Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 292319
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
719 PM EDT Mon Sep 29 2014
...Updated Forecast and Aviation Discussions...
Issued 715 PM EDT Mon Sep 29 2014
Main focus in the short term is where fog will form overnight. Dry
dewpoints made a surge southeastward across the region late this
afternoon. Still think the most concentrated areas of fog will be in
rivers and valleys across our southeastern counties. Have tweaked
the grids a little to match the observational trends towards where
the fog has the best chance to form. Otherwise should be a quiet
.SHORT TERM (Now through Tuesday Night)...
Issued at 250 PM EDT Mon Sep 29 2014
Sfc high pressure will remain in control of the region through Tues
night with upper level ridging moving in late Tues. This will
result in dry conditions with temps slightly above seasonal normals.
Low temps tonight and Tues night will be in the low to mid 50s with
tonight being slightly cooler. Tuesday`s highs will be in the lower
80s...similar to today.
The one forecast concern in the short term period is the possibility
of fog perhaps dense in some areas late tonight into Tues morning.
This morning many places across the area saw fog with patchy dense
fog in some spots. Tonight with light winds, a decent inversion,
and lingering low level moisture, fog will again be possible
especially over south central KY where the least amount of light dry
air advection/mix down has occurred this afternoon. Thus, will
paint south central KY with areas of fog keeping in mind that some
patchy dense fog will again be possible. Over north central KY
patchy fog will be possible with a lesser chance for fog development
over southern Indiana (the driest area).
.LONG TERM (Wednesday through Monday)...
Issued at 253 PM EDT Mon Sep 29 2014
The long term period will begin with weak ridging aloft and winds
shifting to southerly as surface high pressure shifts east.
Temperatures Wednesday and Wednesday night will remain above normal
for this time of year. Highs on Wednesday will be in the upper 70s
to lower 80s with lows in the upper 50s to lower 60s Thursday
We will see a change in the pattern as an upper level trough builds
in through the second half of the week. A cold front associated with
this system will move through Friday bringing with it the best
chance for rain in quite some time. Scattered showers and
thunderstorms look to develop in the warm sector ahead of this
system Thursday afternoon. The best chance for precipitation during
the day will be across southern Indiana and west central Kentucky.
Rain chances will increase into the overnight hours as the front
nears. Will continue with likely pops (70%) for this system
overnight. Severe weather does not look likely, but storms could
produce some gusty winds. In addition PWAT values will rise to
around 1.8" which is above the 90th percentile for this time of
year. Thus, storms will be very efficient rain producers. However,
this system should be pretty progressive, so do not think flooding
will be a major issue, though some ponding of water could occur in
low lying and flood prone areas. The rain will move out as the front
swings through Friday with Friday night expected to be dry. Surface
high pressure will build in behind the front and dry conditions are
expected through the remainder of the forecast period.
Temperatures Thursday will remain warm with highs in the 80s.
Friday`s highs will be tricky with the rain, clouds, and front
moving through. For now it looks like highs will be in the lower
70s. Much cooler air will push in behind the front. Lows will be in
the upper 40s Saturday morning and will be even cooler Sunday
morning in the lower to mid 40s. Highs on Saturday will top out in
the lower to mid 60s. A gradual warm up will then begin through the
second half of the weekend.
.AVIATION (00Z TAF Update)...
Issued at 715 PM EDT Mon Sep 29 2014
Main concern remains fog potential at BWG/LEX. The latter site had
some much drier air mix down this afternoon, dewpoints down to the
low 50s. With forecast lows in the mid 50s, have backed off on MVFR
conditions there towards daybreak. BWG dropped in the last hour or
two as well, but is still right at forecast lows. Considered bumping
up the worst conditions, but climatology in these situations would
indicate a lot of jumping around from MVFR to LIFR conditions at
that terminal around daybreak. In addition, LAV guidance still calls
for the worst category. Conditions should improve quickly after