Area Forecast Discussion
Issued by NWS Wilmington, OH

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000
FXUS61 KILN 230640
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
240 AM EDT Sun Apr 23 2017

.SYNOPSIS...
An area of upper level low pressure will move slowly eastward across
the southeastern states on Sunday. Dry high pressure will remain in
place across the southern Great Lakes and northern Ohio Valley. A
gradual warming trend will begin going into the new week, before a
cold front moves into the region Wednesday night into Thursday.

&&

.NEAR TERM /THROUGH TODAY/...
The ILN CWA remains well on the north side of a complex low
pressure system south of the region, with the upper low
currently centered somewhere near Cairo IL, and the surface low
centered in the Huntsville AL vicinity. There remains a sharp
boundary separating a warm and moist air mass over the
southeastern states from the cool and dry air mass in the Ohio
Valley -- characterized by dewpoints in the 30s and mostly clear
to clear skies.

Entrenched in a cool flow pattern (NE near the surface and ENE
slightly aloft) there will be little change to the overall air
mass today, but a fair degree of warming is expected compared to
yesterday, thanks to a significant increase in insolation. It
should be noted that the theta-e boundary further aloft
(850mb/700mb) remains further north than the surface boundary,
and as the day progresses and the low shifts eastward, some of
the moisture aloft will make an attempt at advecting NW into the
southeastern sections of the ILN CWA. This will probably keep a
few more clouds in these areas (and thus keep temperatures down
by a couple degrees) but chances for precipitation are much less
clear. A 20-percent PoP has been kept in the far southeast this
afternoon, but if current model trends continue to suggest a dry
solution (as the 00Z runs have done) this may be able to be
removed.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
Outside of the off chance of a light shower in the southeastern
CWA this evening, a dry forecast is expected through the rest of
the short term forecast period. Clear skies overnight will allow
for another round of cool temperatures by Monday morning, though
the warmer starting point and continued wind (5-10 knots) will
keep the risk of frost very marginal.

By Monday morning, an expansive area of dry surface high
pressure will stretch from northern Ontario/Quebec through the
Great Lakes, extending SSW through the northwestern Ohio Valley
and into eastern Texas. As this high gradually weakens, wind
flow will begin a clockwise shift in the Ohio Valley, especially
aloft. On the northern periphery of the upper low moving into
the Carolinas, 850mb-700mb theta-e advection will become
pronounced by Monday afternoon, allowing for an increase in
mid-level moisture and clouds during the day. With little change
to the boundary layer air mass, temperatures are unlikely to
gain significantly from Sunday to Monday, but another day of sun
(especially early in the day) will allow for slightly warmer
conditions (particularly in the western CWA).

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Monday and Tuesday should have dry weather with a closed upper
low traveling well to the south, leaving the ILN area under a
ridge of high pressure. With models trending slower, mainly dry
weather will continue into Wednesday, until the threat for
showers and thunderstorms begins in increasing moisture and
instability ahead of an approaching cold front. Thunderstorm
chances will continue Wednesday night and Thursday as the front
swings across the area. Additional showers and thunderstorms
will be possible Friday and Saturday when the front is forecast
to stall and then lift back north toward I-70.

Above normal geopotential heights suggest warmer than normal
conditions. Temperatures forecast to rise into the 70s each day will
indeed be above normal through the period.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Skies have generally cleared out over the region tonight, and
mostly clear skies are expected through the rest of the TAF
period, with just some cirrus at times. Winds will remain out of
the NE through the TAF period as well, with sustained winds of
5-10 knots, gusting to 15-20 knots during the afternoon on
Sunday.

OUTLOOK...No significant weather expected.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...Hatzos
NEAR TERM...Hatzos
SHORT TERM...Hatzos
LONG TERM...Coniglio
AVIATION...Hatzos



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