donsutherland1

Researchers have narrowed the range of climate sensitivity from a doubling of atmospheric CO2. Unfortunately, all of the narrowing occurred at the bottom end of the range. As a result, the range was changed from 1.5C - 4.5C to 2.3C - 4.5C. The full paper can be found here: https://climateextremes.org.au/wp-content/uploads/2020/07/WCRP_ECS_Final_manuscript_2019RG000678R_FINAL_200720.pdf

Tuesday will likely be a little cooler, but readings could still approach or reach 90. I want to see additional guidance before having confidence in the possible weekend storm.

Morning thoughts... At 9 am, temperatures in the region included: New York City-JFK: 80° New York City-LGA: 83° New York City-NYC: 79° Newark: 80° Philadelphia: 78° High temperatures should reach the upper 80s to lower 90s across the region. Estimates for the above cities based on the latest guidance: New York City-JFK: 86° New York City-LGA: 93° New York City-NYC: 90° Newark: 92° Philadelphia: 91° Finally, for the second consecutive weekly period, the ENSO Region 3.4 anomaly was at -0.5°C or below (-0.6°C). The probability of the development of a La Niña ahead of the upcoming winter has continued to increase. Such events following El Niño winters have featured a predominently positive EPO.

Unfortunately, none of the wind reports distinguish between tornadic and straight line winds. The waterspout off of Cape May was listed as an EF1 tornado with 100 mph winds. I didn't see any confirmed storm reports for an EF3. Perhaps there was earlier speculation that the Cape May waterspout was an EF3 tornado.

Very warm temperatures with highs in the upper 80s and lower 90s are likely for tomorrow and Tuesday. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. 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 July 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The SOI was +8.92. On August 6, the SOI was +25.73. That was the highest figure since October 14, 2018 when the SOI was +27.20. In all three August cases where the August ENSO Region 1+2 anomaly was -0.75°C or colder, a La Niña winter followed. The most recent such case was August 2010. Today, the preliminary Arctic Oscillation (AO) figure was +-0.028. On August 8, the MJO was in Phase 5 at an amplitude of 1.626 (RMM). The August 7-adjusted amplitude was 1.976. The MJO's passage through Phase 4 at such a high amplitude is uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 68% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.2°.

Anniversary of the 1723 Hurricane: On this date in 1723, a possible hurricane made landfall in the Middle Atlantic region. The storm brought high winds and heavy rain to such cities as Philadelphia and New York, neither of which appeared to have had any memory of a hurricane. Weather conditions deteriorated rapidly during the mid-morning. In both cities, the wind started from the northeast but then veered to the southeast. The winds diminished during the latter part of the afternoon as the storm pushed away from the region. The Boston News-Letter wrote of the storm's impact on Philadelphia: ...there was a violent northeast storm of wind and rain, the wind shifting till about noon, and then blew very hard at southeast, which caused a great disorder among the shipping, and blew down several chimneys, a great many trees, and it did very much damage to fruit, the tide being very high a wharf was wash'd away, and damage was done to several other. That same newspaper reported the following account from New York: We are likewise inform'd from New York, that they had the like storm, at the same time, which broke up the wharffs from one end of the city to the other, drove all the vessels ashore, except three and broke three sloops to pieces; the tide higher than ever was known here, sugar and goods in warehouses and cellars, were damaged; the market house with several others were blown down, tyles & covering of houses blown off. Vast quantities of boards, timber, staves, boats, canoes and rubbish lies in heaps. The American Weekly Mercury reported the following account of the storm in New York: Yesterday about 8 or 9 a clock the wind came up here at northeast, and veered about more to the southeast and from 12 a clock till 4 it blew very hard, with rain, insomuch that it has broke up all the wharfs from one end of the city to the other, drove all the vessels (except three) onshore, and three sloops are broke all to pieces: the water came up into the city higher than ever was known before and has done abundance of damage to sugar and other goods in merchants cellars, the market house before the coffee house is blown down and several other houses, and the tyles and coverings of many houses were blown off. And if the storm had continued till the next high water, all the houses by the waterside would have been destroyed. All the wharfs round the great dock is drove away. And in the slips there is such vast quantities of boards, timber, staves, boats, canoes and other rubbish lies in heaps in such manner as was never seen here before. The pyrate sloop which Capt. Solgard brought in, was forced to cut her mast and is drove away.

