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MaineJayhawk

NNE Autumn 2013 Thread

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Gonna be a lot of rain in the middle...but the flash freeze and upslope could be interesting. I could see about what this last event produced...like 3-6/4-8" on the backside for the ski areas.

Duration sucks for much more. There's really only maybe 6 hours where it looks good, then maybe another 6 hours of -SN/--SN. The big events definitely meet the 12+ hour criteria.

Positives though look like cut-off H85 and H7 lows just north of FVE, and a fairly deep layer cyclonic flow. And the whole deal gets north of FVE, which is the sweet spot. If we can clut off the H5 low, that will slow it down a bit. My first guess would be Froude near 1 or higher with good mixing in the CAA and strong, deep WNW flow.

850 rh dries out so fast we need to really slow down the upper level low movement.  I agree we need 8-12hrs+ for real deal upslope snow to fire. Not that 4-6 inches of fluff isn't a good finish. But if you want to really get excited you need to see that upslope pattern last from like 4pm to 8am .

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cool.  Thanks guys.  I'm thinking between 10am and 4pm wednesday, will be heavy rain and wind but no frozen.

 

Sounds about right.

Can't rule out some low level valley icing though. These events can get tricky in sheltered valleys where stale cold air lingers at the surface producing some dangerous conditions.

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Low was 9.8F. Looks like 2-3" of snow for the Northern Lakes Region of NH before the changeover. Knowing how well the Plymouth area does with cold air daming maybe we stay in the high 30's through most of the rain. Outside chance of us finishing the storm with some of that snow still on the ground but we will see...

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Low was 9.8F. Looks like 2-3" of snow for the Northern Lakes Region of NH before the changeover. Knowing how well the Plymouth area does with cold air daming maybe we stay in the high 30's through most of the rain. Outside chance of us finishing the storm with some of that snow still on the ground but we will see...

Sounds a little too optimisic to me. I'm leaning on the lower side of front end snow and I think we eventually torch before the cold fropa. I think you'll lose your snow...we'll see.

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With the recent focus on the larger midweek system, there hasn’t been much mention of tonight’s clipper - this one looks to have the greatest effects in the northern tier areas:

 

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE BURLINGTON VT

927 AM EST MON NOV 25 2013

 

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...

THIS AFTERNOON AS CLIPPER SYSTEM APPROACHES FROM THE NORTHERN GREAT LKS REGION. TRACK OF THIS FORTHCOMING SYSTEM WILL TAKE IT ACROSS SOUTHERN QUEBEC BY THE OVERNIGHT HRS. FOCUS OF CLD COVER AND EVENTUAL LIGHT SNOW SHOWERS WILL OCCUR OVER NORTHERN ZONES/HIR ELEV. ANY SNOW ACCUM WILL BE LIGHT WITH D-1" IN NORTHERN VALLEY LOCALES AND 1-2" OVER HIR TRRN. SOUTHERN ZONES A DUSTING AT BEST.

 

There’s really not much of a gap between the end of that system and the start of the larger midweek one, so after the sunny skies today, it looks like there’s going to be quite a stretch or precipitation over the next three days.  The upcoming period will probably represent the last additions to November snowfall, because after the midweek system, the next opportunity for snow appears to be in the Sunday timeframe, which will be December.

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I saw that the afternoon storm maps are out from the BTV NWSWinter Storm Warnings off to the west in New York farther from the storm track, and Winter Weather Advisories to the east in Vermont.  The point forecast for our area along the spine calls for 4 to 8 inches between the front and back ends of the storm.

 

 

 

This may be a situation where its more important to break out the front side and back side observations, because anything that falls on the front end (they have the Advisory out for 1-4" of wet snow tomorrow night) will certainly get washed away prior to the back-end.  The "storm totals" people report or snow totals you hear from NWS or on the news will hopefully say whether that combines both sides or just the back-end.  Snow on the ground at the end of the storm will probably tell the better story. 

 

I can picture telling someone we got 2" of snow last night and they look at you funny because it was only on the ground for an hour, then washed out before that someone woke up, lol. 

 

Its like at the ski area, if a burst of 2-4" falls overnight during grooming first shift (4pm-12am) but disappears prior to opening of the lifts... did it ever really snow at all?  I can't put that snowfall on the snow report, that's for [email protected] sure, lol. 

