donsutherland1

Morning thoughts… It will be mostly sunny and cooler. High temperatures will reach the middle and upper 70s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 75° Newark: 77° Philadelphia: 78° Much warmer air will arrive on Sunday. Normals: New York City: 30-Year: 76.6°; 15-Year: 77.4° Newark: 30-Year: 78.1°; 15-Year: 78.9° Philadelphia: 30-Year: 79.3°; 15-Year: 80.0°

Much cooler air will begin to filter into the region tonight. By Friday morning, the coolest air mass so far this season will cover the region. The temperature will likely slip below 60° for the first time this season at Central Park. However, the early autumnal chill will be short-lived. Noticeably warmer air will likely return early next week. The potential exists for parts of the region to experience 90° or above temperatures at the height of the warmth. Philadelphia and Newark have the best chance at approaching or reaching 90° during the peak of the warmth. New York City will likely top out in the middle or perhaps upper 80s. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -1.0°C for the week centered around September 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -1.00°C. La Niña conditions will likely persist through the fall. The SOI was +7.91 today. The preliminary Arctic Oscillation (AO) was -0.930 today. On September 12 the MJO was in Phase 5 at an amplitude of 0.233 (RMM). The September 11-adjusted amplitude was 0.314 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 76% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 71.1° (1.9° above normal).

Clouds gave way to afternoon sunshine. In response, the mercury rose into the lower and middle 80s. Tomorrow will be another warm day, but much cooler air will begin to filter into the region afterward. The coolest air mass so far this season will cover the region on Friday. However, the early autumnal chill will be short-lived. Noticeably warmer air will likely return early next week. The potential exists for parts of the region to experience 90° or above temperatures at the height of the warmth. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -1.0°C for the week centered around September 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -1.00°C. La Niña conditions will likely persist through the fall. The SOI was +19.97 today. The preliminary Arctic Oscillation (AO) was -0.603 today. On September 11 the MJO was in Phase 5 at an amplitude of 0.314 (RMM). The September 10-adjusted amplitude was 0.243 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 78% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 71.1° (1.9° above normal).

Morning thoughts… It will be variably cloudy. Showers and thundershowers are possible. High temperatures will reach the lower and middle 80s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 82° Newark: 84° Philadelphia: 84° Much cooler air will arrive late in the week. Normals: New York City: 30-Year: 77.4°; 15-Year: 77.8° Newark: 30-Year: 78.8°; 15-Year: 79.5° Philadelphia: 30-Year: 80.0°; 15-Year: 80.5°

Under partly sunny skies, temperatures rose into the 80s across much of the region today. Through midweek, temperatures will average somewhat above normal. Afterward, the coolest air mass so far this season will likely overspread the region. Noticeably warmer air could again return early next week. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -1.0°C for the week centered around September 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -1.00°C. La Niña conditions will likely persist through the fall. The SOI was +19.67 today. The preliminary Arctic Oscillation (AO) was -0.510 today. On September 10 the MJO was in Phase 5 at an amplitude of 0.244 (RMM). The September 9-adjusted amplitude was 0.446 (RMM). 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 September (1991-2020 normal). September will likely finish with a mean temperature near 70.8° (1.6° above normal).

Morning thoughts… It will be variably cloudy. Showers and thundershowers are possible. High temperatures will reach the lower and middle 80s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 82° Newark: 84° Philadelphia: 85° Much cooler air will arrive late in the week. Normals: New York City: 30-Year: 77.7°; 15-Year: 78.2° Newark: 30-Year: 79.2°; 15-Year: 79.8° Philadelphia: 30-Year: 80.4°; 15-Year: 80.8°

A system will likely continue to bring light to occasionally moderate rain to the region tomorrow perhaps into Tuesday. The coolest air mass so far this season will likely arrive late in the week. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +13.91 today. The preliminary Arctic Oscillation (AO) was -0.755 today. On September 9 the MJO was in Phase 5 at an amplitude of 0.446 (RMM). The September 8-adjusted amplitude was 0.722 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.6° (1.4° above normal).