I agree. For now, I take no position on the coming winter. I do have some concerns based on some of the long-range guidance heading into the fall.

FWIW, the EPS seasonal idea has temperature anomalies across North America that are similar to those of winter 1998-99. Fortunately, at least right now, that’s far in the future and a lot can change.

Some of the seasonal models aren’t very appealing. However, at this point in time, skill is very low. Some La Niña events have been snowy, but others have not.

The temperature rose into the lower 80s across much of the region today. Tomorrow will be warmer with temperatures returning to the upper 80s in much of the region and perhaps even lower 90s in some parts of the region. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. 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 July 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The SOI was +8.44. On August 6, the SOI was +25.73. That was the highest figure since October 14, 2018 when the SOI was +27.20. In all three August cases where the August ENSO Region 1+2 anomaly was -0.75°C or colder, a La Niña winter followed. The most recent such case was August 2010. Today, the preliminary Arctic Oscillation (AO) figure was +0.165. On August 7, the MJO was in Phase 4 at an amplitude of 1.966 (RMM). The August 6-adjusted amplitude was 1.988. The MJO's passage through Phase 4 at such a high amplitude is uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.2°.

Thanks for the very kind words, Bluewave. I enjoy reading your posts all the time. Keep up the wonderful contributions.

I wish you a quick and complete recovery from the operation.

Strong thunderstorms moved into parts of the Middle Atlantic region late this afternoon and evening. Two-hour rainfall figures included: Allentown: 0.62"; Reading: 0.82" (4-hour figure: 1.19"); and Wilmington, DE: 0.62". Showers and thundershowers will continue to move through parts of the region during the first half of tonight. Tomorrow will be variably cloudy with some additional showers and thundershowers. Sunday will be much warmer with temperatures returning to the upper 80s and perhaps even lower 90s in many parts of the region. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. 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 July 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The SOI was +22.40. On August 6, the SOI was +25.73. That was the highest figure since October 14, 2018 when the SOI was +27.20. In all three August cases where the August ENSO Region 1+2 anomaly was -0.75°C or colder, a La Niña winter followed. The most recent such case was August 2010. Today, the preliminary Arctic Oscillation (AO) figure was +0.141. On August 6, the MJO was in Phase 4 at an amplitude of 1.985 (RMM). The August 5-adjusted amplitude was 1.853. The MJO's passage through Phase 4 at such a high amplitude is uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. A warm start to the second-half of August is supported by the extended range of the 12z EPS. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 68% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.2°.

Let’s hope we don’t see it during the coming winter.

Central Park reported a temperature of 66 degrees this morning. That was the Park’s coolest temperature since June 29 when the thermometer fell to 65 degrees.

