US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
242 PM EST Wed Jan 15 2020
 
Valid Saturday January 18 2020 - Wednesday January 22 2020
 
Hazards:
- Heavy precipitation across portions of the Central/Northern Plains, the Middle/Upper Mississippi 
Valley, the Great Lakes, the Ohio Valley, the Southern/Central Appalachians, the Mid-Atlantic, and 
the Northeast, Sat-Sun, Jan 18-Jan 19.
- Heavy snow across portions of the Great Lakes, the Upper Mississippi Valley, and the Northern 
Plains, Sat, Jan 18.
- Heavy snow across portions of the Northeast and the Great Lakes, Sat-Sun, Jan 18-Jan 19.
- Flooding possible across portions of the Upper/Middle Mississippi Valley, the Great Lakes, the 
Ohio Valley, and the Tennessee Valley.
- Flooding occurring or imminent across portions of the Lower/Middle Mississippi Valley, the 
Northern Plains, the Tennessee Valley, the Southeast, the Great Lakes, and the Ohio Valley.
- Flooding likely across portions of the Middle Mississippi Valley and the Ohio Valley.
- Much below normal temperatures across portions of the Northern Plains and the Northern Rockies, 
Sat-Sun, Jan 18-Jan 19.
- Much below normal temperatures across portions of the Northern/Central Plains and the 
Upper/Middle Mississippi Valley, Sun-Tue, Jan 19-Jan 21.
- High significant wave heights for coastal portions of the Pacific Northwest, Sat-Sun, Jan 18-Jan 
19.
- Much below normal temperatures across portions of mainland Alaska, Sat-Mon, Jan 18-Jan 20.
- Much below normal temperatures across portions of the Alaska Panhandle, Sat, Jan 18.
 
Detailed Summary:

The main threat in the medium range period will be a low pressure system moving across the central 
into northeastern U.S. through the weekend. With this system, heavy snow is possible along the 
northern tier from the Upper Mississippi Valley across the Great Lakes Friday (now in the short 
range) into Saturday, and also spreading into the interior Northeast Saturday. The low is expected 
to pull away from the Northeast during the day on Sunday, but snow could linger behind the low, 
especially downwind of the Great Lakes. Farther south, a myriad of precipitation types are 
expected--snow, sleet, freezing rain, and rain are all possible, with many areas changing between 
precipitation types--across the Middle Mississippi Valley eastward into northern portions of the 
Ohio Valley and Appalachians on Friday into Saturday, with the Mid-Atlantic and coastal areas of 
the Northeast being impacted Saturday into Sunday. Travel will likely be impacted with this system.

Behind the low pressure system, a strong, cold high pressure system will dive southward from 
central Canada into the Northern Plains/Midwest early next week. This is forecast to usher in 
bitterly cold air to those regions. The Northern High Plains should see below average low 
temperatures this weekend, with high temperatures more than 20 degrees below average. As the high 
moves southward, the much below normal temperatures will impact the Upper/Middle Mississippi Valley 
early next week, with somewhat cooler weather moving into much of the eastern half of the U.S. as 
well by midweek.

An upper-level trough and a dying cold front approaching the Pacific Northwest on Saturday could 
cause waves to swell to significant heights; Saturday appears to have the best chance for these 
significant waves, though wave heights could remain high into Sunday. High winds are possible 
offshore as well on Saturday, but the strongest winds should not make it over land. Precipitation 
is likely in the Pacific Northwest by Tuesday and Wednesday next week ahead of another trough, but 
does not look particularly heavy for this time of the year.

Over Alaska, below normal temperatures are expected for the Panhandle through the end of the week. 
An upper-level low should push northward from the Gulf of Alaska early next week, leading to colder 
than average days for lower elevations of the mainland. Precipitation is likely to affect the 
Panhandle and then along the Gulf of Alaska coast Sunday through Tuesday, but amounts seem too low 
to warrant drawing a hazard area.


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