Morning thoughts… It will be mostly cloudy with some periods of rain. High temperatures will reach the middle 70s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 76° Newark: 77° Philadelphia: 76° Clouds will begin to increase tomorrow. Showers are possible. Normals: New York City: 30-Year: 78.0°; 15-Year: 78.5° Newark: 30-Year: 79.5°; 15-Year: 80.0° Philadelphia: 30-Year: 80.7°; 15-Year: 81.0°

Summer 2022 was the 3rd hottest summer on record, just behind summers 1936 and 2021.

Under mainly sunny skies, temperatures rose into the lower and middle 80s across much of the region. Highs included: Allentown: 81° Bridgeport: 82° Islip: 85° New York City: 86° Newark: 87° Philadelphia: 83° Clouds will increase tomorrow and temperatures will be several degrees cooler than they were today. Afterward, a system could bring a light to moderate rainfall to the region early next week. There remains a degree of uncertainty concerning the amount and duration of precipitation. Out West, Seattle reached 90° for the 13th time this year. That surpassed the record of 12 days, which was set in 2015. All three years with 10 or more such days have occurred since 2015. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +14.14 today. The preliminary Arctic Oscillation (AO) was -0.566 today. On September 8 the MJO was in Phase 5 at an amplitude of 0.718 (RMM). The September 7-adjusted amplitude was 0.578 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.7° (1.5° above normal).

The calendar reads "September," but the thermometer reads more like late August with temperatures pushing toward the middle 80s making for a great beach day. However, rip tides are an issue.

Morning thoughts… It will be partly to mostly sunny and warm. High temperatures will reach the lower and middle 80s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 84° Newark: 85° Philadelphia: 84° Clouds will begin to increase tomorrow. Showers are possible. Normals: New York City: 30-Year: 78.4°; 15-Year: 78.8° Newark: 30-Year: 79.8°; 15-Year: 80.3° Philadelphia: 30-Year: 81.0°; 15-Year: 81.3°

Tomorrow will be fair and unseasonably warm. Clouds will increase on Sunday and temperatures will be several degrees cooler. Afterward, a system could bring an appreciable rainfall to the region early next week. There remains a degree of uncertainty concerning the amount of precipitation. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +18.30 today. The preliminary Arctic Oscillation (AO) was -0.394 today. On September 7 the MJO was in Phase 4 at an amplitude of 0.573 (RMM). The September 6-adjusted amplitude was 0.454 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.7° (1.5° above normal).

Morning thoughts… It will be partly to mostly sunny and warm. High temperatures will reach the lower 80s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 80° Newark: 83° Philadelphia: 84° It will be even warmer tomorrow. Normals: New York City: 30-Year: 78.7°; 15-Year: 79,0° Newark: 30-Year: 80.2°; 15-Year: 80.6° Philadelphia: 30-Year: 81.3°; 15-Year: 81.5°

Salt Lake City's latest-season extreme heat event (Clarke et al., 2014 methodology) concluded today. Below is a list of Salt Lake City's extreme heat events. A disproportionate share have occurred since 2000 and 2010, as the City's climate has warmed.

Warmer air is again returning to the region. Above normal temperatures are likely through Saturday and perhaps Sunday. Afterward, a system could bring at least an appreciable rainfall to the region early next week. The ongoing historic Western U.S. heatwave is concluding. Nevertheless, parts of the West again saw intense heat. Today's preliminary high temperatures included: Cheyenne: 95° (old record: 91°, 1979)***Record 11th 95° day*** Denver: 99° (old record: 94°, 1959) Fairfield (Travis Air Force Base), CA: 115° (old record: 102°, 2004 Los Angeles: 97° (old record: 93°, 1984) North Platte, NE: 103° (old record: 101°, 2013) Reno: 101° (old record: 98°, 2021)***Record-tying 22nd 100° day*** Sacramento: 112° (old record: 105°, 2021) San Jose: 104° (old record: 100°, 1904) Stockton, CA: 112° (old record: 103°, 1977 Ukiah, CA: 110° (old record: 109°, 1944 and 1957) Burbank, CA recorded its 9th consecutive 100° day. That broke the record of 8 consecutive days that was set during August 31-September 7, 1955. In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +15.39 today. The preliminary Arctic Oscillation (AO) was -0.352 today. On September 6 the MJO was in Phase 4 at an amplitude of 0.455 (RMM). The September 7-adjusted amplitude was 0.313 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.7° (1.5° above normal).

