderstorm activity is not anticipated. Some pop-up thunderstorms are possible late in the afternoon and some embedded thunderstorms are expected overnight, especially west of the Connecticut River.
  9. Here's a look at some of the damage from the EF-2 tornado. I was in the area surveying, but had to leave rather abruptly. I did manage to capture some of the damage:   https://vine.co/v/b3beZpe1qI3
  10. Two tornadoes (an EF-2 and an EF-1) touched down in eastern New York on Wednesday, both around 7:00 p.m., according to the National Weather Service (NWS). The stronger tornado, an EF-2, had winds of up to 125 MPH and caused damage along a relatively wide and long path. The tornado width was estimated at 1 mile wide with a track length of 17 miles from Florida to Rotterdam. The second tornado formed just to the southwest of the EF-2 tornado, around the same time. It was a weaker and shorter-lived tornado, but was associated with the same powerful squall line that was moving east-southeast across New York. An upper level shortwave disturbance passed across New York state on Wednesday. Daytime heating across the state helped destabilize the atmosphere. Veering winds aloft created an environment that was conducive for the formation of tornadoes. I was actually chasing the EF-2 tornado, but was too far west to catch up to it. Heavy rain, flash flooding and traffic didn't help matters. As I drove into the Rotterdam area along I-90, I noticed cars parked under overpasses. While they may have not witnessed the tornado, I'm sure they experienced strong winds and may have been aware of the Tornado Warning. Personally, I did not see a lot of damage, but the tracks of the tornadoes were mainly south of I-90, which was my route of travel. PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE ALBANY NY 1209 PM EDT FRI MAY 31 2013 ...PUBLIC INFORMATION STATEMENT... TORNADO TOUCHDOWN IN MONTGOMERY AND SCHENECTADY COUNTIES ON WEDNESDAY MAY 29 2013. LOCATION... BEGAN IN FLORIDA IN MONTGOMERY COUNTY NEW YORK TO ROTTERDAM IN SCHENECTADY COUNTY NEW YORK. DATE...05/29/2013. ESTIMATED TIME...647-700 PM. MAXIMUM EF SCALE RATING...EF-2. ESTIMATED MAXIMUM WIND SPEED...125 MPH. ESTIMATED PATH WIDTH...1 MILE WIDE. PATH LENGTH...17 MILES. BEGINNING LAT/LON...42.8457/-74.2034 ENDING LAT/LON...42.8042/-74.0208 * FATALITIES...NONE. * INJURIES...1. * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS STORM DATA. SUMMARY...PATH WIDTH WAS CONSISTENT ALONG THE ENTIRE PATH LENGTH. MAXIMUM DAMAGE INCLUDED ROOFS TORN OFF OF MULTIPLE STRUCTURES AND HIGH TENSION POWER LINE TOWERS TOPPLED. LARGE NUMBER OF HARD AND SOFT WOOD TREES WERE EITHER TOPPLED...UPROOTED AND OR SHEARED. WIDESPREAD POWER OUTAGES OCCURRED AS WELL. ****************************************************** PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE ALBANY NY 1241 PM EDT FRI MAY 31 2013 ...PUBLIC INFORMATION STATEMENT... TORNADO TOUCHDOWN IN SCHOHARIE COUNTY ON WEDNESDAY MAY 29 2013. LOCATION... SUMMIT AND EAST JEFFERSON IN SCHOHARIE COUNTY NEW YORK. DATE...05/29/2013. ESTIMATED TIME...657 PM TO 702 PM. MAXIMUM EF SCALE RATING...EF-1. ESTIMATED MAXIMUM WIND SPEED...100 MPH. ESTIMATED PATH WIDTH...200 YARDS. PATH LENGTH...2 MILES. BEGINNING LAT/LON...42.515196/-74.554181 ENDING LAT/LON...42.522471/-74.578385 * FATALITIES...NONE. * INJURIES...NONE. * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS STORM DATA. SUMMARY...BRIEF TOUCHDOWN ALONG RIDGE LINE SEEN FROM JUNCTURE OF DUTCH HILL ROAD AND WHARTON HOLLOW ROAD. DOZENS OF SOFT AND HARD WOOD TREES FALLEN IN DIFFERENT DIRECTIONS AND SHEARED OFF. ALSO TREES DOWN IN DIFFERENT DIRECTIONS ALONG ENID ROAD AND PERAGLIA ROAD. Here's a look at radar imagery at 7:00 p.m. when both tornadoes were on the ground: Notice overlap of strong bulk wind shear and MUCAPE leading up to the touchdowns: Here's a look at storm reports from across the area: Here are the tornado tracks to date (2013) in the region: Here's a look at my closest pass to the EF-2 tornado, which was basically at the time that it was reported to have lifted off the ground:
