FXUS61 KILN 180916

Area Forecast Discussion
National Weather Service Wilmington OH
416 AM EST Mon Dec 18 2017

A weak weather disturbance crossing the region will bring
cloudy skies and drizzle to the area today. While clouds will
likely hang on into Tuesday, temperatures will remain mild
ahead of the next weak cold front which will slip through the
area Tuesday evening. This front will bring cooler temperatures
and some sunshine for Wednesday.


H5 zonal flow across the region, will allow a weak disturbance
to move through today. This will produce some weak vertical
motion, which will combine with low level moisture to produce
scattered drizzle across the area. Expect cloudy skies today as
the moisture will be trapped under a strong inversion.

Temperatures will continue to be a little above normal, ranging
from the mid 40s in the north to the upper 40s in nrn KY.


Question for tonight is how long the clouds will last. The depth
of the moisture slowly decreases as the night progresses. Feel
that it will be thin enough by late in the periods that some
breaks may develop in the clouds, especially over the west.
Lows will range from the upper 30s in the north to the lower 40s
over the south.

The region will be caught in a split flow pattern Tuesday and
Wednesday. A weak cold front will come through the region dry
late Tuesday. Ahead of the front, temperatures will warm to the
lower to mid 50s. Slightly cooler conditions are expected
Tuesday night as temperatures fall back to 30-35 degrees.

On Wednesday, an upper level disturbance swings out of the
Southern Plains and into the Tennessee Valley. Precipitation
shield should stay south of the region for Wednesday. Highs on
Wednesday will range from the upper 30s in the north to the mid
40s over the south.


confidence begins getting lower by the end of the week, though
there is large-scale agreement on low pressure developing and
moving northeast into southern Michigan by Friday evening. This
will lead to non-diurnal (warming) temperatures on Thursday
night, with increasing chances for precipitation along and ahead
of the associated cold front on Friday and Friday night. With
regards to the low pressure system, timing, phase, and depth
differences are still significant. This affects not only the
timing of the greatest precipitation chances (which right now
appear to be Friday afternoon, definitely subject to change) but
also in the amount and duration of the precipitation, in large
part due to the inconsistent handling of additional southern
stream forcing and moisture transport. Friday does look like a
day that will almost certainly favor rain as the main (or only)
precipitation type, but some mix to snow behind the cold front
could occur.

By Saturday, differences in the modeled pattern become far too large
to even attempt to approximate or assimilate into a gridded
forecast. After the cold front passes on Friday night into Saturday,
temperatures will certainly cool back down, but additional chances
for precipitation are very uncertain at this point in the forecast


Southerly flow over the region will bring in abundant moisture
in the lowest few thousand feet underneath a lowering inversion
today. Passing vorticity maxima at H5 along with a splotchy H7
upward motion vector are showing that disjointed forcing should
bring patchy drizzle and IFR clouds to the region for the
better part of the day. After about 20-21z, the larger upward
motion has moved east of the region and drizzle should be ending
at all locations. Low clouds will occasionally reach above IFR
and into the MVFR category at times throughout the day, but more
likely in the later day and evening.

OUTLOOK...MVFR/IFR ceilings possible into Tuesday morning. MVFR
ceilings and visibilities possible Friday.




LONG TERM...Hatzos
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