donsutherland1

September Preview: In the New York City area, September has increasingly become an extension of summer. Prior to 2000, a monthly mean temperature of 70° or above was relatively uncommon. Prior to 1950, Central Park saw such warmth about once every 5.4 years. From 1950-1999 (during which New York City has had a mature urban footprint), such warmth was recorded approximately once every 4.5 years. Since 2000, 70° Septembers have occurred about once every 2.0 years. There have been 10 such Septembers during the 2000-2019 period, which is just below the figure of 11 recorded during 1950-1999. Since 2010, New York City has had 7 cases where September had a mean temperature of 70° or above, including the last four years. During the last 30 years, September has had a mean temperature of 69.0°, which is the warmest 30-year period on record for September. During the last 10 years, September has had a mean temperature of 70.5°, which is the warmest 10-year period on record for that month. Records go back to 1869. The 1981-2010 normal temperature for September is 68.0°. New York City's 30-Year Moving Averages for September: 30-Year Period ending: 1990: 68.1° 2000: 68.1° 2010: 68.4° 2019: 69.0° September 2020: Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. The first half of September will likely see a deep trough located over the Great Lakes to Central Canada. However, the Western Atlantic Ridge could blunt the amount of cool air that reaches the New York City area. Afterward, that trough could dissipate. Overall, September will likely wind up with a mean temperature near 70° or about 2° above normal in New York City.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA 1.8 2.0 1.7 0.0 1.0 0.3 0.2 2.7 3.2

Morning thoughts... Temperatures started out mainly in the 50s outside the major cities and lower 60s in such cities as New York, Newark, and Philadelphia. August will end on a cool note under variably cloudy skies. There will be more clouds around than yesterday. Temperatures will reach the middle and upper 70s in the region. Likely high temperatures around the region include: New York City (Central Park): 76° Newark: 77° Philadelphia: 78° Temperatures will likely return to above normal levels near or just after mid-week. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of cooler weather. That trough may persist until near mid-September. 2020 is the record 7th consecutive year that Central Park has had no August temperatures below 60°. The previous record was 3 consecutive years during 1931-33, 1995-97, and 2001-03. The last time the mercury fell below 60° was August 15, 2013 when the temperature fell to 59°. LaGuardia Airport will conclude its warmest summer on record with a mean temperature near 79.5°. The existing record is 79.2°, which was set in 2010.

Arctic sea ice extent fell to 3.995 million square kilometers on JAXA. That makes 2020 the second consecutive year that will have a minimum extent below 4.000 million square kilometers and the third such year on record.

I suspect the problem with the “Green New Deal” has less to do with its climate provisions than with the non-climate provisions. Hopefully, sooner rather than later, science will take precedence over other interests when it comes to addressing the challenge of climate change.

The averages were boosted more by near record and record periods of abnormally high minimum temperatures.

It is. The IPCC is considering increasing the confidence figure for anthropogenic factors being the dominant cause of the ongoing warming to 99%-100% from 95%. The evidence is all but unequivocal now. I agree concerning future generations. That they will bear the highest costs from inaction, they will likely point to that inaction as being among the greatest failures in human history. They won’t be wrong. Moreover, I suspect that when Generation Z attains political leadership, they will make drastic changes (e.g., net carbon neutrality in a decade or less) to address the problem if little has been done. Inaction is squandering the time available for a transition.

Today was a picture perfect late August Day. Bright sunshine, deep blue skies, puffy cumulus clouds, low humidity and an active breeze made for an exceptional day as temperatures topped out in the upper 70s and lower 80s across the region. Tomorrow will see more in the way of clouds than today, but it should still be partly sunny. August will end on a cool note as the temperature remains below 80° in a large part of the region. Beyond midweek, temperatures will likely return to above normal levels. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of cooler weather. That trough may persist until near mid-September. Nevertheless, the first half of September will likely wind up somewhat warmer than normal and September, as a whole, will likely finish at least somewhat warmer than normal. Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature near 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 will likely exceed that figure. There is currently an implied 87% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +22.70. Today, the preliminary Arctic Oscillation (AO) figure was -1.410. On August 29, daily MJO data was unavailable. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Summer 2020 will likely finish with a mean temperature near 76.9°, which would tie 2020 as Central Park's 4th warmest summer with 1949, 1983, and 1993. At LaGuardia Airport, summer 2020 will likely finish with a mean temperature of 79.5°. That would surpass the existing summer record of 79.2°, which was set in 2010. Finally, on August 28, Arctic sea ice extent was 4.059 million square kilometers (JAXA). There is an implied 98% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.806 million square kilometers. The lowest 25% bound is 3.604 million square kilometers.

