US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
421 PM EDT Thu May 28 2020
 
Valid Sunday May 31 2020 - Thursday June 04 2020
 
Hazards:
- Flooding possible across portions of the Southeast, the Great Lakes, and the northern Great Basin.
- Flooding occurring or imminent across portions of the central and northern Plains, the northern 
Rockies, from the mid-Mississippi Valley to the Midwest, and South Carolina.
- Flooding likely across portions of the central Plains, the mid-Mississippi Valley, and the 
northern Rockies.
- Much above normal temperatures across portions of the northern Rockies into the northern High 
Plains, Sun, May 31.
- Much above normal temperatures across portions of the northern and central Rockies, into the 
northern and central High Plains, Sun-Tue, May 31-Jun 2.
- Much above normal temperatures across portions of western Alaska, Sun, May 31.
- Much above normal temperatures across portions of western Alaska, Sun-Mon, May 31-Jun 1.
 
Detailed Summary:

An upper ridge slowly building eastward from the western U.S. into the Plains will spread well 
above normal temperatures from the northern and central Rockies eastward into the High Plains early 
next week.  Although the heat will become less intense than the record high warmth forecast for the 
interior Pacific Northwest for the next three days, high temperatures are expected to soar into the 
90s across the northern and central Plains through next Tuesday before cooler air arrives behind a 
cold front.  Meanwhile, much of the eastern U.S. will start out next week with cooler than normal 
temperatures.  As the ridge of high pressure in the West builds eastward, increasingly warm and 
moist air will gradually filter toward the eastern U.S. next week.  By next Thursday, summer-like 
weather will likely spread into much of the East Coast except in New England where temperatures are 
forecast to be near or slightly below normal.

Precipitation will generally be light for much of the mainland U.S. during the medium-range period. 
 Rainfall amounts could be enhanced by upslope flow next Thursday across West Virginia ahead of a 
cold front approaching from the Great Lakes.

Over Alaska, well-above normal temperatures are forecast for the western portion of the state under 
a nearly stationary upper high.  Meanwhile, a surface high over the Beaufort Sea will gradually 
filter cooler air across the North Slope toward central and western Alaska as the week progresses.  
Ice jam flooding remains a concern over the North Slope as rivers have not yet broken up, while 
minor snowmelt flooding is a possibility in central and southern parts of the mainland.  Farther 
south, an occluded cyclone should track eastward from the Aleutians toward the Alaskan Panhandle.  
It appears that southern to southeastern Alaska will get sustained periods of 
terrain-influenced/enhanced precipitation especially from Sunday (May 31) to Monday (June 1).  The 
06Z GFS did show a batch of heavier precipitation moving into eastern Alaska on June 1 but not in 
previous runs.  On the other hand, the ensemble means do not support higher amounts farther inland 
than the locally higher amounts that tend to hover around the southern mountain peaks.  Rainfall 
amounts are generally forecast to remain below heavy rain criteria for mainland Alaska, but there 
is some potential for the rain to reach the 2-inch threshold over the Panhandle on Monday.