US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
247 PM EST Fri Jan 10 2020
 
Valid Monday January 13 2020 - Friday January 17 2020
 
Hazards:
- Heavy precipitation across portions of the Pacific Northwest, Wed-Thu, Jan 15-Jan 16.
- Heavy precipitation across portions of the Northeast and the Great Lakes, Thu-Fri, Jan 16-Jan 17.
- Heavy rain across portions of California and the Pacific Northwest, Wed-Thu, Jan 15-Jan 16.
- Heavy rain across portions of the Southeast, the Mid-Atlantic, the Lower Mississippi Valley, the 
Southern Appalachians, and the Tennessee Valley, Mon-Tue, Jan 13-Jan 14.
- Heavy snow across portions of California, the Central Great Basin, the Pacific Northwest, the 
Northern Great Basin, and the Southwest, Tue-Fri, Jan 14-Jan 17.
- Heavy snow across portions of the Central Rockies, the Central Great Basin, the Northern Rockies, 
the Northern Great Basin, and the Northern Plains, Mon-Tue, Jan 13-Jan 14.
- Flooding possible across portions of the Central Plains, the Lower Mississippi Valley, the 
Southern Plains, the Middle Mississippi Valley, the Northeast, the Great Lakes, and the Ohio Valley.
- Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Pacific 
Northwest, and the Northern Plains.
- Flooding likely across portions of the Great Lakes, the Middle Mississippi Valley, the Lower 
Mississippi Valley, the Southern Plains, and the Ohio Valley.
- Much below normal temperatures across portions of the Northern Rockies and the Northern Great 
Basin, Mon-Wed, Jan 13-Jan 15.
- Much below normal temperatures across portions of the Central Plains, the Upper Mississippi 
Valley, the Northern Plains, and the Northern Rockies, Mon-Fri, Jan 13-Jan 17.
- High significant wave heights for coastal portions of California and the Pacific Northwest, 
Wed-Thu, Jan 15-Jan 16.
- Much below normal temperatures across portions of the Alaska Panhandle and mainland Alaska, 
Mon-Tue, Jan 13-Jan 14.
- Much below normal temperatures across portions of the Alaska Panhandle, Mon-Thu, Jan 13-Jan 16.
 
Detailed Summary:

A stationary front is expected to reside across the Deep South and Gulf Coast region going into the 
beginning of next week and then slowly lift northward as a warm front.  There will likely be an 
enhanced swath of moderate to locally heavy rainfall extending from Mississippi to eastern North 
Carolina through Tuesday.  Additional rainfall going into mid-week also appears likely, but the 
timing and intensity of this rainfall is in question and therefore we are holding off on 
delineating a second heavy rain area at this juncture.

Across the northwestern U.S., two organized storm systems will keep the weather pattern unsettled 
going into next week.  The heaviest rainfall is expected across northwest California and western 
Oregon, where several inches of rain appears likely for the second half of the work week in 
association with the second storm to move inland.  This will equate to heavy snow for the Cascades 
and the Sierra Nevada, and moderate to heavy snow for portions of the central and northern Rockies 
as the surge of moisture progresses inland.

Across Montana and then over the Dakotas, a bitterly cold arctic air mass will gradually be 
settling southward over the region.  Temperatures are expected to average up to 20 to 40 degrees 
below normal across central and northern Montana by Monday. The frigid air mass should spread 
southeastward to the Dakotas by Tuesday and into Wednesday.  There are differences in the model 
guidance on the eastward extent of the arctic airmass, and therefore additional revisions to the 
much below normal temperature areas will likely be warranted in future updates. Subzero high 
temperatures are currently expected across northern Montana and into North Dakota, and lows 
dropping into the minus 20s.  Some of this arctic air will likely cross the continental divide and 
reach much of interior Washington and northern Idaho for the beginning of the week.

Across Alaska, much below normal temperatures are forecast to continue across southeast portions of 
the mainland Interior through Tuesday then moderate by the middle of next week. Much of the 
Panhandle region should also experience colder than average temperatures through much of the week 
as the arctic air spills over the Canadian Rockies and is slower to erode.

Hamrick