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BTV has a great handle on the situation I think... light mix, to heavy rain, back to light/mod (orographic) snow in VT...while NY could possibly see a heavy mixed precip event with much better front end and back end snows. 

 

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
345 PM EST MON NOV 25 2013

.SYNOPSIS...
PARTLY TO MOSTLY CLOUDY SKIES ALONG WITH A FEW FLURRIES OR LIGHT
SNOW SHOWERS ARE EXPECTED TONIGHT INTO THE FIRST HALF OF TUESDAY AS
WEAK ENERGY PASSES TO THE NORTH ACROSS SOUTHERN CANADA. A
SIGNIFICANT STORM SYSTEM WILL THEN AFFECT THE AREA TUESDAY NIGHT
INTO THURSDAY MORNING WITH WIDESPREAD...AND POSSIBLY HEAVY MIXED
PRECIPITATION. THIS WILL LIKELY PROVE PROBLEMATIC FOR HOLIDAY TRAVEL
INTERESTS DURING THE PERIOD. SEASONABLY COLD AND MAINLY DRY WEATHER
IS THEN EXPECTED BY FRIDAY INTO THE UPCOMING WEEKEND.


&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 345 PM EST MONDAY...FORECAST REMAINS ON TRACK AS WE HEAD INTO
THE EVENING AND OVERNIGHT HOURS AND ONLY SMALL ADJUSTMENTS WERE
NEEDED FOR THE FIRST 12 HOURS OF THE FORECAST...MAINLY TO
INCORPORATE MOST RECENT MODEL TRENDS IN SKY COVER AND
TEMPERATURES. SOLUTIONS PAINT A SIMILAR STORY...SHOWING NORTHERN
STREAM CLIPPER ENERGY PASSING WELL NORTH OF OUR REGION OVERNIGHT.
THIS SYSTEM WILL SPREAD PLENTY OF MID TO UPPER LEVEL CLOUD COVER
ACROSS THE AREA OVER TIME...BUT DYNAMICAL FORCING FOR
PRECIPITATION IS FAIRLY WEAK AND WITH SUCH DRY LOWER LEVELS...IT`S
HARD TO SEE MUCH IN THE WAY OF ORGANIZED ACTIVITY OCCURRING WITH
THIS SYSTEM. THUS WILL CONTINUE THE IDEA OF A FEW/SCT FLURRIES
AND/OR SHSN OVERNIGHT THOUGH MAINLY ACROSS NRN NY/NRN MTN LOCALES.
ACCUMULATIONS LIGHT AT BEST...PERHAPS A LOCALIZED INCH OR TWO
ABOVE 1500 FEET IN FAVORED LOCALES. CHAMPLAIN/CT RVR VALLEYS
MAINLY DRY. WITH DEEPENING SOUTH TO SOUTHWESTERLY FLOW
TEMPERATURES WILL EXHIBIT CLASSIC NON-DIURNAL TRENDS...ESPECIALLY
FROM THE CHAMPLAIN VALLEY WESTWARD WHICH IS TYPICAL UNDER
NOCTURNAL RETURN FLOW EVENTS.


