bluewave

Yeah, next weekend looks like another system with the Euro AI taking the lead. It had this weekends system coming up the coast while the OP Euro and EPS and GFS and GEFS were too suppressed. The GFS and GEFS were the most suppressed. The EPS-AIFS and AIFS single were first showing next weekends system more defined and just offshore last few days while the OP Euro and EPS and GFS were more suppressed. The 0z guidance now has the ridge and trough axis further west allowing the trough to go negative tilt quicker for the benchmark Miller A Southern Stream KU potential. It would be wild if the 10 year major KU snowstorm pattern in January 1996, February 2006, January 2016, and February 2026 worked out. EPS-AIFS and AIFS single are now the highest scoring models

The initial event back in late November was possibly caused by an interaction between the record low Arctic Sea ice and the -QBO. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JD044403 one model, HadGEM3-GC31-MM, has a statistically significant equatorward shift in vortex latitude, deceleration of vortex winds, and increase in sudden stratospheric warmings. Its response is found to be highly state-dependent, significant only in the easterly phase of the quasi-biennial oscillation (QBO). Though we cannot comprehensively conclude why models simulate this range of responses, our analysis does highlight areas for consideration in future work to better constrain the stratospheric response to Arctic sea-ice loss. We explore the role of ensemble size, resolution and basic state, including zonal-mean winds in the polar and midlatitude stratosphere and upper troposphere, as well as the QBO.

The one of the earliest stratospheric polar vortex disruptions back in late November has been a big player this winter.

This has been one of the rare instances of significant aspects of the winter 500 mb pattern becoming established in November and carrying over into the winter.

Following the snowstorm this weekend I would like to see the ridge axis out West back off a little to allow coastal development closer in instead of further offshore like the EPS and EPS-AIFS into next weekend. Many times we get a snow event at the start of a pattern and at the end. So it looks like the snow potential will continue into at least early or perhaps mid-February with the exact storm dates to be determined later. I am happy that the long advertised more active STJ pattern came to pass as there is only so much snow we can get exclusively from Northern Stream disturbances here.

The 540 line is only a rough approximation when the AI doesn’t show the P-Types chart. Right now I would probably use the NAM as the floor for NYC and Long Island with at least 6-8” before any mixing later Sunday. The RGEM and other guidance at 10-12” would probably be the ceiling. I used the kuchera to account for the higher ratios at the start gradually falling back closer to 10:1 later Sunday.

Good signal from the 6z Euro for at least a 6-8” floor around NYC and LI before any sleet potential later Sunday using conservative 10-1 ratios which could be on the low side.

They don’t have the precipitation type and rate for the ECMWF-AIFS like they do for the other models on Pivitol.

Yeah, they don’t have p-types for that model. So we just have to estimate the p-types from the thickness values and compare to the Euro which has p-types. My guess is that we are going to get a very heavy front end thump on Sunday with at least 6-8” potential before any mixing. This has been the case with past SWFEs. We just have to watch the Southeast ridge next few days in the forecasts to refine the amounts.

