donsutherland1

Islip hit 93° so far. That broke the daily record of 92°, which was set just last year.

Flood Watch National Weather Service New York NY 1151 AM EDT Fri Aug 27 2021 NYZ069-071>075-176-178-280500- /O.EXA.KOKX.FF.A.0007.210827T1800Z-210829T0600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Rockland-Southern Westchester-New York (Manhattan)-Bronx- Richmond (Staten Island)-Kings (Brooklyn)-Northern Queens- Southern Queens- 1151 AM EDT Fri Aug 27 2021 ...FLASH FLOOD WATCH IN EFFECT THROUGH LATE SATURDAY NIGHT... The National Weather Service in Upton has expanded the * Flash Flood Watch to include a portion of southeast New York, including the following areas, Bronx, Kings (Brooklyn), New York (Manhattan), Northern Queens, Richmond (Staten Island), Rockland, Southern Queens, and Southern Westchester. * Through late Saturday night * A moist environment could result in heavy rain producing thunderstorms this afternoon into Saturday night. With recent heavy rainfall, it will not take much additional rain to result in flash flooding. The greatest risk looks to be this afternoon through Saturday afternoon. * Rainfall rates of 1 to 2 inches per hour could result in flash flooding, especially in low-lying and poor drainage areas such as highway underpasses. PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. &&

Morning thoughts… Today will be partly sunny and hot. The risk of showers and thundershowers will increase during the afternoon and evening. High temperatures will likely reach the upper 80s and lower 90s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 90° Newark: 93° Philadelphia: 92° Normals: New York City: 30-Year: 81.9°; 15-Year: 81.7° Newark: 30-Year: 83.3°; 15-Year: 83.3° Philadelphia: 30-Year: 84.5°; 15-Year: 84.1° A cooler and occasionally wet weekend lies ahead.

One more hot day lies ahead. Afterward, a front will move slowly through the region and it could stall nearby. The result will be cooler weather with potential showers and thundershowers during the weekend. Meanwhile Tropical Storm Ida has now developed. Ida will pose a threat to the U.S. Gulf Coast early next week. Some of the guidance has it making landfall as a Category 2 or Category 3 hurricane. Through 7 pm CDT, New Orleans has received 65.74" of rain. That is the 2nd highest figure on record for this time of year. As a result, the already saturated ground could exacerbate the risk of flooding from Ida. Fall 2021 will likely be wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.9°C for the week centered around August 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.41°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. Neutral ENSO conditions will likely prevail into mid-September. Afterward, La Niña could begin to develop. The SOI was +5.83 today. The preliminary Arctic Oscillation (AO) figure was -0.640 today. On August 24 the MJO was in Phase 2 at an amplitude of 0.489 (RMM). The August 23-adjusted amplitude was 0.553 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 96% probability that New York City will have a warmer than normal August (1991-2020 normal). August will likely finish with a mean temperature near 77.4° (1.4° above normal).

New NWS portal: https://www.weather.gov/wrh/climate

Morning thoughts… Today will be partly sunny and hot. High temperatures will likely reach the lower 90s in most of the region with some places topping out in the middle 90s. Likely high temperatures around the region include: New York City (Central Park): 90° Newark: 94° Philadelphia: 92° Normals: New York City: 30-Year: 82.1°; 15-Year: 81.9° Newark: 30-Year: 83.5°; 15-Year: 83.4° Philadelphia: 30-Year: 84.6°; 15-Year: 84.3° The very warm weather will continue through tomorrow before it turns cooler for the weekend.

At present, I still lean toward a miss. Hopefully, that thinking is incorrect. Currently, 23/51 (45%) of EPS members (8/25 12z) show 0.35” or more. That is broadly in line with the historical frequency for the 1971-2020 period. As tomorrow is virtually certain to see no rain, I ran the numbers of the 8/27-8/31 period. 60% of cases had < 0.35” rain. 40% had 0.35” or more (20% had 1.00” or more). The National Blend of Models still does not show enough precipitation.

It is. One study suggested that NYC’s climate could resemble that of present-day Virginia Beach by the end of the 21st century.

