385
FXUS61 KILN 181716
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
116 PM EDT Wed Sep 18 2024

.SYNOPSIS...
An upper level low pressure system over the southern Appalachians
will slowly migrate to the east today. This system will offer
clouds and perhaps a sprinkle or light rain shower. High
pressure and dry weather will then persist into the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
18.12Z sounding had fairly decent mid and high level moisture -
and this is manifested in areas of mid cloud/cirrus that are on
a slow diminishing trend per visible satellite loop this
morning. With increased - but shallow - low level moisture over
previous days, expect some cumulus to develop later this morning
or early this afternoon amidst light easterly/northeasterly low
level flow. Some residual showers are working southwestward
across southeast Ohio/West Virginia around the departing upper
trough/vertically stacked cyclone to our southeast, a few
sprinkles or very light showers may still clip the Scioto
Valley and northeast Kentucky. In addition, forecast soundings
for late this afternoon indicated some very weak instability,
and in combination with some semblance of cyclonic flow/upper
troughing, a number of CAMs continue to show a couple of
isolated updrafts trying to form later this afternoon into this
evening, in no particular or favored location. Given concerns of
low level moisture mixing out per ongoing drought conditions,
confidence in these forming is not high enough to mention, and
may be tied to models continued overforecast of low level
moisture in recent weeks. Bumped up afternoon high temps just a
bit based on low level thermals on morning sounding under a mix
of sun and clouds. Rest of forecast on track.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Mid level low over the southern Appalachians to open up and
track east overnight into Thursday. Clouds decrease this evening
with skies becoming mostly clear. This will result in more
favorable radiational cooling conditions leading to lows
dipping into the upper 50s to the lower 60s. With a light low
level northeast flow and mainly clear skies - some fog and
stratus development will be possible. The best threat for
stratus looks to be over the northeast counties but there is
still is a fair amount of uncertainty on placement.

A vort lobe rotating around the western periphery of mid level
trof and an axis of marginal instability may result in the
threat for a shower or thunderstorm east of ILN/s area Thursday
afternoon. This activity should remain well east of ILN/s area
with partly cloudy to mostly sunny sky conditions. Sunshine will
aid warm temperatures reaching highs in the mid and upper 80s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Period starts under high pressure with dry weather expected to
persist from Thursday night through Sunday. Unsettled weather begins
Sunday night with the arrival of mid level short wave energy and
moisture convergence ahead of a boundary, bringing a chance of
showers and a few thunderstorms to northwestern locations. The
threat for showers and storms spreads across the area Monday and
Tuesday as additional short waves and moisture advection coincide
over the Ohio Valley. Severe weather threat is hard to determine at
this point but any measurable rainfall will notable during our
drought.

Temperatures begin hot with highs around 90 Friday and Saturday.
Potential clouds and precip should help curtail readings a bit for
the rest of the long term, with highs in the mid and upper 80s
Sunday and Monday, and the upper 70s to low 80s Tuesday.

&&

.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
Scattered to locally broken VFR cumulus continues to develop
early this afternoon, but expect cloud bases to lift a little
more through the day due to heating so no MVFR potential with
these clouds even if they go broken/ceiling for a brief
period. Most will be scattered in coverage. Light northeast
winds will sometimes go variable in direction due to weak
pressure gradient.

Winds should go calm or light/variable before sunset with vast
majority of cumulus dissipating. With clear/mostly clear skies
tonight, think valley fog will develop and affect LUK as it
usually does on clear/calm autumn nights, and have TEMPO for IFR
visibility there. A separate signal for more widespread / areal
fog is showing up across the area. Confidence is low in how this
may manifest, but felt confident enough to bring some MVFR
visibilities via TEMPO groups into all TAF sites between 08-12Z.
Coverage and favored location is not high, and future forecasts
may need to consider lower visibility based on observational
trends. Background setup (clear skies, longer nights, light
northeast wind, shallow moisture recently having moved into the
area) makes areas of fog (or perhaps low clouds) more probable
later tonight.

Any remaining fog should lift/mix out on Thursday morning with
more scattered cumulus by 18Z, and continued light northeast or
easterly winds.

OUTLOOK...No significant weather expected.

&&

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

&&

$$
SYNOPSIS...AR
NEAR TERM...Binau
SHORT TERM...AR
LONG TERM...Coniglio
AVIATION...Binau