&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 345 PM EST MONDAY...BY TOMORROW FOCUS TURNS TO DEEPENING LOW
PRESSURE RIDING NORTHEAST FROM THE SOUTHEASTERN STATES. MODELS
CONTINUE TO SHOW GOOD PHASING OF THIS SYSTEM WITH DIGGING NRN
STREAM UPPER TROUGH AND SEE NO REASON TO DISCOUNT THE IDEA OF A
WIDESPREAD MIXED/WINTRY PCPN EVENT AFFECTING OUR AREA TOMORROW
EVENING INTO WED/WED NT. FIRST SURGE OF WAA-DRIVEN PRECIP SHOULD
FALL IN THE FORM OF MIXED SN/PL/FZRA DEPENDING ON LOCALE TUESDAY
NIGHT AS INITIAL LOWER TO MID LEVEL THERMAL PROFILES ARE AT OR
SLIGHTLY BELOW FREEZING. THE DEVIL IS ALWAYS IN THE DETAILS
HOWEVER AND AS WE PROGRESS INTO WEDNESDAY CONFIDENCE IS HIGH THAT
THERE WILL BE A SUBSTANTIAL WARM AIR SURGE ALONG AND TO THE
IMMEDIATE EAST OF THE PRIMARY LOW TRACK. AT THIS TIME IT APPEARS
THAT THIS WILL BE FROM NYC NNE THROUGH VT AND AS MEAN 925-850 MB
THERMAL PROFILES SURGE INTO THE +5C TO +10C RANGE MUCH OF THE PCPN
SHOULD TRANSITION TO ALL RAIN ACROSS VERMONT DURING THE DAYLIGHT
HOURS ON WEDNESDAY. FURTHER WEST ACROSS THE ADIRONDACKS INTO THE
SLV...COLDER AIR REMAINS MORE OR LESS ENTRENCHED SO CONSIDERABLY
HIGHER CONFIDENCE IN BETTER SNOW/PL ACCUMULATIONS HERE. OTHER
CONCERNS INCLUDE A POTENTIAL SIGNIFICANT HYDRO RESPONSE ACROSS
SOME OF OUR EASTERN VERMONT RIVERS ON WEDNESDAY. MORE OF THAT
BELOW IN THE HYDRO SECTIONS. GIVEN AFOREMENTIONED TIGHT THERMAL
GRADIENTS AND MESOSCALE EFFECTS OF COLDER NEAR-SFC LAYERS ETC HAVE
LEANED HEAVILY ON THE RAW 4KM WRF 2M TEMPS WHICH APPEAR TO CAPTURE
TRENDS THE BEST. SAFE TO SAY QUITE THE NON-DIURNAL TREND IN THOSE
TEMPERATURES THROUGH TIME AS THE LOW TRACKS TOWARD...ATOP...AND
AWAY FROM THE REGION.

BY WEDNESDAY NIGHT...THERMAL PROFILES CRASH SHARPLY AS LOW PULLS
AWAY AND DECENT DEFORMATION AXIS PULLS THROUGH THE AREA...ESP NRN
NY. THUS CONTINUED ACCUMULATING SNOWS IN NY TO SLOWLY TAPER OFF
LATE...AND RAIN TO TRANSITION BACK TO SNOW/SHSN IN VERMONT. OVERALL
HOLIDAY TRAVEL IMPACTS LIKELY WITH THIS EVENT. FOR VERMONT THIS
WOULD LIKELY OCCUR TUE NT WITH INITIAL WINTRY MIX...THEN AGAIN WED
NT AS RAIN TRANSITIONS BACK TO LIGHT/MODERATE ACCUMULATING SNOWS.
IN NY..ESP DACKS/SLV...A HIGHER IMPACT EVENT EXPECTED WITH
SIGNIFICANT WINTRY MIX/ACCUM SNOWS EXPECTED THROUGH THE PERIOD. AS
RESULT OF THE ABOVE THINKING...HAVE UPGRADED WINTER STORM WATCHES
TO WINTER WX ADVISORIES FOR OUR CHAMPLAIN VALLEY AND VT
COUNTIES...AND WINTER STORM WARNINGS FOR OUR ADIRONDACKS/SLV.


&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 239 PM EST MONDAY...THANKSGIVING...BIG STORM DEPARTED WITH WITH
SOME LEFTOVER MTN -SHSN...BRISK AND COLD WITH WINDS DIMINISHING AS
THE DAY PROGRESSES.

THEREAFTER...RATHER QUIET AS PERSISTENT TROF OF THE PAST WEEK/TWO
GRADUALLY TRANSITIONS INTO ZONAL FLOW. BIG SFC HIGH BUILDS FRI AND
CONTS TO DOMINATE THROUGH THE WEEKEND THEN EXITING LATE SUNDAY AND
MON WITH RETURN FLOW.

IT WILL BE COLD AT THE START WITH A MODERATING TREND WEEKEND AND
BEYOND. PCPN WILL BE SPARSE...WITH SOME SNOW OR SNOW/RAIN SHOWERS
AS A MID LVL DISTURBANCE MOVES THRU MON...OTHERWISE BACK END OF
HOLIDAY TRAVEL SHOULD BE MUCH SMOOTHER THAN THE FRONT END.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...VFR CONDITIONS EXPECTED THROUGH THE PERIOD
BUT CLOUDS WILL GRADUALLY INCREASE AND LOWER LATE THIS AFTERNOON
AND EVENING WITH SOME SCATTERED SNOW SHOWERS IN NY.

