Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
316 AM EDT Tue Sep 21 2021

Valid 12Z Tue Sep 21 2021 - 12Z Thu Sep 23 2021

...Slow-moving cold front to bring heavy rains to portions of the Great
Lakes, Ohio and Tennessee valleys on Tuesday...

...Additional heavy rains likely from the coastal Carolinas to the
southern Appalachians on Tuesday...

...Developing area of low pressure to bring heavy rains and breezy
conditions to portions of the Great Lakes and Ohio Valley on Wednesday...

A strong cold front will continue to slowly push east today, providing a
focus for showers thunderstorms from the Great Lakes to southern Texas. 
While severe thunderstorms are not expected, heavy rainfall is likely,
with scattered flash flooding possible, especially from the Tennessee and
lower Ohio valleys northeastward across Lower Michigan.

An area of low pressure moving north along the front is expected to
strengthen as it tracks through the Ohio Valley into the Great Lakes
Wednesday into early Thursday -- producing breezy conditions and
additional heavy rains.  Heavy rainfall accumulations are likely, with
scattered flash flooding possible from Lower Michigan and northern Ohio
into the upper Ohio Valley and along the central Appalachians.

Meanwhile, moist onshore winds north of a stalled frontal boundary over
the Southeast will support additional heavy rains, with scattered flash
flooding possible across portions of the Carolinas and the southern
Appalachians on Tuesday.  Heaviest rainfall amounts on Tuesday are
expected to occur along the South Carolina and southeastern North Carolina
coasts, as well as along the southern Blue Ridge Mountains.  Additional
heavy rains are expected across the mountains as the front moves through
on Wednesday, before drying out as the front pushes east of the region on
Thursday.

Elsewhere, high pressure and dry conditions can be expected through
midweek across much of the Great Plains and western U.S.  Above-normal
temperatures along the West Coast on Tuesday are forecast to spread east,
with much of the western half of the country expected to see seasonal to
above-normal temperatures on Wednesday.  One exception will be the Pacific
Northwest, where a cold front will drop through, bringing cooler
temperatures into the region on Wednesday.

Pereira

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