Area Forecast Discussion
Issued by NWS Louisville, KY

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817
FXUS63 KLMK 241513
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1113 AM EDT Mon Jul 24 2017

.Forecast Update...
Issued at 1110 AM EDT Mon Jul 24 2017

Satellite reveals morning fog has burned off and high clouds are
streaming in from the southwest. Still looks like the best chances
for isolated to scattered storms will be south of I-64 ahead of a
weak surface front, so no major changes have been made to the
forecast.

&&

.Short Term (Now through Tuesday)...
Issued at 330 AM EDT Mon Jul 24 2017

It`s a quiet morning across central Kentucky and southern Indiana,
with temperatures ranging from the upper 60s to mid 70s. Skies were
mostly clear, with the exception of southern Kentucky, where
convective debris clouds were spreading ENE from Tennessee. Dewpoint
depressions are fairly small this hour, and with mainly clear skies
and light winds, patchy fog is likely by 08-09z. In particular,
areas that saw heavy rain over the weekend will likely have areas of
fog. Certainly can`t rule out locally dense fog either.

A surface cold front was oriented southwest to northeast across
central Indiana early this morning. Surface observations reveal N/NW
winds and dewpoints in the mid 60s to the north of boundary in
northern IL/IN. This boundary will gradually push south, resulting
in weak convergence over central KY this afternoon and evening.
Aloft, we`ll stay in northwest flow with mid-level height rises as
an upper trough propagates over the Eastern Great Lakes.

Latest hi-res models suggest daytime heating will support isolated
to scattered pulse thunderstorms or multicells south of the I-64
corridor. Highest chance for scattered convection this afternoon
will be along/south of the Western KY/Bluegrass Pkwys. A few of the
storms could be strong, with frequent lightning and gusty winds.
However, severe weather is not likely. Moderate destabilization is
expected south of the surface boundary, with MLCAPE up to 1500-2000
J/kg. Deep layer shear will be weak with light winds aloft. Steep
low-level lapse rates and DCAPE over 1000 J/kg will promote downward
momentum transfer with any storms during the afternoon and early
evening.

Convection will likely wane toward sunset, giving way to clearing
skies overnight. Cooler northerly flow will allow lows to range from
the lower 60s to around 70 degrees Tuesday morning. Patchy fog is
likely tomorrow morning as well. The rest of Tuesday looks quite
nice, with sunshine and highs in the 80s. There`s a slight chance
convection over the Tennessee Valley could clip our SW counties
Tuesday, but most will be dry.

.Long Term (Tuesday Night through Sunday)...
Issued at 345 AM EDT Mon Jul 24 2017

During the midweek period, the upper ridge will continue to build
east over the region. This will keep the weather dry on Wednesday,
with highs in the upper 80s/low 90s.

By the Thursday/Friday timeframe, a strong shortwave and associated
cold front will move through the lower Ohio Valley. Widespread
showers and storms will develop along and ahead of the front. The
latest data suggests the most likely time frame of concern will be
Thursday afternoon through Friday morning, but timing uncertainty
remains. The weather over the weekend is looking absolutely
wonderful, with mostly sunny skies, highs generally in the low to
mid 80s, dewpoints in the low to mid 60s, and light refreshing
northerly winds.

&&

.Aviation (12Z TAF Update)...
Issued at 645 AM EDT Mon Jul 24 2017

After a few patches of fog at the start of the period a weak cool
front will drop southward across central Kentucky today. Convection
may accompany the front but should be fairly widely scattered with
not much moisture available and only weak convergence. LEX stands
the best shot at a shower or thunderstorm this afternoon.

Skies will clear tonight but we will likely maintain a light
northeast breeze which may serve to mitigate fog potential somewhat.
Will still include some MVFR BR at fog-prone BWG towards the end of
the forecast period.


&&

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

$$

Update...DM
Short Term........EBW
Long Term.........EBW
Aviation..........13



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