813
FXUS61 KILN 131037
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
637 AM EDT Tue Aug 13 2024

.SYNOPSIS...
A weak upper level disturbance will cross the area early this
morning with a few light showers coming to an end. Otherwise,
high pressure will persist through Wednesday night offering
dry weather. A storm system will move through the Great Lakes
late in the week bringing a chance of showers and thunderstorms.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Northwest mid level flow with a weak embedded shortwave moving
thru the area early this morning. Scattered showers across the
south from a mid level cloud deck will come to an end early this
morning as the shortwave shifts off to the east.

Clouds will decrease this afternoon as the short wave moves
further away from the area. Surface high will remain in place
leading to quiet weather conditions. Highs will be in the lower
80s and middle 80s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Northwest mid level flow with surface high pressure established over
the area tonight. Skies look to be mainly clear with a light low
level northeast flow overnight. Cool lows to range from the upper
50s to lower 60s.

Mid level ridge axis over the MS Valley to nudge a little east
Wednesday offering height/thickness rises. Dry and mostly sunny
sky conditions will be the rule with a warming trend. High
temperatures to range from the lower 80s northwest to the upper
80s southeast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
On Wednesday evening, an area of surface high pressure will be
centered near Lake Ontario, with its influence over the Ohio Valley
beginning to wane as it drifts to the east. Aloft, troughing will be
in place over the northeastern coast, with a somewhat-muted area of
ridging beginning to build into the Ohio Valley from the southwest.
The weather will still be somewhat stagnant heading into Wednesday
night and Thursday morning, as surface flow will remain light until
the surface high gets a little further away from the area.

By Thursday afternoon, the narrow ridge axis will already be moving
through the area. Behind the axis, although surface flow will remain
out of the southeast, flow at 850mb and above will be shifting to
the southwest, with a surge of theta-e moving into the area. This
will allow showers to spread into the area by Thursday afternoon and
evening. Later on Thursday night, boundary layer flow will become
more southerly as well, providing enough theta-e advection ahead of
an approaching mid-level trough to allow fairly widespread
precipitation to develop across the area. The timing for the highest
probability of precipitation now appears to be before 12Z Friday,
with the initial trough axis already moving out of the area by then.

By later Friday, as the overall pattern becomes more amplified,
there is a considerable amount of model spread regarding the
evolution of the trough. This trough may close off into a low over
the Great Lakes, or may remain more progressive as it moves east. In
either case, the Ohio Valley will be on its southern periphery, in a
regime of generally westerly flow -- with chances for precipitation
continuing. PoPs will be kept in the forecast each day from Friday
through Saturday and Sunday, but with gradually diminishing chances
from one day to the next due to temporal forecast uncertainty and
the fact that stronger forcing will likely be displaced to the north
and east with time.

The potential for hazardous weather on Friday remains uncertain, but
with no obvious signs of anything significant. High precipitable
water values (approaching 2") could mean some isolated heavy rain is
possible. Instability and wind shear appear capable of supporting a
low-end severe wind threat on Friday afternoon, with poor lapse
rates being a limiting factor. As these remain low-end and low-
confidence forecasts, will not mention this in the HWO as of yet.

Temperatures in the middle to upper 80s are expected Thursday and
Friday, with cooler values in the lower to mid 80s over the weekend.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Northwest mid level flow with a weak embedded shortwave moving
thru the area early this morning. A few lingering light showers
will be possible across the southern TAF sites. With the low
levels relatively dry - expect these showers to fall from mid
level ceilings.

Precipitation exits the area early with only some mid and high
level clouds thinning out as we head into the afternoon hours.
Main influence from another embedded shortwave expected to
remain north of the TAF sites but some mid level clouds may
re-develop back across KCMH and KLCK this afternoon.

Expect skies to become mostly clear this evening. With light
winds and mainly clear skies - the development of valley fog
will be possible tonight. Have a mention of MVFR vsby restrictions
at KLUK but IFR conditions can not be ruled out.

Light winds will be mainly from the north.

OUTLOOK...Thunderstorms are possible Friday.

&&

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

&&

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