Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Fri Aug 18 2023

Valid 00Z Sat Aug 19 2023 - 00Z Mon Aug 21 2023

...Heavy rainfall and flash flooding becoming more likely over parts of
the Southwest...

...Critical fire conditions expected from the Northwest to the northern
High Plains today...

...Dangerous heat redeveloping over the central U.S.....

Shortwave energy out ahead of Hurricane Hilary will generate scattered
showers and thunderstorms across the Desert Southwest, southern Sierra
Nevada and Central Great Basin tonight. The heaviest rainfall (~1in.) will
occur along the U.S. Mexico border, but rain-sensitive areas in the
Southwest and Four Corners regions could experience flash flooding from
relatively lighter amounts. A Slight Risk of Excessive Rainfall leading to
Flash Flooding is in effect across southeastern California, southern
Nevada/Utah and northwestern Arizona through tonight.

Rain and thunderstorm activity associated with Hilary begin to ramp up
across the Desert Southwest on Saturday. A Moderate Risk of Excessive
Rainfall in effect for much of southeastern California, parts of western
Arizona and southern Nevada on Saturday due to potential flash flooding
concerns over sensitive burn scars, elevated terrain and slot canyons.
Winds and rain rates will intensify more across the Southwest early Sunday
morning into Monday, when the brunt of the storm's damage is expected.
Record low maximum temperatures are likely across the desert Southwest on
Sunday and Monday.

Dangerous heat will continue to intensify and expand into the Plains
states through Saturday, with numerous daily high temperature records
expected, especially in the Central Plains and Texas. The heat wave will
further expand on Sunday and early next week to tinclude much of the
Central and Southeast U.S.. Some locations in the Midwest may see their
hottest day of the year so far this weekend, and portions of the
South-central U.S. and Gulf Coast may further extend their record number
of hours with a heat index reading of at leaswt 110F degrees. The
prolonged nature of the heat wave combined with very warm overnight
temperatures will limit relief from the oppressive daytime heat and
compound overall heat impacts.
   
Kebede

Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php