Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 210611

Area Forecast Discussion
National Weather Service Wilmington OH
211 AM EDT Thu Sep 21 2017

A stagnant weather pattern will set up over the next several
days, with mid-level ridging over the region. Warm temperatures
10 to 15 degrees above normal will continue through the


A stray shower or two may still pop up over the CWA for the
next few hours as a high moisture content airmass continues to
interact with a departing upper level shortwave. Any cells that
might pop will not be deep enough to support thunderstorm
activity and thunder has been removed from the forecast with a
weak 20% coverage added to mainly the southeastern quarter of
the CWA. Did not change the fog forecast tonight given the
unusually moist air over the region.

Fog potential is the greatest concern for tonight, with a
favorable setup in the wind and pressure pattern (overall light
flow with the main axis of the boundary-layer ridging just to
the east). Where skies clear out, conditions will be favorable
for fog to become locally dense, especially in river valleys or
more broadly in the eastern half of the forecast area.


The stagnant weather pattern will essentially remain in place on
Thursday, with broad mid-level ridging extending from the Great
Lakes into the middle Mississippi Valley, and an elongated
surface high centered well northeast of the Ohio Valley region.
Thursday appears to set up as another day with light wind flow
and some chance of afternoon instability, which has resulted in
some inconsistent/weak QPF output across the suite of models.
Looking at soundings, there will be some warming of temperatures
in the 800mb-750mb layer between Wednesday and Thursday, which
will make it less likely for any precipitation to develop. The
chance certainly isn`t zero percent, but appears small or
isolated enough to not include in the main forecast.

Temperatures should be able to rise by a few degrees for both
Thursday and Thursday night.


Strong H5 ridge will be the dominant feature for much of the
forecast period. The ridge will keep Jose off the East Coast and
away from the Ohio Valley, and later on Maria. Meanwhile at the
surface, a surface high centered over the St. Lawrence Valley will
extend southwest into the fa.

The combination of these two features will bring dry condition and
above normal temperatures through the weekend and into early next
week. High temperatures will be about 10 degrees above normal
values through Tuesday as they push into the mid and upper 80s.
Morning lows be around 60.

By Wednesday a cold front will be moving east up the Ohio Valley. It
will bring some scattered convection. The GFS is a little quicker
than the ECMWF and Canadian with the front. Have included 20 PoPs in
the wrn half of the fa for Wednesday. Highs Wednesday will still be
around 80 degrees.


Mid level ridge to build from the Lower MS VLY through the
Eastern Great Lakes. Surface high pressure will remain centered
just to our east over the Upper Ohio Valley. Subsidence over
the area has led to clear skies. The clear skies, light winds
and a moist boundary layer is creating favorable conditions for
fog development, mainly in river valleys. Have IFR VSBY
restrictions at favored KLUK and KILN with mainly MVFR
restrictions at remainder of the TAF sites.

Moisture is shallow, so the fog will burn off quickly after
sunrise. Expect some scattered cu development along with high
level clouds from upstream convection.

Radiation fog development likely again tonight with IFR
restrictions limited to the favored valley location at KLUK.
Through 06Z have limited the restriction to the MVFR category.

OUTLOOK...No significant weather is expected at this time.




NEAR TERM...Franks
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