Under partly sunny skies, the temperature rose into the upper 70s to near 80° this afternoon. Three photos from the New York Botanical Garden from this afternoon:

This year one is seeing an IOD- pattern. Last year one saw among the strongest IOD+ patterns.

Morning thoughts... Today will feature abundant sunshine with temperatures in the middle and upper 70s to perhaps around 80° in the region. Likely high temperatures around the region include: New York City (Central Park): 78; Newark: 80; and, Philadelphia: 80. August will likely end on a cool note with readings several degrees cooler than those of today. Temperatures will likely return to above normal levels near or just after mid-week. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of cooler weather. That trough may persist until near mid-September. LaGuardia Airport remains on course to record its warmest summer on record. Arctic sea ice extent will likely fall below 4 million square kilometers over the next day or two for the second consecutive year and third time on record.

Tomorrow will feature abundant sunshine with temperatures in the middle and upper 70s to perhaps around 80° in the region. August will likely end on a cool note before temperatures again return to above normal levels during the first week of September. The current predominantly warmer than normal pattern will likely persist through much of September, providing a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. However, uncertainty about the possibility of more sustained cool shots has increased in recent days. Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature near 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 68% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +18.63. Today, the preliminary Arctic Oscillation (AO) figure was -1.838. On August 28, daily MJO data was unavailable. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. New York City has had 18 days on which the temperature reached 90° or above during July-August 2020. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.8°. Summer 2020 will likely finish with a mean temperature near 76.9°, which would tie 2020 as Central Park's 4th warmest summer with 1949, 1983, and 1993. At LaGuardia Airport, summer 2020 will likely finish with a mean temperature of 79.5°. That would surpass the existing summer record of 79.2°, which was set in 2010. Finally, on August 28, Arctic sea ice extent was 4.119 million square kilometers (JAXA). There is an implied 95% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.843 million square kilometers. The lowest 25% bound is 3.624 million square kilometers.

Clouds broke for sunshine this afternoon, the temperature rose above 80°, and a brisk breeze blew across the waters of the Long Island Sound.

Afternoon thoughts... As of 2 pm, rainfall totals were as follows: Atlantic City: 0.23” Islip: 0.23” New York City: 0.01” Newark: None Philadelphia: 0.10” White Plains: 0.10” An area of showers and thundershowers was moving mainly eastward across southeastern Pennsylvania with a few widely scattered showers elsewhere in Pennsylvania. Overall prospects for rainfall in the New York City area have decreased. In general, New York City, Newark, and nearby suburbs will see 0.25” rain or less. Exceptions would be areas where thundershowers develop. Parts of Long Island could still pick up 0.50” or more. Western parts of the region could see the clouds begin to break early this evening.

Thank you for the tip. I appreciate it.

Wilmington DE picked up 1.03” rain in the past hour, but that area of intense rainfall is heading east-northeastward and will stay well south of Newark.

Morning thoughts... At 8:55 am, a batch of showers and thundershowers had moved into southwestern Connecticut. The area of rain was pushing northeastward. Additional showers and thundershowers are likely as the remnants of Laura approach the area. Laura will likely exit off the Delmarva Peninsula tonight. The New York City area and adjacent suburbs could pick up 0.25"-0.75" rain. A few locations on Long Island could see some locally higher amounts as Laura begins to tap into Atlantic moisture. August will end with cooler than normal temperatures, but the mercury will rebound early next week. A flash flood watch will go into effect in Phoenix this afternoon and run through tomorrow. The extreme heat that has dominated much of July and August there will relax. A warmup is likely next week there.

