bluewave

It’s all about where the 500 mb anomalies line up. A ridge pulling back to the Aleutians could allow the trough to dig into the Western US in February. That scenario generally isn’t favorable for us since it allows systems coming east to pump the SE Ridge. That’s why we would want to make the most of our +PNA and -EPO interval while it lasts.

Let’s hope we can cash in in this +PNA -EPO while we have it in late January. The latest ensembles moved to the EPS idea of a pattern reversal in early February. The big ridge pulls back to the Aleutians allowing a more neutral to eventually -PNA in early February.

I said some of the models were showing colder potential in late January than we’ll see this weekend. But they have been back and forth in recent days on the magnitude of the cold. Temperatures around 10° tomorrow in NYC would be the coldest in 3 years. I mentioned that less cold suppression could be good for our snowfall prospects. We already have one January 6”+ snowstorm. It would be great to get another before the month is over. The last time we pulled of an early and late January multiple 6”+ snowstorms was 2014. Since 2003, we have had an early January snowfall peak followed by a mid-January lull like this year so far. If we can score a major snowfall event near or after the 20th, then it would match recent snowfall climatology. Snowiest January days since 2003 1-4….9.8 1-7….12.6 1-12…6.6 1-15…6.2 1-18…6.6 1-21…19.5 1-22…9.2 1-23…32.6 1-26…18.9 1-27….18.0 1-28….12.0

The suppression is today with the 959 mb ocean storm and Arctic outbreak right behind it into the weekend. The PNA ridge axis was just a little too far to the east. The Monday phase matches other very active patterns in recent years. Last December featured the big snowstorm followed by the much warmer system on Christmas. We seldom get big follow up snowstorms so soon following 6-10” snowstorms like we got last week. That’s why a winter like 10-11 was so rare to produce 3 KU events in a little over a month. Most years we are lucky to just get 1 KU event.

The models have backed off a bit on the magnitude of the cold they were showing for late January a few days ago. I am hoping this means less of a chance for storm suppression. This more Nino-like pattern has already produced a record STJ in South Florida.

Shallow cold air drain down the Hudson Valley gets NYC close to 10° tomorrow morning.

The pattern started on January 1st and we have already had a 6”+ snowstorm. Since our snowier era began in 2003, only two Januaries had two 6”+ events. Four years had single events that went over 6”. So it would be great if we could get another event to go over 6” by late January or early February. We are already ahead of snowfall expectations in January during a La Niña that gave us under an inch in December. La Niña years bolded Monthly Total Snowfall for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Year Dec Jan Season 2011-2012 0.0 3.4 3.4 2006-2007 0.0 1.9 1.9 2001-2002 0.0 3.3 3.3 2018-2019 T 0.6 0.6 2015-2016 T 28.8 28.8 1999-2000 T 10.5 10.5 1994-1995 T 0.3 0.3 1986-1987 T 16.3 16.3 1972-1973 T 0.9 0.9 1971-1972 T 2.2 2.2 1965-1966 T 9.3 9.3 1953-1954 T 13.1 13.1 1943-1944 T 5.5 5.5 1941-1942 0.1 3.0 3.1 1996-1997 0.2 3.1 3.3 1978-1979 0.2 6.0 6.2 1954-1955 0.2 2.4 2.6 1977-1978 0.3 16.6 16.9 1988-1989 0.4 6.4 6.8 1974-1975 0.4 1.8 2.2 1992-1993 0.5 2.2 2.7 2021-2022 0.6 9.7 10.3 2012-2013 0.9 1.0 1.9 1985-1986 0.9 2.8 3.7 1940-1941 0.9 9.5 10.4

The latest EPS weeklies continue the cold -EPO +PNA for the rest of January. The model begins to shift back to a more Nina-like pattern in early February. Moves the current Nino-like forcing from the Central and EPAC back to the Maritime Continent. So the temperatures begin to moderate then. Any delay in the La Niña forcing to return would keep the colder pattern going a while longer. Plenty of time to check the actual status of the tropical convection once we get to the beginning of February. Jan 17-24 Jan 24-31 Jan 31-Feb 7

Both the EPS and GEFS give us a classic MJO 8 look in late January as the forcing shifts to the EPAC.

The BNL tower temperatures show how quickly the shallow colder radiational cooling temperatures near the surface can rise with a southerly flow off the Atlantic in the upper 40s.

