US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
318 PM EST Wed Jan 16 2019
 
Valid Saturday January 19 2019 - Wednesday January 23 2019
 
Hazards:
Heavy precipitation across portions of California, the Pacific Northwest, and the Northern Great 
Basin, Sat-Sun, Jan 19-Jan 20.
Heavy rain across portions of the Mid-Atlantic, the Lower Mississippi Valley, the Central 
Appalachians, the Tennessee Valley, the Middle Mississippi Valley, the Northeast, the Southern 
Appalachians, the Southeast, and the Ohio Valley, Sat-Sun, Jan 19-Jan 20.
Heavy rain across portions of the Southeast, the Mid-Atlantic, the Lower Mississippi Valley, the 
Southern Appalachians, and the Tennessee Valley, Tue-Wed, Jan 22-Jan 23.
Heavy snow across portions of the Northern Rockies and the Northern Great Basin, Sun, Jan 20.
Heavy snow across portions of the Central Plains, the Mid-Atlantic, the Lower Mississippi Valley, 
the Central Appalachians, the Great Lakes, the Middle Mississippi Valley, the Northeast, the Upper 
Mississippi Valley, the Southern Plains, and the Ohio Valley, Sat-Sun, Jan 19-Jan 20.
Flooding occurring or imminent across portions of the Southeast, the Lower Mississippi Valley, and 
the Southern Plains.
Flooding likely across portions of the Southeast.
High winds across portions of the Central Plains, the Middle Mississippi Valley, the Lower 
Mississippi Valley, and the Southern Plains, Sat, Jan 19.
High winds across portions of the Central Rockies, the Central Plains, the Northern Plains, and the 
Northern Rockies, Tue-Wed, Jan 22-Jan 23.
High winds across portions of the Mid-Atlantic and the Northeast, Sun-Mon, Jan 20-Jan 21.
Much below normal temperatures across portions of the Southeast, the Lower Mississippi Valley, and 
the Southern Plains, Sun-Mon, Jan 20-Jan 21.
Much below normal temperatures across portions of the Central Plains, the Middle Mississippi 
Valley, the Great Lakes, the Upper Mississippi Valley, and the Northern Plains, Sat-Sun, Jan 19-Jan 
20.
Much below normal temperatures across portions of the Northeast, the Central Appalachians, the 
Middle Mississippi Valley, the Mid-Atlantic, the Upper Mississippi Valley, the Great Lakes, and the 
Ohio Valley, Mon-Tue, Jan 21-Jan 22.
High significant wave heights for coastal portions of the Pacific Northwest, Sat, Jan 19.
Heavy precipitation across portions of the Alaska Panhandle, Tue, Jan 22.
 
Detailed Summary:

A series of systems entering the Pacific Northwest the 19th-20th should bring another round of 
coastal/lower elevation rain and mountain snows to the Pacific Northwest though amounts should't be 
nearly as intense as the last round. A brief period of significant waves may also be possible along 
parts of the Washington and Oregon coasts. Farther inland, expect heavy snow in parts of the 
northern Rockies (Idaho) and high winds across the high plains/front range towards the end of the 
period as the pressure gradient intensifies between strong high pressure in the central U.S. and 
lower pressure over the mountain West.

Winter storm likely to develop by end of the short range period and continuing into the medium 
range period from the Midwest to the Northeast. There remains a multi-model signal for a swath of 
heavy snowfall from the Midwest to parts of the Northeast, with heavy rainfall across the lower 
Ohio Valley, the Mid-Atlantic, and the South. Somewhere in between, some models continue to 
indicate a transition zone which may include some mixed precipitation or ice. There continues to be 
plenty of uncertainty on the details of where the heaviest snow and/or ice will occur so 
refinements to these areas are likely as the event gets closer in time. At this time, the best 
chance for accumulating snows exists across the Ohio Valley into New England. High Winds are 
possible early in the period (1/19) across the Southern Plains as the surface low materializes and 
strengthens, as well as along the Mid-Atlantic and Northeast Coast Sunday and Monday as the surface 
low deepens further and moves away from the Coast.

Backside of this system will usher in a very cold air mass with much below normal temperatures 
(anomalies on the order of -12 to -20) across the northern and central Plains Saturday to Sunday, 
moving into the Ohio Valley and the Northeast by early next week. Gusty winds associated with the 
deep surface low combined with cold temperatures may also result in dangerous wind chills for some 
locations. Much below normal temperatures may also reach down towards the Gulf Coast states (from 
Texas to Florida) as well resulting in the possible first freeze for some locations.

In Alaska, heavy precipitation possible along the Panhandle Tuesday as systems move through the 
Gulf. High coastal wind and high waves possible as well, but may not reach criteria to include a 
hazard on the chart. In the Aleutians, a system or two moves through with more possibilities of 
significant waves and/or winds.

Another round of heavy rainfall is possible for parts of the lower Mississippi Valley into the 
Southeast as another surface lows spins up in the lee of the Rockies by middle of next week and 
progresses across the Southern Plains. Still significant uncertainty in the details and timing of 
the system, but an area of heavy rainfall seems possible to likely ahead of the attendance cold 
front. Its possible wintry weather develops along the northern edge of the precipitation shield in 
the central Plains/Midwest but uncertainty on amounts and significance are too high to add a hazard 
to the chart at this time.

Santorelli