Scientific Forecaster Discussion
fxus63 klmk 231913
Area forecast discussion
National Weather Service Louisville Kentucky
313 PM EDT Fri Aug 23 2019
Short term...(this evening through saturday)
updated at 313 PM EDT Fri Aug 23 2019
It's been a cloudy, cool day for much of the region. A cold front
has sagged into southern KY, and a Post-frontal rain band is now
south of the Ohio River. This area of showers lines up pretty well
with the 700 mb front and northern extent of deep moisture. But we
are finally seeing some weak convection closer to the front itself
in south-central Kentucky. Temperatures were able to make it into the
lower 80s in southern KY, and Storm Prediction Center mesoanalysis shows around 1000
j/kg MLCAPE. Precipitable water is at 1.9-2.0 inches near and south
of the front as well, so some heavy rainers will be possible in the
south through this evening. Overall, the severe threat looks low.
Rain chances gradually diminish from north to south across northern
and central Kentucky through this evening. Southern Kentucky will likely dry out
between 00-04z tonight. Clouds are also expected to scatter out from
north to south into tonight as well. Sfc high pressure will slide
east-southeast and strengthen over the Great Lakes. A steady northeast breeze
will advect in drier air, setting the stage for a wonderful
Lows Saturday morning will range from the mid to upper 50s in the
north and the low to mid 60s in the south. Temperatures will warm to
around 80 degrees Saturday afternoon.
Long term...(saturday night through friday)
updated at 219 PM EDT Fri Aug 23 2019
Upper troughs coming in from the plains and weak surface ridging
along the Appalachians will pull Gulf moisture northward, leading to
shower and thunderstorm chances in the long term. Rain chances will
peak Tuesday as a cold front passes through the region from
northwest to southeast. At this point instability and shear profiles
indicate severe weather is unlikely, but with a frontal passage in
August, possibly in the afternoon, it will be something to keep an
One to two inches of rain is in the forecast through Tuesday night
which would be very beneficial especially across north central
Kentucky where moderate drought has developed.
The second half of the week looks less promising for rain as surface
high pressure crosses the Missouri and Ohio valleys, though an upper
trough with occasional disturbances swinging through it will remain
overhead so will hold on to some small pops.
With the occasional rain chances here and upper ridging remaining
over the Desert Southwest, temperatures will be around normal with
highs in the 80s and lows in the 60s.
Aviation...(18z taf issuance)
updated at 151 PM EDT Fri Aug 23 2019
MVFR stratus lingers in a relatively narrow band oriented west to
east south of I-64. Ceilings are now VFR at sdf and Lex, however.
The primary impact at sdf and Lex will be slightly reduced
visibility in light to moderate rain between now and 20-21z. The
band of showers is lagging a sfc cold front, which will continue to
push south through southern Kentucky this afternoon and evening. Post-
frontal winds are out of the northeast at 7-10 kts.
Scattered showers will become more common in vc of bwg and across
the rest of southern Kentucky from 19-20z through 00-03z this evening.
Some sunshine earlier in the day has boosted temperatures near the
Tennessee border, and bwg could see a thunderstorm as well. Any storm could
produce very heavy rainfall over a short time, lightning, and gusty
winds. Clouds clear out this evening and overnight behind the front.
Winds will remain out of the northeast through the day tomorrow.