40/70 Benchmark

I wish I was right about January being all Pacific driven....the added - NAO could shift the focus to the mid atl.

This period will define the winter. If this fails to produce bigtime, its going to be another shitty season.

NYC with 2' and Methuen stuck at 2" into mid January? Why not...

I think Allison would be hiding the children from you at that point

Heh....would be some interesting emotional swings if this were to play out.

That looks just like the March 2023 snowfall that dissapointed the shit out of 95% of SNE....and no one lives in the other 5% except @HoarfrostHubband @ineedsnow

Yea, no thanks. Mid January with a 12" seasonal tally......Booooiiiiinnnngggg

Need to consider many factors, though...for instance, where are we in the cyclone's lifecycle when it nears our latitude....if its occluding, its just going to mean an earlier dry slot, as opposed to much rain...but that is crap for another week. Larger threat of ample WAA if we are still in the cyclogenesis stage, but I am guessing that is either occluding or its imminent given the depth of that low.

Assuming a srong atecedent airmass...yea....wouldn't need a yard stick, though for e MA.

I love the W NE crew trying to talk us in to that being palatable for e MA...

"Some great tunes played before I wrapped my Honda Civic around a telephone pole"

All that matters are the ensembles....and I would have said that if they were meager and the OP should a Feb 6-7, 1978 reenactment-

I'd rank Jan 2011 #3 for deepest packs in my lifetime...behind #1 Feb 2015 and #2 Jan 1996.

Just when we thought we had escaped the omnipresent Tippy velocity surplus...

Yea, OPs are usless, whether they show March 93-east, or Jan 1985.

I will so it sometimes within a few days of a huge event....but yea.

I agree. I was up late last night writing, anyway....wasn't for the runs. Busy stretch with the holidays and 3 kids, so take time to do it when I can.

Yea, 12z EPS isn't much different from 00z...we got about a week to go before deterministic solutions gain any value.

I was in search of Kev's, but much to my chagrin all I could find was an innie

What is your point? We are all aware of the range and inherent limitations....I didn't see people get called out for this when everyone was massaging one another's genitals after last night's runs...

In my blog post about 3 weeks ago, I made mention of how the GEFS were progressing the MJO into phase 7 hear the new year, but other guidance was hanging it up in phase 6. I favored the GEFS, which has worked out. https://easternmassweather.blogspot.com/2024/12/much-milder-balance-of-december-before.html

Yea, the big NAO blocking is the wrinkle for me personally. Everything else about my January call from last fall looks great.

Much Colder Than Forecast December Potential Prelude to Wintry January Brief New Year Relaxation Followed by Return of Winter with Vengeance December 2024 Recap Snowfall was not expected to be abundant during the month of December, so it comes as no surprise that it was in fact below normal across the vast majority of the region. However, that is about where the similarities between the December forecast and the actual sensible weather end. Here is a juxtaposition of the forecast temperature departures across the CONUS in degrees F for the month of December with the actual anomalies. Cleary the forecast for the month of December went awry and any accuracy with respect to regional snowfall was largely a coincidence. The expectation was for a predominately -PNA and a variable to perhaps modestly negative NAO in the mean, but what actually verified was an extremely positive PNA along with a positive NAO. AO Has Been Near Neutral This represents a more protracted early to mid winter deviation from the prominent MC forcing of the modern era along the lines of the 2017 mismatch period considered in the Winter Outlook. It was intimated that his was likely to occur approximately one month ago, when it became apparent that there would be a delay in the development of La Niña. When La Niña is Away (Delayed) The Aleutian Low Will Play The seeds of the December forecast demise were indeed planted during the month of November, when a very pronounced westerly wind burst (WWB) throughout the tropical Pacific halted the development of La Niña, and allowed for an episode of Positive Global Absolute Angular Momentum during the month of December that was more protracted than expected. Since positive GLAAM is indicative of an atmosphere that is generally redolent of El Niño, and negative GLAAM La Niña, this likely contributed to the development of an Aleutian low in the December monthly mean as opposed to the Aleutian ridge evident in the forecast composite. This Aleutian low enabled the potent PNA ridge to sustain in the monthly mean, which of course promotes lower heights and thus colder temperatures downstream over the eastern US despite the passage of the MJO through the Maritime Continent. However, the journey of the MJO through phases 5 and 6 for the vast majority of the month of December may have played a role in the maintenance of a predominately positive monthly NAO, which likely limited regional snowfall. Be that as it may, it appears likely that the MJO will begin to constructively interfere with the prospects for more severe winter weather along the east coast early on in the New Year. Ironically enough, these are prospects that are actually augmented by the much anticipated emergence of La Nina. East Coast Winter Weather Prospects Bolstered by Reemergence of La Niña Clearly the reports of the failure of La Niña to materialize that ran rampant throughout the forecasting industry were premature, as asserted by Eastern Mass Weather throughout the fall and into the early winter season. Indeed, the parallels drawn between the late-blooming cool ENSO event of 2008 and the current one in terms of both the subsurface, as well as the December easterly trade surge have proven valid. Note the parallels in the late recovery of each event during the month of December. Region Date 1.2 3 3.4 4 04DEC2024 0.1 -0.4 -0.3 -0.2 11DEC2024 -0.2 -0.4 -0.6 -0.3 18DEC2024 -0.2 -0.5 -0.8 -0.4 03DEC2008 -0.6 -0.4 -0.6 -0.8 10DEC2008 -0.3 -0.6 -0.8 -0.7 17DEC2008 -0.2 -0.7 -0.8 -0.8 24DEC2008 -0.3 -0.8 -1.0 -0.9 This may lead some forecasters astray in that they are likely to rush the return to an RNA style pattern during the month of January, however, this is a case in which the recent strengthening of La Niña in conjunction with the passage of the MJO into phases 7, 8 and 1 is likely to constructively interfere with its maintenance. This is congruent with the paradoxical positive correlation between the intensity of ENSO and the incidence/extent of deviation from MC forcing detailed in the Winter Outlook. The first significant winter storm threat after the colder transition during the first week of the New Year looks to take place on about January 7. This immensely ominous signature during the second week of the month is very well supported by long range guidance and is slightly earlier than the January 21-February 4 period identified in the seasonal outlook as being conductive to a potential KU event. EPS GEFS GEPS Confidence is further increased by modularity in the vicinity of said date in a show of tele connector convergence. Note varying degrees of recovery of the -WPO/EPO/NAO/AO, as well as the +PNA that herald in a potentially intense bout of cold beforehand. Thereafter, as intimated by the aforementioned mass fields, the GLAAM is likely to finally respond to the late-developing La Niña mid-month, which should ultimately contribute to the return to an RNA pattern in compunction with the approach of the MJO to phase 3. The precise timing of this transition will obviously impact monthly verification, but as it stands currently, the only significant potential deviation with respect to January from the seasonal outlook published in November is the NAO domain. This would pose yet another cold risk relative to the forecast, as the intensity of the cold anomalies would be increased, and they would extend further to the south than originally anticipated. However, the January portion of last fall's outlook appears largely on track, as the MJO is indeed progressing into phase 7 by the New Year as advertised, despite conflicting forecast data. More importantly, this progression is very comparable to the primary analog of 2021-2022. Thus while the mismatch period from the MC forcing that has been so prevalent for the better portion of the last decade has been more protracted than that which occurred during the 2021-2022 analog, the January portion of said period still looks to evolve in a similar manner even if perhaps featuring a greater degree of polar blocking.