LIGHT AND VARIABLE WINDS THIS MORNING WERE EVENTUALLY BECOMING MORE
SOUTH AND SOUTHWEST WITH SPEEDS AROUND 10 KNOTS AND SOME GUSTS TO
20 KNOTS AT KMSS/KBTV OVRNGT.

OUTLOOK 18Z TUESDAY THROUGH FRIDAY...VFR CONDITIONS CONTINUE ON
TUESDAY...THEN LOWER INTO THE MVFR AND IFR CATEGORIES TUESDAY
NIGHT THROUGH THANKSGIVING MORNING AND CLOUDS AND PRECIPITATION
MOVE IN. LOOK FOR MIXED PRECIPITATION LATE TUESDAY
NIGHT...CHANGING TO RAIN ON WEDNESDAY...THEN OVER TO ALL SNOW
WEDNESDAY NIGHT THROUGH THURSDAY MORNING. CEILINGS AND
VISIBILITIES WILL MOVE BACK INTO THE MVFR AND VFR CATEGORIES
THURSDAY AFTERNOON AS SNOW SHOWERS COME TO AN END. VFR CONDITIONS
EXPECTED FOR FRIDAY.

&&

.HYDROLOGY...
AS OF 345 PM EST MONDAY...SREF MEAN AND PLUME OUTPUT ALONG WITH
GLOBAL BLENDED SOLUTIONS ALL SUGGEST A DECENT QPF EVENT ACROSS OUR
AREA. HEAVIEST PCPN SHOULD FALL ACROSS OUR EASTERN AND SOUTHERN VT
COUNTIES WHERE WIDESPREAD 24-HOUR TOTALS SHOULD RANGE FROM 1.5 TO
2.5 INCHES. WHILE SOME OF THIS WILL OCCUR IN THE FROZEN
FORM...MUCH WILL FALL AS LIQUID WITH WATERSHEDS RECEIVING SOME
ADDITIONAL INPUT FROM MODEST HIGHER ELEVATION SNOWMELT. AS A
RESULT...SUBSTANTIAL WITHIN BANK RISES ARE LIKELY ACROSS MANY
EASTERN/SOUTHERN VT WATERSHEDS INCLUDING THE PASSUMPSIC...WELLS
AND THE WHITE. IF TRENDS CONTINUE...FLOOD WATCHES MAY BE NEEDED
FOR PORTIONS OF THIS AREA TUESDAY NIGHT INTO WEDNESDAY.

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This may be a situation where its more important to break out the front side and back side observations, because anything that falls on the front end (they have the Advisory out for 1-4" of wet snow tomorrow night) will certainly get washed away prior to the back-end.  The "storm totals" people report or snow totals you hear from NWS or on the news will hopefully say whether that combines both sides or just the back-end.  Snow on the ground at the end of the storm will probably tell the better story.

 

I can picture telling someone we got 2" of snow last night and they look at you funny because it was only on the ground for an hour, then washed out before that someone woke up, lol.

 

Its like at the ski area, if a burst of 2-4" falls overnight during grooming first shift (4pm-12am) but disappears prior to opening of the lifts... did it ever really snow at all?  I can't put that snowfall on the snow report, that's for [email protected] sure, lol.

 

Yes, great point, that’s very important in a public forecast sense, or reporting for the ski area.  After living in the upslope zone and recording snowfall for a number of years now though, I’ve pretty much acquired the perspective that there’s only minimal connection between snowfall numbers and amount of snow on the ground, but that’s definitely not the way everyone thinks.  The snowfall numbers get entered into the spreadsheet and added, but never subtracted, and since I track snowfall by storm, I typically lump all the numbers together.  But indeed, 1 to 3 inches of snow on the front end with 3 to 5 inches on the back end and a lot of rain in the middle is definitely different that a 4 to 8 inch snowstorm in terms of sensible weather, so you’d never want to make a forecast without detailing those nuances.

