bluewave

Yeah, the warmest SSTs for the period of record during this time of year. https://mco.umaine.edu/gom_sst/

And these unusually potent late fall severe weather patterns in recent years. https://weather.com/storms/tornado/news/2018-10-04-pennsylvania-record-october-tornado-outbreak Tuesday's swarm of tornadoes in parts of the Northeast set an October record in Pennsylvania. It was the state's most tornadic day in over 20 years. https://www.washingtonpost.com/weather/2018/10/24/rare-late-october-tornado-outbreak-hit-massachusetts-rhode-island-tuesday/ October 24, 2018 Cape Cod is a fun summertime vacation destination, and the weather is usually turning increasingly wintry this time of year. Tuesday, the Cape looked more like Oklahoma than New England as several tornadoes tore through Massachusetts and Rhode Island. At least three tornadoes seem likely to have touched down. It’s a region that doesn’t see many twisters any time of year, and this is as late as they come in Southern New England.

Record number of tornado warnings issued from the NWS at OKX for October and November since 2018. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=171&opt=wfo&station=OKX&state=NY&_ugc_state=NY&ugc=NYC059&phenomena=TO&significance=W&cmap=Greens&_r=t&dpi=100&_fmt=png

The December pattern will probably begin to set up during the last week of November. We need a strong cutter or hugger to pump the -NAO into December like last year. All our La Ninas that have near to above normal snows have a front loaded part when we put down snow at some point in December. This was true during our last La Niña Decembers in 2016 and 2017.

Partial collapse of the restaurant according to a report on twitter.

Small planes flipped at Brookhaven airport.

Damage at Chipotle in Suffolk.

This was the first time that I saw asperatus clouds ahead of severe storms on Long Island.

Damage reports in Lynbrook.

Newark gusting to 52 mph with the sting jet like feature behind the line. Newark Liberty PTSUNNY 51 43 74 W38G52

These near record midlevel lapse rates have given us unusually widespread coverage of hail across the area.

Enough hail to whiten the ground in NJ.

These near record midlevel lapse rates are as steep as we see on the Plains with their spring and summer severe outbreaks.

Hopefully, the JMA is correct about us getting -NAO -AO intervals this winter.

We may continue to get -NAO -AO intervals as long as the troposphere remains uncoupled from the SPV.

We could use a powerful storm like we got at the end of November last year. That system created a big wave breaking event over the North Atlantic. It pumped the -NAO ridge into December.

In addition to the severe potential that Walt outlined, there is a sting Jet-like feature right behind the low. So we could be looking at two rounds of higher winds. The low level lapse rates steepen behind the storm in the CAA which could allow westerly 50-60 mph gusts.

Yeah, that’s why we see the temperature back and forth continuing. The models have been too weak day 10 with the Pacific Jet. Notice how the day 5 has more of an Alaska +EPO trough than the day 10 was forecasting. New 120 Old 240

It looks like a battle between the warmer Alaska +EPO trough and cooler ridge near the US West Coast. So we get a series of Pacific storms with warm ups ahead of them and cool downs behind. The monthly temperature departure may not be decided until the end of the month.

The Southeast is winning the November cold departure battle so far.

Pretty good rotation with the warned cell over Suffolk. https://www.spc.noaa.gov/products/md/2021/md1943.html DISCUSSION...KOKX radar imagery has shown a long-lived rotating cluster of convection moving north from the shelf waters of the Atlantic to the south coast of eastern Long Island. The KOKX VAD wind profile shows intense flow fields with an enlarged hodograph. The main limiting factors are scant buoyancy and very weak lapse rates. Nonetheless, the storm-scale forcing associated with the hybrid rotating cluster of convection may enable the risk for damaging gusts to be realized on a localized basis, as the convection moves north from eastern Long Island into CT over the next 1-2 hours.

I think we have moved into a new background state. One where the reduced sea ice near the Kara and Barents seas interacts with the SPV and Urals ridge. Last November into December was a recent example of how the pattern can dramatically reverse. The same went for December 2015 into January 2016. So that may be why seasonal models in the fall have been so far off with the winter NAO state. Our new winter blocking regimes near Greenland have been linked to that Urals ridge. Before 2003, our winter blocking episodes often didn’t have that connection. So it’s very challenging to try and forecast monthly NAO changes during the winter before they actually occur.

Remember, the models didn’t catch onto the winter forecast last year until December was practically starting. These early to mid November runs can have a type of fall forecast barrier effect. So anything beyond week 2 has very little skill.

Maybe since the new December average temperature has risen to around 40°, near to below normal temperatures will be easier with a supporting pattern. ……1991-2020….1981-2010 NYC…..39.1°……37.5°……+1.6° EWR….38.0°……36.5°……+1.5° LGA…..40.0°……38.2°……+1.8°

Yeah, we just don’t want the consolidated look to the polar vortex in the next frame. But that is outside the effective range. A more elongated vortex with higher heights near Greenland and the Aleutians would be better. Still plenty of time to see how it evolves.