Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 052245
Area Forecast Discussion
National Weather Service Louisville KY
645 PM EDT MON OCT 5 2015
...Updated Aviation Discussion...
.SHORT TERM (Now through Sunday)...
Issued at 304 PM EDT Mon Oct 5 2015
The synoptic pattern this afternoon features an omega block across
much of the CONUS, with two cutoff upper-level lows, one just off
the Southeast coast and another across the Desert Southwest. This
will place the Ohio Valley within general ridging aloft through the
short term period bringing seasonably warm and tranquil conditions.
Generally clear conditions will persist this evening. A weak,
moisture-starved system will move mainly across IN/OH tonight
through Tuesday, which may spread some upper-level cloudiness into
the region. This should help keep lows up just a couple of degrees
west of I-65 in the upper 50s, with low/mid 50s expected elsewhere.
Can`t rule out some patchy valley fog towards dawn Tuesday in areas
that don`t see cloud cover overnight.
Tuesday will be another warm October day, but the upper clouds
mentioned above may help keep temperatures just a bit from today`s
readings, especially across the northern CWA. It will all depend on
how thick these clouds are and how long they stick around as to how
warm temperatures will get. For now, highs in the upper 70s to
lower 80s seem reasonable. Overnight lows on Wednesday night will
dip into the 50s and lower 60s, with some additional low-level cloud
cover helping to keep readings warmer north of I-64.
.LONG TERM (Sunday night through Friday)...
Issued at 300 PM EDT Mon Oct 5 2015
The main challenges in the long term period will revolve around a
cold front passage on Friday. Models have come into decent
agreement on the fropa timing with the latest 12Z GFS/ECMWF agreeing
on a Friday fropa with the ECMWF just a tad slower than the Ops GFS
and the 12Z GFS ensembles slightly faster than the 12Z Op GFS.
Although there are slight timing differences amongst models, feel
confident in rain for Friday so did increase POPs to 50-60% with
lower rain chances for Thurs night/Fri night as the front
enter/exits. Looking at model soundings, think we should see showers
and a slight chance for t-storms. Wind profiles don`t look too bad
with 25-35 kts of 0-6 km bulk shear, but instability will certainly
be dependent on cloud cover and exact timing of day. At best we
could see a few stronger storms with gusty winds. However, not
confident enough to bump up t-storm coverage quite yet.
Temperatures on either side of this frontal passage are challenging.
The warmest guidance verified yesterday under mostly sunny skies.
Trended high temps to warmer MOS guidance Wed/Thu ahead of the front
putting highs in the upper 70s/lower 80s with mainly lower 80s for
Thurs. Thur night clouds will overtake the region with precip
arriving over our north sections limiting low temps to the lower
60s. Behind the fropa, highs will cool back into the 60s for Sat
and then slowly warming Sun/Mon back into the 70s. The coolest
night looks to be Sat night/Sun morning with lows bottoming out in
.AVIATION (00Z TAF Update)...
Issued at 645 PM EDT Mon Oct 05 2015
Plan on VFR conditions through the TAF period as surface high
pressure remains in place over the Ohio Valley. Generally light ENE
winds will persist with scattered high clouds spilling over the area
tonight into Tuesday morning.