Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 291648

Area Forecast Discussion
National Weather Service Louisville KY
1248 PM EDT MON AUG 29 2016

...Updated Aviation Discussion...

...Forecast Update...
Issued at 1235 PM EDT Mon Aug 29 2016

The cluster of showers that formed this morning over south central
KY has diminished.  This may be due to a weak subsidence region
behind the shortwave that passed through this morning.  High-res
models have trended a bit drier for this afternoon.  According to
the 12Z NAM, we`ll be completely dry.  For now went ahead and bumped
POP coverage down to isld as some storms may still fire along left
over boundaries.

Issued at 950 AM EDT Mon Aug 29 2016

Updated the forecast to remove morning fog wording and account for a
small cluster of showers/storms that has developed over south
central KY.  This cluster of convection is courtesy of an upper
level shortwave dropping south around the ridge center.  While some
shortwave models indicate we`ll see more disturbances to kick off
convection this afternoon, others keep us largely dry in an area of
weak subsidence behind this morning`s shortwave.  Will continue 20-
30% POPs attm as none of the models seem to be performing well above
the rest.  Plenty of instability will be present today in a weakly
capped environment with a light wind profile.  Thus, when storms do
pop, expect pulse type storms.  A few stronger cells may contain
gusty winds, small hail, and brief heavy rainfall.

Afternoon temperatures still look to warm into the upper 80s/lower
90s resulting in heat indices in the 95-102 degree range.

.SHORT TERM (Now through Tuesday)...
Issued at 305 AM EDT Mon Aug 29 2016

Upper ridge remains parked east to west across the Ohio Valley, with
a weak easterly surface gradient under it. Low-confidence convective
forecast today, as it will depend on whether enough boundaries are
lingering behind Sunday`s convection to focus new storms this
afternoon. Hi-res models are not showing much, but they don`t have a
great handle on the current lack of precip over the area. That being
said, will continue the theme of isolated/scattered POPs beginning
mid/late afternoon, once we touch convective temps around 90F.
Dynamics too weak for organized severe wx, but plenty of moisture
and instability to support pulse threats of heavy rain and marginal
severe winds. Outside of any storms, temps in the lower 90s and
dewpoints in the lower 70s will be enough to push heat indices near

Will not carry precip chances on Tuesday, as there is even less to
focus convection, and the deep moisture starts to erode, with
precipitable water dropping below 1.5 inches and dewpoints trending
down into the mid/upper 60s. Ridging aloft is still strong enough to
support max temps touching 90.

.LONG TERM (Tuesday Night through Sunday)...
Issued at 305 AM EDT Mon Aug 29 2016

Long-awaited pattern shift comes mid-week with an upper trof
digging into the Great Lakes. POPs will be limited to 20-30% on
Wednesday afternoon/evening as the cold front comes through in
pieces, and a weak easterly gradient ahead of the front limits any
surface convergence along the boundary.

A much more pleasant air mass will follow for Thursday through
Saturday as a 1027mb high builds into the Great Lakes. Temps will
run a few degrees below normal both day and night, with dew points
dropping into the upper 50s/lower 60s.

Later in the weekend, the surface high will retreat far enough east
to set up return flow, and upper ridging starts to build from the
west. Therefore expect Sunday temps to recover to near normal, with
dewpoints rising back into the muggy range.


.AVIATION (18Z TAF Update)...
Issued at 1246 PM EDT Mon Aug 29 2016

The main issue for the TAFs this afternoon will be whether any
storms affect the terminals. The latest short term model guidance
suggests that coverage of storms will be fairly isolated this
afternoon. The best chance may be at BWG as a few storms fired not
far to the north of there this morning along an old boundary.
However, given the low coverage expected, have removed VCTS from the
TAFs for this afternoon. Otherwise, mainly VFR conditions are
expected with light northeasterly winds. BWG may also have a brief
period of light fog tomorrow morning.


.LMK Watches/Warnings/Advisories...


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