Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
335 AM EDT Mon Sep 13 2021

Valid 12Z Mon Sep 13 2021 - 12Z Wed Sep 15 2021

...Tropical Storm Nicholas to produce torrential rainfall, strong winds,
and high surf from the Texas coast to southern Louisiana with
life-threatening storm surge and flooding possible; High Risk of Excessive
Rainfall near the Upper Texas Coast today...

...A hotter than normal mid-September in store across most of the mainland
U.S, Excessive Heat Warnings issued in parts of the Southwest....

...Severe weather possible from the Central Plains to the Great Lakes and
Northeast; Elevated Risks for fire weather in parts of the West...

Tropical Storm Nicholas continues to track north towards the Texas coast
with landfall likely to occur somewhere between Corpus Christi and
Galveston Bay Monday evening. Some rain bands out ahead of Nicholas have
already reached the Texas coast with an increasingly widespread area of
rainfall expected to arrive as Nicholas inches closer to land later today.
The Weather Prediction Center (WPC) has issued a High Risk for Excessive
Rainfall for a small portion of the Upper Texas Coast, highlighting just
how significant the threat for flash flooding could become later today.
Nicholas is set to generate tropical storm force winds along the coast as
well as battering surf and dangerous storm surge. That said, the storms
slow progressing over the Upper Texas coast and into southern Louisiana
means rounds of torrential rainfall, day after day, is anticipated for
these areas. WPC's latest Excessive Rainfall Outlook features a remarkable
three straight days worth of Moderate Risks (level 3/4) for portions of
the Texas coast and southern Louisiana. Localized totals of up to 20
inches of rain is possible across parts of the Texas and Louisiana
coastlines through the mid-week, with widespread amounts between southern
Texas and southwest Louisiana around 5 to 10 inches. Rainfall amounts of
this magnitude will likely lead to areas of flash flooding that could be
life-threatening where the heaviest totals and highest rainfall rates
transpire.

Temperature-wise, a mid-September heat wave focused in the Southwest and
Central Plains the last couple days extends its reach into the
Mid-Atlantic today. The hottest conditions are centered in the Desert
Southwest where Excessive Heat Warnings remain in place through Monday
afternoon. The central High Plains will sweat out one more day of
abnormally hot conditions (highs coming close to hitting triple digits in
spots) but a passing cold front brings some relief from the heat on
Tuesday. The late season summer heat only continues to build in the
Mid-Atlantic with high temps in the low 90s and very mild morning lows for
mid-September. In fact, some parts of the Ohio Valley and northern
Mid-Atlantic could break daily record warm lows this morning. Abnormally
cool conditions are likely in parts of the Deep South thanks to widespread
cloud cover from Tropical Storm Nicholas. The Pacific Northwest can also
expect seasonally cooler temps today and again on Wednesday as another
Pacific cold front sweeps through the region.

Tropical Storm Nicholas is not the only active weather maker in the Lower
48. An elongated frontal boundary working in tandem with an emerging wave
of low pressure out of the central Rockies will act as a catalyst for
scattered areas of heavy showers and thunderstorms from the Upper Midwest
to the interior Northeast. Some severe weather is possible as the Storm
Prediction Center does have a pair of Slight Risks (level 2/5) in place
fore parts of the Midwest and northern Mid-Atlantic today. As the wave of
low pressure in the Plains ejects east towards the Great Lakes on Tuesday,
the best odds for severe weather takes shape once again in the Midwest as
the cold front swings through the region. Severe storms may contain
damaging winds and large hail, along with locally heavy rainfall rates
that may lead to some instances of flash flooding. Lastly, fire weather
conditions remain problematic in parts of the West as a few Elevated Risk
areas have been issued in parts of the central High Plains, the Great
Basin, and Snake River Valley.

Mullinax

Graphics are available at www.wpc.ncep.noaa.gov/basicwx/basicwx ndfd.php