  11. As a warm front lifts into the Northeastern United States on Wednesday, a warmer, more humid air-mass floods into the Northeast. Some thunderstorm development is forecast and some of those storms may be capable of reaching severe limits, particularly across portions of New York and west-central New England. Low threat (Conditions are somewhat favorable for severe thunderstorms) Interior New England, New York, northwestern New Jersey and norther Pennsylvania: As a warm front clears, an increasingly unstable air-mass overapreads the area, along with increasing dew-points. Once lingering showers, patchy fog and drizzle clear, some daytime heating will begin to fuel the atmosphere. The severe thunderstorm threat relies on a few factors. Although daytime heating is important, it should be noted that bulk wind shear values are forecast to be low to moderate, with the strongest helicity displaced northeast into central and northern New England. A line or broken lines of thunderstorms are expected to develop along a trough during the afternoon. The focus is on central and eastern New York, as well as western Massachusetts and southern Vermont. This area has a fair amount of overlap with respect to wind shear, instability, helicity and proximity to a shortwave passing near the Canadian-United States border. MLCAPE and lifted index values are somewhat supportive of severe thunderstorms, especially assuming there is a fair amount of sunshine to promote destabilization. It is also in this region that both the ARW and NMM model forecast reflectivities indicate a relatively strong squall line dropping southeast between about 5 p.m. and 9 p.m. local time. The threat appears to be mainly strong winds, but isolated hail is another possibility. Although the tornado threat is low, should wind shear coincide enough with higher helicity values, there could be a spin up or two. This area is being monitored and may be upgraded to a moderate threat of severe thunderstorms, should model guidance trends continue. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Elsewhere in green: A few scattered showers and thunderstorms are possible across the region, as far south as the middle Appalachians. Across the coastal plain of New England, decaying thunderstorms could hold together as they approach Interstate 95. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.
  12. As a warm front lifts into the Northeastern United States on Wednesday, some thunderstorm development is forecast and some of those storms may be capable of reaching severe limits. Low threat (Conditions are somewhat favorable for severe thunderstorms) Central Pennsylvania and portions of Maryland: A warm front is expected to lift into the Northeast on Wednesday. The focus is across the warm sector where some strong wind shear combines with surface/low-level instability to enhance the severe thunderstorm threat. The strongest wind shear and helicity values are projected to move across New York and New England, but there may be enough overlap across portions of the mid-Atlantic states to initiate some severe thunderstorms. The threats at this time look to be for damaging winds and isolated tornadoes. This is heavily dependent on timing and the ability of enough daytime heating to steepen lapse rates. The 15z SREF was showing an area of 1000-2000 J/kg MLCAPE across southern Pennsylvania during Wednesday afternoon. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Elsewhere in green: Although a large area is outlined in green, no organized area of severe thunderstorms is expected here. However, there is marginal atmospheric support for a few damaging wind gusts. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.
  13. That's pretty interesting and there definitely was some CAPE in place as well. As someone else said before, in New England we can see tornadoes under some seemingly weak setups, yet there are times where CAPE is through the roof and the atmosphere is very unstable and very little severe weather is reported.   A lot of it comes back to small scale processes and local topography can help (or hurt) setups.
