US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
337 PM EST Thu Nov 26 2020
 
Valid Sunday November 29 2020 - Thursday December 03 2020
 
Hazards:
- Heavy precipitation across portions of the Tennessee Valley, the Ohio Valley, the Great Lakes, 
the Southern/Central Appalachians, the Southeast, the Mid-Atlantic, and the Northeast, Mon-Tue, Nov 
30-Dec 1.
- Heavy rain across portions of the Southern Plains, the Lower Mississippi Valley, and the 
Southeast, Wed-Thu, Dec 2-Dec 3.
- Heavy rain across portions of the Lower Mississippi Valley, the Tennessee Valley, the Ohio 
Valley, the Southern Appalachians, the Southeast, and the Mid-Atlantic, Sun, Nov 29.
- Heavy rain across portions of the Southern/Central Appalachians, the Mid-Atlantic, and the 
Northeast, Mon, Nov 30.
- Heavy rain across portions of the Northeast, Tue, Dec 1.
- Heavy snow across portions of the Great Lakes and the Ohio Valley, Mon-Tue, Nov 30-Dec 1.
- Flooding occurring or imminent across portions of the Southeast.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sun-Wed, Nov 
29-Dec 2.
- High winds across portions of mainland Alaska and the Aleutians, Sun-Mon, Nov 29-Nov 30.
- High winds across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Nov 30-Dec 1.
 
Detailed Summary:

The eastern U.S. can expect hazardous weather through the first half of next week. A surface low 
pressure system is forecast to develop over Louisiana Sunday, strengthening as it lifts 
northeastward Monday ahead of combining upper-level lows. This phased, deep upper low should then 
move slowly northward across the Ohio Valley and Great Lakes region through midweek along with its 
surface low. This weather pattern will lead to the possibility of heavy rain and thunderstorms 
across the Lower Mississippi/Tennessee Valleys toward the Southeast on Sunday, transitioning 
northward across the Mid-Atlantic and Northeast on Monday into Tuesday. The precipitation type 
across the Eastern Seaboard should stay rain given warm temperatures ahead of the cold front, and 
gusty winds are possible there especially Monday. Any enhanced rain amounts could cause 
flooding/flash flooding issues, and the potential for strong to severe thunderstorms will continue 
to be monitored as well. Farther west on the backside of the low, precipitation is likely to 
transition to snow for portions of the Great Lakes, Ohio Valley, and higher elevations of the 
Appalachians Monday and Tuesday, with snow potentially lingering in the Great Lakes on Wednesday. 
Uncertainty remains regarding placement and amounts of snow as it wraps around the low, but those 
are the areas to watch for now. Gusty winds are also possible for the Upper Great Lakes underneath 
the upper low.

Another upper-level trough/low is forecast to drop southward across the Rockies and Four Corners 
region Tuesday-Thursday, and ahead of this system another round of rain is possible for western and 
central portions of the Gulf Coast from midweek forward. Temperatures are not expected to be 
hazardous through the period, though it will be cooler than normal across the southern tier of the 
U.S., particularly for the Mississippi/Tennessee/Ohio Valleys and Southeast. Periods of above 
average temperatures are forecast for portions of the northern tier. No drought relief is expected 
for the West, with only a quick round of modest precipitation likely in the Pacific Northwest early 
in the week.

Alaska is also likely to see an active medium range period. An initial surface low near the Gulf of 
Alaska coast on Sunday could cause periods of generally moderate precipitation from Southcentral 
Alaska into the Panhandle Sunday into Monday. Additionally, a quite deep surface low is forecast to 
track south of the Aleutians (causing high winds there) Sunday and Monday, moving into Southcentral 
Tuesday and Wednesday. A deep plume of Pacific moisture (atmospheric river) is likely to take aim 
at the Southcentral coast and Panhandle ahead of the cold front associated with the low, causing 
heavy precipitation totals over those areas especially Tuesday and lingering Wednesday. Strong 
winds are also a threat, and some notably high wave heights are possible in the Gulf as well. 
Temperatures are expected to warm throughout next week, with the exception of the Alaska peninsula 
and the far southwestern mainland.

Tate