-- Discussion containing changed information from previous version are highlighted. --
192
FXUS61 KILN 021715
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
115 PM EDT Thu May 2 2024

.SYNOPSIS...
Warm temperatures are expected again today as surface high
pressure shifts off to our southeast. A few showers and thunderstorms
will be possible this afternoon. More widespread showers and
thunderstorms will develop during the day on Friday as a low
pressure system moves through the Ohio Valley.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Ongoing fcst remains on track for today, with an unseasonably
warm afternoon on tap as highs reach into the mid to upper 80s.
Did bump up temps a degree or two across the board given
plentiful sunshine, especially through the first half of the
day.

A residual boundary remains draped across the heart of the ILN
FA this morning, with sfc DPs ranging from the lower 60s near/S
of the OH Rvr to the upper 40s near the I-70 corridor. Amidst
light southerly sfc flow, would expect that the richer LL
moisture should slowly drift back to the N through the
afternoon. But as it does so, the shallow moisture should also
mix out somewhat (especially for the southern half of the ILN
FA), leading to lower sfc DPs (lower 50s) S of I-70 by late day,
with mid/upper 50s near/N of I-70 toward late afternoon. So with
this in mind, the potential for a few spotty late
afternoon/evening SHRA/TSRA should be confined to areas near/W
of I-75 and near/N of I-70, likely "maxing out" in EC IN and WC
OH this evening. Even with this being said, the overall
potential for spotty activity is somewhat low, with the best
coverage centered in the 22z-02z time frame near a corridor from
Fayette/Union Cos IN to Shelby/Auglaize Cos OH. Gusty winds in a
favorable DCAPE environment will be the primary threat with any
stronger cores, but there are questions regarding the intensity
of any storm that is able to develop.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Any lingering thunderstorm activity will taper off this evening
with the loss of daytime heating with skies becoming mostly
clear.

A mid level short wave will lift northeast across the Ohio
Valley late tonight and into the day on Friday in developing
southwest flow aloft. This will be accompanied by a weak
surface wave that will lift northeast across our region through
the day on Friday. This will result in an increase in clouds
later tonight with showers and a chance of thunderstorms
overspreading the region during the day on Friday. Instability
and shear will remain fairly marginal and this will help limit
any severe potential.

Lows tonight will be in the upper 50s to lower 60s with highs
on Friday ranging from the mid 70s west to the lower 80s east.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Looking like quite an active period in store for the extended
forecast, persisting into next week with ridging set up in the
southern stream and large scale troughing in the north. Temperatures
throughout the extended remain above average... around 5-10+ degrees
above climatological normals.

The northern jet stream trough located near the Hudson Bay area will
be wrapping up and pulling its occluded/ cold front through the
region during the overnight hours. Showers continue to work through
the FA, moving from west to east. Forecast soundings still indicate
some weak, elevated instability lingering, so have kept thunder in
the forecast overnight. Overnight lows drop to the low 60s.

Saturday, a shortwave moving through the southern stream looks to
ride up the larger flow pattern and move through the Ohio Valley.
Forcing with this one is weak but should be enough to promote
showers/storms throughout the day on Saturday. Right now, highest
probability of more widespread precip will be east of I-75, given
placement and trajectory of shortwave (although, all areas will have
a chance for thunderstorms given the humid airmass in place).
Overall, do not have high confidence in precip forecast. High
temperatures in the mid/upper 70s.

More of the same on Sunday and Monday with another couple of
shortwaves moving through the southern flow, bringing renewed
chances for showers and storms. Again, forcing isn`t overly
impressive and therefore, signal for precip timing/location is weak.
Have gone with the blend and kept chance to low end likely PoPs in.

The next somewhat stronger signal for storms arrives mid-week as the
upper level trough in the northern stream occludes with its surface
low, pulling the cold front through the Ohio Valley. Interestingly,
both CIPS Analog Guidance and Colorado State Machine Learning both
light up during this time. However, right now we`re still too early
to really have much confidence. Will be something to watch.

&&

.AVIATION /18Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Aside from a FEW/SCT VFR Cu sprouting about, mainly clear skies
will prevail through the first part of the TAF period. A spotty
SHRA or two may develop between about 21z-03z NW of KDAY, but
expect that all local sites will remain dry through tonight.

The VFR Cu should wane in coverage near/after sunset, with
mid/high clouds overspreading from the WSW through the
nighttime. More widespread SHRA/iso TSRA activity will
approach/move in past 12z Friday, with the greatest coverage
likely focusing near SW terminals of KCVG/KLUK near/after 18z.
There will be slow-moving SHRA, with embedded TSRA, around
through the afternoon Friday, lingering through the evening as
well. During the daytime, CIGs will gradually lower from VFR in
the AM to MVFR into the PM. This will occur progressively from W
to E between about 15z-19z. The MVFR CIGs may redevelop/expand
and lower even more Friday night.

Light southerly winds around 7-9kts will prevail through the
daytime before subsiding and becoming nearly calm past sunset.
Light SW winds around 12z will go more westerly during the
daytime Friday, but should generally stay around 5kts into the
afternoon.

OUTLOOK...Thunderstorms are possible at times from Friday
through Monday. MVFR ceilings are possible Friday night into
Saturday.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...JGL
NEAR TERM...KC/JGL
SHORT TERM...JGL
LONG TERM...CA
AVIATION...KC