  14. The National Weather Service (NWS) reported that an EF-0 tornado touched down in eastern Massachusetts Thursday afternoon, shortly after 4:30 p.m. An upper level low lifted northward through New England on Thursday. An unseasonably cold air mass was in place, resulting in cold temperatures aloft. It was the combination of low Lifted Condensation Levels (LCL's) and moderate wind shear aloft that helped create an environment that was marginally supportive of tornado development. It is possible that a land-sea interaction with winds off of the nearby ocean may have played a role in spawning this tornado. The NWS reported that it was a case of a cold air funnel. The tornado touched down in Stoughton, M.A. in Norfolk County and stayed on the ground for 0.25 miles. The tornado was a strong EF-0 with maximum sustained winds of 85 MPH. Damage was minimal, but a local car dealership reported seeing the tornado and had some vehicles blown around by the winds. Looking back at historical tornadoes in the Northeastern United States, the helicity values and amounts of instability in place on Thursday were relatively low compared to prior tornadic events. However, it was the low LCL heights and moderate wind shear that did elevate the tornado potential somewhat. On a scale of 0-5, 0 being unfavorable and 5 being highly favorable for tornadoes (based on local climatology), the environment yielded a value of 1.9. A note that a 2.5 value would be equal to the mean of past tornadoes. PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE TAUNTON MA 158 PM EDT FRI MAY 10 2013 ..TORNADO CONFIRMED IN STOUGHTON IN NORFOLK COUNTY MA LOCATION... STOUGHTON IN NORFOLK COUNTY MA DATE...MAY 9 2013 ESTIMATED TIME...431 PM EDT MAXIMUM EF-SCALE RATING...EF0 ESTIMATED MAXIMUM WIND SPEED...85 MPH MAXIMUM PATH WIDTH...50 YARDS PATH LENGTH...0.25 MILES BEGINNING LAT/LON...42.10N / 71.10W ENDING LAT/LON...42.10N / 71.10W * FATALITIES...0 * INJURIES...0 * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS STORM DATA. ..SUMMARY THE NATIONAL WEATHER SERVICE IN TAUNTON MA HAS CONFIRMED A BRIEF TORNADO TOUCHDOWN IN STOUGHTON MA ON MAY 9 2013. THE TORNADO TOUCHED DOWN AT A CAR DEALERSHIP ON ROUTE 138 WHERE IT WAS CAPTURED BY A SECURITY CAMERA AND RECORDED ON CELL PHONE CAMERAS BY SEVERAL OF THE DEALERSHIP EMPLOYEES. THREE RV TRAILERS...WEIGHING ABOUT 5000 POUNDS EACH...WERE PUSHED BACK ABOUT 6 FEET AGAINST A CHAIN LINK FENCE. ONE TRAILER WAS LIFTED ABOUT 15 FEET INTO A LIGHT POLE BUT LANDED ON ITS WHEELS WITH MINIMAL DAMAGE. AN ALUMINUM DOOR ABOUT 20 FEET HIGH AND 15 FEET WIDE WAS BLOWN OUT OF THE SERVICE GARAGE. EYEWITNESSES REPORTED CEILING TILES BEING LIFTED INSIDE THE DEALERSHIP AS THE TORNADO PASSED OVERHEAD. THE TORNADO ENTERED A WOODED AREA JUST TO THE NORTHEAST OF THE DEALERSHIP. ABOUT 0.25 MILES AWAY...TWO LARGE PINE TREES WERE DOWNED ON ERICA DRIVE AND DEAN ROAD BEFORE IT DISSIPATED. BASED UPON A SURVEY OF THE DAMAGE...THE TORNADO IS CLASSIFIED AS EF0 ON THE ENHANCED FUJITA SCALE WITH MAXIMUM WINDS OF 85 MPH. THE PATH LENGTH WAS 0.25 MILES AND THE MAXIMUM WIDTH WAS ABOUT 50 YARDS. Here's a look at radar imagery about a half hour before the time of the tornado: The Supercell Composite Parameter was relatively low, although some slightly higher values did target the area near the tornado touchdown: The only severe weather report in the Northeast on Thursday was that tornado in Massachusetts!
