Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 011050
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
650 AM EDT Fri Aug 1 2014

.SHORT TERM (Now through Saturday)...
Issued at 328 AM EDT Fri Aug 1 2014

Early morning satellite imagery showing mostly clear skies across
much of southern Indiana and west-central Kentucky.  Some mid-high
level cloudiness was located over east-central KY but was starting
to move off to the east.  Kentucky Mesonet observations and NWS
observations show temperatures generally in the upper 50s to the
lower 60s early this morning.  Expect temperatures to fall slightly
over the next few hours with overnight minimums cooling into the
upper 50s to around 60.

For today/tonight, the multi-model consensus continues to advertise
some precipitation potential in two areas.  The first is across our
northwestern CWA across southern IN, with a secondary area down
toward the I-75 corridor of east-central KY.  A relative minimum in
precipitation potential still looks to exist across north-central
and south-central KY where the models show a continued relative
minimum in precipitable water values.  Feel that best threat areas
for precipitation are in the two areas outlined above...with perhaps
the more favored region being across our NW where weak vorticity
maximum passing through may aid in providing enough lift to get some
isolated showers/storms going.  Highs today look to warm into the
middle to upper 80s.  Warmest spots look to be across our
south/southwestern areas near Bowling Green where upper 80s will be
likely.

Deeper moisture looks to increase slightly tonight ahead of the next
vorticity max swinging through.  While upper forcing looks
sufficient, decent stability looks to be in place to limit overall
coverage below 10 percent.  Thus, will carry some isolated PoPs
early this evening, but shut off PoPs after sunset.  Lows look to
cool into the 60-65 degree range.  The SuperBlend guidance seems to
have a decent handle on temps through this period.

For Saturday, another stringy vorticity max will rotate through the
region.  Overall the model guidance seems to indicate that this will
pass through faster leaving less forcing in place during the
afternoon hours.  It appears that isolated diurnally driven
convection will be possible.  The best chances look to be out near
the I-75 corridor region of central KY.  Expected cloud cover will
likely limit temperatures to a certain extent on Saturday compared
to Friday.  Highs of 78-82 look likely across the Bluegrass region
during the afternoon hours with lower to middle 80s across much of
central/south-central KY.  Warmest readings will likely be down near
KBWG where readings of 85-90 will be possible.

.LONG TERM (Saturday Night through Thursday)...
Issued at 300 PM EDT Fri Aug 1 2014

Strong 500mb ridging off the southeastern coast is blocking the
movement of the current longwave western ridge and Great lakes
troughing that has been in place for several days now. For the
latter portion of this weekend, mid-level troughing aligned over the
Commonwealth will essentially weaken in place as a shortwave
disturbance is forecast to move southeast across the western Great
Lakes Monday. Weak surface high pressure will develop across
Illinois Sunday ahead of this incoming shortwave. This will shift
our surface winds to light northeasterly late Saturday and bring in
drier air with lower PWATs.

Any lingering isolated to scattered thunderstorms will diminish
Saturday night and clear skies will develop Sunday, very likely
lasting through at least Tuesday. Under full early August sun and
subsidence, expect a warming trend, with highs at or just exceeding
90 by Tuesday and Wednesday. Overnight lows will not become too
uncomfortable until late Wednesday, generally staying in the mid to
upper 60s. Light southwest flow will arrive Wednesday, which will
begin a trend toward more uncomfortably humid conditions by late
Wednesday or early Thursday. Lows early Thursday will likely remain
in the lower 70s.

A shortwave will move across Michigan either Thursday or Friday
according to the ECMWF or the slower GFS. The GFS has slowed in it
most recent run, and holds off the threat for storms until late
Thursday while the ECMWF brings in a decent chance of precipitation
during the day Thursday. Will go with a blend of these two models,
bringing a chance of storms in Thursday.

&&

.AVIATION (12Z TAF Update)...
Issued at 648 AM EDT Fri Aug 1 2014

VFR conditions are expected at the TAF sites through the upcoming
forecast period.  Surface winds will start off light and variable
this morning and then become light out of the east-northeast by mid
morning.  Diurnal cumulus field will likely develop after 01/15Z and
isolated convection is expected to develop across the region this
afternoon.  The convective coverage is expected to be too sparse to
include in the TAF package at this time.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&

$$

Short Term........MJ
Long Term.........JSD
Aviation..........MJ





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