40/70 Benchmark

No changes from Saturday. https://easternmassweather.blogspot.com/2025/01/final-call-for-early-wednesday-am-light.html

God, this winter sucks and blows.

Mixed Results Concerning January Forecast & Look Ahead to Potentially More Eventful February Paradoxical Warmer & Snowier Regime Possible Moving Forward January 2025 Review The main premise for the January 2025 portion of the winter outlook was that a potent -WPO/+PNA couplet would fuel a January 2022 like mismatch from the Maritime Content forcing that has been so prevalent over the course of the last several years. This portion of the forecast worked out about as well as it possibly could have, as the MJO did indeed make it into the west-central Pacific to trigger the anticipated extra tropical Pacific response. Note that the MJO did not travel through phase 8 this month, as it did during the analog month of January 2022. However, its extensive journey through phase 1 represents a trivial difference considering the similarities in the two adjacent phases. Thus the predominate tropical forcing of the two months was highly analogous, as forecast, but there were some important differences within the polar domain that ultimately biased the month significantly colder relative to forecast. Nuances of the Polar Vortex Lead Forecast Astray January 2025 was forecast to feature a very strong polar vortex (PV) and consequently, a +AO and NAO in the mean, much like January 2022 (.85, 1.08 mean monthly AO/NAO). Here is the polar vortex composite from January 2022, with the stratosphere pictured on top, and the tropospheric PV on the bottom. Now here is the PV composite from January 2025 for comparison. The vortex is of considerable intensity and reasonably well centered over the pole, however, note that it is neither perfectly aligned or coupled down through the troposphere, where the vortex is slightly weaker and more displaced away from the NAO domain. This allowed for high latitude blocking to prevail in this region, as evidenced by both the monthly NAO activity: And the 500mb composite. This clearly resulted in a much colder than forecast month, especially over the Ohio River Valley and southeastern half of the country. The forecast across New England was not impacted as adversely (Normal to +2 forecast versus Normal to -2 reality) as the rest of the eastern US due to decreased correlation with the NAO, which is where the error was. And ironically enough, less snowfall than anticipated, as the very suppressed pattern resulted in an even drier month than forecast. The error was primarily within the NAO domain, as the AO behaved in a more volatile manner and looks to finish the month approximately near neutral to somewhat positive. Now as the month of January draws to a close, the MJO will approach the Maritime continent, as high latitude blocking abates and the pattern modifies. While this will undoubtedly mean the end of the uncharacteristically and historic wintry weather to the south, that will not necessarily the case for the northeast. February 2025 Preview: "Warmer and Snowier" There are no major changes to the original forecast philosophy for February 2025. Here are the original thoughts from early November, which remain valid. February Analogs: 2011, 2008, 2000, 1999,1972 The polar vortex should begin the month very strong, but watch for a potential SSW from about mid month onward. The pace of moderate storms should increase for the first time all season, just as the warmer weather returns in February, however, a notable difference from many recent months of February is that it should not be prohibitively warm so as to entirely preclude some appreciable snowfall across the majority of the region. The month should finish 1 to 3F above average with near normal to perhaps just below normal snowfall. Northern New England should see above normal snowfall as the cold air source lurks close by in southeastern Canada, which will produce several front-end snowfall for much of southern New England and perhaps even into the northern mid Atlantic at times. "SWFE"....AKA "Southwest Flow Events- While there is currently little support for a major stratospheric warming during the month of February, research implies that there is a threat from mid month into March. While the signal is not as strong as it was in recent analog years, such as 2018 and 2023, there are two reasons why this month should not be nearly as warm as other recent months of February, regardless of whether the PV remains of considerable intensity. First of all, the guidance is in fairly strong agreement that the MJO will traverse the MC phases at a very low amplitude. In fact, the ECMWF actually implies that the wave will dissipate, however, it is expected to persist at a relatively low amplitude through the MC phases given the ECMWF's proclivity to underestimate the amplitude of waves in this region over the last several years. Secondly, seasonal guidance continues in strong agreement with the Eastern Mass Weather February 2025 forecast H5 composite, which implies that the PV will remain close enough for southern Canada to remain fairly cold. The general pattern is also supported across ensemble guidance in the medium to longer range. This rather close proximity of the PV to the CONUS is illustrated well by the forecast for both the EPO and WPO to remain negative, which will act to keep Canada fairly cold given the developing positive NAO working in conjunction with the fact that the cold air thus far this season has beeb biased towards the western hemisphere. This will undoubtedly supply some cold enough antecedent air masses for an increase in wintry precipitation across the region relative to January, especially given that elevating heights across the southeastern US courtesy of a persistent RNA pattern will ensure more precipitation will make it up the coast. It is this agglomeration of factors that will foster the "warmer and (somewhat) snowier" February pattern. What is slightly more nebulous is whether or not the cold pattern will return. Certainly the coldest weather of the season has already been observed, however, there are some subtle suggestions that the transition to spring will not be swift. Possible Colder Pattern Resumes Late Month The development of the prevalent RNA pattern for the month of February is very high confidence, as it is well supported by the passage of the MJO though the MC phases of 4, 5 and 6. Thereafter, there is evidence to support the progression of the MJO into phase 7. This may imply a return of the western CONUS ridging that had been very prevalent throughout the first half of this winter season. And any potential warming of the polar stratosphere would also likely mean a return of at least some degree of high latitude blocking to end the season, as well.

Bit of a February preview, which should offer somewhat more snowfall...not major changes from November. https://easternmassweather.blogspot.com/2025/01/mixed-results-concerning-january.html

Here is a look back at January, which turned out significantly colder than expected. https://easternmassweather.blogspot.com/2025/01/mixed-results-concerning-january.html

Finally, an exciting development this winter....hell, I may shitcan the mid week flurries and blog about your mental status-

Because I live nearly in NH.

I wouldn't expect it to be particularly strong.

Exactly my feeling heading into the season...but its not a slam dunk like 2018 and 2023.

I would probably be much better north of you, but hopefully not too bad there.

Exactly....this is why I was telling people that the EMI only matters if the event is appreciably strong. I predicted a modest Modiki La Niña, like 2008-2009...but its not a death-knell at that intensity. My work this year has been far from perfect, but better showing than the past couple of years.

I could totally see a Modoki El Niño next year.

I just meant for January, not the season.

I didn't feel anything in Methuen.

No, I think my forecast has been decent....just taking about the winter.

I'm resigned to failure for another season at this point....however, I do see reason for optimism moving forward this decade.

Yes.

See, this is why I can't wrap my mind around people hugging the IRI guidance like 9 months out....Christ, just last fall they had La Nina failing.

2008 also peaked late, and was followed by a healthy el Nino....its the best analog in terms of ONI and is the reason I never gave up on La Nina when most did.

Eric Fisher bought it...he was going 10-14".

Not so warm up here near the frosty Atlantic...he needs to move farther away from that nasty equator.

Right...but they tossed my 31" in Marxh 2018....not sure how that works.

-0.2 again this AM....decent stretch of cold, fake or not.

I like your chances

BTW, anyone associating use of that analog with 90" in 30 days or 115" on the season is the weenie.