US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
312 PM EST Wed Dec 26 2018
 
Valid Saturday December 29 2018 - Wednesday January 02 2019
 
Hazards:
Heavy rain across portions of the Lower Mississippi Valley, the Tennessee Valley, the Mid-Atlantic, 
the Southern Appalachians, the Southeast, and the Southern Plains, Sat-Tue, Dec 29-Jan 1.
Flooding possible across portions of the Central Plains, the Northern Plains, the Southern Plains, 
the Middle Mississippi Valley, the Mid-Atlantic, the Upper Mississippi Valley, and the Great Lakes.
Flooding occurring or imminent across portions of the Southeast and the Mid-Atlantic.
Flooding likely across portions of the Central Plains and the Upper Mississippi Valley.
Much below normal temperatures across portions of the Central Plains, the Central Rockies, the 
Central Great Basin, the Southern Rockies, the Southern Plains, and the Southwest, Sat-Wed, Dec 
29-Jan 2.
Much below normal temperatures across portions of the Central Plains, the Great Lakes, the Upper 
Mississippi Valley, and the Northern Plains, Sat, Dec 29.
 and Tue-Wed, Jan 1-Jan 2.
Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Sun-Tue, Dec 
30-Jan 1.
High winds across portions of mainland Alaska and the Aleutians, Sat, Dec 29.
High winds across portions of mainland Alaska, Sun-Mon, Dec 30-Dec 31.
High significant wave heights for coastal portions of mainland Alaska and the Aleutians, Sat, Dec 
29.
 
Detailed Summary:

A lingering cold front across the Gulf of Mexico and Southeast will accompany a wave of low 
pressure or two starting Dec. 29th. As a surface low tracks across the northern Great Lakes on 
Monday and Tuesday, more moisture could spread across the Southeast. This will lead to an extended 
period of light-to-moderate rain from the central Gulf Coast to the southern Appalacians. The exact 
location of the heaviest rain amounts will be dependent on the position of the front in the Gulf. 
Precipitation could fall as snow along the northern fringe given the suffiently cold air.  

High pressure will settle in across the Rockies and Plains behind the ongoing winter storm, this 
will lead to temperatures much below average on Dec. 29th. Fresh snow cover will help enforce 
temperatures 10-20F below normal. A low pressure system will then track across the Pacific 
Northwest and Northern Plains by Dec. 31st, bringing light snowfall. This system will be 
responsible for another shot of arctic air. Temperatures will once again drop well below normal 
across portions of the Northern Plains and Upper Mississippi Valley on Jan. 1st and 2nd. High 
temperatures could struggle to reach above 0 across northern Minnesota and parts of the eastern 
Dakotas.

In Alaska, a deep surface cyclone is forecast to move north of the Aleutians on the 31st and 
towards the Gulf by the 2nd. This may result in significant waves (>20 ft) or high winds (>50 
knots) across portions of the Aleutians and possibly into parts of the western Panhandle. High 
winds and heavy preciptation will possibly affect the Alaska Panhandle into southern mainland 
Alaska.

Snell