US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
405 PM EDT Wed Jul 01 2020
 
Valid Saturday July 04 2020 - Wednesday July 08 2020
 
Hazards:
- Heavy rain across portions of the Upper Mississippi Valley and the Northern Plains, Sat-Sun, Jul 
4-Jul 5.
- Heavy rain across portions of the Southeast, Sat-Mon, Jul 4-Jul 6.
- Flooding possible across portions of the Middle Mississippi Valley and the Ohio Valley.
- Flooding occurring or imminent across portions of the Middle Mississippi Valley and the Northern 
Plains.
- Excessive heat across portions of California and the Southwest, Sat-Tue, Jul 4-Jul 7.
- Excessive heat across portions of the Southeast, Sat-Wed, Jul 4-Jul 8.
- Much above normal temperatures across portions of the Central Plains, the Middle Mississippi 
Valley, and the Southern Plains, Wed, Jul 8.
- Much above normal temperatures across portions of the Great Lakes, the Mid-Atlantic, the 
Northeast, the Central Appalachians, and the Upper Mississippi Valley, Sat-Wed, Jul 4-Jul 8.
- Much above normal temperatures across portions of the Upper Mississippi Valley, Sat-Sun, Jul 
4-Jul 5.
- Much above normal temperatures across portions of the Northeast, Tue-Wed, Jul 7-Jul 8.
 
Detailed Summary:

The medium range period (Sat 7/4 - Wed 7/8) is highlighted by temperatures that are hot as a 
firecracker. 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 peninsula remain much above normal and upper level ridging 
returns next week. The hottest temperatures versus normal are expected to take place from the Upper 
Midwest and 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 in the 
upper 70s could lead to heat indices approaching the century mark. Lastly, ensemble guidance is 
hinting at the development of a large upper ridge forming over the southern High Plains and Rockies 
towards the middle of next week. High temperatures could make a run at 100 degrees and heat indices 
over 100 degrees in the central Plains.

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 frontal boundaries and upper level disturbances will trigger 
episodes of showers and thunderstorms, some of which could be severe and/or contain heavy rainfall. 
The most anomalous upper trough will transpire 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. Where guidance becomes 
increasingly unclear is the positioning and movement of the trough, which makes areas at risk for 
heavy rainfall tricky. The heaviest precipitation is currently forecast to extend from the Florida 
Panhandle to the South Carolina coast. 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 north of the 
Yukon. Rounds of showers are possible across interior Alaska but totals look to remain below 
threshold. Temperature wise, western Alaska warm to above normal levels but are also just below 
threshold. The state continues to be monitored for any increased fire weather potential through the 
first full week of July.

Mullinax