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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 121348
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
948 AM EDT Fri Apr 12 2024

.SYNOPSIS...
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Showers and gusty winds can be expected today in the cool
westerly flow behind departing low pressure. High pressure is
forecast to provide dry weather on Saturday. The threat for
thunderstorms returns Sunday as low pressure tracks to the Great
Lakes.
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&&

.NEAR TERM /UNTIL 9 PM THIS EVENING/...
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The main item of interest for the near term period is going to
be the very breezy conditions, especially once some of the SHRA
begins to drift E by early afternoon and diurnally-enhanced
mixing gets underway. Steepening LL lapse rates will support
ample vertical mixing, which should become increasingly deep
late into the afternoon. The mixing over a slightly deeper layer
should promote wind gusts in the 30-35kt range for most spots,
especially near/N of I-70. In fact, it is locales near and NE of
a line from Darke Co OH to about Ross Co OH where the greatest
potential for gusts in excess of 35kts should evolve,
particularly between about 18z-23z. While the probs (according
to latest HREF data) of gusts to 35kts is relatively high
(>=70%) in these areas, the probs of gusts reaching 40kts or
greater is markedly lower (generally =<30%). This is most likely
owing to the winds within the mixed layer itself likely staying
near/below 40kts (or 46 MPH). So while a few spots may reach
wind advisory criteria (>=46 MPH), the prevailing probs suggest
this should be a more isolated instance. Nevertheless, will
highlight this potential in the HWO and with an SPS.

The other item of interest this afternoon will be the pivot of
midlevel energy back in from the W late in the day, supporting
another focused area for forcing and lift extending from EC IN
into SW OH and N KY, especially by/after 20z. This will
coincide with an axis of decent SB-instby on the order of
500-750 J/kg, despite meager LL moisture (sfc DPs generally in
the mid/upper 40s). With the steep lapse rates and an axis of
abrupt/enhanced forcing and lift, expect that there will be a
wing of scattered convection that develops within this corridor,
particularly near a line from Fayette/Union Cos IN into parts
of N KY and extreme far SW OH (such as Brown Co). This
convection, which is expected to have some TS to it given the
deeper (albeit very skinny) nature of the CAPE (with good LL and
midlevel lapse rates). The concern here is not necessarily the
expected development of SCT TSRA near the Tri-State between
20z-01z, but the potential that the convective processes
associated with this activity could help translate stronger
winds from aloft to the sfc. While it is still somewhat unlikely
that gusts could reach or exceed 50kts (58 MPH, thus indicating
a severe storm), certainly the potential is there for storm-
induced/enhanced gusts in the 45-55 MPH range (well above the
prevailing synoptically-induced gusts of 35-40 MPH expected in
this area outside of storms). And, of course, with /very/
saturated grounds, it may not take a "severe" gust to cause
trees to topple or isolated power outages. This potential, for
convectively-enhanced wind gusts near or in excess of 50 MPH,
has been added to the HWO within this favored corridor from EC
IN through the Tri-State/N KY. The storm activity (which could
very well include some isolated small hail given the cold temps
aloft) should dwindle beyond sunset, yielding to quieter
conditions by late evening.

Highs today will generally top out in the lower 50s in central
OH to the upper 50s in far SE IN and N KY.
-- End Changed Discussion --

&&

.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SATURDAY/...
After sunset, quieter conditions /finally/ make a return
locally as skies clear and winds subside gradually toward
midnight and beyond. Lows tonight should bottom out in the upper
30s to lower 40s. With the maintenance of steady light
(10-15kts) westerly wind even late into the night, the
potential for frost development is very low.

Sunny skies prevail on Saturday as highs reach into the 60s.
High level clouds will be on the increase toward the evening as
a sfc ridge axis drifts E through the OH/TN Vlys. This will mark
the beginning of an extended period of above, to much above,
normal temperatures in the region.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A weak surface low will move east into the lower Great Lakes from
the Upper Midwest overnight Saturday. This low will nose into a
surface ridge extending northward from the Ohio Valley into MI. Mid
level energy to the northwest will interact with it and bring a low
chance of rain to the norther CWA early Sunday morning. As the low
dips southward and weakens into a w-e trough and eventually a
stationary front that bisects the forecast area from w-e by Monday
morning. As this happens, scattered showers are expected, maximized
northeast and east of Columbus.

High pressure building to the north will help shift the front south
to the Ohio River by Monday morning, with it dissipating shortly
thereafter. Later Monday night, moreso on Tuesday, a warm front will
develop along the remnants of the earlier boundary and move
northeast. Some scattered activity cannot be ruled out but the warm
sector setting up on Tuesday is expected to inhibit activity.

As is typical with a northward moving warm front, it is wrapped into
a low that generally pushes a cold front eastward into the region.
This setup for Tuesday night and Wednesday is no different. The best
chances for showers and storms has been pegged pretty well for these
past forecasts and model runs to occur on Wednesday and potentially
gain instability with daytime heating. This will be associated with
a pre-frontal trough that moves east through a receptive
environment. The cold front and more robust storms should occur a
bit behind this - Thursday into Thursday evening, with strong high
pressure drying out the region overnight Thursday and Friday.

Southerly flow and warm advection will cause readings to rise into
the 70s on Sunday and Monday, mid 70s to around 80 Tuesday through
Thursday, falling into the 60s for highs behind the front on Friday.

After starting out in the upper 40s in the east and lower 50s in the
west Saturday night, overnight lows will remain in the 50s and 60s
through Thursday night.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Additional SHRA is moving back into the area, initially toward
KILN/KCVG/KLUK through 15z, then elsewhere for KCMH/KLCK after
15z. This activity will linger into early afternoon, continuing
at times through early evening for KCVG/KLUK before drier
conditions settle back in after about 00z Saturday. The steadiest
SHRA will be accompanied by VSBY reductions to MVFR, with even some
TSRA possible for KCVG/KLUK past about 21z or so.

A mix of VFR/MVFR CIGs will prevail through the first part of
the TAF period, before going more solidly MVFR by 15z. MVFR
CIGs will hold tight through about 21z before transitioning back
to more VFR and eventually scattering out from W to E between
00z-06z Saturday. Skies will trend clear past 06z.

WNW winds around 15-18kts, with gusts around 25kts, will
prevail through the morning hours before increasing during the
afternoon with steepening LL lapse rates and enhanced vertical
mixing. WNW winds around 20-25kts, with gusts to around 35kts,
are expected by mid afternoon. Winds should decrease toward the
end of the period.

OUTLOOK...Thunderstorms are possible on Sunday and Tuesday.

&&

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

&&

$$
SYNOPSIS...Coniglio
NEAR TERM...KC/Coniglio
SHORT TERM...KC
LONG TERM...Franks
AVIATION...KC