US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
235 PM EST Wed Dec 30 2020
 
Valid Saturday January 02 2021 - Wednesday January 06 2021
 
Hazards:
- Heavy precipitation across portions of California, the Central Great Basin, the Pacific 
Northwest, and the Northern Great Basin, Sat-Wed, Jan 2-Jan 6.
- Heavy precipitation across portions of the Central Great Basin, California, and the Southwest, 
Wed, Jan 6.
- Heavy rain across portions of California, Wed, Jan 6.
- Heavy rain across portions of the Southeast and the Mid-Atlantic, Sat, Jan 2.
- Heavy snow across portions of the Northern Rockies and the Northern Great Basin, Sat-Sun, Jan 
2-Jan 3.
- Heavy snow across portions of the Northern Great Basin, Sun-Tue, Jan 3-Jan 5.
- Heavy snow across portions of the Northeast, Sat, Jan 2.
- Flooding possible across portions of the Middle Mississippi Valley, the Lower Mississippi Valley, 
the Southern Plains, and the Ohio Valley.
- High winds across portions of the Central Plains, the Northern Plains, and the Northern Rockies, 
Sun, Jan 3.
- Much below normal temperatures across portions of the Southern Plains, Sat, Jan 2.
- High significant wave heights for coastal portions of California and the Pacific Northwest, 
Tue-Wed, Jan 5-Jan 6.
- High significant wave heights for coastal portions of the Pacific Northwest, Sat-Sun, Jan 2-Jan 3 
and Tue-Wed, Jan 5-Jan 6.
- Heavy precipitation across portions of the Alaska Panhandle, Sat-Sun, Jan 2-Jan 3.
 
Detailed Summary:

The medium range period (Saturday, January 2nd to Wednesday, January 6th) will be fairly active 
across both the western and eastern United States. Starting in the East, a slow-moving cold front 
will reach the Southeast by Saturday and bring a surge of moisture from the Gulf of Mexico. Heavy 
rain will be possible from the Florida Panhandle to eastern North Carolina. Meanwhile farther 
north, an area of low pressure is forecast to swing across New England on Saturday and potentially 
bring heavy snow to parts of northern New England. Another round of wintry precipitation is 
possible across the Northeast and New England between Sunday and Monday as a separate area of low 
pressure develops along the aforementioned cold front and moves northeast. However, this portion of 
the forecast remains highly uncertain. Confidence is increasing on the system passing close enough 
to the Northeast to bring winter weather impacts, but ultimately a heavy snow and/or heavy 
precipitation area was not added to the hazards chart today due to uncertainty with the magnitude 
of precipitation forecast to fall across the region. 

Across the western U.S., multiple storm systems will make for an unsettled start to 2021. Large 
scale upper-level troughing will be responsible for the extended period of active weather and high 
elevation snow, with several smaller scale systems bringing locally hazardous weather. Several 
inches of rain are forecast along coastal sections of the Northwest and northern California, with 
potentially feet of snow falling across the Sierra and Cascade mountains between Saturday and 
Wednesday. Significant waves could lead to coastal hazards across the Northwest during this time 
period as well. Heavy snow is also forecast to enter the northern Rockies of Idaho and Montana 
through early next week. As energy ejects into the northern Plains by Sunday, high winds with gusts 
over 50 mph could reach the surface across the northern High Plains. By Wednesday, there is 
potential for a potent Pacific storm system to drop far enough south to bring heavy rain along the 
central California coast, as well as heavy precipitation along the central and southern Sierra 
Nevada. 

Much of the United States should see temperatures near or above average to start off the month of 
January. There will be one exception however, southwest Texas. Temperatures on Saturday across this 
area will be 10 to 20 degrees below average. Low temperatures could dip into the single digits 
thanks to fresh snow cover from a snowstorm currently occurring.

Weather across Alaska will remain fairly quiet as a powerful hurricane-force storm over the 
Aleutians weakens by Saturday. Heavy precipitation (rain along the coast/lower elevations and snow 
inland/higher elevations) will remain a concern across the Panhandle Saturday and Sunday. 
Otherwise, much of the central and western portions of the state will experience below average 
temperatures.

Snell