Area Forecast Discussion
Issued by NWS Louisville, KY

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724
FXUS63 KLMK 281044
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
644 AM EDT Wed Jun 28 2017

...Updated Aviation Discussion...

.Short Term (Now through Thursday)...
Issued at 245 AM EDT Wed Jun 28 2017

Dry air mass in place with surface high pressure centered over the
Appalachians. Warming trend starts today as the high retreats east
to the Hampton Roads area and heights begin to rise. Low-level
thickness progs suggest highs today will be roughly 5-6 degrees
warmer than Tuesday, but humidity levels will remain comfortable as
Gulf moisture won`t really arrive until Thursday.

Gulf really opens up on Thursday with enough low-level moisture to
drive precipitable water back up to more seasonal values, and the
main challenge is the northward extent of where diurnal convection
can develop in the warm advection pattern. Will continue the theme
of slight chance POPs roughly along and south of the Cumberland
Parkway. Modest instability and weak shear will prevent any
organization of storms. Dry forecast across the rest of the area as
the approaching cold front remains far enough north to be a non-
factor.

.Long Term (Thursday night through Tuesday)...
Issued at 245 AM EDT Wed Jun 28 2017

Precip chances will ramp up Friday into Friday night as an upper
trof swings through the Upper Midwest and drives a surface cold
front into the Ohio Valley. Rain chances will be maximized on Friday
night just ahead of the front, but will linger into at least
Saturday as the boundary hangs up somewhere over the Ohio or
Tennessee Valley. Have gone to a dry forecast Sat night/Sun as
latest runs suggest the front could push far enough south to allow a
bubble of high pressure into the area, but confidence is not high
and the change in air mass is minimal. Better rain chances on Monday
and Tuesday as progressive disturbances aloft will cause the front
to oscillate, but not enough confidence to go higher than 50% POP as
the timing remains uncertain.

&&

.Aviation...(12Z TAF Issuance)
Issued at 640 AM EDT Wed June 28 2017

VFR weather is forecast throughout the TAF period. Skies will remain
mostly sunny. Surface winds will remain light and variable this
morning. South winds will increase to 5-10 kts by 15z or so.

Surface winds will remain slightly elevated overnight as low
pressure tracks into the Great Lakes. Of concern by 06z tonight will
be increasing southwest winds just off the surface. Expect a 35 kt
SW low-level jet as low as 1500-2000 ft. Low-level winds could be
fairly stratified given the nocturnal inversion.

&&

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

$$

Short Term........RAS
Long Term.........RAS
Aviation..........EBW



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