NWS Sunday Evening Forecast Discussion – 10 p.m.

An extremely positively tilted but stretched trough in the Ohio Valley will drift slightly southward as the remnant upper level low ejects eastward in the trough. Cold advection at the surface with a high pressure system building eastward out of the Rockies, combined with rich low level moisture tonight will bring a fog potential to the area. However, evaporational cooling allowed by low clouds advecting southward and high clouds streaming from the gulf will keep the fog threat from being uniform.

The result will be variable clouds tonight with patchy fog depending on winds and cloud cover with temps near normal. After morning fog and low clouds expect improving conditions as surface high builds in from the west with seasonable temps.

Not quite as confident with the forecast through the week, but confidence in a dry forecast still remains good. On the other hand, by the weekend all bets are off. The overall pattern remains with active southern stream and a bit of a convoluted and evolving northern branch through the week.

A large upper low over the four corners area ejects as a new upper low undercuts the upper ridge on the west coast. This lead low then opens up and progresses eastward through the week dragging a poorly defined, dry cold front through the area Tuesday night through Wednesday morning. Main energy with this system skirts by to our north centered over the Ohio Valley. Models continue to keep any precipitation just north of the area, brushing extreme northern Alabama. A Strong surface high settles into the mid Mississippi Valley, which should keep us in a more or less continuous northerly flow Wednesday and Thursday.

Daniel Sparkman
dsparkman@wvuatv.com
WVUA Weather