  15. As a cold front moves towards the East Coast on Saturday, some thunderstorm development is possible during the afternoon and early evening hours. Low threat (Conditions are somewhat favorable for severe thunderstorms) Mid-Atlantic region (east of Appalachians), lower Hudson Valley and SW New England. Conditions will destabilize in a warm, somewhat moist air-mass before an approaching cold front swings from west to east through the area. The biggest question mark is how much daytime heating will take place. Across Virginia, there will likely be more heating and with higher dew-points here as well, in the mid-60's, some thunderstorm development is likely. Some of these storms could reach severe limits. Further north, across eastern Pennsylvania, interior New Jersey, southeastern New York, northwestern Connecticut and the Berkshires, the threat of severe thunderstorm activity relies heavily upon daytime heating. The NAM continues to show some scattered showers and mid-level moisture limiting the destabilization process. With that said, the SREF/NAM/GFS still show a narrow finger of somewhat unstable air in this region. CAPE values between 250-500 J/kg, LI values around -2 and bulk shear around 30kt could result in a few thunderstorms reaching severe limits. Dew-points are progged to reach the lower 60's by the NAM. The 18z NAM simulated radar shows a squall line developing from Baltimore to Philadelphia to Poughkeepsie. However, this line is relatively short-lived as it collapses upon reaching the coastal plain and western Connecticut. It should be noted that helicity values increase towards the northeast, especially in New England. This may work to offset the slightly less unstable atmosphere. Bottom line, some thunderstorms may produce damaging winds from the mid-Atlantic region into southwestern New England. Some hail is possible here, but there's a stronger potential for severe hail further south. The tornado risk is relatively low, although Significant Tornado Parameter (STP) values indicate that a brief tornado or two could form anywhere in the yellow shading. Local topography across the Appalachians could aid in some rotation with any cells. When running the numbers, the tornado parameters are a bit below the mean tornado environments for historic tornadoes in the region, but are higher than what verified on Thursday with the brief EF-0 tornado in eastern Massachusetts. A few renegade thunderstorm cells could fire ahead of a cold front Saturday afternoon, especially across Virginia, where there may be a few supercells. A squall line along the cold front is more likely, advancing through eastern Pennsylvania early in the afternoon and towards the NYC metropolitan area and the coastal plain by mid to late afternoon. Instability will be key in the formation of and ability of this line to maintain itself. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Mid and upper Appalachians and portions of southern New England. Shower and thunderstorm activity is likely across the entire area, but less daytime heating will limit the severe weather threat. As one moves eastward, especially towards the coastal plain of New England, the threat decreases significantly. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.
  16. I've been creating daily 6-day forecasts for the better part of this year, with a focus on inland Connecticut. Before making any forecast, I take a close look at the computer model forecasts through Day 6, including a few forecast techniques to see how verification pans out. In April, I had 29 days worth of data, out of a possible 30, to measure forecast accuracy. As expected, forecast error generally increases with time. It is interesting to note a spike at Day 5 and a decrease at Day 6. That goes back to two particular days that had poor Day 5 forecasts vs. actual temperatures. The spread is relatively uniform as well. The error with the NAM model does seem to increase faster with time than the others, which is not a surprise. DGEX data was used for Days 5 and 6. With respect to my own forecasts, I measure verification as a mean of inland temperatures across the state. When I look at the computer models, I choose Meriden (KMMK) as a central point. This is due to its location near the center of the state. With that said, since my own verification is slightly different than the control (KMMK), this may skew results slightly. For that reason, I will be