Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 210813

Area Forecast Discussion
National Weather Service Wilmington OH
413 AM EDT Fri Oct 21 2016

Low pressure will continue to move northeast today slowing pulling
the backedge of the rain eastward with it. A much colder airmass
will filter into the region today and Saturday, before warmer air
works back into the region for Sunday.


The center of low pressure and a cdfnt are located over West
Virginia early this morning. This has allowed winds to turn to the
north and temperatures to fall into upper 40s and 50s. However,
sharp H5 trof will swing thru the fa this morning. This is
combining with a deformation axis to produce a secondary band of
rain across IN into wrn OH.

It will take a good part of the morning for deformation zone to
work thru the fa, and to bring an end to the chance of rain. Some
rain could linger in the extreme eastern counties into early

Strong pressure gradient on the backside of the low will keep
winds gusty, especially this morning. Gusts 20-30 mph will be
possible. CAA will persist through the day with 850 mb
temperatures dropping down below 0C by late afternoon. This will
counteract the drier air trying to build in this afternoon, to
linger the clouds today. With the cloud cover, temperatures
will be limited to the lower to mid 50s, with a few spots in the
Cincy Tri-State making the upper 50s.


By 00Z the H5 trof axis will be into the Appalachians, leaving
the fa in nw flow both at the sfc and aloft. Feel that there will
be enuf cold air aloft to linger the clouds overnight. The clouds
will help keep temperatures up a little, but they still be a
little below normal falling in the upper 30s and lower 40s.

Surface high pressure will begin to build up into the Tennessee
Valley. While this keep dry conditions on Saturday, lingering cold
air aloft will allow for clouds to redevelop especially during the
afternoon. This will keep temperatures in the 50s, ranging from
the lower 50s in the east to the mid 50s in the west.

Saturday night will see H8 temperatures warming, but think that
the atmosphere will decouple enough for a small diurnal drop in
temperatures. Lows Saturday night will drop back into the lower to
mid 40s.

On Sunday, southwest winds at the sfc will bring warm air back
into the region. A few high clouds could affect the region in fast
flow aloft, but there will be plenty of sunshine and temperatures
should make the mid to upper 60s for highs.


Sunday night into Monday morning a shortwave will push southeast
down mid-level ridging and around the upper level low. The GFS is
slightly more progressive and weaker with the shortwave compared
to the ECMWF. Both 20.12z model runs bring the shortwave slightly
further west than yesterday and therefore try to bring the heart
of the colder air slightly further west as well. The ECMWF and the
GFS push the front through the area by Monday evening. The frontal
passage also appears to be a dry frontal passage as PWATs remain
around 0.60". Behind the front highs will cool down back to normal
as the heart of the cold air still misses the area (850 mb
temperatures around 4 degrees C).

Tuesday the upper level trough will finally head east of the area
taking the cooler air with it. Wednesday into Thursday a shortwave
will eject out of the midwest and approach the area. This means
clouds will begin to increase on Wednesday and into Thursday. Have
also introduced a chance of rain into the forecast Thursday as the
low approaches. PWATs on the GFS rise to above 1.00" with limited
instability. Upper level forcing looks good though as the ILN
forecast area is in the diffluent side of the trough axis and
widespread PV moves over the area. For now have just edged the
chance of precipitation up as model consistency remains low at this


A weak area of low pressure east of the terminals continues to
lift northeast away from the area. Waves of -SHRA will continue to
push northeast through the area during the overnight hours as the
deformation axis slowly pivots eastward. Have seen some
redevelopment of -SHRA west of main pcpn and hi-res models are
picking up well on this additional development. As such, have
added prevailing pcpn at all sites except KCVG and KLUK through
the overnight.

Latest model runs are suggesting that back edge of deformation
axis pcpn will be a bit slower to swing east through the area
during the morning and early afternoon. As such, expect pcpn to
come to an end around 14z for western sites of KDAY, KCVG, and
KLUK and around 18z for eastern sites of KCMH and KLCK. Heaviest
pockets of pcpn may result in brief MVFR VSBYs.

CIGs will hover around 1k ft across all terminals through 15z and
will likely bounce periodically between IFR and low MVFR during
that span. IFR CIGs will be more likely in pockets of higher pcpn.
CIGs will gradually go MVFR and potentially even VFR for western
sites during the afternoon. However, do think that CIGs will
remain MVFR across the east through at least 00z Saturday.

As the sfc low continues to pull away from the area, a tighter
pressure gradient will move in, allowing for
northerly/northwesterly winds of around 15 kts with gusts to 25
kts through the afternoon. Although the tight gradient will
persist longer for eastern sites into the evening, do expect a
gradual weakening trend past 00z Saturday.

OUTLOOK...No significant weather expected.




LONG TERM...Haines
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