The big reversal may be related to the recon mission and dropsondes over the EPAC giving the models more information since yesterday. https://www.nco.ncep.noaa.gov/status/messages/ SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD 0300Z TUE JAN 11 2022 00Z GFS is running on time. UPDATED 00Z RAOB RECAP... 91348/PNI - Purged temp/moisture 812-767mb...wet bulb effect. 70414/SYA - TTBB missing. 72357/OUN - 10148. 72632/DTX - 10142. 72403/LWX - No report for NAM. Available for GFS. 27 dropsondes were available for GFS ingest in support of the Atmospheric River recon over the Eastern Pacific. Liddick/SDM/NCO/NCEP SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD 0305Z WED JAN 12 2022 00Z GFS is running on time. UPDATED 00Z RAOB RECAP... 76225/CUU - Purged spurious wind data at 867mb. 91334/TKK - Purged temp/moisture 483-415mb...wet bulb effect. 70414/SYA - 10145. 72357/OUN - 10148. 72632/DTX - 10142. 78384/GCM - 10142. 72582/LKN - TTAA missing for NAM. Full report for GFS. 72202/MFL - No report for NAM. Available for GFS. 21 dropsondes were available for GFS ingest to support Atmospheric River Recon in the East Pacific. Liddick/SDM/NCO/NCEP

The first -10 or lower temperature departure day in NYC since the July 4th and Memorial Day weekends. CLIMATE REPORT NATIONAL WEATHER SERVICE NEW YORK, NY 443 PM EST TUE JAN 11 2022 ................................... ...THE CENTRAL PARK NY CLIMATE SUMMARY FOR JANUARY 11 2022... VALID TODAY AS OF 0400 PM LOCAL TIME. CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1869 TO 2022 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) TODAY MAXIMUM 24 1248 AM 69 2020 39 -15 37 MINIMUM 15 1058 AM 3 1968 28 -13 28 AVERAGE 20 34 -14 33

This Arctic shot came in on a NW flow across the Great Lakes which were still very warm from December. You can see how the Arctic air moderated crossing SE of the lakes. The models did a good job with the big spread between the 850 mb temperatures and the surface. The next Arctic front will come through Friday night. This one will have more of a NNW flow avoiding the warmer lakes. So while the 850s won’t be as cold, the 2m low temperatures could be several degrees colder than today. More NNW flow for early Saturday NW flow moderating across the lakes today

Past dramatic December to January La Niña flips usually occurred with a SSW event. This year we did it without a SSW. The current reversal is being driven by the convection shift from the Western to Central Pacific. Plus we already have much more snow in early January from Atlantic City to NYC Metro than in the past La Niña years. That being said, the favorable patterns in those years lasted into the first week of February. More La Niña-like patterns made a return by the 2nd week of February. So it will be interesting to see how we can keep this pattern going.

Yeah, the ridge along the West Coast into Alaska is still going strong at the end of the EPS run on January 26th.

Yeah, the models have a very strong Alaskan blocking pattern mid to late January. Starting to see some long range runs even colder than this week into the weekend. While the long range CFS has its accuracy issues, it’s now continuing the late January pattern into early February. I have noticed that these very strong Alaska blocking patterns can take longer than the models forecast to begin to break down. So just something to watch as we approach the start of February. New run Old run

Yeah, Saturday morning looks like it will be colder than today. Both GFS and Euro drop NYC to near 10°. The next Arctic shot will come a with more NNW flow which doesn’t pass over the warmer Great Lakes like today. Models have below zero readings for the interior.

Yeah, the continued forcing near the dateline is keeping that strong Alaskan blocking pattern going.

That’s why we like to look at where the actual 500mb anomalies are located. Plus the vendors have their own custom teleconnection indices which differ from the CPC official values that we are all familiar with. The Alaskan blocking signal is so strong for week 2, that it will probably hold into the last week of the month.

NYC needs to get down to 13° tomorrow in order to beat the lowest temperature of the last two winters. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Ending Date Lowest Min Temperature Oct 1 to Apr 30 Missing Count 2021-04-30 14 0 2020-04-30 14 0 2019-04-30 2 0 2018-04-30 5 0 2017-04-30 14 0 2016-04-30 -1 0 2015-04-30 2 0 2014-04-30 4 0 2013-04-30 11 0 2012-04-30 13 0 2011-04-30 6 0 2010-04-30 13 0

Yeah, also an impressive week 2 Arctic outbreak signal from an ensemble mean for much of the CONUS.

Yeah, numerous opportunities with so many shortwaves rotating around the Hudson Bay vortex in mid to late January.

I am very sorry for your loss. Yeah, the long range models have been pretty insistent in the IO convection firing near the warm pool south of India by February. MJO phases 2 and 3 can be good for us during a La Niña in February. But convection shifting closer to phase 4 would allow the +PNA ridge to pull back close to the Aleutians. So it will be interesting to see what the models come up with as we get closer to February.

It will be interesting to see how long we can keep the MJO away from the Maritime Continent after the recent SST cooling in that region.

Yeah, looks like a very active pattern on the EPS. This is one of the most dramatic December to January Pacific reversals that we have ever seen. The models are looking very Nino-like after one of the most extreme La Niña Decembers on record. Recent SOI drop 9 Jan 2022 1007.02 1008.30 -27.74 8.33 9.43 8 Jan 2022 1008.45 1008.65 -22.65 9.56 9.77 7 Jan 2022 1011.09 1008.10 -7.63 10.53 9.97