US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
349 PM EDT Mon Aug 12 2019
 
Valid Thursday August 15 2019 - Monday August 19 2019
 
Hazards:
- Heavy rain across portions of the Central Plains and the Middle Mississippi Valley, Thu-Fri, Aug 
15-Aug 16.
- Heavy rain across portions of the Southeast, Thu-Mon, Aug 15-Aug 19.
- Flooding occurring or imminent across portions of the Northern Plains.
- Flooding likely across portions of the Central Plains.
- Excessive heat across portions of California and the Southwest, Thu, Aug 15.
- Heavy precipitation across portions of mainland Alaska, Thu-Fri, Aug 15-Aug 16.
- Heavy rain across portions of the Aleutians, Thu-Sun, Aug 15-Aug 18.
- High winds across portions of the Aleutians, Thu, Aug 15.
- High significant wave heights for coastal portions of mainland Alaska and the Aleutians, Thu, Aug 
15.
 
Detailed Summary:

While model guidance contains plenty of uncertainty for much of the medium range period, it appears 
that a surface low pressure system will meander in the Northern Plains through early next week. As 
moisture flows into the vicinity of its fronts, heavy rainfall is possible. Heavy rain looks to 
focus in the Central Plains and Middle Mississippi Valley late in the workweek, possibly shifting 
into the Upper Midwest by the weekend. Uncertainty with both the rainfall amounts and placement 
precluded drawing a hazard area farther to the northeast at this point, however. Elsewhere, ample 
Gulf moisture combined with a dying stationary front could lead to a multi-day period of heavy 
rainfall along parts of the central to eastern Gulf Coast. 

A generally warm pattern is expected to remain over the southern and eastern portions of the 
continental U.S., with high temperatures forecast to be a few to 10 degrees above average in the 
Southwest and California on Thursday and spreading into the Ohio Valley by the beginning of next 
week. There will be potential for excessive heat across the Southwest particularly on Thursday, 
when temperatures will be highest. Meanwhile, the northwestern to north-central U.S. can expect 
temperatures that are a few degrees below average. 

Over Alaska, a front is expected to stall over the Aleutians toward the end of the week, providing 
a focus for repeated rainfall there. Additionally, the relatively strong low associated with with 
the front will create a strong pressure gradient favorable for strong winds and potentially 
significant waves. As moisture flows into interior Alaska, precipitation is expected through the 
end of the week generally along and north of the Alaska range. With below average temperatures 
forecast, precipitation could fall as snow in the Brooks Range, North Slope, and higher elevations 
of the Alaska Range.

Tate