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This may be a situation where its more important to break out the front side and back side observations, because anything that falls on the front end (they have the Advisory out for 1-4" of wet snow tomorrow night) will certainly get washed away prior to the back-end.  The "storm totals" people report or snow totals you hear from NWS or on the news will hopefully say whether that combines both sides or just the back-end.  Snow on the ground at the end of the storm will probably tell the better story. 

 

I can picture telling someone we got 2" of snow last night and they look at you funny because it was only on the ground for an hour, then washed out before that someone woke up, lol. 

 

Its like at the ski area, if a burst of 2-4" falls overnight during grooming first shift (4pm-12am) but disappears prior to opening of the lifts... did it ever really snow at all?  I can't put that snowfall on the snow report, that's for [email protected] sure, lol. 

 

From my personal perspective, these are two separate events. I think forgoing the watch is fine, because I have fairly low confidence in 6+ in 12 hours (needing 50% confidence for watch). We may very well total more than that combined front and backside, but public impact certainly won't seem that way.

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There’s nothing to report in terms of new snow accumulations from my location in Waterbury, but I see that there is some activity off to the south as has been noted here in the forum.  It doesn’t appear that the BTV NWS has had to alter their projected snow accumulations maps for this morning, so I’ll just reference the one in the post from yesterday.  The advisories map has been updated now, at least with respect to adjoining forecast offices, and the Winter Weather Advisories extending into northern New Hampshire are visible.

 

26NOV13A.jpg

 

The point forecast for our location remains similar to yesterday, with 1 to 3 inches snow/sleet projected for the front end of the storm, ¾ - 1” of rain in the middle, 3 to 5 inches of snow on the back end through Wednesday night, and a bit more snow lingering into Thanksgiving Day.

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Snowing a bit this way as well with a dusting.

 

WWA are up for mountain peeps

 

attachicon.gifStormTotalSnowFcst.png

 

About the same here in the west end of Portland, 1/4" or so. The ride from the miscoast to Portland this morning was crazy. With the snow covered roads, cars were sliding off everywhere.

 

26.4°F

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I’ve really been enjoying the NWS hourly weather graph option for their point forecasts, and checking out the data for our location, it really provides a nice visual representation of the “sandwich” nature of the upcoming storm.  You can actually tailor the plots to just the parameters you want to see, so for the first time today I tried that, removing the ones that were unrelated (thunder, etc.) or of less interest.  Anyway, there’s no freezing rain anticipated here based on the tool, but I left it in since it’s one of the mixed bag precipitation types.  It looks like this feature is available throughout the NWS offices, so kudos to them for putting together such a nice feature that’s both graphical and quantitative.

 

26NOV13B.jpg

 

These sort of storms always represent a fun challenge with respect to dissecting out the liquid equivalent contributed by the various precipitation types, so it should be a good workout for the back yard weather tools.  With the up and down nature of this event, as well as the holiday, I’ll probably have the web cam up and running a lot, so feel free to check in on what it’s showing as the storm progresses:

 

J&E Productions Web Cam

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Is that before or after 2-5" rain? Seriously, that much liquid is going to do some damage at sugarloaf and SR. Would hate to be skiing on T-Day on glare ice.

 

That's through 7am on Wednesday, so it would be pre-flooding rains.  I might be going out for a Thanksgiving morning hike, and I'm very curious about how much ice I'll have to deal with.  Microspikes may not cut it!

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About 3/4" here in Plymouth. Jackpot!

 

A little bit disappointed that I'm headed back to mass tonight... I'm interested to see how this verifies up here. All rain back home.

 

Rain, snow, freezing rain, and sleet before 3am, then freezing rain and sleet between 3am and 5am, then rain, freezing rain, and sleet after 5am. Low around 30. Southeast wind 5 to 10 mph. Chance of precipitation is 100%. New ice accumulation of 0.1 to 0.3 of an inch possible. New snow and sleet accumulation of 1 to 3 inches possible.

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For pfreak and J spin, do you see parts of nw vt being hit by a second piece /lagging piece of energy tomm pm. I think btv disco mentions this but im not sure and was wondering if it is a trowal feature , either way i thought it bears watching as thermal profiles are dropping around that time.

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2.5" of snow total here in Eastern Brunswick, ME. Liquid equivalent of 0.17". A 15:1 ratio. Snow is still spitting but this definitely produced more than I expected. Now, we gear up for 2-3 inches of rain. 

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