Laura will likely exit off the Delmarva Peninsula late tomorrow night. The system has the potential to bring an area of 1"-3" rain with locally higher amounts across parts of Virginia and the Delmarva Peninsula, along with another area with pockets of moderate to perhaps heavy rain along a frontal boundary to its north. The New York City area and adjacent suburbs could pick up 0.25"-0.75" rain. August will likely end on a cool note before temperatures again return to above normal levels during the first week of September. The current predominantly warmer than normal pattern will likely persist through much of September, providing a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Parts of the West continued to experience near record and record high temperatures. Select high temperatures included: Death Valley: 115°, Kingman, AZ: 105° Lake Havasu City, AZ: 113° Las Vegas: 106° Needles, CA: 115° Palm Springs, CA: 116° Phoenix: 112° Tucson: 107° (tied record set in 1998) Yuma, AZ: 113° Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature near 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 60% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +9.65. Today, the preliminary Arctic Oscillation (AO) figure was -1.512. On August 27, daily MJO data was unavailable. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. New York City has had 18 days on which the temperature reached 90° or above during July-August 2020. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Summer 2020 will likely finish with a mean temperature near 76.9°, which would tie 2020 as Central Park's 4th warmest summer with 1949, 1983, and 1993. At LaGuardia Airport, summer 2020 will likely finish with a mean temperature of 79.4°. That would surpass the existing summer record of 79.2°, which was set in 2010. Finally, on August 27, Arctic sea ice extent was 4.157 million square kilometers (JAXA). There is an implied 93% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.857 million square kilometers. The lowest 25% bound is 3.618 million square kilometers.

This afternoon, the temperature rose into the middle 80s in New York City under mainly sunny skies. Four photos from The New York Botanical Garden:

