US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
308 PM EST Thu Nov 25 2021
 
Valid Sunday November 28 2021 - Thursday December 02 2021
 
Hazards:
- Heavy rain across portions of the Pacific Northwest and the Northern Great Basin, Sun, Nov 28 and 
Tue, Nov 30.
- Flooding possible across portions of the Pacific Northwest.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Nov 
30-Dec 1.
- Heavy precipitation across portions of mainland Alaska, Mon, Nov 29.
- Much below normal temperatures across portions of mainland Alaska, Sun-Wed, Nov 28-Dec 02.
 
Detailed Summary:

On Sunday, a weak plume of moisture will stream into parts of the Pacific Northwest.  The moisture 
will trigger heavy rain across portions of the Olympic Peninsula and the Northern Cascades.  The 
moisture plume ends overnight Sunday.  However, another plume of moisture will stream into the 
Northwest, producing another area of heavy rain over the Olympic Peninsula and the Northern 
Cascades on Tuesday. 

Meanwhile, an area of low pressure and associated front over the Lower Great Lakes will move off 
the Northeast Coast by Monday.  The associated pressure gradient will produce some gusty wind over 
Lake Michigan on Sunday but will be lower than any criteria for high wind hazard but will produce 
unpleasant conditions for any shipping left on the lake.  Moreover, a warm front over the Northern 
Plains will move eastward into Canada by Monday. Another warm front will develop over the Northern 
Plains on Wednesday, likewise, moving into Canada by Thursday. These fronts and associated 
upper-level ridging will allow temperatures to become above average over the area west of the 
Mississippi Valley.  Nevertheless, above normal, warm temperatures in the cold season are not 
considered a hazard.

Most of the hazards will be over Alaska.  A deep upper-level low will be over the Alaskan mainland, 
along with high pressure at the surface, keeping temperatures much below normal over parts of the 
Southwestern mainland and parts of the Interior Mainland on Sunday through Thursday.

Meanwhile, on Sunday, low pressure just south of the Aleutians will move eastward into the Gulf of 
Alaska by Tuesday.  Moisture from the Pacific will stream into Kodiak Island and adjacent parts of 
the mainland to produce an area of heavy precipitation on Monday.  As the low moves into the Gulf 
of Alaska Coast, the moisture will stream into the Alaska Panhandle on Tuesday and Wednesday, 
producing an area of heavy precipitation. 

Ziegenfelder