creating 6-day forecasts specifically for Meriden as a go-forward. The Euro and MAV MOS rank fairly close, but it is very interesting to note that the negative (cold) bias the Euro has is almost a mirror reflection of the MAV MOS positive (warm) bias: The MAV MOS appears to correct some of its bias towards Days 5 and 6. That can perhaps be partially explained by the fact that MOS is skewed towards climatological temperatures. The NAM also seems to have somewhat of a cool bias. I re-project highs from the NAM for Day 1, but that re-projection seems to over compensate the bias, at least in the case of April. Explaining the models/forecasts... Q: My forecast high temperatures for inland Connecticut. (mean of inland stations) MAV MOS: Forecast high temperatures for KMMK. (06z model run) ECMWF: Forecast grid-point high temperatures for KMMK. (00z model run) NAMDGEX: Approximate high temperatures for KMMK. These values are interpolated off of a graphical forecast, so the numbers are estimated. I use the NAM for Days 1-4 and the DGEX for Days 5 and 6. (06z model runs) 850mb: An 850mb forecast technique that I have been working on for quite some time. Because this technique is based off of Danbury (KDXR), that station is used for verification. LAMP MOS: Forecast high temperatures for KMMK. (most recent run in morning) NAM Re-projection: This takes into account the actual 9 a.m. temperature vs. the 06z forecast for 9 a.m. for KMMK. That error is then re-projected into the high temperature forecast. Example: If the 9 a.m. temperature was 2°F warmer than forecast, then 2°F is added to the high temperature forecast. Consensus: A mean of each forecast above, including my previous forecast (continuity) How accurate was a Euro/MAV MOS blend? Well, not only do the opposing biases balance out close to zero, but the overall forecast error was less than any other forecast technique for Days 2-6: It's pretty interesting to see the results. It goes beyond comparing computer model verification. In order to become a better forecaster, I want to see what forecasts have worked out, which ones haven't and if I have any biases. This is only one month's worth of data, so more will need to be compiled over the long-run to see how models perform. I also expect that different models/techniques will perform differently depending on the season, weather pattern, etc.
  17. A cold front is forecast to move from west to east across the East Coast on Wednesday. The result could mean scattered thunderstorms along the front, along with a few severe thunderstorms. (Marginal threat) Middle Appalachians into DE, PA, inland NJ and interior NY. A similar setup to this past Friday is expected on Wednesday, with a cold front moving across the area during the afternoon and evening hours. The only difference here is that the cold front is not as strong as that scenario (last Friday) and less convective activity is expected. Ahead of the cold front, some marginal destabilization is expected as near-surface temperatures rise into the 70's, slightly steepening lapse rates. As a result, Lifted Index values between 0 and -2 are forecast. MUCAPE is meager, with values generally less than 500 J/Kg. Although dew-points are forecast to be in the mid to upper 50's, wind shear and helicity is forecast to be somewhat less than the last event. Bulk shear of 30 to 50kt is forecast across eastern Pennsylvania, coupled with storm relative helicity values of 100-200, so some isolated damaging wind gusts are possible. (Low threat) Interior Virginia, Central Maryland and portions of eastern Pennsylvania. In this region, the timing of the cold front corresponds closely with the peak daytime heating. There's also a sliver of 500 to 1000 J/Kg CAPE values expected in south-central Pennsylvania, down into Maryland and Virginia. It's also in this general area that there is a marginal tornado threat, however the tornadic setup on Wednesday is also less impressive than it was last Friday. Graphics to differentiate between the damaging wind and tornado threats: (No appreciable severe weather threat) Southern New England, Long Island and coastal plain of New Jersey. The cold front does not make it into this area until midnight or a few hours afterward. At that time, moisture is very limited, wind shear values relax and there should be little to no instability to fuel thunderstorm activity. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.
