Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 271736

Area Forecast Discussion
National Weather Service Louisville KY
136 PM EDT SAT AUG 27 2016

...Updated Aviation Discussion...

...Forecast Update...
Issued at 955 AM EDT Sat Aug 25 2016

Updated the forecast to add a 20% POP mainly along and west of I-65
for late morning/early afternoon.  The latest HRRR suggests some
convective development could occur along a trailing boundary from an
overnight MCV as the atmosphere destabilizes.

Temps still look on track with highs in the lower 90s and heat
indices reaching the 100 degree or just over in many locations this

.SHORT TERM (Now through Sunday)...
Issued at 305 AM EDT Sat Aug 27 2016

Expect today to be largely a repeat of Friday as a strong upper
ridge centered over Virginia extends westward across the Ohio
Valley. The ring of fire was active overnight as storms over the
Tennessee Valley lifted NW into western Kentucky, and are now
weakening over SW Indiana.

With convective temperatures solidly into the 90s over most of
Kentucky, will keep most of the area dry for today and tonight. Will
carry slight chances over southern Indiana, as leftover boundaries
from the weakening cluster of storms to our west could light up this
afternoon. Also will carry slight chance over south-central
Kentucky, as storms from Tennessee could edge NW just across the
border. Temps will again reach the lower 90s, with heat index values
approaching 100 this afternoon.

Confidence decreases on Sunday, as the ridging remains strong, but
the synoptic models suggest that an MCS could develop along the
quasi-stationary front over Illinois/Indiana and dive southward into
the Ohio Valley by early Sunday. Will bring chance POPs into
southern Indiana first thing Sun morning, and expand across central
Kentucky through the day as outflows and differential heating could
finally focus convection.

.LONG TERM (Sunday night through Friday)...
Issued at 300 AM EDT Sat Aug 27 2016

Upper ridge will remain oriented east to west across the Ohio Valley
through midweek, resulting in continued heat and humidity. Gradual
breakdown in the mid-level cap will allow for at least isolated
diurnal convection, so will continue to carry a 20-30 POP each
afternoon. Weak flow will prevent any organization, so SVR threat
remains minimal.

Thu-Fri will see the pattern shift as a deep upper trof digs into
eastern Canada, and faster NW flow sets up over the Ohio Valley.
Latest GFS and ECMWF agree on a strong Canadian high building into
the Great Lakes, pushing a more pleasant air mass into the region.
This forecast reflects that with temps near or just below climo, and
dewpoints around 60. However, there still remains some bust
potential, mainly depending on the eventual fate of any tropical
activity, including the increasingly ragged 99L.


.AVIATION (18Z TAF Update)...
Issued at 130 PM EDT Sat Aug 27 2016

A complex of storms was moving through SDF and points NE and will
slowly continue to do so through the afternoon hours.  This complex
should provide SDF with VCTS for the next few hours.  Later this
afternoon, expect convective develop over south central KY close to
BWG.  Not confident with t-storm chances yet since it will be isld,
but did include VCSH in BWG TAF.  LEX should stay far enough under
the upper ridge to remain convection free for the day.

Tonight expect winds to become light/vrb or calm with some fog
chances possible mainly at BWG/SDF if it rains at the terminal this
afternoon/evening.  Will keep fog light compared to MOS guidance at
this time.

Tomorrow scattered showers/storms are expected mainly during the
afternoon hours just beyond 18Z.


.LMK Watches/Warnings/Advisories...


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