February 2022 Obs/Disco

[40/70 Benchmark]

2 hours ago, HIPPYVALLEY said:

 

We can notice how is skipped Ray's hood.  

I got 1/4 inch.

[tamarack]

9 hours ago, 40/70 Benchmark said:

I got 1/4 inch.

Barely made 0.2" here, where snow squalls (and svr TS) go to die.  Two squalls in 8 days, 0.3" total.

February temp will finish about +2.  It was running +4.7 thru last Wednesday.

[weathafella]

I walked out-not realizing it snowed!  0.4.  Must have been a good one!

[40/70 Benchmark]

February 2022 Review & March Preview

February Forecast Moderate Success; Vortex Disruption Delayed Rather Than Denied

Here is a review of the February 2022 portion of the winter outlook that was originally issued early last November.

Forecast Review:

 

February 2022 Outlook

February Analogs: 1955, 1956, 1971, 1996, 2006 (x2), 2001 (x3), 2018, 2012, 1965, 1975, 1972, 2008, 2011,1985

 

"The month of February is the most difficult portion of the forecast because there will be a great deal of flux. Not only between the potential SSW that may parallel that which was observed on February 13, 2018:

But also a PNA that is more likely to fluctuate from the more stagnant RNA of January, as la nina begins to decay and loosen its grip on the pacific. Here is an extended range forecast for the polar vortex from the European model courtesy of meteorologist Giacomo Masato:

Note that guidance implies a recovery to a strong vortex in January, as per the Eastern Mass Weather forecast, however, the analogs suggest that the disruption could even begin to take place in later January. This is crucial to the forecast because if it does in fact delay until March, then blocking will not redevelop until spring and the second half of the season could be mild.

Nonetheless, the month of February should begin very mild, but winter is likely to gradually return as the Pacific also becomes a bit less hostile and the Aleutian ridge that had retrograded last month begins to edge back closer to the west coast and a bit more poleward towards Alaska. This will allow more proficient cold delivery through the plains to bleed into the northeast, leading to an active pattern of overrunning, SWFEs and Miller B cyclogenesis.

The month should average anywhere from near normal to 2 degrees above average. Warmest near the east coast and the mid atlantic, coldest north and well inland. But again, the risk is for a much warmer outcome.

The primary risk during February is that if a major disruption of the PV does NOT occur, then the month may remain fairly mild".

 

 

The Results:

In hindsight, this was a very accurate forecast overall in terms of sensible weather, as the region did indeed finish slightly above average for the month, and the primary modes of cyclogenesis were in fact overrunning, SWFEs and Miller B events. 

 

Forecast Precipitation:

 

Versus Actual:

 

Forecast Temps:

Versus Forecast Temp Departures

 

 

Forecast H5 anomalies:

The poleward ridging in the Pacific that is so reminiscent of the eastern biased la nina composite was very well forecast. 

 

This did indeed allow for the delivery of arctic air throughout the east at times, however, note the absence of high latitude blocking

 

 Versus the forecast analog composite:

 

The primary reason for this discrepancy with respect to the polar domain is the failure of the major SSW predicted to occur between approximately January 23 and February 11. 

 

Ultimately this did not impact the monthly temperature departure as forecast because the more hostile polar fields were offset by a slightly more favorable Pacific than advertised, thus the forecast was still successful, and the warmer risks mentioned as a result of SSW failure did not materialize. As we begin to look ahead towards the month of March, it is important to remember that European guidance last fall seemed to indicate that the polar vortex would be most prone to major disruption during this month.

Which was about a month later than the Eastern Mass Weather outlook indicated, thus this is a period to continue to monitor as the season draws to a conclusion.

 

Implications of Potential Stratospheric Warming in March

It appears as though the European guidance will indeed prove correct with respect to the increased vulnerability of the polar vortex during the month of March, as there is currently agreement between both both the GFS and European suites that a split will occur.

 

 

 

Upon a perfunctory examination, it would appear as though the Eastern Mass Weather forecast of a polar vortex split to occur by February 11 was simply a few weeks too late. However, this particular event is induced largely via tropospheric wave breaking, and is this not the product of a SSW. Thus this portion of the Eastern Mass Weather winter outlook will in fact be be wrong, and instead any impacts from this event via cold air outbreaks will be fleeting, as the vortex rapidly recovers the second week of the month.

 

 

What this does mean is that the month of March is unlikely to be as severe as originally predicted last fall, as noted by the explicitly stated warm risks in the event that the SSW event did not occur. What this does NOT mean is that the month will be absolutely devoid of wintry weather.  As evidenced by the month of February, the Pacific will play a role, as well as the overall shape and character of the 

polar vortex. Note in the image above that while it has indeed recovered and is no longer bifurcated, it is not extremely consolidated and is in fact elongated in the direction of the northeast US. This should allow for a cold source to be at least near by, which should provide winter precipitation throughout at least northern New England, and opportunities points further south. The Pacific will be fairly conducive to cold intrusions through the first week of the month, however, it is unlikely to remain as favorable throughout the duration of the month as February did. There is support for troughing to develop and encompass much of the western US during the second week of the month, perhaps somewhat like the month of December, which certainly implies that warmer risks in the absence of the originally forecast high latitude blocking will prove more viable than during the month of February. 

 

 

However, there will be periods with cold lurking nearby at least though mid month.

 

 

Thus although the season is unlikely to go out as the lion it was advertised to last fall, there are also some signs that it may not exactly go out as a lamb, either. The month will like finish near average to slightly above average.