North American snow cover as of Sunday night:
I don’t yet trust modeling beyond 6 days for our part of the country on specifics, but with ANOTHER Strat Warm event (SSW) taking place signals are mounting for a realignment of air masses and jet streams across the Northern Hemisphere which bear watching to see if we can further awake old man winter below I-40.
That window of opportunity/door ajar that I’ve written about in past posts remains, with signs of widening. However, I think the cold will be hit and run again, not locking in place, but some of the models disagree with me. The biggest difference this time compared to the last PV disruption is more of the Stratosphere level polar vortex is expected on this side of the hemisphere and the equatorial Pacific MJO appears to be moving into a less warm air phase going forward and there’s at least briefly some +PNA influence. [long time readers/followers know, others can google].
For now I think our yo-yo thermometer pattern continues into March.
Storm systems are lined up from the West Coast to the Western Pacific and the Orient to keep weather in the news for much of the nation into next month.
After feeling and seeing today the “backlash” on the backside of the Midwest-New England snowstorm we will have temperatures moderate by late week as a weak jet stream ridge builds back over our region:
But then the primary global models GFS/ECMWF show a big change with a polar plunge of the jet stream with a ridge out West and an upper level trough over the East:
The Greenland blocking (-NAO) and North Pole SSW Polar Vortex split (-AO) work in tandem.
It will bring into the U.S. some of the coldest air of the winter so far with dangerous single digits to below-zero temps from MN to OH or farther this weekend and next week. Temperatures in Midwest could be 30 below-normal in some areas as a finger of the Stratospheric Polar Vortex extends down into Great Lakes region:
While the primary jet stream storm track for this month is forecast most often from the Southern Plains to Ohio River Valley and Mid-Atlantic/New England it CAN sometimes get suppressed (sink South), and IF the timing is right with moisture we could end up with a real winter precip chance (NO specific storms to track at this time worth talking about, yet). But that could change suddenly.
ANALOGS FROM GFS TEMPERATURE CATEGORY:
ANALOG TEMP GUIDANCE BELOW ZERO PROBABILITY:
The 540 1000-500mb Thickness line is the approximate rain/snow line (but only IF IF there is moisture), we will be near that periodically on the weekend and next week and once in a while beyond that through the month. Too soon to know if there’ll be moisture.
Guidance suggest after the next cold snap temperatures moderate by late next week closer to normal again maybe even above-average by the following weekend. (but as noted I do not trust anything in our region beyond 6 days for specifics).
NAEFS Temp guidance:
CFS Model February average temps:
ANALOG FEBRUARY PRECIPITATION ANOMALY:
FORECAST SURFACE CHART FRIDAY FEB 5:
FORECAST SURFACE CHART SATURDAY FEB 6:
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