US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
411 PM EDT Tue May 18 2021
 
Valid Friday May 21 2021 - Tuesday May 25 2021
 
Hazards:
- Heavy rain across portions of the Southern Plains, Fri-Sat, May 21-May 22.
- Flooding possible across portions of the Central Plains, the Middle Mississippi Valley, the Lower 
Mississippi Valley, and the Southern Plains.
- Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi 
Valley, the Lower Mississippi Valley, and the Southern Plains.
- Flooding likely across portions of the Central Plains, the Lower Mississippi Valley, and the 
Southern Plains.
- Much above normal temperatures across portions of the Great Lakes and the Upper Mississippi 
Valley, Fri-Sun, May 21-May 23.
- Much above normal temperatures across portions of the Southeast and the Mid-Atlantic, Mon-Tue, 
May 24-May 25.
 
Detailed Summary:

The main weather hazard during the medium-range forecast period (Friday, May 21 - Tuesday, May 25) 
will be anomalous warmth in the Midwest and East Coast. A troughing pattern in the west will lead 
to an active period of rain and thunderstorms for parts of the Northern/Southern Plains. There's a 
chance for heavy rainfall along the Texas coast on Friday as the dipole of upper level troughing in 
the west and ridging in the east pulls Gulf moisture into eastern Texas and into the 
Plains/Mississippi Valley. This rain threat may be of particular concern given the already high 
soil moisture and ongoing flooding across the region. Meanwhile, rain and thunderstorms will be the 
mode across much of the Northern/Southern Plains this weekend. Rainfall, particularly over parts of 
the border between Canada and the Northern Plains will be much needed due to an ongoing severe 
drought in that. The eastern migration of the upper-level dipole will lead to warm air advection 
into the Midwest and Great Lakes this weekend. This warmth will be anomalous as some places across 
Michigan and Wisconsin may see their temperatures reach up into the mid to upper 80s, which would 
be between 15-20 degrees above average. This anomalous warmth will spread into the Mid-Atlantic and 
Southeast by the beginning of next week, when a prolonged period of above average high temperatures 
and increased humidity may lead to the threat for excessive heat. Temperatures are likely to be 
well above normal for much of the Virginia Piedmont down into Southern Georgia between Monday and 
Tuesday.

A quiet period is expected for Alaska during the medium range period as a sequence of waves are 
likely to produce light precipitation along the Gulf coast this weekend.

Kebede