The local storm report from yesterday’s severe thunderstorms: 000 NWUS51 KOKX 280250 LSROKX PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE NEW YORK NY 1050 PM EDT THU AUG 27 2020 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0348 PM TSTM WND DMG WATERBURY 41.56N 73.04W 08/27/2020 NEW HAVEN CT SOCIAL MEDIA LARGE TREE UPROOTED ON LOUNSBURY STREET 0350 PM TSTM WND DMG NAUGATUCK 41.49N 73.05W 08/27/2020 NEW HAVEN CT SOCIAL MEDIA TREE AND BRANCHES DOWN ON A HOUSE 0400 PM TSTM WND DMG SOUTHBURY 41.49N 73.22W 08/27/2020 NEW HAVEN CT SOCIAL MEDIA VIDEO OF A TREE DOWN BLOCKING 1 LANE ON I-84 0404 PM TSTM WND DMG MONTOWESE 41.35N 72.86W 08/27/2020 NEW HAVEN CT SOCIAL MEDIA NUMEROUS TREES AND BRANCHES SNAPPED AND DOWNED IN MONTOWESE SECTION OF NORTH HAVEN WITH TIME ESTIMATED BY RADAR 0406 PM TSTM WND DMG NORTH HAVEN 41.38N 72.86W 08/27/2020 NEW HAVEN CT TRAINED SPOTTER MULTIPLE LARGE TREES UPROOTED NEAR I91 AND I40 0410 PM TSTM WND DMG NORTH HAVEN 41.38N 72.86W 08/27/2020 NEW HAVEN CT SOCIAL MEDIA VIDEO OF MULTIPLE LARGE TREES DOWN. 0410 PM TSTM WND GST NEW HAVEN 41.31N 72.92W 08/27/2020 M69 MPH NEW HAVEN CT MESONET 0410 PM TSTM WND GST NEW HAVEN 41.31N 72.93W 08/27/2020 M69 MPH NEW HAVEN CT MESONET 0412 PM MARINE TSTM WIND SOUTH END 41.25N 72.90W 08/27/2020 M40 MPH NEW HAVEN CT WXFLOW MEASURED GUST AT LIGHTHOUSE POINT. 0414 PM TSTM WND DMG NORTH HAVEN 41.38N 72.86W 08/27/2020 NEW HAVEN CT TRAINED SPOTTER MULTIPLE LARGE TREES DOWN WITH EXTENSIVE DAMAGE TO HOMES ON PALMER ROAD. 0415 PM TSTM WND DMG BRANFORD 41.28N 72.81W 08/27/2020 NEW HAVEN CT TRAINED SPOTTER NUMEROUS LARGE TREES AND POWER LINES DOWN ACROSS BRANFORD. 0416 PM TSTM WND DMG BRANFORD 41.28N 72.81W 08/27/2020 NEW HAVEN CT NWS EMPLOYEE TREE TOPS TWISTED AND POWER LINES DOWN ON FEATHERBED LANE. 0420 PM HIGH SUST WINDS 3 SE BRANFORD 41.24N 72.76W 08/27/2020 M46 MPH NEW HAVEN CT MESONET 0422 PM TSTM WND DMG WALDEN 41.56N 74.19W 08/27/2020 ORANGE NY TRAINED SPOTTER SEVERAL LARGE TREE LIMBS DOWN WITH MEDIUM SIZED TREES SNAPPED. 0438 PM TSTM WND DMG CUTCHOGUE 41.01N 72.49W 08/27/2020 SUFFOLK NY SOCIAL MEDIA LARGE BRANCH DOWN. 0440 PM TSTM WND DMG CUTCHOGUE 41.01N 72.49W 08/27/2020 SUFFOLK NY SOCIAL MEDIA LARGE TREE LIMB DOWN NEAR OREGON RD AND BRIDGE LANE 0440 PM TSTM WND DMG SOUTHOLD 41.06N 72.43W 08/27/2020 SUFFOLK NY LAW ENFORCEMENT TREE DOWN BLOCKING RT 48. 0450 PM MARINE TSTM WIND REEVES PARK 40.97N 72.71W 08/27/2020 M53 MPH SUFFOLK NY WXFLOW MEASURED GUST. 0450 PM MARINE TSTM WIND 1 SSE DUCK ISLAND ROADS 41.24N 72.50W 08/27/2020 M48 MPH ANZ330 CT LAW ENFORCEMENT BOATER MEASURED WIND GUST. 0450 PM TSTM WND DMG GREENPORT 41.10N 72.37W 08/27/2020 SUFFOLK NY LAW ENFORCEMENT TREE DOWN AND BLOCKING WILLOW ST. 0456 PM MARINE TSTM WIND 2 SE PONQUOGUE 40.84N 72.48W 08/27/2020 M40 MPH SUFFOLK NY WXFLOW 0504 PM TSTM WND DMG SOMERS 41.33N 73.69W 08/27/2020 WESTCHESTER NY LAW ENFORCEMENT TREE DOWN BLOCKING SOMERS ROAD BETWEEN SOMERSET DRIVE AND CRANE ROAD. 0515 PM HAIL SOUTH SALEM 41.27N 73.55W 08/27/2020 M0.88 INCH WESTCHESTER NY TRAINED SPOTTER REPORTS OF NICKEL SIZED HAIL LASTING FOR SEVERAL MINUTES. 0516 PM TSTM WND DMG SOUTH SALEM 41.27N 73.55W 08/27/2020 WESTCHESTER NY LAW ENFORCEMENT TREE DOWN ON NY-123 NORTH OF ELMWOOD ROAD. 0518 PM TSTM WND DMG POUND RIDGE 41.21N 73.57W 08/27/2020 WESTCHESTER NY LAW ENFORCEMENT NUMEROUS TREES AND WIRES DOWN ON THE NORTH SIDE OF TOWN. 0526 PM TSTM WND DMG WILTON 41.18N 73.42W 08/27/2020 FAIRFIELD CT LAW ENFORCEMENT TREES DOWN ON DANBURY RD 0530 PM TSTM WND DMG WESTPORT 41.12N 73.35W 08/27/2020 FAIRFIELD CT LAW ENFORCEMENT NUMEROUS TRESS AND WIRES DOWN ACROSS WESTPORT. 0534 PM TSTM WND DMG WESTPORT 41.12N 73.35W 08/27/2020 FAIRFIELD CT FIRE DEPT/RESCUE *** 1 INJ *** TREES DOWN AND WIRES ON CAR WITH PEOPLE TRAPPED ON WILTON ROAD. ONE PERSON ATTEMPTED TO EXIT AND WAS SHOCKED. 0538 PM TSTM WND DMG WESTPORT 41.12N 73.35W 08/27/2020 FAIRFIELD CT LAW ENFORCEMENT POWER POLES DOWN ON OLD HILL ROAD. ROAD IS CLOSED. 0623 PM TSTM WND DMG THOMPSON RIDGE 41.57N 74.33W 08/27/2020 ORANGE NY LAW ENFORCEMENT TREES DOWN ON STATE HIGHWAY 302 NORTH OF CR17 0624 PM HAIL MONTGOMERY 41.52N 74.24W 08/27/2020 M1.00 INCH ORANGE NY TRAINED SPOTTER REPORTED QUARTER SIZED HAIL. 0624 PM TSTM WND GST MONTGOMERY 41.52N 74.24W 08/27/2020 E70 MPH ORANGE NY TRAINED SPOTTER ESTIMATED 70 MPH WIND GUST ALONG WITH QUARTER SIZED HAIL. 0652 PM HAIL CENTEREACH 40.87N 73.08W 08/27/2020 M0.75 INCH SUFFOLK NY NWS EMPLOYEE LASTED FOR 3 MINUTES 0700 PM TSTM WND DMG CARMEL 41.41N 73.68W 08/27/2020 PUTNAM NY LAW ENFORCEMENT NUMEROUS TREES AND POWER LINES DOWN THROUGH THE TOWN 0700 PM TSTM WND DMG MAHOPAC 41.37N 73.74W 08/27/2020 PUTNAM NY LAW ENFORCEMENT NUMEROUS TREES SNAPPED AND UPROOTED. POWER LINES DOWN. 0703 PM HAIL PATCHOGUE 40.76N 73.02W 08/27/2020 M0.75 INCH SUFFOLK NY TRAINED SPOTTER 0705 PM TSTM WND DMG BREWSTER 41.40N 73.62W 08/27/2020 PUTNAM NY LAW ENFORCEMENT MULTIPLE LARGE TREES DOWN ON POWER LINES. 0718 PM TSTM WND DMG RIDGEFIELD 41.27N 73.50W 08/27/2020 FAIRFIELD CT SOCIAL MEDIA VIDEO OF A LARGE TREE DOWN ON A HOUSE. 0742 PM TSTM WND DMG 1 SW NORTH WILTON 41.20N 73.48W 08/27/2020 FAIRFIELD CT LAW ENFORCEMENT TREES DOWN ACROSS ROCKY BROOK RD 0744 PM TSTM WND DMG 1 W NORTH WILTON 41.21N 73.48W 08/27/2020 FAIRFIELD CT LAW ENFORCEMENT TREES DOWN ON JOURNEY'S END RD 0746 PM TSTM WND DMG PATERSON 40.91N 74.16W 08/27/2020 PASSAIC NJ LAW ENFORCEMENT TREES AND WIRES DOWN ON E 22ND STREET. 0751 PM MARINE TSTM WIND 2 SE PONQUOGUE 40.84N 72.48W 08/27/2020 M44 MPH SUFFOLK NY WXFLOW 0817 PM TSTM WND GST NEWARK AIRPORT 40.67N 74.22W 08/27/2020 M71 MPH UNION NJ ASOS 0826 PM TSTM WND DMG 1 ESE OCEANSIDE 40.63N 73.62W 08/27/2020 NASSAU NY LAW ENFORCEMENT WIRES DOWN ON MURDOCK AVENUE JUST WEST OF LAWSON BOULEVARD 0829 PM MARINE TSTM WIND 3 SSE POINT LOOKOUT 40.56N 73.56W 08/27/2020 M55 MPH ANZ355 NY WXFLOW 0831 PM TSTM WND DMG ATLANTIC BEACH 40.59N 73.72W 08/27/2020 NASSAU NY LAW ENFORCEMENT WIRES AND POWER LINES DOWN ON PUTNAM BOULEVARD 0835 PM MARINE TSTM WIND 1 SW BREEZY POINT 40.55N 73.93W 08/27/2020 M40 MPH QUEENS NY WXFLOW 0850 PM MARINE TSTM WIND 15 S ATLANTIC BEACH EST 40.37N 73.70W 08/27/2020 M49 MPH ANZ355 NY BUOY 0854 PM MARINE TSTM WIND 8 S SEAGATE 40.47N 74.01W 08/27/2020 M55 MPH ANZ338 NY MESONET A MARINE THUNDERSTORM WIND GUST OF 48 KNOTS WAS REPORTED AT AN ELEVATION OF 18 FT 0910 PM MARINE TSTM WIND 26 S ROBERT MOSES STATE 40.25N 73.16W 08/27/2020 M45 MPH ANZ373 NY BUOY && $$ MW