Today saw temperatures rise into the lower and middle 90s across much of the region. Tomorrow will be a similar day. 90° Days for Select Cities (through August 25): Albany: 4 (2020: 13 days; 5-Year Average: 13.6 days) Allentown: 22 (2020: 24 days; 5-Year Average: 27.6 days) Baltimore: 46 (2020: 46 days; 5-Year Average: 44.6 days) Boston: 22 (2020: 14 days; 5-Year Average: 17.2 days) Bridgeport: 10 (2020: 11 days; 5-Year Average: 13.4 days) Burlington: 13 (2020: 20 days; 5-Year Average: 13.0 days) Harrisburg: 32 (2020: 35 days; 5-Year Average: 30.6 days) Hartford: 22 (2020: 39 days; 5-Year Average: 29.0 days) Islip: 7 (2020: 8 days; 5-Year Average: 9.4 days) New York City-JFK: 9 (2020: 12 days; 5-Year Average: 10.2 days) New York City-LGA: 23 (2020: 34 days; 5-Year Average: 29.4 days) New York City-NYC: 15 (2020: 20 days; 5-Year Average: 18.2 days) Newark: 37 (2020: 33 days; 5-Year Average: 31.2 days) Philadelphia: 33 (2020: 36 days; 5-Year Average: 34.6 days) Scranton: 17 (2020: 25 days; 5-Year Average: 16.4 days) Washington, DC: 42 (2020: 46 days; 5-Year Average: 50.8 days) New York City-Newark Average: 21 (2020: 22 days) ...Expected: 23 (based on regression equation tied to JFK-LGA-EWR data) Much of the remainder of this week will feature unseasonably warm temperatures. Cooler weather and possibly some rain will arrive for the weekend. Fall 2021 will likely be wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.9°C for the week centered around August 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.41°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. Neutral ENSO conditions will likely prevail into mid-September. Afterward, La Niña could begin to develop. The SOI was +10.07 today. The preliminary Arctic Oscillation (AO) figure was -0.600 today. On August 23 the MJO was in Phase 2 at an amplitude of 0.586 (RMM). The August 22-adjusted amplitude was 0.672 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 90% probability that New York City will have a warmer than normal August (1991-2020 normal). August will likely finish with a mean temperature near 77.3° (1.3° above normal).

For reference, these are the locations at the highest latitude (eastern North America) that I could find that recorded one or more cases where July and August both received 10” or more of rain: Norfolk (36.85N): 2004 July: 10.89”; August: 11.11” 2011 July: 10.89”; August: 10.79” Salisbury, MD (38.36N): 2017 July: 11.31”; August: 12.23” Wallops Island, VA (37.88N): 2004 July: 12.10”; August: 11.18” Note: All of these cases occurred 2000 or later.

The 12z ECMWF is now wetter for Saturday.

Meanwhile, Tucson recorded 8.06” of rain in July.

Yes, JFK hit 90 yesterday. Central Park could only manage 89.

Morning thoughts… Today will be mostly sunny and hot. High temperatures will likely reach the lower 90s in most of the region with some places topping out in the middle 90s. Likely high temperatures around the region include: New York City (Central Park): 90° Newark: 95° Philadelphia: 95° Normals: New York City: 30-Year: 82.3°; 15-Year: 82.0° Newark: 30-Year: 83.6°; 15-Year: 83.1° Philadelphia: 30-Year: 84.8°; 15-Year: 84.4° The very warm weather will continue through Friday before it turns cooler for the weekend.

Much of the region saw temperatures rise into the upper 80s and lower 90s. 90° Days for Select Cities (through August 24): Albany: 4 (2020: 13 days; 5-Year Average: 13.6 days) Allentown: 21 (2020: 24 days; 5-Year Average: 27.6 days) Baltimore: 45 (2020: 46 days; 5-Year Average: 44.6 days) Boston: 21 (2020: 14 days; 5-Year Average: 17.2 days) Bridgeport: 10 (2020: 11 days; 5-Year Average: 13.4 days) Burlington: 12 (2020: 20 days; 5-Year Average: 13.0 days) Harrisburg: 31 (2020: 35 days; 5-Year Average: 30.6 days) Hartford: 21 (2020: 39 days; 5-Year Average: 29.0 days) Islip: 6 (2020: 8 days; 5-Year Average: 9.4 days) New York City-JFK: 9 (2020: 12 days; 5-Year Average: 10.2 days) New York City-LGA: 22 (2020: 34 days; 5-Year Average: 29.4 days) New York City-NYC: 14 (2020: 20 days; 5-Year Average: 18.2 days) Newark: 36 (2020: 33 days; 5-Year Average: 31.2 days) Philadelphia: 32 (2020: 36 days; 5-Year Average: 34.6 days) Scranton: 16 (2020: 25 days; 5-Year Average: 16.4 days) Washington, DC: 41 (2020: 46 days; 5-Year Average: 50.8 days) New York City-Newark Average: 20 (2020: 22 days) ...Expected: 22 (based on regression equation tied to JFK-LGA-EWR data) Tomorrow could be a degree or two warmer. In addition, the humidity will begin to increase. Much of the remainder of this week will feature unseasonably warm temperatures. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.9°C for the week centered around August 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.41°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. Neutral ENSO conditions will likely prevail into mid-September. Afterward, La Niña could begin to develop. The SOI was +12.20 today. The preliminary Arctic Oscillation (AO) figure was -0.976 today. On August 22 the MJO was in Phase 2 at an amplitude of 0.675 (RMM). The August 21-adjusted amplitude was 0.962 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 87% probability that New York City will have a warmer than normal August (1991-2020 normal). August will likely finish with a mean temperature near 77.3° (1.3° above normal).