Morning thoughts… It will be partly to mostly sunny and warmer. High temperatures will reach the upper 70s and lower 80s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 78° Newark: 82° Philadelphia: 83° It will begin to turn warmer tomorrow. Normals: New York City: 30-Year: 79.0°; 15-Year: 79.3° Newark: 30-Year: 80.5°; 15-Year: 80.8° Philadelphia: 30-Year: 81.6°; 15-Year: 81.8°

Sunshine will return tomorrow and it will turn warmer. Near normal to somewhat above normal temperatures will then continue through the weekend. The ongoing intense heatwave will begin to wind down tomorrow in the West. Today's preliminary high temperatures included: Billings: 102° (old record: 97°, 1998) Boise: 104° (old record: 97°, 1955) ***New September record*** Casper: 96° (old record: 94°, 1978) Cheyenne: 97° (old record: 90°, 1959) ***New September record*** Death Valley, CA: 122° (tied record set in 2021) Denver: 99° (old record: 95°, 1933 and 2013) Fresno: 111° (old record: 108°, 1904) Glasgow, MT: 106° (old record: 96°, 2003) ***New September record*** Great Falls: 100° (old record: 95°, 1998) Havre, MT: 104° (old record: 99°, 1998) ***New September record*** Helena: 102° (old record: 96°, 1998) ***New September record*** Pocatello: 100° (old record: 97°, 1979) Reno: 104° (old record: 98°, 2021) Sacramento: 107° (old record: 105°, 2020) Salt Lake City: 107° (old record: 99°, 1979) ***Tied all-time record*** In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. On September 7, Philadelphia picked up 1.22" of rain. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +15.57 today. The preliminary Arctic Oscillation (AO) was -0.436 today. On September 5 the MJO was in Phase 4 at an amplitude of 0.305 (RMM). The September 6-adjusted amplitude was 0.586 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 64% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.5° (1.3° above normal).

Salt Lake City has concluded a historically hot August 30-September 7. The average high temperature exceeded the existing record by 8.1°. It also exceeded a composite made up of all the prior daily records during that period by 4.1°.

Morning thoughts… It will be mostly cloudy and cool. Clouds could begin to break this afternoon or evening. High temperatures will reach the lower and middle 70s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 81° Newark: 84° Philadelphia: 87° It will begin to turn warmer tomorrow. Normals: New York City: 30-Year: 79.3°; 15-Year: 79.5° Newark: 30-Year: 80.7°; 15-Year: 81.0° Philadelphia: 30-Year: 81.9°; 15-Year: 82.0°

Today was another historic day in terms of the ongoing unprecedented late-season heatwave in the West. Select records:

The slow-moving front responsible for today's rainfall is gradually moving eastward. Some additional showers are likely tomorrow. Temperatures will remain somewhat below normal. The ongoing intense heatwave will continue into Thursday in the West. Today's preliminary high temperatures included: Bakersfield, CA: 115° (old record: 111°, 1904) ***Tied September record*** Boise: 101° (old record: 98°, 1955) Cheyenne: 95° (old record: 91°, 1978, 1998, 2013 and 2020) Death Valley, CA: 125° (old record: 123°, 2020 ***Tied September record*** Denver: 98° (old record: 97° (2013 and 2020) Las Vegas: 110° (tied record set in 1979) Phoenix: 110° (tied record set in 1979) Redding, CA: 115° (old record: 111°, 2020) Reno: 106° (old record: 96°, 1944, 1998 and 2021) ***New September record*** Sacramento: 114° (old record: 109°, 2020) ***Tied September record set yesterday) Salt Lake City: 106° (old record: 98°, 2013) ***New September record*** San Jose: 109° (old record: 105°, 2020) ***New all-time record*** St. George, UT: 111° (old record: 110°, 2020) ***Tied September record*** Stockton, CA: 114° (old record: 110°, 2020) ***New September record*** Ukiah, CA: 117° (old record: 113°, 2020) ***New all-time record*** In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +18.25 today. The preliminary Arctic Oscillation (AO) was -0.347 today. On September 4 the MJO was in Phase 4 at an amplitude of 0.591 (RMM). The September 3-adjusted amplitude was 0.632 (RMM).