  18. The National Weather Service (NWS) confirmed that an EF-1 tornado touched down in New York state Friday evening, shortly before 8 p.m. A strong cold front moved across Pennsylvania and New York state late Friday evening. At the same time, a marginally unstable air-mass was in place closer to the surface. With moderate to strong wind shear in place and significant storm relative helicity in place, the stage was set for damaging winds and even a marginal tornado threat. As a result, a Tornado Watch for a large portion of Pennsylvania and New York state. A tornado touched down near Bainbridge, N.Y. in Chenango County and stayed on the ground for 3.2 miles. The tornado was a strong EF-1 with maximum sustained winds of 110 MPH. Looking back at historical tornado environments in the same general area, the wind shear and helicity values in place on Friday were actually more "severe" than the climatological mean for past tornadoes. The only thing that was lacking was instability, as there was very little in place. Despite this fact, strong, twisting and turning winds aloft combined with an approaching squall line ahead of a cold front resulted in the tornado. PUBLIC INFORMATION STATEMENT...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON, NY 954 AM EDT MON APR 22 2013 ...TORNADO CONFIRMED FROM 4 SSE BAINBRIDGE IN CHENANGO COUNTY TO 3 S SIDNEY IN DELAWARE COUNTY NEW YORK... UPDATED DATA ON LAT/LON POINTS AND WIDTH. LOCATION... FROM 4 SSE BAINBRIDGE IN CHENANGO COUNTY TO 3 S SIDNEY IN DELAWARE COUNTY NEW YORK DATE...APRIL 19 2013 ESTIMATED TIME...753 PM TO 758 PM EDT MAXIMUM EF-SCALE RATING...EF1 ESTIMATED MAXIMUM WIND SPEED...110 MPH MAXIMUM PATH WIDTH...200 YARDS YARDS PATH LENGTH...3.2 MILES BEGINNING LAT/LON...42.2481N / 75.4516W ENDING LAT/LON...42.2674N / 75.3939W * FATALITIES...0 * INJURIES...0 * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS STORM DATA. ..SUMMARY THE NATIONAL WEATHER SERVICE IN BINGHAMTON, NY HAS CONFIRMED THAT A TORNADO TOUCHED DOWN ABOUT 4 MILES SSE OF BAINBRIDGE IN CHENANGO COUNTY...TRACKED NORTHEAST ABOUT 3.2 MILES...AND THEN ENDED ABOUT 3 MILES SOUTH OF SIDNEY IN DELAWARE COUNTY NEW YORK FROM 753 PM EDT TO 758 PM EDT ON APRIL 19 2013. THE TORNADO TOUCHED DOWN BETWEEN INTERSTATE 88 AND HIGHWAY 206...ON EAST AFTON ROAD...WHERE 2 POWER POLES WERE SNAPPED AND A CAR WAS DESTROYED BY A LARGE TREE BRANCH. ANOTHER VEHICLE WAS ALSO DAMAGED. SEVERAL TREES WERE SNAPPED OR UPROOTED. A BARN HAD MINOR ROOF DAMAGE. THE TORNADO CONTINUED NORTHEAST AND CROSSED HIGHWAY 206...WHERE A FARM EQUIPMENT BUILDING AND A MOBILE HOME WERE HEAVILY DAMAGED...AND A STORAGE TRAILER WAS DESTROYED. OTHER NEARBY HOMES HAD MINOR DAMAGE...AND A CARPORT WAS LIFTED AND MOVED 75 FEETFARTHER DOWN ITS PATH...THE TORNADO INTENSIFIED TO A HIGH END EF1 STRENGTH WHILE TRAVELING IN THE VICINITY OF HOUCK DRIVE. IN THIS AREA IT UPROOTED OR SNAPPED MANY 1 TO 2 FOOT DIAMETER TREES ALONG ITS PATH...BOTH HARDWOODS /MAPLES/ AND SOFTWOODS /PINES/...WITH THE LARGEST MORE THAN 3 FEET WIDE. IT ALSO CAUSED STRUCTURAL DAMAGE TO A SINGLE FAMILY RESIDENCE AND GARAGE...WHILE TRANSPORTING A SIGNIFICANT AMOUNT OF DEBRIS A HUNDRED YARDS OR MORE. THE TORNADO THEN CROSSED INTO DELAWARE COUNTY...DOWNING SEVERAL MORE TREES ON SOME PROPERTIES ALONG HIGHWAY 8 BEFORE DISSIPATING. Here's an SPC archived radar image from 00z, just minutes after the tornado touched down. A noticeable kink can be seen along the squall line near the location of the tornado, along with the approximate track below it: Here are some more storm reports from Friday:
  19. A strong cold front approaches the Appalachians Friday afternoon and evening. Along that cold front, a squall line with thunderstorms is currently expected is develop. (Marginal threat) Middle Appalachians into Pennsylvania, northwestern New Jersey and interior New York: Daytime heating is expected to push temperatures into the low to mid-70's in the valley locations with mid to upper 60's in the higher elevations. Low and mid-level clouds will likely limit just how unstable the atmosphere can get. As a result, relatively low SBCAPE below 500 J/KG combined with near-zero or marginally negative Lifted Index values are expected. Despite strong winds aloft and effective bulk shear values increasing to 35 to 50kts along a cold front, the lack of instability will likely minimize the threat of severe weather. In addition, dew-points are forecast to stay in the 50's, perhaps coming close to 60° in Maryland and eastern