US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
401 PM EDT Thu Jul 02 2020
 
Valid Sunday July 05 2020 - Thursday July 09 2020
 
Hazards:
- Heavy rain across portions of the Upper Mississippi Valley and the Northern Plains, Sun, Jul 5 
and Tue-Thu, Jul 7-Jul 9.
- Heavy rain across portions of the Southeast and the Lower Mississippi Valley, Sun-Mon, Jul 5-Jul 
6.
- Heavy rain across portions of the Southeast, the Mid-Atlantic, the Southern Appalachians, and the 
Tennessee Valley, Mon-Wed, Jul 6-Jul 8.
- Flooding occurring or imminent across portions of the Middle Mississippi Valley and the Northern 
Plains.
- Excessive heat across portions of the Southeast, California, and the Southwest, Sun-Thu, Jul 
5-Jul 9.
- Excessive heat across portions of the Central Plains, the Middle Mississippi Valley, the Lower 
Mississippi Valley, and the Southern Plains, Wed-Thu, Jul 8-Jul 9.
- Much above normal temperatures across portions of the Northeast, the Central Appalachians, the 
Mid-Atlantic, the Upper Mississippi Valley, the Great Lakes, and the Ohio Valley, Sun-Thu, Jul 
5-Jul 9.
 
Detailed Summary:

The headlining weather hazard during the medium range period (Sun 7/5 - Wed 7/9) are the areas of 
sizzling summer heat across parts of the Lower 48. A dome of high pressure over the Southwest and 
northern Mexico should make for excessively hot conditions from southern Arizona to the high desert 
of Southern California. Meanwhile, south Florida will contend with steamy conditions both day and 
night much of the period. Sea surface temperatures surrounding the Florida peninsula remain much 
above normal and upper level ridging returns next week. The hottest temperatures versus normal are 
expected to take place from the Great Lakes this weekend to northern New England next week. Max 
temperature departures will hover around 12 degrees above normal in these regions, which combined 
with dew points near 70 degrees could lead to heat indices approaching the century mark. Lastly, 
all signs continue to point towards the development of a large upper ridge forming over the 
Southwest beginning the middle of next week. High temperatures could make a run at 100 degrees and 
heat indices ranging between 105-110 degrees in the parts of the central Plains and Missouri Valley.

Precipitation-wise, the two most active regions look to be the northern Plains and the Southeast. 
As a series of upper-level disturbances track through the Northwest, they emerge in the High Plains 
of Montana and the Dakotas. Passing upper level disturbances and corresponding frontal boundaries 
will trigger episodes of showers and thunderstorms, some of which could be severe and/or contain 
heavy rainfall. The most anomalous upper trough this weekend and early next week along the Gulf 
Coast and over the Southeast. With both the Gulf of Mexico and Atlantic moisture sources available, 
there should be plenty of scattered showers and storms that form along a stationary front 
stretching from the Lower Mississippi Valley to the Southeast coast. The positioning and movement 
of the trough remains unclear, which means where the heaviest precipitation sets up could change. 
The heaviest precipitation is currently forecast to extend from the Florida Panhandle, up through 
Georgia and into portions of the western Carolinas. There is still the potential for heavier 
rainfall elsewhere in the Southeast depending on the positioning and speed of the upper trough.

Alaska remains hazards-free as the state is wedged between a large upper level ridge over the Gulf 
of Alaska and northeast Pacific, an upper low over northeast Russia, and an upper low over the 
Yukon. Scattered showers should track across interior Alaska next week with locally heavy totals 
possible along the Alaska Range. Temperature wise, western Alaska looks to start the period on a 
warm note, but as troughing develops over the state next week, expect cooler than normal 
temperatures to return across much of the mainland. The state continues to be monitored for any 
increased fire weather potential through the first full week of July.

Mullinax