Parts of southern New York State and Connecticut saw severe thunderstorms this afternoon. North of the frontal boundary, readings stayed mainly in the 60s and 70s. South of the front, temperatures topped out into the upper 80s and lower 90s. High temperatures included: Albany: 69° Allentown: 93° Baltimore: 94° Bridgeport: 88° Harrisburg: 95° Hartford: 77° Islip: 90° New York City-JFK: 92° New York City-LGA: 94° New York City-NYC: 90° Newark: 93° Philadelphia: 93° Washington, DC: 93° 90° Days for Select Cities (through August 27): Albany: 13 (2019: 12 days) Allentown: 24 (2019: 24 days) Baltimore: 44 (2019: 59 days) Boston: 14 (2019: 15 days) Burlington: 20 (2019: 8 days) Harrisburg: 34 (2019: 33 days) Hartford: 39 (2019: 27 days) Islip: 8 (2019: 8 days) New York City-JFK: 12 (2019: 7 days) New York City-LGA: 34 (2019: 26 days) New York City-NYC: 20 (2019: 15 days) Newark: 31 (2019: 28 days) Philadelphia: 35 (2019: 35 days) Scranton: 25 (2019: 12 days) Washington, DC: 43 (2019: 62 days) New York City-Newark Average: 24 (2019: 19 days) ...Expected: 25 (based on regression equation tied to JFK-LGA-EWR data) Tomorrow will be another very warm day. However, the month could end on a cool note before temperatures again return to above normal levels during the first week of September. Overall, the September 1-15 period could run several degrees above normal in the Middle Atlantic region. After having made landfall as a Category 4 hurricane with maximum sustained winds of 150 mph near Cameron, LA, Laura weakened but continued to bring heavy rain to parts of the Gulf region. Through 8 pm, select daily rainfall amounts included: Lafayette, LA: 5.71" (old record: 3.77", 1967) Little Rock: 2.78" Pine Bluff, AR: 2.69" (old record: 1.37", 2017) Shreveport: 2.04" (old record: 1.76", 1940) Laura will likely exit off the Delmarva Peninsula late Saturday night. The system has the potential to bring an area of 1"-3" rain with locally higher amounts across parts of Virginia and the Delmarva Peninsula, along with another area with pockets of moderate to heavy rain along a frontal boundary to its north. The New York City area and adjacent suburbs could pick up 0.25"-0.75" rain. The current predominantly warmer than normal pattern will likely persist through much of September, providing a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Parts of the West continued to experience near record and record high temperatures. Select high temperatures included: Death Valley, CA: 114° Denver: 96° Flagstaff: 87° Kingman, AZ: 104° Lake Havasu City, AZ 113° Las Vegas: 106° Needles, CA: 115° Palm Springs, CA: 116° Phoenix: 113° (tied record set in 1981 and tied in 2009) Pueblo, CO: 98° Tucson: 107° Yuma, AZ: 115° Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature near 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 61% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was -0.67. Today, the preliminary Arctic Oscillation (AO) figure was -0.507. On August 26, daily MJO data was unavailable. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. New York City has had 18 days on which the temperature reached 90° or above during July-August 2020. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Summer 2020 will likely finish with a mean temperature near 76.9°, which would tie 2020 as Central Park's 4th warmest summer with 1949, 1983, and 1993. At LaGuardia Airport, summer 2020 will likely finish with a mean temperature of 79.4°. That would surpass the existing summer record of 79.2°, which was set in 2010. Finally, on August 25, Arctic sea ice extent was 4.173 million square kilometers (JAXA). There is an implied 93% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.840 million square kilometers. The lowest 25% bound is 3.575 million square kilometers.

