***Bitter cold across much of the nation and more to come...southern Mid-Atlantic snowstorm later today/tonight...northern stream system brings some snow on Thursday to DC-to-Philly-to-NYC corridor***
Paul Dorian
Overview
The average temperature across the nation this morning (8AM ET) was 15.4 degrees (F) which is well below-normal for this time of year. Map courtesy NOAA, weathermodels.com
Arctic air covers much of the nation today with a particularly tight grip on the central states where numerous daily low temperature records have been set all the way from the Dakotas to the Rio Grande Valley region of southern Texas. The average temperature across the continental US earlier today was 15.4°F which is well below normal for this time of year and only the state of Florida could boast about warm weather conditions.
In addition to the widespread cold, accumulating snow fell yesterday across portions of the Middle Mississippi Valley and significant snow today will spread from the Tennessee Valley to the southern Mid-Atlantic region. The DC metro area will be on the northern edge of today’s “southern stream” system and can receive a coating to an inch or so; especially, across the southern suburbs. On Thursday, a “northern stream” wave in the upper atmosphere will pass right over the Mid-Atlantic region and likely result in some snow or snow shower activity in the DC-to-Philly-to-NYC corridor. The week ends with yet another very cold and windy day on Friday in the Mid-Atlantic region with well below normal temperatures and even lower wind chill values.
Numerous daily low temperature records were challenged or broken this morning across the central states all the way from the Dakotas to Texas as bitter cold Arctic air continues to maintain its grip on much of the nation. Map courtesy coolwx.com, NOAA
Details
When you are breaking daily low temperature records in places like Glasgow, Montana (-29°F) and Minot, North Dakota (-29°F) then you are very likely dealing with an extremely cold air mass and indeed, that is the case again today across the central states from the Dakotas to Texas. In many of these central US locations, the prior daily low temperature records have stood for many decades and it is no picnic either across the eastern US where, for example, low-to-middle teens were reached this morning in many of the suburbs along the Mid-Atlantic’s I-95 corridor. The Arctic chill will not go away too quickly across the northeastern part of the nation as a reinforcing blast of cold air will push into the Great Lakes, Mid-Atlantic and Northeast US on Friday on the backside of intensifying low pressure over the western Atlantic.
Two sets of “weather warnings” of interest today as issued by NOAA…Extreme Cold” warnings across much of the central US (dark blue) and “Winter Storm” warnings across the Tennessee Valley and southern Mid-Atlantic (pink). Map courtesy NOAA/WPC
The aforementioned low pressure system is organizing today over the northern Gulf region and will slide in an east-to-northeast direction reaching the waters off the Carolina coastline by early tomorrow. Later tomorrow, the low pressure system will continue on an east-northeast path and intensify rapidly as it pushes farther out into the western Atlantic Ocean. The rapid intensification will take place later tomorrow when there is a “phasing together” of an upper-atmosphere wave of energy in the northern stream with southern stream energy.
The wave of energy in the southern stream will produce significant snowfall later today and early tonight from the Tennessee Valley to the southern Mid-Atlantic region. The threat zone in the southern Mid-Atlantic includes eastern North Carolina (where ice will be part of the equation), southeastern Virginia, and the southern half of the Delmarva Peninsula. In some spots such as Norfolk or Virginia Beach in southeastern Virginia, as much as 10 inches of snow can accumulate and half a foot of snow is possible in Richmond. The DC metro area will be skirted by today’s southern stream system with some snow or snow shower activity that can leave a coating to an inch or so; especially, across the southern suburbs…watch for slippery spots.
While the surface low pressure system will be well off the east coast on Thursday, a wave of energy in the northern stream will pass directly overhead of the Mid-Atlantic region. This is likely to result in some snow or snow shower activity on Thursday across the DC-to-Philly-to-NYC corridor. Map courtesy NOAA, tropicaltidbits.com
On Thursday, as the surface low pressure intensifies out over the western Atlantic, the northern stream wave in the upper atmosphere will pass directly over the Mid-Atlantic region and this will enhance upward motion and produce quite unstable conditions. As a result, there is likely to be some snow or snow shower activity on Thursday in the DC-to-Philly-to-NYC corridor and small accumulations of a coating to an inch or so are possible…watch for slippery spots. On the backside of the departing low pressure, another very cold and windy day is in store for the Mid-Atlantic region with well below-normal temperatures and even lower wind chill values.
While temperatures are likely to moderate across much of the nation during the first half of next week, there are indications of another widespread cold air outbreak by late next week for the Great Lakes, Mid-Atlantic and Northeast US. The tropospheric polar vortex will become re-positioned over the Hudson Bay region of Canada later next week and this is a favorable location for the transport of cold air masses from northern Canada into the central and eastern US. Map courtesy ECMWF, Weather Bell Analytics
Looking ahead, there are signs that additional Arctic air outbreaks may be destined to reach the central and eastern states. The tropospheric polar vortex is likely to drop into the Hudson Bay region of Canada by late next week and its associated deep upper-level trough may extend all the way from Canada to the southeastern US. This kind of upper air pattern would be quite favorable for the influx of cold air masses from northern Canada into the central and eastern US as we close out the month of February and begin the new month of March...looking like Punxsutawney Phil may have been right.
The overall pattern looks quite cold going into early March across the central and eastern US with deep upper-level trough of low pressure extending from the Hudson Bay region of Canada to the Southeast US. Map courtesy ECMWF, weathermodels.com
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
Follow us on Facebook, Twitter, YouTube
Video discussion: