Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
336 AM EDT Fri Aug 17 2018

Valid 12Z Fri Aug 17 2018 - 12Z Sun Aug 19 2018

...Slight risk of severe thunderstorms and flash flooding for the
Northeast with heavy rainfall impacting areas from the Mid-Atlantic to the
Southeast...

...Monsoonal rains may lead to flash flooding across the Southwest...

...Fire weather continue for the western U.S. through tonight...


Active weather is expected across regions from the Northeast to the
Tennessee Valley southward into the southern Plains today. A front slowly
pushing eastward combined with with deep southerly flow pulling abundant
moisture northward will create an environment conducive to showers and
thunderstorms. By this afternoon and evening, scattered to widespread
thunderstorms are expected especially across the Northeast, Mid-Atlantic
and Ohio Valley. Heavy rainfall is expected particularly along the surface
front lifting northward into the Northeast and New England where there is
a chance of excessive rainfall. In addition, a slight risk of severe
thunderstorms is also expected for parts of the Northeast and New England
this afternoon. Another batch of heavy rainfall will concentrate across
parts of the Southeast and Tennessee Valley. By Saturday, the front will
be draped across the Mid-Atlantic and into the southern Plains--creating
more rounds of convection across these regions along with much of the
Southeast.  Some lingering showers can be expected for the Northeast;
however most of the heavier precipitation will be farther south. By
Sunday, as the front sinks south and east, precipitation will begin to
taper off across the Mid-Atlantic while continuing across the Southeast
and southern Plains.

Monsoonal moisture will continue to move into the Southwest which will
fire off convection throughout this region through the weekend. Most of
the activity will occur in the late afternoon and evening. Flash flooding
will be a concern for areas in favorable terrain and urban regions. Check
the latest WPC excessive rainfall outlook to see which areas are of the
most concern. Fire weather will be a concern for areas across the Pacific
Northwest and Intermountain West today as isolated thunderstorms could
trigger additional fires via lightning. Gusts from these thunderstorms
could also quickly spread fires. Most of this area is under a red flag
warning which expires tonight. By Saturday, a cold front will move south
across this region bringing showers and thunderstorms from the northern
Plains to western Montana. By the end of the weekend, thunderstorms across
the Plains can be expected--where there is a marginal risk for severe
thunderstorms for the High Plains and a slight risk of excessive rainfall
for parts of the southern Plains.


Reinhart



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