bluewave

Tuesday looks like it may be the first time that we had a 597 dm backdoor pattern in July. The forecast 597 dm height is among the highest on record for July. In the past, this has been associated with record heat instead of a cooler easterly flow.

Updated for the 6.18 max at Locust Valley, NY NY-NS-32 Locust Valley 0.3 E Lat: 40.8813 Lon: -73.5813 Date Precip in. 07/09/2021 5.81 07/10/2021 0.37 Totals : 6.18 in.

The next record WAR pattern this week will have more clouds, convection, and onshore flow than the previous ones. So the high temperature potential will be lower. But the mid to upper 70s Miami dew points will make it feel warmer than the actual temperatures.

Several stations just had their wettest first 9 days of July on record. So it’s no surprise that July is off to a cooler start. Seems like the only way to keep our summer temperatures down these days is to have a deluge. EWR….+0.6…..4.75 NYC…..-2.1……6.79 LGA……-2.0…..4.74 JFK……-1.1…….3.72 BDR…….-2.1…..7.63 ISP………-1.3.…4.58

Nearly 10.00” since June 30-July 1 near the North Shore. NY-NS-32 Locust Valley 0.3 E Lat: 40.8813 Lon: -73.5813 * indicates Multi-Day Accumulation Report Station NY-NS-32 Date Precip in. 07/01/2021 0.52 07/02/2021 1.26 07/03/2021 1.67 07/04/2021 -- 07/05/2021 -- 07/06/2021 -- 07/07/2021 0.22 07/08/2021 -- 07/09/2021 5.81 Totals : 9.48 in.

The July 1-9 record rainfall could be signaling that the all-time June high of 103° at Newark will be the warmest of the summer. This was earliest in the season that we had a tropical storm or hurricane following a 100° day by a very wide margin. The usual pattern in the past was to have the 100° heat in July or August with the tropical system in August or September. This seasonal cycle getting moved up to late June and early July is unprecedented since at least 1944. Newark closest 100° dates followed by a tropical storm or hurricane 8-5-44….102°………9-15-44……Great Atlantic Hurricane 7-31-54…103°……...8-31-54……Hurricane Carol….10-15-54….Hurricane Hazel 8-2-55….100°……….8-13-55……TS Connie…..8-17-55….TS Diane 7-21-91...102°……….8-19-91……Hurricane Bob 7-5-99….103°…….…9-16-99…..TS Floyd 7-22-11…108°……….8-28-11……Hurricane Irene 7-18-12…104°……….10-29-12…Hurricane Sandy 6-30-21…103°………7-9-21……..TS Elsa

Nearly 6.00 so far along the North Shore. Station Number: NY-NS-32 Station Name: Locust Valley 0.3 E Observation Date 7/9/2021 9:30 AM Submitted 7/09/2021 9:38 AM Total Precip Amount 5.81 in. Notes Still raining heavily Taken at registered location Yes Snow Information New Snow Depth NA New Snow Water Equivalent NA Total Snow Depth NA Total Snow Water Equivalent NA Duration Information Precipitation Began -- Precipitation Ended -- Heavy Precip Began -- Heavy Precip Lasted -- Duration Time Accuracy -- Additional Information Additional Data Recorded No Submitted 7/09/2021 9:38 AM Flooding --

3.81 at the Wantagh mesonet with north winds gusting to 40 mph.

3.76 at the Wantagh mesonet with clearing to our SW.

3.56 at Wantagh since yesterday.

3.05 now in Wantagh with roughly half the total falling in the last hour.

I have flash flooding here in SW Suffolk with a small lake around my place in the grass. While the Wantagh mesonet may not be under the heaviest band, they picked up 1.00 in just 30 min and are at 2.50 so far.These are some of my heaviest rates of the last few years.

Very heavy downpour here in SW Suffolk with flash flooding developing. Due to the tropical nature of the rainfall, the radar is underestimating the rate of rainfall here. The echoes in orange are more like a red summer thunderstorm.

0.91 in 10 minutes and 1.56 in 20 at the peak.

The graph, shown above, looks at temperature patterns observed in the Pacific Northwest over the last 70 years and applies what is known as Generalized Extreme Value (GEV) theory to it. The fit, shown in red, looks pretty reasonable. 2/ One of the features of GEV is that it sometimes predicts that a statistical system as a finite limit. That occurs when the data presents a downward curving slope, as it does here. 3/ To be concrete, the analysis presented above says: In the 70 years prior to 2021, the worst observed heatwave for the region corresponds to an average of ~35 °C (95 °F). The GEV model estimates the worst possible is ~37 °C (99 °F). But in 2021, we reached 39.5 °C (103 °F). 4/ The GEV model said that 39.5 °C was "impossible", but it happened anyway. Now obviously, if it happened then it was actually possible, so what is it really telling us? 5/ It suggests that the 2021 heatwave may have had a qualitatively different origin or dynamics than all the other Pacific Northwest heatwaves of the last 70 years. 6/ That kind of thing happens sometimes with extremes in physical systems. For example, 70 years of normal rain data may badly fail to predict how much rain is possible during a hurricane, because a hurricane is dynamically different from normal rain-producing processes. 7/ The statistics suggest that the Pacific Northwest heat storm was not merely more extreme than past events, but perhaps also qualitatively different. So, *if* the event was qualitatively different from past events, then we ask in what way? 8/ The first option is that the heat storm was a proverbial hurricane, e.g. a rare dynamical interaction that has always been possible, but so rare that in 70 years of data we never observed a weather pattern that was qualitatively similar. 9/ The second option is that we are seeing unfamiliar dynamics because the climate system has changed at large scales in ways we don't yet fully understand. I consider this the scarier option. 10/ Right now, we don't know the answer. In all likelihood, entire PhDs will be written about the Pacific Northwest heat storm. But nature has thrown us a scary curve ball, and we'll have to wait and see if this was just an exceedingly rare one-off or a sign of more to come. 11/11

Pretty good 12z agreement on the axis of heaviest rains right through NYC Metro.

Central Park OBS since 1991 being much cooler than Newark is an illusion created by the trees growing over ASOS. When the sensors were free of obstructions like all official weather sites, NYC would be equal to or warmer than Newark on some days. The ASOS back in the 30s to 70s was in a more open area like the softball fields are today. That’s the only reason why the warmest week in Central Park can’t get warmer than 1977. Notice how our other stations have had their warmest week in more recent times. NYC ASOS beneath a dense canopy marked KNYC That area was more open before the tree growth of the last 40 to 50 years like nearby softball fields. Warmest weeks around our area Maximum 7-Day Mean Avg Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 91.2 1993-07-13 0 Maximum 7-Day Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 87.4 1993-07-13 0 87.4 1977-07-21 0 Maximum 7-Day Mean Avg Temperature for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 88.3 2006-08-03 0 Maximum 7-Day Mean Avg Temperature for WESTCHESTER CO AP, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 83.4 2013-07-20 0 Maximum 7-Day Mean Avg Temperature for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 86.4 2013-07-21 0 Maximum 7-Day Mean Avg Temperature for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 84.3 2013-07-20 0 Maximum 7-Day Mean Avg Temperature for IGOR I SIKORSKY MEMORIAL AIRPORT, CT Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 84.8 2013-07-20 0

This is a continuation of the stronger WAR with a more tucked in storm track like the last several years. New run Old run