Area Forecast Discussion
Issued by NWS Wilmington, OH
FXUS61 KILN 230653
Area Forecast Discussion
National Weather Service Wilmington OH
253 AM EDT Sun Apr 23 2017
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 /UNTIL 6 PM THIS EVENING/...
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
.SHORT TERM /6 PM THIS EVENING 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/...
With the upper level low now slower and inland than previously
forecast, systems have slowed down for the immediate long term.
For Monday night into Tuesday, some clouds will rotate westward
into the region from slow moving upper level low to our east. A
modifying airmass will still boost temperatures into the mid and
upper 70s on Tuesday.
Next piece of s/wv energy to eject out of a long wave trough
(from the Pacific NW to the southern Plains to the western
Great Lakes) is now expected to affect the region Wednesday
night into Thursday. With a dry Wednesday and southerly flow,
highs on Wednesday should warm into the lower perhaps mid 80s.
The threat for showers and storms is now forecast for Wednesday
night into Thursday as aforementioned s/wv moves through our
region along with a surface cold front.
Have been waiting for the models to come into better agreement
by weeks end and into next weekend. Unfortunately, there
continues to be considerable disagreement on how far east/south
mid weeks cold front will get and how fast it will return as a
warm front. The uncertainty calls for a very broad brushed
forecast, keeping a chance of showers and thunderstorms going
through this period. Temperatures will remain warm with mainly
70s and perhaps a few lower 80s in our southeast CWFA.
.AVIATION /07Z 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
OUTLOOK...No significant weather expected.