Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
353 PM EDT Sun Aug 17 2014
Valid 00Z Mon Aug 18 2014 - 00Z Wed Aug 20 2014
...Heavy rains and flash flooding possible over the Tennessee Valley and
...Severe weather threat across the Dakotas and Nebraska will continue
into Sunday evening...
...The Four Corners region will see an increase in shower and thunderstorm
activity early this week...
Showers and thunderstorms will continue to ignite along and south of a
wavy frontal boundary stretched from the Southern Plains to the
Mid-Atlantic coast. An organized axis of precipitation is expected to
develop to the east of a surface low along front...which should slowly
track eastward through the lower Ohio Valley Sunday night into Monday. An
abundance of Gulf moisture feeding into the organized area of storms will
allow for heavy rains and heighten the risk for flash flooding across the
Tennessee Valley and Southern Appalachians. The threat for heavy rains
will shift eastward into portions of the Mid-Atlantic states Monday night
into Tuesday as the low tracking through the Ohio Valley weakens and a
second low develops and deepens off the Virginia coast.
The threat for strong to severe thunderstorms will continue across the
Dakotas and Nebraska Sunday night...beneath an upper disturbance dropping
into the north central U.S.. Conditions will remain unsettled with this
system as it crosses into the Upper Midwest and Great Lakes early this
week...and enough moisture across the region could lead to periods of
heavy rains within developing showers and thunderstorms.
An upper low diving southward off the California coast will help draw
anomalous moisture northward into the Southwest and across the Four
Corners states. The increase in moisture should foster widespread shower
activity across the region Monday...and especially Tuesday...afternoon.
Orographic effects could lead to localized areas of heavy rains and flash
flooding within the higher elevations of Arizona.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php