The unprecedented late-season heatwave that has scorched parts of the West has resulted in numerous locations seeing their hottest September 1-5 period on record. A sample of locations is below.

Clouds gradually pushed into the region this afternoon ahead of a slow-moving front. Showers and thunderstorms along that front will lead to a significant rainfall through early Wednesday. A general 1.00"-2.00" rainfall appears likely with locally higher amounts. Drought-stricken southern New England could see 1.50"-3.00" or rain with some locally much higher amounts. Already, a small part of Rhode Island has seen 3"-6" or rain. Ahead of the front, temperatures climbed well into the 80s. Highs included: Baltimore: 87° Bridgeport: 83° Islip: 85° New York City: 88° Newark: 87° Philadelphia: 90° Washington, DC: 87° The ongoing intense heatwave will continue into Wednesday (and Thursday at some locations) in the West. Today's preliminary high temperatures included: Casper: 97° Cheyenne: 95° (old record: 94°, 2020) ***Record 8th 95° or above day*** Death Valley, CA: 121° ***Record 5th 120° or above day in September*** Denver: 97° Fairfield (Travis Air Force Base), CA: 117° (old record: 96°, 1958) ***New all-time record*** Redding, CA: 113° Reno: 102° (old record: 100°, 2020) Sacramento: 114° (old record: 108°, 1988) ***New September record*** Salinas, CA: 103° (old record: 97°, 2004) Salt Lake City: 104° (old record: 100°, 2020) ***New September record for the 3rd time in 5 days*** San Francisco: 97° (old record: 94°, 2004) San Jose: 104° (old record: 99°, 2008) Santa Rosa, CA: 112° (old record: 101°, 1923 and 2008) ***New September record*** In the 6 past cases when the June AO averaged +0.750 or above (1950-2021), 67% of the following August and September cases featured above normal temperatures. The August ECMWF forecast shows a warmer than normal September in the Northeast. This warmth would be consistent with the ongoing warming that has been occurring in September. On August 18, the SOI fell to -32.90. Since 1991, there were 8 cases when the SOI fell to -30 or below during the August 10-25 period. That outcome has often preceded a wetter than normal September in parts of the Northeast. Mean September rainfall figures for those 8 cases: Boston: 4.38" (normal: 3.55"); New York City: 5.08" (normal: 4.31"); and, Philadelphia: 5.12" (normal: 4.40"). Very wet years outnumbered very dry ones by a 2:1 ratio in Boston and 3:1 ratio in both New York City and Philadelphia. 63% of cases saw at least one day with 1" or more rainfall in Boston. 88% saw at least one day with 1" or more in New York City and Philadelphia. 50% of those cases saw at least one day with 2" or more daily rainfall in Philadelphia. In sum, the SOI may be offering a signal that there will be some drought relief for the northern Mid-Atlantic and southern New England regions in September. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around August 31. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.62°C and the ENSO Region 3.4 anomaly has averaged -0.95°C. La Niña conditions will likely persist through the fall. The SOI was +19.26 today. The preliminary Arctic Oscillation (AO) was -0.792 today. On September 3 the MJO was in Phase 4 at an amplitude of 0.549 (RMM). The September 2-adjusted amplitude was 0.587 (RMM).

Morning thoughts… It will be mostly cloudy and cooler. Rain and thunderstorms are likely, especially later today and tomorrow. A general 1.00”-2.00” of rain is likely with locally higher amounts. Southern New England will see a general 1.5”-3.00” rainfall with some higher amounts. High temperatures will reach the upper 70s and lower 80s in most of the region. Central New Jersey southward will see warmer temperatures. Likely high temperatures around the region include: New York City (Central Park): 81° Newark: 84° Philadelphia: 87° Somewhat cooler than normal conditions are likely through Thursday. Normals: New York City: 30-Year: 79.9°; 15-Year: 80.0° Newark: 30-Year: 81.3°; 15-Year: 81.5° Philadelphia: 30-Year: 82.5°; 15-Year: 82.4°