US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
321 PM EST Fri Nov 22 2019
 
Valid Monday November 25 2019 - Friday November 29 2019
 
Hazards:
- Heavy precipitation across portions of the Central Great Basin, California, and the Southwest, 
Wed-Fri, Nov 27-Nov 29.
- Heavy precipitation across portions of the Great Lakes and the Upper Mississippi Valley, Tue-Wed, 
Nov 26-Nov 27.
- Heavy rain across portions of California and the Southwest, Wed-Fri, Nov 27-Nov 29.
- Heavy snow across portions of the Central Great Basin, California, and the Southwest, Tue-Fri, 
Nov 26-Nov 29.
- Heavy snow across portions of the Southern Rockies, the Central Rockies, the Central Great Basin, 
and the Southwest, Wed-Fri, Nov 27-Nov 29.
- Flooding occurring or imminent across portions of the Northern Plains.
- Much below normal temperatures across portions of the Northern/Central Great Basin, the Northern 
Rockies, California, and the Pacific Northwest, Thu-Fri, Nov 28-Nov 29.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Wed-Fri, Nov 
27-Nov 29.
- Heavy precipitation across portions of mainland Alaska, Tue-Thu, Nov 26-Nov 28.
- Heavy snow across portions of mainland Alaska, Tue-Thu, Nov 26-Nov 28.
- High winds across portions of mainland Alaska, Tue-Wed, Nov 26-Nov 27.
- High significant wave heights for coastal portions of mainland Alaska, Tue-Wed, Nov 26-Nov 27.
 
Detailed Summary:

In the central U.S., model guidance is indicating the potential for a surface low pressure system 
to spin up Monday in the Central High Plains, tracking northeastward quickly on Tuesday across the 
Upper Midwest. Precipitation is possible along this low track, with the potential for snow on the 
backside of the low. Currently it appears the best chance for snow is across the Rockies to Central 
Plains Monday into Tuesday, moving quickly into the Middle/Upper Mississippi Valley Tuesday and 
into the Upper Great Lakes region on Wednesday. The exact track of the low as well as the rain/snow 
line are certainly still in question, but a heavy precipitation hazard area is in place for 
portions of Wisconsin and Michigan. As the low moves eastward Wednesday, precipitation could spread 
into the Northeast Wednesday into Thursday, generally as rain nearer the coast and as snow for 
interior New England. Farther south, the surface low should sweep a cold front across the Lower 
Mississippi to Tennessee and Ohio Valleys, so there is potential for some rainfall on Tuesday there.

However, the larger-scale system of concern in the medium range is a deep upper-level trough/low 
that is currently expected to strengthen Wednesday along the West Coast and move slowly eastward 
through Friday. This will lead to below normal temperatures Thursday and Friday due to the lowering 
heights across the West, with parts of the Northwest experiencing minimum temperatures in the 
single digits and teens. The system should also provide strong lift for precipitation in much of 
the West, with higher elevations like the Sierra Nevada generally receiving heavy snow and lower 
elevations like Southern California receiving heavy rain. This precipitation is forecast to last 
through the later half of the week.

In Alaska, a strong surface low moving up the Bering Strait could cause strong winds and the 
potential for significant waves/localized coastal flooding across the Alaskan West Coast--the 
Seward peninsula and into northwestern Alaska. Additionally, heavy precipitation is expected to 
spread eastward from this region into the mainland midweek, with the potential for another low to 
cause heavy precipitation in the Panhandle. Upstream of the aforementioned troughing along the 
CONUS West Coast, upper-level ridging will build into Alaska, leading to much above normal 
temperatures for the Alaska mainland. However, temperatures are currently forecast to remain below 
freezing for the northern half of the state.


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