US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
407 PM EST Tue Nov 23 2021
 
Valid Friday November 26 2021 - Tuesday November 30 2021
 
Hazards:
- Heavy precipitation across portions of the Pacific Northwest, Sat, Nov 27 and Tue, Nov30.
- Heavy rain across portions of the Pacific Northwest, Sat, Nov 27 and Tue, Nov30.
- Flooding possible across portions of the Pacific Northwest.
- Much below normal temperatures across portions of the Middle Mississippi Valley, the Lower 
Mississippi Valley, the Ohio Valley, and the Tennessee Valley, Fri, Nov 26.
- Much below normal temperatures across portions of the Southeast, the Southern Appalachians, and 
the Tennessee Valley, Sat, Nov 27.
- Heavy precipitation across portions of mainland Alaska, Mon, Nov 29.
- Heavy precipitation across portions of the Alaska Panhandle, Tue, Nov 30.
- Much below normal temperatures across portions of mainland Alaska, Fri-Mon, Nov 26-Nov 29.
 
Detailed Summary:

Frigid temperatures and heavy precipitation will be the main weather hazards across the country 
during the medium range period (Friday, November 26th - Tuesday, November 30th). The low pressure 
system responsible for heavy rain in southeastern Texas on Thanksgiving will go on to produce some 
snowfall over the Northern Appalachians, particularly the Adirondacks and northern Vermont/New 
Hampshire on Friday. Cooler air settles over the Middle Mississippi and Tennessee Valleys on the 
backside of the cold front impacting the Northeast. Night time temperatures will drop into the low 
30s and upper 20s across the region, which will be a 15-20 degree departure from normal. This cold 
air mass will move into the East and Gulf coasts by Friday night and Saturday. First freezes of the 
season are likely for portions of the Southeast on Friday night, which may impact sensitive soils 
in the region. A much below normal hazard continues for this area as a result. Significant weather 
threats for the Eastern third of the country will depart with this system on Sunday.

Meanwhile over the Pacific Northwest, an Atmospheric River event and low pressure system will 
produce heavy precipitation over the mountain ranges of Washington State. An eastern Pacific 
shortwave embedded within an approaching upper-level ridge will cause a plume of moisture to stream 
into British Columbia and higher elevations of the Pacific Northwest on Saturday. Warm air in place 
will mean that any precipitation that falls over the Olympic mountains will be in the form of rain, 
however, higher elevations of the northern Cascades may receive several inches of snowfall. Things 
will quiet down for the area on Sunday and Monday before a shortwave trough brings more heavy rain 
to the Olympics and snow to the higher elevations of the northern Cascades on Monday. Warm air 
builds across the West and Central U.S. under upper-level ridging beginning Friday.

High pressure over the western mainland of Alaska will contribute to the persistence of an 
anomalously cold air mass over the region this weekend. A potent low pressure system will arrive in 
the Gulf by Monday, leading to the advection of substantial moisture into much of the Gulf coast, 
from Kodiak down through the Panhandle. Heavy precipitation is expected for the southern Gulf coast 
(Kodiak through higher elevations of Kenai) on Monday before the axis of heaviest precipitation 
shifts into the Panhandle on Tuesday. Latest guidance, particularly EC/CMC, suggest lighter 
precipitation totals on Monday over the southern coast from this system, but the 12z GFS continues 
to push for heavy amounts.

Kebede