It’s interesting how our coldest low temperatures during the 2010s and 2020s were during our warmest winters. The early February 2023 cold was in a sea of warm. Same story with the only below 0° in NYC since 1994 during the 2015-2016 winter. It’s funny that the back to back cold winters of 2013-2014 and 2014-2015 couldn’t produce a below 0° reading in NYC. Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb lowest temperatures Click column heading to sort ascending, click again to sort descending. 2025-2026 16 38 2024-2025 10 0 2023-2024 17 0 2022-2023 3 0 2021-2022 10 0 2020-2021 14 0 2019-2020 14 0 2018-2019 2 0 2017-2018 5 0 2016-2017 14 0 2015-2016 -1 0 2014-2015 2 0 2013-2014 4 0 Monthly Data for February 2023 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. NY CARMEL 4N COOP -10 CT OXFORD WATERBURY WBAN -9 CT DANBURY COOP -7 CT GROTON COOP -6 CT MERIDEN MARKHAM MUNICIPAL AP WBAN -6 CT DANBURY MUNICIPAL AP WBAN -5 CT NORWICH PUBLIC UTILITY PLANT COOP -5 CT GUILFORD COOP -5 NY SHRUB OAK COOP -4 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN -4 NY MATTITUCK COOP -4 CT GROTON NEW LONDON AP WBAN -4 NY PORT JERVIS COOP -4 NJ CHARLOTTEBURG RESERVOIR COOP -3 NY MONTGOMERY ORANGE COUNTY AP WBAN -3 CT NEW HAVEN TWEED AP WBAN -3 NY WEST POINT COOP -2 NY ORIENT POINT STATE PARK COOP -2 NY RIVERHEAD RESEARCH FARM COOP -1 NY WESTHAMPTON GABRESKI AP WBAN 0 NY BAITING HOLLOW COOP 0 NY UPTON COOP - NWSFO NEW YORK COOP 0 NY MONTAUK AIRPORT WBAN 0 NY WESTCHESTER CO AP WBAN 1 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 1 NY SYOSSET COOP 2 NJ TETERBORO AIRPORT WBAN 2 NY CENTERPORT COOP 3 NY ISLIP-LI MACARTHUR AP WBAN 3 NY NY CITY CENTRAL PARK WBAN 3 Monthly Data for February 2016 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. NY CARMEL 4N COOP -13 CT MIDDLETOWN 4 W COOP -12 CT SAUGATUCK RESERVOIR COOP -10 CT DANBURY MUNICIPAL AP WBAN -10 CT DANBURY COOP -10 CT ANSONIA 1 NW COOP -9 CT MOUNT CARMEL COOP -9 NY WESTHAMPTON GABRESKI AP WBAN -9 NY PORT JERVIS COOP -9 NJ CHARLOTTEBURG RESERVOIR COOP -8 NY SHRUB OAK COOP -8 CT MERIDEN MARKHAM MUNICIPAL AP WBAN -8 CT GROTON NEW LONDON AP WBAN -8 CT GROTON COOP -8 NY YORKTOWN HEIGHTS 1W COOP -8 NY WEST POINT COOP -7 CT NORWICH PUBLIC UTILITY PLANT COOP -7 CT TRUMBULL COOP -7 CT NEW HAVEN TWEED AP WBAN -6 CT IGOR I SIKORSKY MEMORIAL AIRPORT WBAN -6 NY MONTGOMERY ORANGE COUNTY AP WBAN -5 NY MATTITUCK COOP -5 NY UPTON COOP - NWSFO NEW YORK COOP -5 CT STAMFORD 5 N COOP -5 NY BAITING HOLLOW COOP -4 NY SETAUKET STRONG COOP -3 NY RIVERHEAD RESEARCH FARM COOP -3 NY MOUNT SINAI COOP -3 CT PUTNAM LAKE COOP -3 NY WESTCHESTER CO AP WBAN -3 NY SHIRLEY BROOKHAVEN AIRPORT WBAN -2 NJ CALDWELL ESSEX COUNTY AP WBAN -2 NY MONTAUK AIRPORT WBAN -2 NY CENTERPORT COOP -2 NJ TETERBORO AIRPORT COOP -1 NY WEST NYACK COOP -1 NY NY CITY CENTRAL PARK WBAN -1 NJ TETERBORO AIRPORT WBAN -1 NY ISLIP-LI MACARTHUR AP WBAN 0 NJ CRANFORD COOP 0 NJ NEWARK LIBERTY INTL AP WBAN 0 NJ CANOE BROOK COOP 0 NJ HARRISON COOP 0

It looks like that model is counting mixed precip as snow as the 540 line is north of us during Sunday afternoon like the regular Euro.

Looks like most of us should see at least 6” before any mixing potential Sunday with the stronger Southeast ridge and weaker 50/50 low than originally forecast. New run Old run

This December was a more amplified version of 1958 and 1980. Both years featured very strong ridges in the -WPO Bering Sea and Western U.S. regions. But this December was more +EPO -PNA.

The unusually early SSW in late November has been a really big player this winter so far.

The -20° to -33° lows were fairly widespread across your region during the historic January 1994 Arctic outbreak. Monthly Data for January 1994 for Sussex County, NJ Click column heading to sort ascending, click again to sort descending. SUSSEX 1 NW COOP -29 NEWTON COOP -26 SUSSEX 8 NNW COOP -20 HIGH POINT PARK COOP -18 Monthly Data for January 1994 for Pike County, PA Click column heading to sort ascending, click again to sort descending. HAWLEY 1 E COOP -31 Monthly Data for January 1994 for Wayne County, PA Click column heading to sort ascending, click again to sort descending. PLEASANT MOUNT 1 W COOP -22 Monthly Data for January 1994 for Orange County, NY Click column heading to sort ascending, click again to sort descending. WALDEN 1 ESE COOP -27 MIDDLETOWN 2 NW COOP -23 Monthly Data for January 1994 for Sullivan County, NY Click column heading to sort ascending, click again to sort descending. LIBERTY 1 NE COOP -20 Monthly Data for January 1994 for Ulster County, NY Click column heading to sort ascending, click again to sort descending. SLIDE MOUNTAIN COOP -21 Monthly Data for January 1994 for Dutchess County, NY Click column heading to sort ascending, click again to sort descending. RHINEBECK 4SE COOP -33 MILLBROOK COOP -29 STORMVILLE COOP -22 POUGHKEEPSIE COOP -20