US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
323 PM EDT Fri May 17 2019
 
Valid Monday May 20 2019 - Friday May 24 2019
 
Hazards:
- Heavy rain across portions of the Plains and the Mississippi Valley, Mon-Tue, May 20-May 21.
- Severe weather across portions of the Central and Southern Plains, Mon, May 20.
- Severe weather across portions of the Central Plains and the Middle Mississippi Valley, Tue, May 
21.
- Flooding possible across portions of the Central and Southern Plains and the Mississippi River 
Basin.
- Flooding occurring or imminent across portions of the Central Plains, the Mississippi and 
Missouri River Basins, and the Northern Rockies.
- Flooding likely across portions of the Northern Great Basin.
- Excessive heat across portions of the Southeast, Thu-Fri, May 23-May 24.
- High winds across portions of the Southern Rockies and the Southern High Plains, Mon, May 20.
- Much below normal temperatures across portions of California, the Central Great Basin, and the 
Southwest, Mon-Wed, May 20-May 22.
- Much below normal temperatures across portions of the Northern and Central Plains, Mon-Tue, May 
20-May 21.
 
Detailed Summary:

A reinforcing mean upper level trough across the Western U.S. will be responsible for a variety of 
hazards across the western and central parts of the country during the medium range period (May 
20-24). The main concern for hazardous weather will be across the Central U.S. in the beginning 
part of next week as a leading storm system ejects into the Plains on Monday. This will likely 
bring a threat for heavy rainfall and/or severe weather to a large part of the Central and Southern 
Plains on Monday, shifting north and east into parts of the Northern Plains and the Mississippi 
Valley by Tuesday. This system could also result in a period of high winds for parts of the 
Southern Rockies and Southern High Plains next Monday. Across the rest of the Western U.S., expect 
favored terrain from California into the Rockies to see some significant totals (including snow in 
the higher terrain) as multiple waves of energy move through the mean trough next week, but at this 
time coverage remains limited for high-confidence areas exceeding hazards chart thresholds. 

Temperatures across much of the Western U.S. will remain below to much below normal underneath of 
the amplified upper level trough. The highest anomalies should focus over parts of the Northern and 
Central High Plains and into the Plains with a secondary area across parts of interior California, 
the Central Great Basin, and the Southwest the beginning of the week, with temperatures expected to 
moderate at the end of the week. While minimum temperature anomalies earn't overly impressive 
(which would typically be used as criteria for the hazards chart), daytime highs could be 20+ 
degrees below normal with overnight lows near freezing in some places. For this reason, a much 
below normal temperatures area was maintained for both of the aforementioned areas.

Meanwhile, a building ridge across the Eastern U.S. will support warmer than normal temperatures by 
the end of the next week. The main hazardous threat will be across the Southeast where daytime 
highs may reach into the upper 90s by next Thursday, with possible higher heat index values. 
Farther north into parts of the Mid-Atlantic and Ohio Valley, maximum temperature anomalies could 
be in the +10 to +15 degree range, but with less extreme heat indices. For simplicity purposes, the 
hazards outlook area for excessive heat focuses across the Southeast for now where these types of 
temperatures would be the highest experienced thus far this year. 

Alaska will continue to be relatively quiet next week. A central Pacific storm may approach the 
Aleutians or southern Mainland coast late in the week but so far expect any effects to remain below 
hazard criteria.

Santorelli