US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
302 PM EDT Wed Aug 14 2019
 
Valid Saturday August 17 2019 - Wednesday August 21 2019
 
Hazards:
- Heavy rain across portions of the Middle Mississippi Valley, Sat, Aug 17.
- Heavy rain across portions of northern Florida, Sat-Sun, Aug 17-Aug 18.
- Flooding occurring or imminent across portions of the Northern Plains.
- Excessive heat across portions of the Southwest, Tue-Wed, Aug 20-Aug 21.
- Excessive heat across portions of the Lower Mississippi Valley and the Southern Plains, Sat-Mon, 
Aug 17-Aug 19.
 
Detailed Summary:

The medium range period (Sat - Wed) remains relatively quiet in terms of any widespread 
precipitation hazards. A low pressure system/associated frontal system exiting the Upper Midwest at 
the beginning of the period may bring a threat for heavy rainfall mainly across Iowa into northwest 
Illinois on Sat, Aug 17. Across Florida, models continue to show a signal for heavy rainfall across 
the big bend region of Florida as significant moisture interacts with a nearly stationary frontal 
boundary. The heaviest rains may stay just offshore in the northeast Gulf, but there is potential 
that heavier rains could impact parts of northern Florida. As a result, a small heavy rain area was 
maintained from yesterday's chart for Sat Aug 17 to Sun Aug 18.

A generally warm pattern will persist over the southern tier of the U.S. with daytime highs running 
above average underneath stubborn upper level ridging. The best chance for excessive heat will be 
across parts of south and eastern Texas into northern Louisiana where temperatures and high 
humidity could result in heat indices in excess of 105 degrees this weekend into early next week. 
By the end of the period (Tue/Wed), excessive heat may return to lower elevations of the Southwest 
with daytime highs forecast to be around 110-115 degrees and overnight lows in the upper 80s. 
Excessive heat areas were included for both regions discussed.

In Alaska, a stalled front across the western Aleutians should be weakening by the beginning of the 
medium range period, with a mainly localized threat for heavy rainfall lingering into the weekend. 
On Tuesday-Wednesday next week, a deep surface low approaches the Aleutians bringing the potential 
for windy and general unsettled weather to the region. At this point, the wind/precipitation 
hazards look to be below criteria with significant waves not really a concern for the low populated 
and rocky western Aleutians. This system will need to be monitored for changes in the forecast, but 
at this time no significant hazards were included on today's chart for Alaska.

Santorelli