Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 231906
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
306 PM EDT Thu Apr 23 2015

.SHORT TERM (Now through Friday Night)...
Issued at 300 PM EDT Thu Apr 23 2015

...Frost/Freeze for Tonight...

With a sfc high pressure center moving through southern Indiana and
central Kentucky tonight, strong subsidence and good rad cooling
will result.  Sfc winds will go calm or light and variable late this
evening and remain that way through much of the night.  We may start
to see a few upper level clouds late but nothing that will hinder
the cooling all that much.  With these ideal cooling conditions in
place for tonight, think that a good portion of the area from Paoli,
IN to E-town, KY to Lake Cumberland and portions east should see
sub-freezing temps tonight.  For this area, will issue a Freeze
Warning.  For locations along a Jasper to Leitchfield to
Tompkinsville line, think that areas of frost will develop as temps
fall into the low to mid 30s with near sfc moisture still plentiful
enough.  This area will warrant a Frost Advisory.  Debated a Frost
Advisory for Bowling Green and surrounding counties but feel that
with the sfc high moving to eastern KY by 12Z, this area should
start to see temps level off earlier and/or experience a slight rise
in temps by sunrise.  Frost/Freeze products will run from 3 AM to 9
AM EDT (2 AM To 8 AM CDT) Friday.

Any frost will quickly dissipate by mid morning as temps rise well
above freezing.  For the rest of the day Friday, we`ll see
increasing mid and high level clouds ahead of the next weather
system.  Temperatures will be warmer in the low to mid 60s for highs.

Friday night an upper level wave and a weak sfc trough will move
north through the area providing showers and isolated elevated
t-storms.  Showers/storms will be most numerous around and after
midnight.  Steady moderate to at times heavy rainfall will be
possible as this convection moves through with 0.25 to 0.75 inches
of rainfall possible Fri night.  Low temperatures should range from
the lower 40s to lower 50s.

.LONG TERM (Saturday through Thursday)...
Issued at 252 PM EDT Thu Apr 23 2015

...A Chance of Severe Storms on Saturday...

At 12Z Saturday low pressure will be near Kansas City with
widespread showers and thunderstorms along and either side of a warm
front reaching into the Ohio and Tennessee Valleys. The low will
head to the ESE during the day, reaching the lower Wabash Valley by
evening with its warm front extending eastward through southern
Indiana and northern Kentucky.  The GFS has been pretty consistent
with this idea for its past five runs, and this morning`s ECMWF has
trended slightly toward the GFS in this regard. Showers and
thunderstorms will continue to be widespread in association with the
warm front.

South of the front, much of central Kentucky will get into the warm
sector of the cyclone.  This area will have the potential to become
very unstable by afternoon with steep mid-level lapse rates and
plenty of CAPE above a low-level cap that should weaken and possibly
disappear.  There will be some dry air aloft to help with downburst
potential, and wet bulb zero heights around 8k feet indicate large
hail to be a possibility.  There will be enough shear, along with
low LCLs, that we can`t rule out isolated tornadoes, especially in
far southern Kentucky during the early to mid afternoon.

The best chance for severe weather appears to be west of I-65 and
south of the Ohio River, though we`re still a couple of days out so
nothing is set in stone.  A lot will depend on the track of the low
and where exactly the warm front and its related convection set up.

Rainfall amounts should generally be in the 1 to 1.5 inch range,
with the heaviest amounts over northern Kentucky and southern
Indiana.  Of course, with thunderstorms there can be large
differences from one spot to the next.  The sunshine, winds, and
very low dew points of the last few days have really helped to dry
things out, so any flooding issues from this rain would likely be in
the form of localized flash flooding under particularly heavy
showers.

Depending on the placement of the warm front, high temperatures on
Saturday could range from the middle 50s in the northern Blue Grass
and southeast Indiana to the middle 70s in southern Kentucky.

The rest of the long term period is quiet and mostly dry.  A
southern system moving along the Gulf coast mid-week may throw a few
showers into southern Kentucky Tuesday night and Wednesday.

&&

.AVIATION (18Z TAF Update)...
Updated at 100 PM EDT Thu Apr 23 2015

High pressure will dominate the region through the TAF period.
Northwest winds will be gusty at SDF/LEX this afternoon before all
TAF site winds go calm or light and variable late this evening.
Expect increased high and mid level clouds tomorrow ahead of the
next weather system.  Light winds will be predominantly from the
southeast tomorrow.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...FREEZE WARNING from 3 AM EDT /2 AM CDT/ to 9 AM EDT /8 AM CDT/
     Friday FOR KYZ025-028>043-045>049-053>057-064>067-077-078-
     081-082.

     FROST ADVISORY from 2 AM to 8 AM CDT Friday FOR KYZ023-024-026-
     027-062-063-074>076.

IN...FREEZE WARNING from 3 AM to 9 AM EDT Friday FOR INZ076>079-084-
     090>092.

     FROST ADVISORY from 2 AM to 8 AM CDT Friday FOR INZ083-089.

&&

$$

Short Term........AMS
Long Term.........13
Aviation..........AMS




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