40/70 Benchmark

My post wasn't meant to infer anything about the future. I was simply reflecting on January.

Good call.

+.5" 19.5"

100% literally over? I doubt it, but climo snowfall is now a long shot.

Yea...I remember. I was in Uganda for that.

Keep in mind, the PV remaining rather stout maybe more beneficial in terms of winter prospects in February, than if we saw a SSW. Those tend to excite and subsequently stagnate the MJO when they occur...and it will be in shitty phases this month. This is partly why Feb 2018 was a wall of warmth.

I agree...I don't think its wall-to-wall furnace like 2018. There will be some snow.

This will be the main diff from January, IMO...there will be a source region lurking in Canada, as opposed to Sibera.

Lots of weather wisdom accrued in that time.

Yea, mid month is a window. Agree. Looks like the brutal modoki la nina forcing relaxes some ...

17.5" on the month, which is a hair above normal...remarkable considering the magnitude of the monthly positive temp anomaly. That is what a very active pattern will do at this latitude in the heart of winter.

Very Active January Much Milder Than Forecast Cold Start to February Belies the Overall Tenor of the Month The month of January verified as several degrees above average across the northeastern US: This was clearly much warmer than the January forecast, which was near normal: One reason for the terrible forecast was the very active Pacific jet stream, which although it was expected to be prominent at certain points over the course of the season and supply a very active storm track, it was was more of a factor than anticipated due to the fact that the polar jet never became involved. This is apparent when looking at the actual H5 composite versus what actually transpired. Cold Unavailable for Active Storm Track It is very apparent froM the Eastern Mass Weather January 2023 H5 forecast composite that the polar domain was expected to interact with the aforementioned Pacific parade of storm systems. However, high latitude blocking never rematerialized as forecast, after the original episode in December. It is important to note that interestingly enough, there was in fact cold air available, as evidenced by the mean negative AO value for the month. But since the storm track remained inland and there was no cold air available, it is easy to discern why much of the east coast experienced little to no snowfall, despite such an active storm track. When considering why that was the case it is important to remain mindful of the fact that nothing within the global atmosphere occurs in a vacuum. It is apparent from the January 2023 annotation above that the NAO remained decidedly positive throughout the month of January. This combined with some subtle nuances with respect to the Pacific pattern acted to ensure that storms tracked inland from the coast. And perhaps more importantly, trap the main hemispheric reservoir of cold in Siberia, thus preventing it from being entrained into the active parade of storm systems. Here is the PNA plot for the month of January: While it did in fact average positive, as forecast, the higher heights were focused in the western portion of the PNA domain and off of the west coast, which only served to augment troughing along the west coast. This configuration largely mimicked the RNA pattern of December, however, unlike December, January featured a +NAO, which worked in conjunction with the western biased +PNA to ensure an inland storm track. And given the fact that there was no Aleutian ridging or cross polar flow to tap the cold supply in Siberia, there was very little antecedent cold to allow for southwest flow events or front end snowfall for the coast. January 2023: This is not at all unlike the evolution of January 2002, which was a double weighted year in the seasonal analog forecast composite. January 2002: Thus while the month did feature some el nino like qualities, as anticipated, the cold air was never able to link with the active storm track. The latter was an unexpected occurrence. The main question now moving forward into February becomes is there any hope for sustained winter east... Mild February Remains on Track after Frigid Start February Analogs: 1955, 1956, 1975, 1976, 1984, 1986, 1989, 1990, 1997, 2001, 2008, 2011,2017, 2018, 2022 Despite the deviation from the forecast with respect to January, the thought process with respect to February has changed little since November. There should be an intense, albeit brief, bout of arctic air as a polar vortex descends on the region this weekend. This will be accompanied by very dangerous wind chills, so dress accordingly if outside. For the balance of the month, the vast majority of snowfall this month will come from overrunning and warm air advection processes. The pattern will continue to be particularly hostile to major east coast snow storms. However, there should be a transition to a more traditional la nina like pattern in which a cold air will be in supply over Canada. Although cold will flirt with the region during episodes of poleward Aleutian ridging at time this month, it will enter out west first and then slowly bleed south and east in a modified fashion with prominent -PNA present. NAO blocking should remain absent and the polar vortex intact, thus precipitation issues will continue to be prominent outside of northern New England. Thus there should be some light to moderate snowfall threats throughout the month. Here is the latest CFS guidance, which conveys this general sentiment of a "gradient" like, overrunning pattern. This is in general agreement with the forecast composite from last fall. Overall, the pattern should vacillate between a traditional "modoki" la nina like pattern, which is very mild over the east, and a gradient type of pattern. The latter features a pronounced reservoir of cold over the source region despite a lack of blocking, similar to the 1973-1974, 1975-1976, and 2007-2008 seasons. Here we can see that after the initial arctic plunge this weekend, the MJO filtered forcing assumes a modoki la nina like regime, which will coincide with the very mild pattern (much like the February forecast composite) that will ensue once the arctic shit departs. What is also apparent is that there may be a some potential for a bout of wintry weather near mid month, as the modoki forcing regime may abate, as implied in the filtered MJO plot above. Whether or not that happens or not is dubious. There is more support from the GFS camp, which eventually takes the MJO wave into the more favorable phases. But the European suite decays the wave in phases 4 and 5, which are very mild for the east coast. The trend this season given the well coupled la nina has been for the MJO to excite in phases 4-6, and for for guidance to over amplify it in phases 7-3, which are cooler for the eastern US. Thus this is the outcome that should be favored. However, this should be monitored given that the MEI continues to elevate, as the cool ENSO influence in the atmosphere wanes. Needless to say, somewhat cooler and more wintry weather is likely to return around mid month.