Temperatures will rebound tomorrow and Friday. In addition, tomorrow could see a widespread severe thunderstorm outbreak. However, the month could end on a cool note before temperatures again return to above normal levels during the first week of September. Overall, the September 1-15 period could run several degrees above normal in the Middle Atlantic region. Laura will likely exit off the Delmarva Peninsula late Saturday night or very early Sunday morning. The system has the potential to bring an area of 1"-3" rain with locally higher amounts across parts of Virginia and the Delmarva Peninsula, along with another area with pockets of moderate to heavy rain along a frontal boundary to its north. The New York City area and adjacent suburbs could pick up 0.50" or more rain if some of the guidance verifies. There remains some uncertainty concerning the location of the front. The current predominantly warmer than normal pattern will likely persist through much of September, providing a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Parts of the West continued to experience near record and record high temperatures. Select high temperatures included: Death Valley, CA: 117° Denver: 97° (tied record set in 1936 and tied in 1985 and 2015) Flagstaff: 86° Kingman, AZ: 106° (tied daily record set in 1924) Lake Havasu City, AZ: 118° Las Vegas: 108° Needles, CA: 117° Palm Springs, CA: 118° (old record: 116°, 1924, 1944 and 1967) Phoenix: 112° Pueblo, CO: 98° Tucson: 101° Yuma, AZ: 115° (old record: 113°, 1879, 1910, 1944, 2011 and 2017) Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature near 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 67% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was -6.13. Today, the preliminary Arctic Oscillation (AO) figure was +0.325. On August 25, daily MJO data was unavailable. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°. Summer 2020 will likely finish with a mean temperature near 76.9°, which would tie 2020 as Central Park's 4th warmest summer with 1949, 1983, and 1993. At LaGuardia Airport, summer 2020 will likely finish with a mean temperature of 79.4°. That would surpass the summer record of 79.2°, which was set in 2010. Finally, on August 25, Arctic sea ice extent was 4.205 million square kilometers (JAXA). There is an implied 92% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.835 million square kilometers. The lowest 25% bound is 3.539 million square kilometers.

