US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
340 PM EST Wed Nov 18 2020
 
Valid Saturday November 21 2020 - Wednesday November 25 2020
 
Hazards:
- Heavy rain across portions of the Pacific Northwest and the Northern Great Basin, Mon-Wed, Nov 
23-Nov 25.
- Heavy rain across portions of the Central/Southern Plains, the Lower/Middle Mississippi Valley, 
the Great Lakes, and the Ohio Valley, Sat-Sun, Nov 21-Nov 22.
- Heavy rain across portions of the Middle/Lower Mississippi Valley, the Southern Plains, and the 
Ohio/Tennessee Valleys, Tue-Wed, Nov 24-Nov 25.
- Heavy snow across portions of the Pacific Northwest and the Northern Great Basin, Tue-Wed, Nov 
24-Nov 25.
- Flooding occurring or imminent across portions of the Southeast and the Mid-Atlantic.
- Heavy precipitation across portions of mainland Alaska, Sat, Nov 21.
- High winds across portions of mainland Alaska, Sat, Nov 21.
 
Detailed Summary:

A series of upper-level disturbances will be the impetus for hazardous weather over the CONUS 
during the medium range period (Saturday, November 21st - Wednesday, November 25th). The first wave 
of low pressure will arrive over the Pacific Northwest on Friday. As this shortwave propagates 
east, it will organize an area of surface low pressure along the lee of the Rockies which will 
later be the focus for heavy rain over the Mid-South into the Midwest on Saturday and Sunday. Light 
snowfall may mix in some places within the cold sector of this system. Temperatures are likely to 
remain above average for much of the eastern U.S. throughout the medium range.

Another disturbance is forecast to impact the Pacific Northwest on Monday. This system may produce 
some heavy rainfall for the region before deepening over the Rockies and generating heavy rainfall 
over the Middle to Lower Mississippi Valley and Tennessee Valley on Tuesday and Wednesday. A 
stronger closed upper-level low arrives along the Northwest coast on Tuesday. This potent system is 
forecast to produce heavier rainfall from the Panhandle of Alaska down to the Pacific Northwest on 
Tuesday and Wednesday. Heavy snow is also expected for Northern Cascades during this time period.

In Alaska, an upper-level low will spin up over the Aleutians on Friday. This will develop a low 
pressure system that will generate high winds for the islands and mainland on Saturday. Heavy 
precipitation will also be a threat over the southwestern mainland on Saturday as the surface low 
moves toward the Gulf of Alaska. This area of low pressure may produce heavy precipitation and high 
winds for portions of the Panhandle of Alaska heading into midweek.

Kebede