Yes, ISP has a 90 mph gust. My initial numbers were from the National Hurricane Center’s report. Below is the PNS: PUBLIC INFORMATION STATEMENT SPOTTER REPORTS NATIONAL WEATHER SERVICE NEW YORK NY 854 AM EDT TUE OCT 30 2012 THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE RECENT STORM THAT HAS BEEN AFFECTING OUR REGION. APPRECIATION IS EXTENDED TO HIGHWAY DEPARTMENTS...COOPERATIVE OBSERVERS...SKYWARN SPOTTERS AND MEDIA FOR THESE REPORTS. THIS SUMMARY IS ALSO AVAILABLE ON OUR HOME PAGE AT WEATHER.GOV/NYC ***********************PEAK WIND GUST*********************** LOCATION MAX WIND TIME/DATE COMMENTS GUST OF MPH MEASUREMENT CONNECTICUT... ANZ330... 2 S GROTON 76 300 PM 10/29 MESONET ...FAIRFIELD COUNTY... BRIDGEPORT AIRPORT 76 549 PM 10/29 ASOS GREENWICH 70 520 PM 10/29 TRAINED SPOTTER NORWALK 69 830 PM 10/29 PUBLIC TRUMBULL 68 540 PM 10/29 TRAINED SPOTTER DANBURY AIRPORT 68 711 PM 10/29 ASOS ...MIDDLESEX COUNTY... 3 SW MIDDLETOWN 58 643 PM 10/29 MESONET ...NEW HAVEN COUNTY... MADISON 85 520 PM 10/29 PUBLIC ...NEW LONDON COUNTY... GROTON AIRPORT 75 335 PM 10/29 ASOS STONINGTON 70 300 PM 10/29 EMERGENCY MNGR NEW JERSEY ...BERGEN COUNTY... 1 SSE TEANECK 76 731 PM 10/29 MESONET TETERBORO 72 747 PM 10/29 ASOS NORTH ARLINGTON 63 348 PM 10/29 SKYWARN SPOTTER ...ESSEX COUNTY... NEWARK AIRPORT 78 751 PM 10/29 ASOS FAIRFIELD 72 741 PM 10/29 MESONET 1 ESE FAIRFIELD 72 741 PM 10/29 MESONET CALDWELL AIRPORT 70 614 PM 10/29 ASOS ...HUDSON COUNTY... 1 ENE BAYONNE 77 805 PM 10/29 MESONET HARRISON 68 720 PM 10/29 CO-OP OBSERVER ...PASSAIC COUNTY... CLIFTON 80 930 PM 10/29 SKYWARN SPOTTER NEW YORK ...ANZ338... 2 N TOMPKINSVILLE 90 824 PM 10/29 MESONET ...ANZ355... BUOY 44065 69 514 PM 10/29 NY HARBOR APPROACH BUOY ...ANZ370... BUOY 44025 74 250 PM 10/29 BUOY ...KINGS COUNTY... CONEY ISLAND 69 642 PM 10/29 MESONET FLATBUSH 58 905 PM 10/29 MESONET ...NASSAU COUNTY... SYOSSET 82 703 PM 10/29 SKYWARN SPOTTER 1 E POINT LOOKOUT 80 750 PM 10/29 JONES BEACH COAST GUARD 3 E LIDO BEACH 79 615 PM 10/29 MESONET BAYVILLE 77 521 PM 10/29 MESONET 2 NNE GLEN COVE 77 521 PM 10/29 MESONET OYSTER BAY 67 338 PM 10/29 SKYWARN SPOTTER ...NEW YORK COUNTY... CENTRAL PARK 62 313 PM 10/29 ASOS ...ORANGE COUNTY... ORANGE LAKE 61 745 PM 10/29 MESONET MONTGOMERY 58 740 PM 10/29 ASOS ...QUEENS COUNTY... 2 SSE JACKSON HEIGHT 79 802 PM 10/29 MESONET NYC/JFK AIRPORT 85 802 PM 10/29 ASOS (direction 100 degrees) BREEZY POINT 78 830 PM 10/29 MESONET NYC/LA GUARDIA 74 655 PM 10/29 ASOS ..SUFFOLK COUNTY... EATONS NECK 96 655 PM 10/29 MESONET-ELEVATED 71FT (Est 87 mph at 10m) ISLIP AIRPORT 90 626 PM 10/29 ASOS - 78KT 4 ENE PLUM ISLAND 85 435 PM 10/29 MESONET EAST MORICHES 81 600 PM 10/29 MESONET EAST FARMINGDALE 79 723 PM 10/29 ASOS UPTON 79 150 PM 10/29 MESONET PATCHOGUE 77 701 PM 10/29 SPOTTER FIRE ISLAND 75 435 PM 10/29 MESONET POINT O'WOODS 73 350 PM 10/29 MESONET 1 ENE MONTAUK HIGHWAY 73 220 PM 10/29 MESONET 2 WSW FISHERS ISLAND 71 300 PM 10/29 MESONET 1 S BLUE POINT 70 608 PM 10/29 MESONET OCEAN BEACH 68 715 PM 10/29 MESONET 1 NW EAST HAMPTON 66 355 PM 10/29 MESONET ...WESTCHESTER COUNTY... WHITE PLAINS 72 705 PM 10/29 ASOS $$ DS

Tomorrow will be unsettled with showers and thunderstorms around. Some of the thunderstorms could produce heavy downpours. Warmer weather will return for the weekend. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. 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 July 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The Region 3.4 anomaly is the lowest such figure in July since 2010. Since weekly recordkeeping commenced in 1990, July 1998 was the only other summer following an El Niño winter that saw a comparably cool Region 3.4 anomaly. Both cases went on to have a very warm September and warmer than normal autumn. They diverged in December with the state of the Arctic Oscillation (AO) making a decisive difference. The SOI was +25.73. That was the highest figure since October 14, 2018 when the SOI was +27.20. In all three Augustcases where the August ENSO Region 1+2 anomaly was -0.75°C or colder, a La Niña winter followed. The most recent such case was August 2010. Today, the preliminary Arctic Oscillation (AO) figure was +0.409. On August 5, the MJO was in Phase 4 at an amplitude of 1.854 (RMM). The August 4-adjusted amplitude was 1.646. 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.