Pennsylvania. However, a few isolated strong thunderstorms could develop Friday afternoon ahead of a cold front. There is a marginal threat of a few damaging wind gusts associated with a squall line along the cold front Friday afternoon into Friday night. (Low threat) Interior Virginia, east of the Appalachians: The atmosphere is likely to become slightly more unstable further south. SBCAPE values of 500 to 750 J/KG are forecast based off of SREF guidance. Lifted Index values as low as -3 combined with dew-points in the 60's and higher helicity values would support more strong to severe thunderstorm activity. Based off of this, there is a low threat of severe thunderstorms with damaging winds and large hail in this area. Some isolated thunderstorm cells are possible Friday afternoon, but locally severe storms could develop along a squall line Friday night as the cold front approaches. There is a marginal threat for an isolated tornado or two, but confidence in this potential is not particularly high at this point. (No appreciable severe weather threat) Connecticut (southern new England), NYC, Long Island and coastal plain of NJ/DE: With more of a marine influence allowing for less daytime heating, there is no appreciable threat of severe weather in these areas. Also, with the cold front not expected to move through until after midnight Friday (into early Saturday), this further implies that the severe weather threat is virtually non-existent. With that said, some locally strong wind gusts are possible as a decaying squall line and associated cold front moves through late Friday night into early Saturday morning. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. Learning is an ongoing process as I learned a lot about severe weather forecasting last spring/summer and there's still a lot more to cover. Experience also helps!
  20. A strong low pressure system is forecast to move up into the Great Lakes by Thursday and eventually into southeastern Canada late Friday into Saturday. A potent cold front associated with this storm will move towards the Appalachians by the second half of Friday. (For Wednesday and Thursday, severe thunderstorm activity is probable for the Mississippi Valley and portions of the western Ohio River Valley. I see a marginal setup for severe storms from Central N.Y. into the middle Appalachians. Even though a strong shortwave and upper level jet is expected to move into New York state and Pennsylvania, there are several factors which will likely limit the severe threat... With low-level moisture and clouds, daytime heating will not be maximized along the East Coast. Right now, the areas shown in green can expect gradually steepening lapse rates. However, dew-points are only expected to be in the mid-50's to around 60 north of Washington D.C., along with 2-meter temperatures in the mid-60's to lower 70's. eastern Pennsylvania and New Jersey could get well into the 70's, but with the front lagging further to the west, there really isn't much of a trigger to kick off any storms in that area. The SREF/NAM/GFS/Euro are actually fairly similar in timing and overall evolution of this storm system. Without much heating, relatively low CAPE values are forecast. The SPC SREF does show a ribbon of slightly negative (0 to -2) Lifted Index values from central Pennsylvania southward. This indicates a marginally unstable atmosphere. As one goes further south into Virginia, the severe weather indices increase, including dew-points into the 60's. This is why that area is outlined in a "low" threat potential. Wind shear values are a bit more supportive for severe weather, but even here, the storm system loses some of its punch as it reaches the Appalachian mountains. Effective bulk shear of 40-45kts is forecast across the region. Some strong winds aloft are expected with the front, but this area of stronger winds lags far enough back to really minimize the severe weather threat. Overall threats... -Damaging wind gusts could be supported anywhere in the green or yellow shadings. -In the yellow shading, there's a very slight risk of hail and isolated tornadoes. -In New England, gusty winds are possible with a band of rain and thunderstorms late Friday night into early Saturday, but damaging winds are not terribly likely. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. Learning is an ongoing process as I learned a lot about severe weather forecasting last spring/summer and there's still a lot more to cover. Experience also helps!
