697 
FXUS63 KLMK 241051
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
651 AM EDT Fri Jul 24 2020

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 308 PM EDT Fri Jul 24 2020

Upper level high pressure will build over the central and SE US as 
surface high pressure builds in across much of the Great Lakes and 
Ohio Valley. This will result in patchy AM fog and isolated showers 
and thunderstorms this afternoon, mainly south of the Parkways. 

Current radar shows a broken line of convection bisecting central KY 
with two storms producing frequent lightning moving eastward across 
Nelson and Washington Counties. These cells are gradually weakening 
and expected to dissipate within the next couple of hours. Current 
satellite shows patchy fog developing in areas where clouds have 
cleared. A few sites are reporting fog, most notably Huntingburg 
(HNB) in southern Indiana and Bowman Field (LOU), which currently 
have visibility restricted to 1/2 and 3/4 mile, respectively.  

Expect fog to quickly dissipate shortly after sunrise and give way 
to mostly sunny skies. Cross section shows dry air moving into the 
area from the north while the deeper moisture remains across the 
southern portion of central KY. As a result, chances of isolated 
showers and thunderstorms again will be possible today, mainly south 
of the Parkways. 

Max temps this afternoon will reach into the upper 80s to lower 90s. 
Clearing skies overnight will result in another patchy fog scenario 
for Saturday morning.

.Long Term...(Saturday through Thursday)
Issued at 319 AM EDT Fri Jul 24 2020

Saturday through Sunday Night...

Broad upper level ridge axis is forecast to build into the Ohio 
Valley for the weekend.  Overall this would result in a drier 
weather pattern for southern Indiana and much of northern Kentucky. 
Only exception looks to be across southern KY where scattered 
showers and storms probably will develop each afternoon.  Under a 
general light northeasterly flow, we should see less humid 
conditions for the weekend.  Highs are likely to top out in the 
upper 80s to around 90 in most locations.  A few of the urban center 
may make it into the lower 90s.  Overnight lows will primarily be in 
the upper 60s to the lower 70s. 

Monday through Friday...

By late weekend and into early next week, the model guidance 
continues to show the upper level ridge flattening out quite a bit 
as a strong mid-level wave digs southward toward Ontario. A surface 
cold front looks to push through the region in the Monday night and 
Tuesday time frame.  Timing of the front is still hard to pin down 
and overall storm severity will depend if it comes through at the 
diurnal min/max for instability.  Wind aloft are not all that 
strong, though plenty of surface moisture will be available.  Model 
proximity soundings do show a bit of CAPE during the diurnal max 
period, so at least storms with torrential rainfall, gusty winds, 
and quite a bit of lightning will be possible as this feature 
pushes through the region.

The front looks to clear the area late Tuesday and early Wednesday 
and it will be noticeably cooler and less humid behind the front. We 
will remain in a northwesterly flow aloft for the remainder of the 
week.  For the last week or so, experimental signal analysis has 
been suggesting the next upper wave to approach the region in the 
Friday/Saturday period.  The dynamical models are starting to catch 
on to this signal, and if it holds, another round of storms looks 
likely for late week.

Highs on Monday should top out in the upper 80s to around 90, but 
Tuesday should feature cooler conditions with highs in the mid 80s. 
For Wednesday through Friday, daytime highs will likely top out in 
the 83-88 degree range with overnight lows middle 60s.

&&

.Aviation...(12Z TAF Issuance)
Issued at 747 AM EDT Fri Jul 24 2020 

Morning satellite and regional observations reveal fog mostly 
confined to river valleys and low-lying areas. Thicker fog is 
currently being reported at HNB, while the other TAF sites are 
unrestricted. Fog should burn off quickly after sunset giving way to 
VFR conditions with light and variable winds. Chances of showers and 
storms still exist south of the Parkways (BWG), but chances are less 
than 30 percent at this time so will leave out any mention in TAF. 
Clearing overnight will be accompanied by near calm winds, which 
will likely result in another morning of patchy fog across the 
region.

&&

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

$$

Short Term...CG
Long Term...MJ
Aviation...CG