Yack...active storm track correct, near normal temps, incorrect. https://easternmassweather.blogspot.com/2023/01/very-active-january-much-milder-than.html

Thoughts on February similar to last fall....mild, but maybe a window mid month? Canada should at least be colder... https://easternmassweather.blogspot.com/2023/01/very-active-january-much-milder-than.html

Its these winter's that don't go as planned that are the most informative....the seasons like 2009-2010, when everyone and their dog knows to forecast cold and snow, don't do as much to advance seasonal forecasting....as orgasmic as they can be on the d-drip front.

I'll admit this is something that I need to pay more attention to in season....when the winter goes the unsavory route, I tend to check out and not pay much attention, aside from brieg blog update cameos.

You should put something out next year...you have a ton to offer, John.

Trying to develop a conceptualization that adequately captures the complexity of the global atmosphere remains a fool's errand.

Human kind's throught process is still far too linear for seasonal forecasting....too many generic relationships, indexes and correlations are over simplified, which leads us astray.

Man, we have really just rolled snake eyes this year....uber NAO block in December....that interacts with the PV in such a manner that all of the energy phases west. +PNA January....that is biased west and off of the coast, so that a semi-permanent trough remains anchored along the west coast. -AO January.....that teams with a +NAO to focus all of the cold in Siberia like Jan 2002. Now Feb begins with a historic arctic blast that squashes the storm track, until it lifts out in time to rain. "Just a bit ironic....don't ya think"

I am pretty happy with how my December thoughts played out, dearth of snowfall be damned...and think I am on the right track for Feb. Unfortunately, all I got right in January was the active storm track....problem is it was like +8 instead of normal. Of course.....the shit part works out. Great-

I think the tropics have dictated that you take the under on amplification when the MJO is in the wheelhouse phases for eastern weenies, and the over when in the milder phases. That is the gist of my next blog.

Yes. Well stated.

And that was still a good winter...would have been epic had that one landed.

Yea, the return rate on nearly wire-to-wire winter seasons is just about non-existent, at least at this latitude.