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fxus61 Kiln 130036 
afdiln

Area forecast discussion
National Weather Service Wilmington Ohio
736 PM EST Tue Dec 12 2017

Synopsis...
high pressure will briefly build into the area tonight and early
Wednesday. Later in the afternoon, low pressure will track
southeast and into the Ohio Valley, crossing east through
Northern Ohio in the evening. A ridge of surface high pressure
oriented west to east will bring dry weather for Thursday and
Thursday night.

&&

Near term /until 6 am Wednesday morning/...
lake enhanced band of snow will continue to change orientation
from a more NW-se to WNW-ESE this late afternoon and early
evening. Upper level trough will pass east of Ohio this evening
and remove upper level support for these showers, which will
quickly give way this evening. Skies should clear from SW-NE,
with little cloud cover noted to the southwest of the region
this afternoon.

Gusty northwest winds will still be present for the bulk of the
evening hours and then calm down once the gradient loosens up
overnight. The clearing and lightening of the winds will help
the region to drop into the teens tonight.

&&

Short term /6 am Wednesday morning through Wednesday night/...
a slight warmup is expected tomorrow as southerly winds will
pick up and a warm front sets up north of the County Warning Area. Warm is still
a relative term, with upper 30s expected SW of Metro cincy and
around 30 over and NE of Metro Columbus.

Low pressure will track into the area late in the day, and an
upper level shortwave will be the kicker to provide enough lift
ahead of the surface low to initiate snow showers, primarily
for the northern half of the County Warning Area. A secondary shortwave will
follow the first in the evening, bringing another potential
round of snow and then ending any snow threat as it exits the
area.

Highs may be warmer tomorrow in the southwest if the sun is more
abundant. Regardless of the surface temperatures, the cold
nature of the atmosphere above it will only permit snow to be
the weather type of the day. Significant accumulations are not
expected, though an inch or two will remain possible for the
northern half of the County Warning Area tomorrow afternoon and evening.

While the snow potential remains higher over the next few days,
snow totals in the forecast appear to be too high and could be
realistically shaved by half. Adding up 2 and 3 tenths in
several 6 hour blocks given the presence of snow was putting a
higher total in place than what is actually expected. A more
realistic expectation for wednesday's snow would be on the order
of an inch in central Ohio and maybe a half inch northeast of
Metro Cincinnati.

&&

Long term /Thursday through Tuesday/...
northwest flow aloft with surface high pressure building across the
region Thursday. This high will offer dry weather conditions and cold
temperatures. Expect thursdays temperatures to be 10 to 15 degrees
below normal, with highs from the lower 20s northwest to the lower
30s southeast.

Surface low to track through the northern Great Lakes Friday. Best
precipitation to stay to iln/S north closer to the surface wave. Will
carry low chance pop of snow showers north. Temperatures look to be
around 10 degrees below normal, with highs Friday ranging from the
upper 20s north to the mid 30s south.

Upper level flow backs westerly with ridge building into the region.
Southerly low level flow develops Saturday with temperatures warming
to near normal. Expect highs Saturday to range from the mid 30s
northeast to the mid 40s southwest.

Mid level flow backs southwesterly with moisture spreading back into
the area early next week. European model (ecmwf) appears to be an outlier with
GFS/Canadian solutions weaker and more progressive. Will continue
chance pops with the best chance southeast Sunday. Based on thermal
profiles, across the north expect rain and snow during the day
changing to snow Sunday night with mainly rain south. Temperatures
Sunday look to be above normal with highs from 40 north to the upper
40s south. This pcpn event looks to be progressive with pcpn ending
early Monday. Temperatures looks to be close to normal with mondays
highs ranging from the the upper 30s north to the mid/upper 40s
south.

Model solution spread increases by the middle of next week, so
confidence decreases. Using a blended approach will continue a dry
forecast Tuesday into Wednesday with surface high pressure over the
area. Temperatures to moderate a little with highs Tuesday from the
around 40 north to the upper 40s south.

&&

Aviation /00z Wednesday through Sunday/...
low level flow is beginning to back off of Lake Michigan. This
means the snow showers will continue to lift northeast, and
will be limited to cmh/lck for the first few hours of the taf
period. At cvg/luk, SC is already coming to and end. The
southern edge of the SC will see a gradual progression to the NE
through 06z.

Models and satellite loop is showing an area of ac over WI/Illinois
that will swing in overnight ahead of a digging 500 mb S/W.

Forecast for Wednesday is still up in the air. The bulk of the
synoptic models are keeping the overrunning pcpn north of the fa
for period. This is now being supported by the latest runs of
the rap and hrrr, which now reach out until 18z. The two wrfs
and the 18z Canadian regional have more isentropic lift ahead of
the low and are bringing a swath of snow into the tafs between
15-18z. Decided to lean towards the former solution, but even
this solution is showing a chance of snow at cmh/lck during the
morning and lasting into the afternoon. For the other tafs, the
chance of snow will wait unto; the sfc low gets closer to the
region.

Outlook...MVFR ceilings and visibilities along with wind gusts
to 25 kt possible Wednesday night. MVFR ceilings and
visibilities possible Friday and Sunday.

&&

Iln watches/warnings/advisories...
Ohio...none.
Kentucky...none.
In...none.

&&

$$

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