US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
340 PM EST Tue Feb 25 2020
 
Valid Friday February 28 2020 - Tuesday March 03 2020
 
Hazards:
- Heavy precipitation across portions of the Pacific Northwest, Mon-Tue, Mar 2-Mar 3.
- Heavy rain across portions of the Central Plains, the Lower Mississippi Valley, the Tennessee 
Valley, the Great Lakes, the Middle Mississippi Valley, the Southeast, the Southern Plains, and the 
Ohio Valley, Mon-Tue, Mar 2-Mar 3.
- Heavy snow across portions of the Pacific Northwest, the Northern Rockies, and the Northern Great 
Basin, Mon-Tue, Mar 2-Mar 3.
- Heavy snow across portions of the Southern Rockies, the Central Rockies, and the Central Great 
Basin, Sun-Tue, Mar 1-Mar 3.
- Flooding possible across portions of the Southeast, the Middle Mississippi Valley, the Great 
Lakes, and the Ohio Valley.
- Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Tennessee 
Valley, the Middle Mississippi Valley, the Southeast, the Southern Plains, and the Ohio Valley.
- Flooding likely across portions of the Central Plains, the Southeast, and the Southern Plains.
- Much below normal temperatures across portions of the Southeast, the Great Lakes, the Ohio 
Valley, and the Upper Mississippi Valley, Fri-Sun, Feb 28-Mar 1.
- High winds across portions of mainland Alaska and the Aleutians, Fri-Sun, Feb 28-Mar 1.
- Much below normal temperatures across portions of mainland Alaska, Fri-Tue, Feb 28-Mar 3.
- Much below normal temperatures across portions of mainland Alaska, Fri, Feb 28.
- High significant wave heights for coastal portions of the Aleutians, Sat-Sun, Feb 29-Mar 1.
 
Detailed Summary:

In the wake of the short range winter storm, colder than average temperatures will spread across 
the eastern half of the U.S. underneath an upper-level trough through the weekend. The coldest air 
will be focused from the Midwest to Great Lakes region into the Ohio Valley. Another area where 
below average temperatures are likely to persist is the Florida peninsula, where both high and low 
temperatures will be 10 to 15 degrees below normal through Sunday.

The western U.S. will see ridging over the beginning of the period (and warm temperatures), which 
is expected to shift into the central U.S. as another upper-level trough comes into the eastern 
Pacific and then into the Southwest early next week. Precipitation could spread across the West 
with this, but is not forecast to be particularly heavy. One exception could be upslope flow 
leading to heavy snow across portions of the Central Rockies by Sunday and beyond. As the upper 
trough continues tracking eastward toward the Southern Plains toward midweek, Gulf moisture ahead 
of it will flow into the Southern/Central Plains eastward and cause the potential for heavy 
rainfall into the Mississippi, Ohio, and Tennessee Valleys, where flooding could be a threat. Some 
light wintry precipitation is possible on the northern edge in the Midwest, but this looks to be 
primarily a rain event for now. Onshore flow coming into the Northwest upstream of this trough 
could create some heavy precipitation (lower elevation rain and higher elevation snow) by Monday 
and Tuesday, though there is still some model disagreement, with precipitation amounts depending on 
the depth of a potential shortwave.

Much of mainland Alaska is expected to remain cold over the period underneath generally upper-level 
troughing. The southwestern part of the state could have temperatures moderate somewhat by early 
next week as there is the possibility for the troughing to relax, but model guidance varies with 
this. One feature that is expected more confidently over Alaska is a deep surface low tracking 
north of the Aleutians into the Bering Sea late this week into the weekend. This low will cause 
high winds and significant waves across the Aleutians, and should bring some precipitation with it 
to the Aleutians, southwestern mainland, and the south-central Gulf of Alaska coast as a long fetch 
of moisture streams into those areas. However, model guidance was not terribly high with its 
amounts, so did not delineate a heavy precipitation area for now, but it will continue to be 
monitored.

Heavy rainfall is a possibility over Hawaii with an upper-level low over the islands and ample 
moisture getting pulled into the feature Saturday onward.


Tate