Some wind gusts from Sandy: East Moriches: 82 mph Farmingdale: 90 mph Great Gull Island: 85 mph Jones Beach: 81 mph Long Beach: 83 mph New York City-JFK: 85 mph Syosset: 82 mph

Some additional photos of the tree damage following Isaias: Larchmont, NY: Mamaroneck, NY: As of this afternoon, large sections of the Village of Larchmont remain without power.

Today, the SOI was +25.73, which was its highest figure since October 14, 2018. In all three August cases when the SOI rose to +25.00 or above and the August ENSO Region 1+2 anomaly was -0.75C or below, winter saw a La Niña. The most recent such case was August 2010.

Due to my Internet being down I will have to see if I can get the data when it’s back up.

I suspect 70+ mph gusts were fairly common on Long Island. The network of quality stations is somewhat limited, so there are a lot of areas for which there was no data. Even across the Sound, there were many trees that were snapped or uprooted, especially close to the Sound. The damage there is comparable to March 2010. Inland by a few miles, the tree damage is less severe.

Isaias brought high winds and heavy rains to the region today. Isaias passed west of New York City with maximum sustained winds of 70 mph. At the time, Isaias was racing north-northeastward at 40 mph. Parts of the region experienced wind gusts past 70 mph. Sites reporting wind gusts of 70 mph or above included: Berkeley Twp, NJ: 75 mph Blue Point, NY: 71 mph Cape May NOS, NJ: 75 mph Grasonville, MD: 71 mph Great Gull Island, NY: 73 mph Great South Bay, NY: 75 mph Farmingdale, NY: 78 mph Jackson Heights, NY: 73 mph New York City-JFK Airport: 70 mph Ocean City, NJ: 72 mph Rutgers, NJ: 70 mph Smyrna Landing (2 NW), DE: 96 mph Stony Brook, NY: 75 mph Toms River, NJ: 70 mph Maritime Stations: Barnegat Inlet Light, NJ: 75 mph Long Beach Island: 109 mph Daily record rainfall was set at sites including: Albany: 3.91" (old record: 1.40", 1915) Allentown: 4.92" (old record: 2.47", 1915) Binghamton: 1.53" (old record: 0.78", 1959) Burlington: 2.03" (old record: 1.74", 1995) ***through 8 pm*** Philadelphia: 4.16" (old record: 2.74") Scranton: 2.42" (old record: 1.33", 1974) Wilmington, DE: 4.48" (old record: 2.00", 1915) Following Isaias' passage, the clouds broke, the sun returned and the wind diminished. As Isaias heads northward into Canada, tranquil and warmer weather will be in store for tomorrow. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. 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 July 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The Region 3.4 anomaly is the lowest such figure in July since 2010. Since weekly recordkeeping commenced in 1990, July 1998 was the only other summer following an El Niño winter that saw a comparably cool Region 3.4 anomaly. Both cases went on to have a very warm September and warmer than normal autumn. They diverged in December with the state of the Arctic Oscillation (AO) making a decisive difference. The SOI was +2.55. Today, the preliminary Arctic Oscillation (AO) figure was +0.427. On August 3, the MJO was in Phase 4 at an amplitude of 1.074 (RMM). The August 2-adjusted amplitude was 0.781. 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.

Some tree damage from Isaias: From Larchmont, NY: From Mamaroneck, NY:

Five photos and two short video clips from Tropical Storm Isaias: Early morning well in advance of Isaias’ arrival During the storm During the storm During the storm After Isaias’ departure Two short video clips: https://youtu.be/3mv0Q22aPdo https://youtu.be/IurUZ8HuTy0