Temperatures topped out in the upper 80s and lower 90s across the region. Parts of the area also saw thundershowers during the late afternoon and evening. Hartford reached 90° this afternoon. That was the record 39th 90° or above day there. The old record was 38 days, which was set in 1983. Tomorrow will be noticeably cooler before temperatures rebound on Thursday and Friday. However, the month could end on a cool note before temperatures again return to above normal levels during the first week of September. Overall, the September 1-15 period could run several degrees above normal in the Middle Atlantic region. The remnants of Laura could exit off the Delmarva Peninsula this weekend. The system has the potential to bring an area of 1"-3" rain with locally higher amounts along or near its path and another area with pockets of heavy rain along a frontal boundary to its north. The New York City area and adjacent suburbs could pick up 0.50" or more rain if some of the guidance verifies. There remains some uncertainty about Laura's track and the location of the front. The current predominantly warmer than normal pattern will likely persist through much of September, providing a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Parts of the West continued to experience near record to record warmth. Select high temperatures included: Death Valley, CA: 119° Denver: 97° Flagstaff: 85° Kingman, AZ: 106° (tied record set in 1919 and tied in 1985) Lake Havasu City, AZ: 113° Las Vegas: 110° Needles, CA: 117° Palm Springs, CA: 117° (tied record set in 1962) Phoenix: 112° Pueblo, CO: 101° Tucson, AZ: 107° (old record: 106°, 1901, 1985, 2001 and 2002) Yuma, AZ: 115° Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.7° - 96.9°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 70% probability that August will exceed July's monthly record. The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.55°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was -3.22. Today, the preliminary Arctic Oscillation (AO) figure was +0.769. On August 24, daily MJO data was unavailable. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 94% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Finally, on August 24, Arctic sea ice extent was 4.237 million square kilometers (JAXA). There is an implied 92% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.831 million square kilometers. The lowest 25% bound is 3.508 million square kilometers.

Hartford has recorded its record 39th 90-degree day.

The summer average for HPN will probably increase from around 70.7 to around 71.2 or 71.3. Summer averages have been increasing about 0.5 degrees per decade.