Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 281732

Area Forecast Discussion
National Weather Service Louisville KY
132 PM EDT THU APR 28 2016

...Updated Aviation Discussion...

...Forecast Update...
Issued at 1015 AM EDT Thu Apr 28 2016

A weak cold front reaches from an occlusion over south central
Illinois southward along the Mississippi River. Over southern
Indiana and central Kentucky slow destabilization is underway, which
will peak during the late morning and early afternoon hours. As the
front moves eastward and we approach convective temperatures in the
middle and upper 70s, some shower and thunderstorm development will
be possible. Moisture is somewhat limited, keeping coverage to
widely scattered. Development is expected to begin along or just
east of Interstate 65 around the lunch hour. Convection will then
head east, exiting the eastern LMK counties late this afternoon.
Sounding progs show dry sub-cloud air near the surface, suggesting a
few wind gusts will be possible (DCAPE is already approaching 1000
as of this writing). Cold temperatures aloft support the
possibility of small hail. The best chances for any hail or gusty
winds will be from the Blue Grass to the Lake Cumberland region mid-

.SHORT TERM (Now through Friday)...
Issued at 300 AM EDT Thu Apr 28 2016

Vigorous upper low over the NE/IA border, which spawned a fairly
nice line of storms across here last night despite earlier
convection robbing some instability, continues to influence our
weather. Even in the wake of that line, broad isentropic lift as
well as a theta-e ridge and energy aloft over the region is allowing
new pockets of convection to develop early this morning.  The energy
aloft, in the form of lower heights, should flatten out by late
morning. Daytime heating and moisture still east of the I-65
corridor may allow for some mid/late afternoon development in that
region. Highs should get to around 80 with some sunshine today.

Loss of insolation and drier air moving in from the west should
quickly kill any further convection this evening. With winds dying
off and under clear skies, we should see lows drop to near the lower 50s. Friday looks to be a great day, with that
dry air in place and skies mostly sunny, at least in the morning.
Our next system will bring a chance for rain for the weekend, but
clouds should start streaming in ahead of it Friday afternoon. These
clouds, along with a weak northwesterly flow should limit highs to
the 70s for most locations.

.LONG TERM (Friday Night through Wednesday)...
Issued at 300 AM EDT Thu Apr 28 2016

Warm front south of the region Friday night should lift into the
area Saturday. Lift along this front should bring in some showers
Friday night. A vortmax on the west side of the departing ridge
aloft may combine with this lift to produce some elevated
thunderstorms as well, mainly west of the I-65 corridor. Then during
the day Saturday, the warm front should lift across the region. We
should at this point tap into Gulf moisture in the warm sector of
this system, which will allow for widespread showers and scattered
storm coverage. Cloud cover and timing of the frontal passage will
limit temperatures from getting too warm during the day, with highs
ranging from the upper 60s to the mid 70s.

Proximity to the front, southwest flow aloft, and moisture pool
should keep in solid rain chances Saturday night and Sunday. Rain
chances beyond that will depend on how far the front gets out of our
area. Yesterday, guidance was not showing it stalling near/just
south of the area, but today`s runs of the GFS/EC give us a dry day
Monday. The GEM is more wet though hanging the trough up through
Monday. Previous forecast had dry conditions for all but our
southeast third (i.e., east of a Monroe to Franklin county line) and
this still seems reasonable, despite that GEM solution. Temperatures
on the cold side of this front should be below normal for Monday.

For both Tuesday and Wednesday, the models bring a couple of troughs
across the region. The first should pass through dry, but has a
little better chance for rain so will go low-end chance pops (i.e.,
20-30 pct) for now. Will keep temps near normal, but a little warmer
than Monday.


.AVIATION (18Z TAF Update)...
Updated at 125 PM EDT Thu Apr 28 2016

Only TAF concerns will be gusty winds and perhaps an isolated
shower/storm near SDF/LEX this afternoon.  Did add VCSH in the TAF
for SDF/LEX with the latest HRRR indicating some widely scattered
cells could make it into these terminals.  Won`t include any flight
restrictions at this time though due to isld nature.  WSW winds will
gust to around 18-22 kts at all TAF sites this afternoon as well.

This evening any convection chances should diminish and skies look
to become clear.  With the atmosphere remaining a little mixy aloft,
don`t anticipate many fog issues overnight although may need to look
at an MVFR tempo for BWG around dawn in later TAF issuances.  Few-
sct mid level clouds look likely for tomorrow under lighter winds.


.LMK Watches/Warnings/Advisories...


Short Term.....RJS
Long Term......RJS
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