537 
FXUS63 KLMK 301732
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
132 PM EDT Wed Oct 30 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Breezy and dry with above-normal temperatures today.

*  Widespread rain showers with scattered thunderstorms are expected 
   for Thursday and Thursday night.  Gusty thunderstorm winds of 35-
   40 mph will be possible with rainfall amounts of 0.50-1.25 inches.

*  Mainly dry weekend with the next chance of substantial rain 
   coming by late Tuesday into Wednesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 321 AM EDT Wed Oct 30 2024

Synopsis...Short-term period will be characterized by shortwave 
trough ejecting across the Central US and into the Upper Midwest 
while anomalous mid-level ridge remains anchored over the East 
CONUS, although inching eastward in response to the track of the 
trough. At the lower levels, weak surface low will gradually deepen 
as it tracks across Kansas/Iowa driving a cold front close to the 
Lower Ohio Valley tonight. In addition, broad surface high will sit 
over the Mid-Atlantic which will help tighten the pressure gradient 
across the forecast area.
  
Today...Current satellite imagery depicts upper clouds slowly 
streaming across the area which in tandem with light southerly flow 
have maintained a gentle temperature drop this morning. Furthermore, 
low-level clouds are noted entering the Tennessee Valley at this 
hour, but downstream development/advection is somewhat uncertain 
given ongoing interaction with topography and drier environment over 
the Ohio Valley. Regardless of cloud cover, dry weather will 
continue today as well as breezy southerly winds with gusts around 
20-25 mph and some isolated reports close to 30 mph. As for 
temperatures, reduced upper cloud cover (per HREF cloud cover output 
and GFS forecast soundings) plus constant warm air advection will 
support well above-average highs and a chance of near-record high at 
SDF. 

Tonight...Low-level mass response associated with the trough and 
strengthening pressure gradient between the front and the surface 
high pressure will yield a strong LLJ developing in the Mid 
Mississippi with some of that momentum nearing the forecast area 
after midnight. As a result, the boundary layer might remain 
sufficiently mixed overnight to mention frequent gusts around 15 mph 
or more before sunrise. Last but not least, dry conditions will be 
in place for the most part with rain chances increasing towards dawn 
as the front approaches from the northwest and isolated, low-topped 
showers manifest in the warm sector.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 321 AM EDT Wed Oct 30 2024

Thursday through Saturday Night...

A negatively tilted upper trough axis will move into the Great Lakes 
during the day on Thursday.  The associated surface cold front will 
trail off to the southwest and push through our region Thursday 
evening bringing much needed rainfall to the area.

Southwest flow ahead of the cold front will result in mild 
temperatures once again on Thursday along with a continued increase 
in moisture.  PWATs look to rise above 1.5 inches which is well 
above seasonal normals for the region.  Scattered showers will 
develop within the warm advection scheme during the daytime hours, 
mainly west of I-65.  The pressure gradient will remain quite strong 
here with gusts of 25-30 mph outside of convection.  Within the 
showery convection, gusts of 35-40 mph will be possible. Highs on 
the day will be in the 74-79 degree range.  By late afternoon and 
into the evening hours, convection looks to become more widespread 
as stronger synoptic scale forcing overspreads the region.  Model 
proximity soundings across western KY show lapse rates increasing 
into the 6.5-7.0 C/km range where stronger heating occurs.  With the 
front arriving toward sunset, we'll loose some of our heating and 
MLCAPE values may only reach into the 250-500 J/kg range.  Low-level 
wind fields are impressive with a 45-50kt belt of winds pushing 
thorugh the region.

Overall convective scheme appears to be mostly rain showers with 
some embedded/isolated thunderstorms.  The risk of severe weather on 
Thursday would tend to favor areas west of our CWA where stronger 
heating will take place.  Instability looks to decrease with time 
and eastward extent Thursday evening.  Damaging winds would be the 
primary severe weather hazard over western KY due to that 45-50kt 
low-level jet pushing through and convection mixing some of that 
higher momentum air down.  SPC day two risk has been pushed back to 
the west slightly, and we agree with that.  For this forecast will 
be running high PoPs west of I-65 during the day, with high PoPs 
east of I-65 for Thursday night.  As of this writing, trick-or-treat 
activities Thursday night look to have poor weather with moderate to 
occasionally heavy rainfall moving through the region.  Rainfall 
amounts of a half to as much as 1.25 inches will be possible with 
this band of convection pushing through.  

Shower activity will likely linger into the overnight period and 
diminish quite rapidly by Friday morning.  A return to seasonal 
temperatures are expected with lows Friday morning ranging from the 
lower 40s across southern IN to the low-mid 50s across far southern 
KY.  Mostly sunny skies are expected for the day on Friday with highs 
in the 65-70 degree range.  Lows Friday night will range from the 40-
45 degree range over southern IN and the northern half of KY with 
upper 40s across southern KY.

Saturday looks to feature dry conditions with partly sunny skies and 
temperatures warming into the upper 60s/lower 70s over southern IN 
and the northern half of KY.  Across southern KY, highs in the 70-75 
degree range are expected.  Lows Saturday night will be a bit milder 
as a southwest flow redevelops.  Readings should cool into the upper 
40s to the lower 50s.

Sunday through Tuesday...

By Sunday, the upper flow over the CONUS will amplify once again 
with a large scale trough axis moving into the western CONUS with 
downstream ridging over the eastern US.  This will support another 
warm up in temps for our area.  The frontal boundary from Thursday 
will lift northward as a warm front on Sunday and may bring some 
isolated/scattered showers to western KY and into southern IN. Highs 
will be in the 74-79 degree range with overnight lows in the 55-60 
degree range.

The upper level flow will remain quite amplified as the western 
CONUS trough continues to dig into the four corners region.  A 
strong southwest boundary layer flow will remain in place with 
scattered rain showers likely affecting mainly far western KY/IN on 
Monday. It will be mild with readings in the 75-80 degree range. 
Latest guidance suggests that the upper trough axis will open up and 
push eastward bringing unsettled weather to the Ohio Valley late 
Tuesday and into Wednesday. Highs Tuesday will remain mild with 
readings in the 75-80 degree range.

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
Issued at 132 PM EDT Wed Oct 30 2024

VFR conditions will continue through most of the forecast period as 
the region remains under upper ridging ahead of an approaching cold 
front. Towards the end of the period, a northeast to southwest 
oriented line of showers with a few embedded thunderstorms along the 
front will move from west to east through the area. Southern gusty 
winds will continue to be the main concern this period. Later 
tonight, concerns focus more on the development of a LLWS as a LLJ 
develops.

&&

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

&&

$$

SHORT TERM...ALL
LONG TERM...MJ
AVIATION...KDW