834 
FXUS63 KLMK 190640
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
240 AM EDT Wed Aug 19 2020

.Short Term...(Today and tonight)
Issued at 235 AM EDT Wed Aug 19 2020

High pressure over Michigan is sending drier air into the Ohio 
Valley today. However, a 5H trough remains overhead, and there is 
lingering moisture south of I-64 behind yesterday's system. 
Convective temperatures will be easily surpassed today and with the 
trough overhead scattered thunderstorms are expected to develop this 
afternoon in the area of best instability, generally south of a 
Bowling Green-Danville line. Though there will be very little shear 
for any storm organization, freezing heights suggest some small hail 
could be possible in the strongest storms near the Tennessee border. 
High temperatures today will be around 80, which is several degrees 
below normal.

Tonight that high to our north will sprawl from the Midwest to New 
England and will provide us with pleasant weather. Might be a good 
night to open up the windows as the mercury tumbles into the middle 
and upper 50s in southern Indiana and north central Kentucky...the 
lower 60s in southern parts of the Commonwealth...on light northeast 
breezes.

&&

.Long Term...(Thursday through Tuesday)
Issued at 230 AM EDT Wed Aug 19 2020

The first half of the long term will be under the influence of upper 
level troughing with chances of afternoon convection, after which 
subtropical high pressure will dominate the region resulting in 
a return to hot and muggy conditions for the beginning of next week. 

By Thursday, broad surface high pressure over the OH Valley and 
Great Lakes will result in another dulcet day for most of the CWA as 
morning mins bottom out in the upper 50s to lower 60s. Light NE 
winds will help keep humidity at bay for southern Indiana and the 
northern half of KY, but dew points and PWATs increase to our south, 
which will result in greater chances of afternoon showers and 
thunderstorms, mainly south of the Parkways. Highs will reach into 
the low to mid 80s. 

Friday and Saturday, an upper level low at the base of the longwave 
trough will begin to make its way from the lower MS Valley 
northeastward into the OH Valley. In doing so, return flow will 
result in increased moisture and an increase in areal chances of 
diurnal showers and storms. By Sunday, high pressure will begin to 
build in as the upper low exits to the NE. Drier air aloft and mid 
level capping should quell any widespread convection, though enough 
instability and moisture will remain to warrant mention of slight 
chance for most of the CWA. Expect highs for Friday and Saturday to 
range in the low to mid 80s. Sunday will see an increase in temps as 
highs on the day reach more solidly into the mid 80s.  

Expect seasonably warm and muggy conditions to return for the first 
half of next week as high pressure covers most of the CONUS. 1000-
850 thickness values suggest max temps will range in the mid to 
upper 80s during this timeframe, with urban areas flirting with low 
90s.

&&

.Aviation...(06Z TAF Issuance)
Issued at 112 AM EDT Wed Aug 19 2020

Low level moisture lingering behind yesterday's showers/storms is 
manifesting itself in IFR/MVFR ceilings early this morning. That is 
expected to continue for the first several hours of the TAF period at 
LEX and BWG. SDF/LOU is right on the northern edge, and have seen a 
few clouds around 900' so far. Still, at this time it appears that 
the main cloud deck will stay just barely south of the airfields, 
and in the TAFs will go with just a couple hours of TEMPO IFR at the 
start of the forecast when the cloud deck should be at its nearest 
approach to those two airports.

HNB should stay well north of the low clouds. Northeast breezes will 
keep fog minimal, but HNB has already briefly dropped to 5SM and IMS 
to 2 1/2SM in spite of the breeze. With scattered clouds in the area 
plus drier air advecting in, will go with just BCFG at HNB for now.

Any low clouds and patchy fog should break up in the hours around 
sunrise, followed by a pleasant day. Winds will continue to come in 
from the northeast off of high pressure over Michigan. A few gusts 
into the teens will be possible by late afternoon.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Short Term...13
Long Term...CG
Aviation...13