US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
351 PM EDT Thu Mar 25 2021
 
Valid Sunday March 28 2021 - Thursday April 01 2021
 
Hazards:
- Heavy precipitation across portions of the Northeast, Sun, Mar 28.
- Heavy rain across portions of the Southeast, the Lower Mississippi Valley, the Southern 
Appalachians, and the Tennessee Valley, Wed, Mar 31.
- Heavy snow across portions of the Pacific Northwest and the Northern Great Basin, Sun, Mar 28.
- Heavy snow across portions of the Northern Rockies, Mon, Mar 29.
- Severe weather across portions of the Southeast and the Mid-Atlantic, Sun, Mar 28.
- Flooding possible across portions of the Northeast, the Lower Mississippi Valley, the Ohio 
Valley, and the Tennessee Valley.
- Flooding occurring or imminent across portions of the Middle/Lower Mississippi Valley, and the 
Ohio Valley.
- High winds across portions of the Northern Plains, Mon-Tue, Mar 29-Mar 30.
- High winds across portions of the Mid-Atlantic and the Northeast, Sun-Mon, Mar 28-Mar 29.
- Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Mar 
30-Mar 31.
- Heavy snow across portions of mainland Alaska, Sun-Mon, Mar 28-Mar 29.
- High winds across portions of mainland Alaska and the Aleutians, Sun-Mon, Mar 28-Mar 29.
 
Detailed Summary:
In the medium-range forecast period (Sunday, March 28th to Thursday, April 1st), a low over Lake 
Huron and the associated front will move eastward to Southeastern Canada by Monday.  The system 
will produce an area of heavy precipitation over parts of Northern New England on Sunday.  The area 
of heavy precipitation will produce mountain snow and valley rain on Sunday.  The trailing front 
will move across Virginia and the Carolinas on Sunday. The front will produce severe thunderstorms 
over the region.  The previous low over the Northeast will become very deep as the low moves off 
the Northeast Coast.  The pressure gradient associated with the low will produce high wind along 
the coast from parts of New England to parts of the northern Mid-Atlantic Coast on Sunday and 
Monday.   

On Sunday, moisture will stream onshore over parts of the Pacific Northwest for a short time ahead 
of the next front to come onshore off the Pacific.  The moisture will help produce an area of heavy 
snow over the Cascades on Sunday and an area of heavy snow over parts of the Bitterroot Mountains 
on Monday.  Meanwhile, the low and the associated front moving onshore over the Pacific Northwest 
and Western Canada will deepen while continuing to move eastward, just north of the U. S./Canadian 
border on Tuesday, and then move northward over Hudson Bay by Wednesday.

The deep low will have a strong pressure gradient associated with producing an area of high wind 
over parts of the Northern High Plains and into the Northern Plains on Monday and Tuesday.   The 
associated front will move across the Lower Mississippi Valley into the Southeast on Wednesday into 
Thursday.  Moisture from the Western Gulf of Mexico will stream northward over the region, 
intersecting the boundary, producing an area of heavy rain over parts of the Lower Mississippi 
Valley, Tennessee Valley, and the Southern Appalachians on Wednesday.  

For Alaska, an area of deep low pressure over the Bearing Sea on Sunday will move into the Western 
Mainland on Monday.  The strong pressure gradient around the low will produce high wind over the 
Aleutians into the Alaska Peninsula and parts of the Southwest Mainland on Sunday and Monday.  The 
same storm will produce heavy snow over parts of the Southwest into parts of the South-Central 
Mainland on Sunday into Monday.  In particular, the heavy snow will develop over the Nulato Hills, 
the Kuskokwim Mountains, and the western parts of the Alaska Range.  As the system moves east 
across the Gulf of Alaska, moisture will stream inland over the Alaska Panhandle and into parts of 
the eastern section of the South-Central mainland on Tuesday into Wednesday, producing an area of 
heavy precipitation.

Ziegenfelder