Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 251657

Area Forecast Discussion
National Weather Service Louisville KY
1257 PM EDT WED MAY 25 2016

...Forecast Update...
Issued at 1255 PM EDT Wed May 25 2016

North/south loosely organized complex of showers/storms continues to
slowly drift eastward across western Kentucky. A break in the cloud
cover and an increase in surface dewpoints has allowed SBCAPE to
increase to near 1000 J/kg. Shear environment remains weak and
messy, so overall not expecting anything strong to severe but just
the chance of more typical summer-like showers/storms. Some gusty
winds, lightning and brief heavy rain is possible as this line
drifts into our western areas this afternoon. POPs were brought up
west of I-65 through the evening. Otherwise, forecast is on track so

Issued at 1025 AM EDT Wed May 25 2016

Extensive mid/high cloud deck this morning combined with slightly
drier air has kept instability axis well west of the forecast area.
A weak decaying upper level system passing through western/central
Kentucky produced light morning showers, but recent returns have
diminished. Some light sprinkles or showers are possible generally
most locations will be dry.

Convection across southern IL and far southwest KY is just slowly
drifting to the east, but wanes as it moves into the less favorable
environment. Will maintain just slight chances through the
afternoon, mainly across southern Indiana and west of I-65 where the
greater moisture resides. Highs are still on target for the low/mid

.SHORT TERM (Now through Thursday)...
Issued at 315 AM EDT Wed May 25 2016

Mild conditions have held on through the night, with light south
breezes and slowly increasing dewpoints. Aside from a few radar
returns that suggest isolated light rain showers over south central
Kentucky, we are almost entirely precip-free as new convection
advertised by most of the models has failed to materialize over the
lower Ohio and Wabash Valleys, and an earlier MCS has almost
completely fizzled over western Tennessee.

Short-term forecast confidence is sorely limited due to this poor
model initialization. Expect an increasingly muggy low-level air
mass to evolve today, with isolated to scattered shower and
thunderstorm chances. Ongoing MCSs over Kansas and Oklahoma will
likely gust out before reaching the Mississippi, but these will bear
watch for any MCV development that could serve as a trigger here
later tonight. Again will limit POPs to slight or low chance, with
the best chances over southern Indiana as the upper flow pattern
would seem to favor disturbances tracking ENE across there.

Expect more of the same on Thursday as it is becoming increasingly
difficult to pin down the upper impulses that may trigger convection
over the Ohio Valley. Precip chances will remain limited to chance,
and temps will continue to run several degrees above normal by day,
and trend warmer each night.

.LONG TERM (Thursday night through Tuesday)...
Issued at 310 AM EDT Wed May 25 2016

Upper ridging over the southeast CONUS will be the main player
through the weekend into early next week, resulting in warm and
muggy conditions. Upper trofiness will hold over the Plains, and
impulses will round this trof and head into the Great Lakes, with
scattered showers and storms possible if any of these disturbances
track close enough to the Ohio Valley.

For now will largely broadbrush POPs in the 20-30% range, but at
this point would not brand any day a washout. As disturbances become
more clear, will likely see some POPs bumped up while others could
be removed. Temps will be modulated primarily by clouds and any
convection that pops in the afternoons, with the main theme being
above normal. The real unknown, especially late in the weekend, will
hinge on the fate of a subtropical system that most of the models
show off the Carolina coast. If this system is strong and/or close
enough, we could get into the subsidence region on its western
flank. That would cut into precip chances and give temps a better
chance of cracking 90 on Monday and/or Tuesday.


.AVIATION (12Z TAF Update)...
Issued at 644 AM EDT Wed May 25 2016

The chance for showers and/or storms remains the challenge for this
TAF period. Model guidance continues to output too much
precipitation, so will keep the forecast on the drier side. The best
chance for some light showers will be at BWG this morning. SDF and
LEX could see a brief shower or two as well this morning into the
early afternoon. However, confidence is less at these sites, so will
carry only VCSH. There could be another round of showers move
through tonight, but given the low confidence, will keep the
forecast dry for now.

VFR ceilings and visibilities are expected through this TAF period.
Winds will shift from southeasterly to southerly today and will pick
up though mid day.


.LMK Watches/Warnings/Advisories...


Short Term.....RAS
Long Term......RAS
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