That may have been a cold core storm that developed a warm core along its unusual path.

Even more remarkable, no tropical storms or hurricanes made U.S. landfall.

I hope it does, but my thinking is that it won’t reach or exceed 10”.

After reviewing hourly .PDF data that goes back to 1889, an extended Central Park record of hourly rainfall of 1.50” or above. The electronic database only goes back to 1943. Note: all hours are in standard time.

Morning thoughts… The rain has departed, but heat and humidity have arrived… Today will be mostly sunny and very warm. High temperatures will likely reach the upper 80s and lower 90s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 89° Newark: 94° Philadelphia: 93° Normals: New York City: 30-Year: 82.5°; 15-Year: 82.2° Newark: 30-Year: 83.8°; 15-Year: 83.8° Philadelphia: 30-Year: 85.0°; 15-Year: 84.6° The very warm weather will continue through Friday.

It’s here between 4 pm and 5 pm: https://www.ncei.noaa.gov/pub/orders/IPS/IPS-74711DFB-9854-456D-9E64-CB10A972122E.pdf 9/4/1913 has 3.05” between 11 pm and 12 am.

There was a 2.73” hourly amount on July 28, 1913.

Henri moved away from the region after producing the highest 3-day summer rainfall on record in Central Park. During August 21-23, 8.19" of rain was measured. That easily surpassed the prior 3-day summer record of 7.20" from August 11-13, 1955. South of New York City, temperatures soared well into the 80s and 90s. Baltimore, Harrisburg, Newark, Philadelphia, and Washington, DC all saw the thermometer reach 90° or above. That heat will move northward tomorrow. Much of the remainder of this week will feature unseasonably warm temperatures. 90° Days for Select Cities (through August 23): Albany: 4 (2020: 13 days; 5-Year Average: 13.6 days) Allentown: 21 (2020: 24 days; 5-Year Average: 27.6 days) Baltimore: 44 (2020: 46 days; 5-Year Average: 44.6 days) Boston: 20 (2020: 14 days; 5-Year Average: 17.2 days) Bridgeport: 10 (2020: 11 days; 5-Year Average: 13.4 days) Burlington: 9 (2020: 20 days; 5-Year Average: 13.0 days) Harrisburg: 29 (2020: 35 days; 5-Year Average: 30.6 days) Hartford: 21 (2020: 39 days; 5-Year Average: 29.0 days) Islip: 6 (2020: 8 days; 5-Year Average: 9.4 days) New York City-JFK: 8 (2020: 12 days; 5-Year Average: 10.2 days) New York City-LGA: 21 (2020: 34 days; 5-Year Average: 29.4 days) New York City-NYC: 14 (2020: 20 days; 5-Year Average: 18.2 days) Newark: 34 (2020: 32 days; 5-Year Average: 31.2 days) Philadelphia: 32 (2020: 36 days; 5-Year Average: 34.6 days) Scranton: 16 (2020: 25 days; 5-Year Average: 16.4 days) Washington, DC: 40 (2020: 46 days; 5-Year Average: 50.8 days) New York City-Newark Average: 20 (2020: 22 days) ...Expected: 21 (based on regression equation tied to JFK-LGA-EWR data) The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.9°C for the week centered around August 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.41°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. Neutral ENSO conditions will likely prevail into mid-September. Afterward, La Niña could begin to develop. The SOI was +5.04 today. The preliminary Arctic Oscillation (AO) figure was -1.173 today. On August 21 the MJO was in Phase 2 at an amplitude of 0.963 (RMM). The August 20-adjusted amplitude was 1.443 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 83% probability that New York City will have a warmer than normal August (1991-2020 normal). August will likely finish with a mean temperature near 77.3° (1.3° above normal).

This report suggests that 1.46” was the hourly figure on 8/12/1926 not 2.48” (p.91).

This shows that there is potentially a lot of good information that could become accessible to researchers and the public with a large-scale digitization effort.