Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 271301
Area Forecast Discussion
National Weather Service Louisville KY
901 AM EDT TUE SEP 27 2016
Issued at 900 AM EDT Tue Sep 27 2016
The fog has begun to mix out this morning with the sunrise and
heating beginning. There are still a few patches of dense fog, but
these should improve rapidly over the next half an hour to an hour.
Updated the forecast to include fog for another hour, but will let
the SPS go as conditions are improving rapidly.
.SHORT TERM (Now through Wednesday Night)...
Issued at 245 AM EDT Tue Sep 27 2016
Compared to 24 hours ago, it`s 15 to 20 degrees colder across
southern Indiana and central Kentucky, and finally the weather is
more in line with what the calendar shows - late September.
The synoptic pattern featured a large deep closed low over Lake
Superior while yesterday`s cold front has made it down to northern
GA and western NC. Despite cold and dry air advection, residual low-
level moisture across south-central KY and light winds have produced
patchy but dense fog, and this may impact some for the morning
commute. Otherwise, skies were mostly clear.
For today, expect a near seasonable, early fall day with readings
topping out in the mid to upper 70s. The aforementioned upper low
will drop down into Wisconsin/Michigan. Our area should be far
enough away to see any sensible weather impacts, so plan on mostly
sunny skies, afternoon breezes out of the west, and dry conditions.
Evening temperatures will drop quickly after sunset and bottom out
in the upper 40s to low 50s tonight under mostly clear skies. Strato-
cu associated with the upper low will work into central and southern
Indiana toward daybreak Wednesday.
On Wednesday, the upper low center swings into Indiana while pieces
of energy pivot around it. The cold temps aloft and surface
temperatures in the 70s will steepen lapse rates enough to produce
diurnally driven rain showers across southeast Indiana and the
northern Bluegrass, and will advertise 35-45 percent chances.
Further southwest toward Bowling Green, chances are less, around 15-
20 percent. Once daytime heating wanes, rain shower coverage should
drop off to less than 15 percent. Lows will be mainly in the upper
40s to mid 50s, warmest for areas that see lingering strato-cu
through the night.
.LONG TERM (Thursday through Tuesday)...
Issued at 247 AM EDT Tue Sep 27 2016
Thursday - Saturday...
The upper low is still forecast to stall and wobble over the lower
Ohio Valley during this period, and the 27.00z guidance is in
reasonable agreement with this scenario. Overall, expect cooler
temperatures, especially daytime highs, with periodic chances for
rain showers. While the entire area may see rain showers, it won`t
be a washout every day, and the highest chances at this point
continue to be across southern Indiana and along/east of I-65. The
highest coverage of precipitation is expected during the afternoon
coinciding with peak heating.
Temperatures will be seasonably cool with readings in the mid 60s to
lower 70s. Areas that see more clouds and showers could struggle to
reach these forecast readings, as some of the gridded guidance has
highs staying in the 50s, especially around the Bluegrass. Expect
tighter diurnal ranges with lows in the upper 40s to low 50s area
Sunday and Monday...
Forecast models show the upper low kicking out toward the northeast
Saturday night into Sunday, paving the way for moderating
temperatures, less cloud cover and dry conditions. A model consensus
approach has highs solidly in the 70s and lows in the 50s going into
the next work week.
.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Tue Sep 27 2016
BWG has VLIFR fog this morning which will be improving over the next
hour or two. They should be back to VFR by 13Z or so. The rest of
the TAF period is VFR for all TAF sites as sfc high pressure and an
upper trough remain in control of the region. Winds will remain WSW
under 7 kts through the TAF period. BWG may see some light br again