US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
342 PM EDT Mon Mar 29 2021
 
Valid Thursday April 01 2021 - Monday April 05 2021
 
Hazards:
- Heavy snow across portions of the Northeast, Thu, Apr 1.
- Flooding possible across portions of the Southeast, the Mid-Atlantic, the Southern Appalachians, 
and the Tennessee Valley.
- Flooding occurring or imminent across portions of the Southeast, the Lower Mississippi Valley, 
the Southern Appalachians, the Ohio Valley, and the Tennessee Valley.
- Heavy snow across portions of mainland Alaska, Fri-Sat, Apr 2-Apr 3.
 
Detailed Summary:
In the medium-range forecast period (Thursday, April 1st to Monday, April 5th), the hazards chart 
looks very quiet during this forecast period.   One hazard will be the threat of heavy snow over 
parts of the Northeast on Thursday.  Low pressure over the Northeast will move northeastward into 
Southeastern Canada by Friday.  Besides the heavy snow, the system will produce rain over the 
coastal parts of the Northeast and light snow over other parts of the Northeast into parts of the 
Central Appalachians, also on Thursday.  Behind the front, high pressure over the Southern Plains 
northeastward to the Upper Mississippi Valley/Upper Great Lakes will move eastward to Mid-Atlantic 
by Saturday.  Part of the high will advance off the Mid-Atlantic Coast on Sunday, while the other 
half settles over the Southeast on Sunday, nudging northward to the Central Appalachians by Monday. 
 Even though it is at the very beginning of the growing season over parts of the country, the high 
will bring temperatures below normal over parts of the Ohio Valley to the Gulf Coast and the 
Southeast to the Mid-Atlantic on Thursday and Friday.   The minimum temperatures will be in the mid 
to upper 20s to low 30s over the Ohio Valley and the upper 20s to low to mid 30s over the Tennessee 
Valley and the low to mid 30s over the Gulf Coast States on Thursday and Friday morning.  
Temperatures will rebound to the 40s by Sunday.  Additionally, the winds will be high along and 
just offshore over the Gulf of Maine and the Gulf of Mexico on Thursday morning, then quiet down.

In the meantime, a front extending from the Northern Plains to Northern California, on Friday, will 
move eastward to Great Lakes by Sunday.  There will be no precipitation or very light along the 
boundary as it moves eastward.  Elsewhere, weak moisture will move onshore over the West Coast on 
Sunday.  The moisture will interact with a deep upper-level trough just offshore to produce light 
precipitation over parts of the West Coast and into the Sierra Nevada Mountain on Sunday. 

For Alaska, an area of deep low pressure moving off the Eurasian continent, on Thursday will move 
into the Bearing Sea on Friday will move into the Western Mainland on Saturday.  The pressure 
gradient around the low and the high over the North Pacific will produce strong wind over the 
Aleutians into the Alaska Peninsula on Friday and Saturday.   The wind will be below the criteria 
for high wind over the region, though.  The storm will produce heavy snow over parts of the 
Southwest into parts of the South-Central Mainland on Friday into Saturday.  In particular, the 
heavy snow will develop over the Nulato Hills, the Kuskokwim Mountains, parts of the Alaska 
Peninsula, and the western parts of the Alaska Range.  As the system moves east across the Gulf of 
Alaska and into the Alaska Panhandle, the system will produce coastal rain and interior/higher 
elevation snow over parts of the Southeast mainland and the Alaska Panhandle.  The precipitation 
amounts will be below the criteria for heavy precipitation with this storm.

Ziegenfelder