  21. Here are some maps that I compiled from various sources. Most of the reports came in through the National Weather Service, with a few from this forum and social media reports that passed through quality control. Snowfall amounts were greatest across the higher terrain of Tolland County. This was due to a persistent band of moderate to heavy snow, as well as the altitude as temperatures were marginal through a portion of the event. Totals in the Connecticut River valley and the immediate shoreline were generally lower than surrounding areas. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:
  22. I don't really expect much snowfall at all tonight. For some continuity and a slight amount of uncertainty, I painted the entire area with 2" or less of snow. Eastern Conn. and northern R.I. have perhaps a 50/50 shot at 1-2": of snow, while the rest of the area has a high probability of receiving less than 1". Temperatures and moisture look very marginal and although some precipitation should back southern sections of southern New England, I don't see it being a big deal. There may be a few slushy roads for the Thursday morning commute. I don't think it's fair to make a total snowfall map for both events. The coastal plain should rise several degrees above freezing during the day on Thursday with most inland areas also cracking 32F. Also, western areas that may see no accumulation at all tonight could easily end up with some of the higher amounts tomorrow night. The snow Thursday night into Friday morning ("Round 2") looks a bit more significant. It gets tricky nailing down enhanced snow along an inverted trough across eastern N.Y. and western New England. At the same time, precipitation closer to a center of low pressure well south of Cape Cod may bring a period of snow to northeastern Conn., northern R.I. and interior eastern Mass. Here, it's a big question mark where totals could verify either low or high. The computer models are having issues nailing down precipitation totals, while some say widespread amounts over 6" could be realized in my eastern 3-6" zone. I don't see it happening, but take that for what it's worth. The confidence for the latter forecast is only moderate, but this will be my last snowfall map for the period. Confidence is higher for the first round.
  23. Just a very brief discussion: Low pressure slowly moves east of the mid-Atlantic coast Wednesday night into Thursday. A relatively broad storm with possible multiple low centers spin around and pinwheel periods of snow (some rain mixing in at the coastal plain) through the region from Wednesday into Friday. This looks to be an elevation-dependent event, but heavy amounts or precipitation across eastern Mass., eastern Conn. and much of R.I. will help offset some of the "snow losses." In those areas, 1 to perhaps 2" liquid equivalent precipitation could still result in a solid 5-10, perhaps 12" heavy, wet snowfall. The highest risk for 12" would probably be in southern Worcester County. Power outages are a concern, especially in southern and eastern areas. There, the water content will be higher and stronger winds are expected. Forecast confidence is moderate...the shoreline and southeastern Mass. could see an even sharper gradient. The banding nature of snow and timing with respect to day vs. night will be crucial in determining snowfall amounts. The snowfall totals above are cumulative, so a total of 10" may actually result in a snow-depth of 7" (for example) by midday Friday. The computer models are in decent agreement, although the GFS is a lot more conservative than all other guidance. I feel the GFS has had issues with this storm, despite originally bringing it back when the other models were keeping it south. Recall that the GFS backed off on the blizzard the day it started and totals were close to double what it had predicted.
  24. Outside of the hilly terrain across the interior, this snow event does not look like a big deal. I expect 3-6"+ across the east slopes of the Berkshires and much of Worcester County. Connecticut only sees a brief period of rain, with generally 1-3" across the northern hills. The boundary layer temperatures are simply too marginal for much to change, especially with dew-points in the upper 20's as of early Tuesday evening. Downstream observations don't indicate that cold air damming across New England will verify stronger than modeled.