Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 210144
Area Forecast Discussion
National Weather Service Louisville KY
944 PM EDT SAT AUG 20 2016
Issued at 942 PM EDT Sat Aug 20 2016
Surface front now approaching south-central Indiana and western
Kentucky as of mid-evening, and is steadily marching east through
the area. Our environment is much less favorable for convection now
that daytime heating is lost, and a weakening line of showers
remains across central Kentucky.
HRRR and other hi-res guidance in good agreement showing this line
slowly moving east/southeast, stalling some over south-central
Kentucky. That`s where the chances of showers and perhaps an
isolated thunderstorm will remain after midnight. It`s not until the
main upper trough axis swings through that the deeper moisture will
be really pushed out of the area. Further north into southern
Indiana, look for drier air to work in overnight with west/northwest
By daybreak, temperatures are expected to range from the low 60s
across southwest Indiana to the low 70s across southern Kentucky.
Precipitation chances were adjusted for the near-term, otherwise the
forecast is in good shape.
.SHORT TERM (Now through Sunday Night)...
Issued at 255 PM EDT Sat Aug 20 2016
...A Few Strong Storms Possible Late This Afternoon and Evening...
Multiple showers have developed over the region this afternoon with
t-storm activity a little more sparse than originally anticipated.
Expect rounds of showers and scattered storms to continue through
tonight until the approaching cold front passes through the region
late tonight. The best precipitation coverage for southern
IN/northern KY including the Louisville Metro area would be between
now and approx. 10pm. Rounds of showers and isld/sct storms should
linger over portions of central/southern KY through the early
morning hours until the front clears the region. As far as t-storm
strength, think that severe storm chances are relative low and even
the chance for strong storms is low. With a very moist airmass in
place, feel the main issues with evening/overnight convection will
be brief heavy downpours and cloud to ground lightning in any storms
that develop. A wind gust threat still exists with a few strong
storms producing wind gusts up to around 40-45 mph.
For Sunday, a much more pleasant airmass and partly cloudy skies
await us behind the cold front. Temperatures will fall back into
the upper 70s to around 80 for highs and humidity levels will drop
off quite a bit. Dewpts are expected to dive into the upper
50s/lower 60s bringing an end to the mugginess. Forecast low temps
for Sun night will fall into the mid 50s to around 60 which is 5-10
degrees below normal for this time of year.
.LONG TERM (Monday through Saturday)...
Issued at 310 PM EDT Sat Aug 20 2016
Monday - Tuesday...
Dry weather and below normal temps are expected at the beginning of
the work week as sfc high pressure and a relatively flat upper level
pattern dominate the Ohio Valley. Expect highs to range through the
lower 80s Mon/Tue with lows in the upper 50s/lower 60s. Plenty of
sunshine is expected both days.
Wednesday - Saturday...
An active return flow will set up by Wed with chances for storms
both Wed/Thu as a weak cold front approaches. This boundary looks
to pass SE through the region sometime Thu/Fri, but may linger near
our southern KY counties through the weekend. Thus, low storm
chances will remain in the forecast through Saturday.
As for temps, expect an increase in temps into the upper 80s for
highs by mid week and then a slight adjustment downward for late
week into the mid 80s behind the front. Low temps will range
through the 60s and lower 70s.
.AVIATION (00Z TAF Update)...
Issued at 645 PM EDT Sat Aug 20 2016
A line of heavy showers and isolated to scattered thunderstorms will
pass through SDF between 00-01z, then into the LEX area between 02-
04z. Expect gusty winds and heavy downpours resulting in IFR
visibilities. At BWG, showers and perhaps a thunderstorm will remain
scattered through about 04z.
The cold front and wind shift will arrive after midnight with the
possibility of a MVFR to high-end IFR stratus deck across central
Kentucky. Confidence on this is medium as there isn`t a lot
upstream, but with nighttime cooling and plenty of low-level
moisture, the setup seems reasonable. Some of the soundings even
show the potential for drizzle to occur overnight into the pre-dawn
For Sunday, expect west/northwest winds to usher in drier air.
Better mixing by late morning and into the afternoon will promote
gusts to 15-20 kts at SDF and LEX. Look for morning stratus clouds
to lift/scatter toward 15-18z.