Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
352 AM EDT Wed Sep 15 2021

Valid 12Z Wed Sep 15 2021 - 12Z Fri Sep 17 2021

...Tropical Depression Nicholas to supply copious amounts of rainfall to
the central Gulf Coast...

...Passing cold front to trigger showers and thunderstorms from the Ohio
Valley to the Northeast, some of which could be severe and produce
excessive rainfall rates...

...Mid-September heat wave to continue in parts of the Northeast today,
more widespread anomalous heat in the Heartland on Thursday; Elevated fire
weather conditions in the Rockies and High Plains...

Topical Depression Nicholas is forecast to meander over Louisiana today
and into Thursday, directing plenty of tropical moisture at the central
Gulf Coast. A Moderate Risk of Excessive Rainfall is positioned from
south-central Louisiana on east to the Florida Panhandle. Additional
rainfall totals of 2-5 inches with localized totals up to 10 inches
possible where training thunderstorms set up. Thursday features more
rounds of heavy showers and thunderstorms in the Deep South, prompting the
issuance of a Slight Risk for Excessive Rainfall once again along the
central Gulf Coast. As Nicholas continues to weaken, so will rainfall
rates across the Deep South, but lingering areas of showers and
thunderstorms look to stick around the Deep South through the end of the
work-week. 

Farther north, a passing cold front is responsible for the development of
showers and thunderstorms from the Ohio and Tennessee Valleys on north
into the Northeast today. The areas most at risk are the Northeast and
northern Mid-Atlantic where Slight Risks for both severe weather and
Excessive Rainfall have been issued. Thunderstorms producing Excessive
Rainfall rates may lead to areas of localized flash flooding while severe
storms could contain tornadoes, damaging wind gusts, and hail. As this
front tracks east and weakens on Thursday, a new frontal system tracking
across the North-Central U.S. looks to spawn thunderstorms across the
Upper Midwest, some of which could be severe. Lastly, the Pacific
Northwest may see an uptick in showers as a Pacific storm system ushers in
Pacific moisture late Thursday into early Friday.

Elsewhere, anomalous mid-September heat maintains a firm grip throughout
much of the Lower 48. Much of the Plains and major Northeast cities can
expect high temps on the order of 10 to 15 degrees above normal. The
Northeast cools down to an extent on Thursday thanks to a cold frontal
passage, but daily average temperature anomalies look to remain above
normal. Meanwhile, the heat only continues to build in the Heartland with
high temps soaring into the low-mid 90s in the central High Plains. In the
West, fire weather remains a concern with Red Flag Warnings posted for
parts of the northern Rockies and High Plains today. Favorable fire
weather conditions look to linger into Thursday with Elevated Risks posted
from the Great Basin and central Rockies to the northern High Plains.

Mullinax

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