Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
319 AM EDT Thu May 18 2023

Valid 12Z Thu May 18 2023 - 12Z Sat May 20 2023

...Above-normal temperatures continue in the West...

...There are Slight Risks of Excessive Rainfall leading to Flash Flooding
over portions of the Central/Southern Plains and South Carolina coast
today...


Upper-level ridging over the West will continue to generate above average
temperatures for the next several days. The Pacific Northwest will be the
focus for the most anomalous heat with high temperatures in the 80s and
90s representing a 20-30 degree positive temperature anomaly. The evenings
will be warm too with lows in the 50s and 60s. High and low temperature
records may be tied or broken across the Northwest through this weekend
with Saturday being the hottest day of the week. The warm air will expand
into the Northern Plains on Friday.

Showers and thunderstorms will develop around a strengthening cold front
that will sweep through the Great Plains and Upper Midwest today. Rainfall
will be more stratiform and less convective over the Upper Midwest.
Meanwhile, some intense storms may develop along the southern section of
the front, from eastern Colorado to central Kansas/Oklahoma, where a
Slight Risk of Excessive Rainfall leading to Flash Flooding is in effect
for late this afternoon and through the evening. Showers and storms will
continue to develop along the cold front as it washes across the Midwest
and into the Appalachians on Friday. Cooler air will filter into the
Plains on the backside of the cold front as high pressure builds over the
region.

Elsewhere, a coastal low pressure system with quasi-stationary fronts will
generate thunderstorms and heavy rainfall over portions of coastal
Georgia/South Carolina beginning this afternoon and continuing into the
evening. There's an elevated chance of flash flooding over portions of
coastal South Carolina, due to the presence of substantial moisture,
instability and forcing provided by the developing surface wave. Between
1-3" of rainfall is expected to accumulate over coastal South Carolina
with isolated amounts approaching 4" possible today. Scattered showers and
thunderstorms will spread northward into coastal North Carolina on Friday.
High pressure over the East Coast will begin to move offshore today, but
below average temperatures are still expected for much of the Northeast
and Mid-Atlantic through Friday before moderating.


Kebede

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