US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
300 PM EST Fri Dec 28 2018
 
Valid Monday December 31 2018 - Friday January 04 2019
 
Hazards:
Heavy precipitation across portions of the Pacific Northwest and the Northern Great Basin, Wed-Fri, 
Jan 2-Jan 4.
Heavy rain across portions of the Southeast, the Mid-Atlantic, the Lower Mississippi Valley, the 
Southern Appalachians, and the Tennessee Valley, Mon-Thu, Dec 31-Jan 3.
Heavy rain across portions of the Great Lakes, the Central Appalachians, and the Ohio Valley, Mon, 
Dec 31.
Heavy rain across portions of the Northeast, Mon-Tue, Dec 31-Jan 1.
Heavy snow across portions of the Northeast and the Great Lakes, Mon-Tue, Dec 31-Jan 1.
Flooding possible across portions of the Lower Mississippi Valley, the Central Appalachians, the 
Tennessee Valley, the Great Lakes, the Middle Mississippi Valley, the Mid-Atlantic, the Southern 
Appalachians, the Upper Mississippi Valley, the Southeast, and the Southern Plains.
Flooding occurring or imminent across portions of the Southeast, the Mid-Atlantic, the Lower 
Mississippi Valley, and the Southern Plains.
Flooding likely across portions of the Central Plains, the Southeast, 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, Mon-Thu, Dec 
31-Jan 3.
Much below normal temperatures across portions of the Central Plains, the Great Lakes, the Upper 
Mississippi Valley, and the Northern Plains, Tue-Wed, Jan 1-Jan 2.
Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Jan 1-Jan 
2.
High significant wave heights for coastal portions of mainland Alaska and the Aleutians, Mon, Dec 
31.
 
Detailed Summary:

As a surface low tracks across the northern Great Lakes on Monday and Tuesday, more moisture and 
another wave of low pressure is expected to spread across the Southeast and Ohio Valley. This will 
lead to an extended period of widespread rain, heavy at times, from the central Gulf Coast to the 
southern Mid-Atlantic from Mon, Dec 31 to Thurs, Jan 3. Another area of heavy rain will be possible 
along the surface low from the Ohio Valley into the Northeast on Dec 31. The exact location of the 
heaviest rain amounts will be dependent on the position of the frontal boundary and surface low 
track. Heavy snow will be possible along the northern edge of the precipitation shield, including 
the Great Lakes and northern New England.

A low pressure system will also track across the Pacific Northwest and northern Plains by December 
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 January 1st and 2nd. High temperatures could struggle to reach above 
zero across northern Minnesota and parts of the eastern Dakotas. The Southern Rockies will also see 
temperatures much below normal, thanks to a persistent upper trough and fresh snow cover. Another 
round of active weather will affect the Northwest by Wed, Jan 2 and be responsible for heavy 
mountain snow across the Cascades, with heavy rain in the lower elevations.

For Alaska, a deep surface cyclone is forecast to move north of the Aleutians on the 31st and 
towards the Gulf of Alaska by the 2nd. This may result in significant waves (>20 ft) across 
portions of the Aleutians and possibly into parts of the western Panhandle. Heavy precipitaion will 
be possible with the approaching low pressure across the Alaska Panhandle.

Snell