Area Forecast Discussion
Issued by NWS Wilmington, OH

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474
FXUS61 KILN 230613
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
113 AM EST Fri Feb 23 2018

.SYNOPSIS...
Copious moisture  will combine with multiple weather
disturbances riding along a slow moving front to produce heavy
rainfall and flooding tonight through Saturday. Dry weather is
expected with the arrival of high pressure Sunday through
Tuesday. Above normal temperatures are forecast to persist
through the period.

&&

.NEAR TERM /THROUGH TODAY/...
Our region remains in a relative precipitation lull this
evening. Have added areas of drizzle occurring in saturated
shallow moisture, a precursor to rain arriving later tonight.

An embedded s/wv in a very moist southwest flow aloft will
interact with a northward moving warm front overnight. A decent
LLJ will develop to our southwest, and this will impinge on the
warm front, producing substantial moisture convergence. As a
result, showers will develop and increase from our southwest
late. Models are also showing at least elevated instability, so
a chance of thunderstorms is also mentioned. With PWATs forecast
to approach 1.50 inches (which is typical of July and about 3
sigma values above climo) the potential for moderate to heavy
rainfall exists. Points along and south of the Ohio River have
already received 1 to 3 inches of rain today. Thus, any
additional rainfall will likely go directly into runoff due to
saturated soils, resulting in continued or renewed flooding.
Based on model QPF foot prints, the threat for moderate to heavy
rain may affect locations along the I-70 corridor as well. This
rainfall combined with future rainfall this weekend has
prompted an expansion of the flood watch in these locations.
Temperatures will not change that much this evening, but then
rise, especially south, as the warm front lifts north.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
Showers and embedded thunderstorms should be ongoing over much
of the region Friday morning. A cold front is forecast to move
into the region from the west during the day. This boundary will
intersect the northeast advancing warm front. Precipitation
should taper off behind cold frontal passage while continuing
near the cold front and warm fronts. Additional moderate to
heavy rainfall is expected. High temperatures will range from
the mid 50s northwest to the lower 70s southeast.

For Friday night, the cold front will slip south of the Ohio
River where it will eventually stall. There should be a lull in
the precipitation threat across the north, with chances
continuing along and south of the Ohio River. The cold frontal
boundary will begin moving back northward as a warm front late
as more s/wv energy in the midlevel ripples once again into the
region. Thus, have PoPs ramping up late. Lows will range from
the lower 40s northwest to the upper 50s southeast.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Anomalously strong sub tropical ridge over the southeast with a
moist southwesterly flow focused into the Ohio Valley to begin the
long term forecast period. An active wet weather pattern to continue
into Sunday leading to a continued flood threat.

Mid level shortwave and deepening surface low to eject northeast
from the central plains into the Great Lakes Saturday night/Sunday.
Strong low level jet of 70-80 kts will provide anomalous moisture
into the area and marginal instby across the area. Moisture will
pool ahead of a front moving into the area late Saturday night/early
Sunday with precipitable water values approaching 1.5 inches, which
is a record value for this time of year.

Will continue with categorical pops Saturday night. High shear low
cape severe weather setup showing a signal with Sherb 0-3km
parameter Saturday night. In tightening pressure gradient will have
winds gust up to 35 mph.

With the front expected to sweep east through the area early Sunday
a drying trend to develop. Surface high pressure will build across
the Great Lakes offering dry weather from Sunday into the middle of
next week. Expect early highs on Sunday with temperatures falling
into the 40s and lower 50s in the afternoon.

Temperatures to turn cooler but still above normal with highs Monday
from the upper 40s north to the mid 50s south. Temperatures Tuesday
look to be around 10 degrees above normal, with highs from the lower
50s north to the upper 50s south.

Model solution differences develop at mid week regarding how fast
moisture returns on the backside of retreating surface high
pressure. Will limit pops low chance Wednesday afternoon south and
then across the entire FA Thursday. Mild temperatures to continue
with highs in the 50s Wednesday and Thursday.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
IFR cigs/vsbys will be found over much of the region for the
next few hours. A shot of rain will work in from the southwest
before daybreak and last for a few hours. This is associated
with the passage of a low level jet towards daybreak. A brief
inclusion of LLWS may be necessary at CVG/LUK as it passes but
the highest wind speeds will be above the 2kft threshold.
Likewise, given the strong dynamics present there may be
significant slant-wise convection to produce thunder. Will be
monitoring both of these potentials upstream and amend if they
present themselves. Rain will be an early shot and see some
passing showers through the early afternoon. Focus for showers
then shifts southeast and away from the TAF sites, but the
proximity of the axis of good rainfall is too close to not
include VCSH for the bulk of the daylight hours today.

Later in the evening, models are hinting that cigs may improve
if the lower thousand feet could lose its broken characteristic.
A large dry area noted above 1kft would bring VFR conditions if
the low stratus scatters out.

CVG should see a return to IFR late in their 30 hour TAF as the
next batch of rain overspreads the region in the predawn hours
Saturday.

OUTLOOK...MVFR/IFR ceilings and visibilities are likely into
Saturday night. MVFR ceilings may linger Sunday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Flood Watch through Sunday morning for OHZ053>056-060>065-
     070>074-077>082-088.
KY...Flood Watch through Sunday morning for KYZ089>100.
IN...Flood Watch through Sunday morning for INZ050-058-059-066-
     073>075-080.

&&

$$
SYNOPSIS...Coniglio
NEAR TERM...Coniglio/Hickman
SHORT TERM...Hickman
LONG TERM...AR
AVIATION...Franks



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