US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
330 PM EDT Mon Jul 13 2020
 
Valid Thursday July 16 2020 - Monday July 20 2020
 
Hazards:
- Flooding occurring or imminent across portions of the Northern Plains.
- Flooding likely across portions of the Northern Plains.
- Excessive heat across portions of the Central and Southern Plains, the Mississippi Valley, the 
Midwest, and the central Gulf states, Thu-Sun, Jul 16-Jul 19.
- Excessive heat across portions of the Mid-Atlantic, Sat-Mon, Jul 18-Jul 20.
 
Detailed Summary:

The medium range period (Thursday, July 16 - Monday, July 20) will continue to feature a 
summer-like pattern with expanding heat across the Central/Eastern states, and isolated 
opportunities for heavy rainfall. The main storm track should be across the northern tier states as 
a main frontal boundary shifts from the Northern Plains to the Upper Great Lakes this weekend. This 
will likely bring the threat for at least locally heavy rainfall and strong thunderstorms, although 
there remains enough disagreement in the models to not include any defined areas at this time. 

The main threat for medium range however will be an expanding dome of upper level high pressure 
across much of the central and eastern parts of the U.S.. Combined heat and humidity values will 
result in excessive heat (with heat indices in excess of 105 degrees) from parts of the Southern 
Plains to the central Gulf states, and also northward into the middle Mississippi Valley. Excessive 
heat will also expand northward into parts of the Plains/Upper Midwest and the Ohio Valley into the 
weekend as well, where heat indices could exceed 100 degrees. These values would come close to 
criteria for the day 3-7 hazards chart and so an expansive excessive heat area was included today 
for much of the middle part of the country for the time period July 16-19. By the weekend into 
early next week, the heat should subside somewhat across the Central U.S., but will continue to 
build across parts of the Mid-Atlantic. A second excessive heat area was included for much of the 
I-95 corridor/Mid-Atlantic from the Carolinas to New York City for heat indices 100-105 expected in 
many places.

No widespread weather hazards are expected across Alaska between Thursday and Monday. Temperatures 
are expected to remain below average, especially across the northern half of the state. An area of 
low pressure could reach the southern Mainland later this weekend, but impacts from this seem 
relatively minor at this time.

Santorelli