US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
337 PM EST Fri Feb 05 2021
 
Valid Monday February 08 2021 - Friday February 12 2021
 
Hazards:
- Heavy precipitation across portions of the Lower Mississippi Valley, the Tennessee Valley, the 
Ohio Valley, the Southern/Central Appalachians, the Southeast, and the Mid-Atlantic, Thu-Fri, Feb 
11-Feb 12.
- Heavy rain across portions of the Southern Plains, the Lower Mississippi Valley, the Tennessee 
Valley, the Southern Appalachians, the Southeast, and the Mid-Atlantic, Thu-Fri, Feb 11-Feb 12.
- Heavy snow across portions of the Middle/Upper Mississippi Valley, the Great Lakes, and the Ohio 
Valley, Mon, Feb 8.
- Heavy snow across portions of the Northeast and the Great Lakes, Tue, Feb 9.
- Much below normal temperatures across portions of the Northern Rockies, the Northern/Central 
Plains, the Upper/Middle Mississippi Valley, the Great Lakes, and the Ohio Valley, Mon-Fri, Feb 
8-Feb 12.
- Much below normal temperatures across portions of the Central/Southern Plains, the Middle/Lower 
Mississippi Valley, the Great Lakes, and the Ohio Valley, Wed-Fri, Feb 10-Feb 12.
- Much below normal temperatures across portions of the Southwest, the Southern Rockies, the 
Central/Southern Plains, the Middle/Lower Mississippi Valley, the Tennessee Valley, the Ohio 
Valley, the Great Lakes, the Central/Southern Appalachians, the Mid-Atlantic, and the Northeast, 
Fri, Feb 12.
- Much below normal temperatures across portions of mainland Alaska, Mon-Thu, Feb 8-Feb 11.
- Much below normal temperatures across portions of mainland Alaska, Mon-Tue, Feb 8-Feb 9.
 
Detailed Summary:

The medium range period (Monday, February 8th to Friday, February 12th) will be characterized by a 
persistent Arctic surface high across the Northern/Central Plains. In the upper levels, broad 
troughing should extend across much of the CONUS as a deep upper low meanders around northern 
Ontario. This pattern will lead to bitterly cold air over the north-central U.S. for the entire 
period, while expanding south and east with time until it reaches the Southern Plains to the Lower 
Great Lakes region by Friday. Low temperatures that are 15 to 30 degrees below average will be 
widespread, and current forecasts show temperatures of 40 degrees below average are possible in 
parts of Montana in particular around Tuesday. Some locations in the far Northern Plains could stay 
below 0F even for high temperatures for multiple days in a row. Overall, the first major intrusion 
of Arctic air into the CONUS will cause persistent, dangerous cold. Lake effect snow can also be 
expected in this pattern given mostly unfrozen Great Lakes.

Along the southern and eastern edge of the Arctic high, periods of precipitation are possible 
through the period as at least some moisture overruns frontal systems, and in association with 
upper-level energy moving through the main trough. First, some snow is possible in portions of the 
Midwest to the Upper Great Lakes region on Monday. While this snow does not look to be extremely 
heavy, the current forecast shows that the Chicago area could see impactful snow. From there, snow 
is expected to spread into the Interior Northeast on Tuesday, which could be heavy in upstate New 
York (as lake enhancement and upslope flow over the Adirondacks combine) and eastward into parts of 
New England. Then there is quite a bit of uncertainty with other systems that could traverse south 
of the high pressure system. Current forecasts seem to show there is potential for heavy 
precipitation in the southeastern quadrant of the CONUS north of the front in the Gulf of Mexico 
for the latter half of the workweek. On the northern side, given the cold air in place, this could 
be in the form of impactful snow or ice. The pattern is in place for icy conditions somewhere, but 
locations are highly uncertain at this time.

Over Alaska, an upper-level low is still expected to pinch off over the mainland and cause much 
below average temperatures starting Monday of next week. Bitterly cold temperatures are forecast to 
reach into the -40s for parts of the North Slope and the Yukon Flats of eastern Alaska, while below 
average temperatures by 20-30 degrees are likely for much of the mainland. Temperatures may become 
less anomalous in the Brooks Range and North Slope by midweek and across the state by the end of 
the week, as upper-level ridging serves to weaken the upper low, and as the Arctic surface high 
retreats. Relatively weak surface low pressure systems over the Gulf of Alaska could lead to snow 
across coastal portions of the south-central mainland and eastward into the Panhandle at periods 
during the workweek, but model disagreements remain in terms of precipitation amounts and timing, 
and at this point look to remain below hazards thresholds.


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