Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Sat Jul 15 2023

Valid 12Z Sat Jul 15 2023 - 12Z Mon Jul 17 2023

...Dangerous heat wave to remain anchored over the West this weekend;
growing hotter in the South by early next week...

...Excessive Rainfall and severe weather to transpire across the eastern
half of the Lower 48...

...Canadian wildfire smoke is responsible for Air Quality alerts in parts
of the North Central U.S. and Ohio Valley...

The West will be mired in the midst of a dangerous heat wave thanks to a
strong ridge of high pressure stationed over head for the next few days.
Daytime highs will routinely range between 10-20F above normal, equating
to daytime temperatures approaching the century mark in the interior
Northwest, between 100-110F in central and southern California, and
115-120F+ in the high desert of southern California, southern Nevada, and
Arizona. These values will also likely amount to numerous daytime record
highs being broken this weekend in the Southwest and Great Basin. While
the core of the hottest temperatures is setting up in the Southwest,
sultry conditions persist in the south central U.S. and in South Florida.
Daytime highs in the 90s to low 100s with oppressive humidity levels will
allow heat indices to range frequently between 105-110F each afternoon.
All affected regions will struggle to cool off each night, making for
little in the way of relief even well after the sun sets Saturday and
Sunday evenings. There are no shortage of Excessive Heat Warnings and Heat
Advisories that stretch from the West Coast to the Gulf Coast. For more
information on the impacts of this eat wave, please visit heat.gov.

The heat wave in the West will keep the West quite dry this weekend, but
it is quite the opposite east of the Rockies where widespread showers and
thunderstorms are forecast. A pair of frontal systems tracking through the
Midwest and Northeast will be the catalysts for rounds of strong-to-severe
storms. Today, WPC's Excessive Rainfall Outlook highlights three Slight
Risks areas: one in the southern High Plains, the central Appalachians,
and the interior Northeast. The Marginal Risk (threat level 1/4) spans
from the southern Rockies to the East Coast, placing a large portion of
the U.S. population at risk for flash flooding. The Storm Prediction
Center has its own Slight Risk area for parts of eastern NM and the TX
Panhandle, along with a Marginal Risk from the Tennessee Valley on north
into the eastern Great Lakes. By Sunday, the Excessive Rainfall threat
becomes a bigger concern as WPC has hoisted a Moderate Risk (threat level
3/4) for much of the Northeast. There is also the potential for severe
storms in the Midwest and in the Northeast Sunday afternoon and evening.

While temperatures will be seasonal to slightly below normal in parts of
the northern High Plains and Midwest, these regions are set to contend
with poor air quality throughout the weekend. The poor air quality is due
to wildfire smoke from western Canada being directed into the north
central U.S.. Canadian wildfire smoke will reach the Great Lakes and Ohio
Valley by Sunday. Lastly, there is an Elevated threat for fire weather in
parts of the the Columbia River gorge of northern OR and central WA on
Sunday.

Mullinax


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