830 
FXUS63 KLMK 060744
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
344 AM EDT Wed Oct 6 2021

.Short Term...(Today and tonight)
Issued at 335 AM EDT Wed Oct 6 2021

Our weather remains under the influence of a closed upper low over 
northern Arkansas this morning. This low will slowly slide northward 
into west-central Missouri by Thursday morning. Stalled boundary 
currently cutting across central Kentucky will drift northward today 
as a warm front. Providing plenty of deep moisture across the region 
with PWAT values between 1.50" to 1.60" and dew points in the upper 
60s to near 70. 

Hi-res models show a couple waves of showers and storms working from 
south to north throughout the day today. The first looks to be 
associated with a 500mb vort max that will bring occasional showers 
through the morning. The next wave arrives in the afternoon sparking 
scattered areas of showers and thunderstorms. Models soundings 
continue to show a nearly unidirectional southerly wind profile with 
just some slight veering below 500mb. Instability looks to be around 
1500-2000J/kg. Low LCLs combined with modest effective SRH values 
around 100 M2/S2 could lead to rotating or splitting updrafts 
providing a marginally weak tornado threat with any afternoon 
storms. Cloud cover this morning and today would likely limit 
instability later this afternoon along with generally weak shear for 
most of our CWA (20-25kts). The best dynamics for any strong to 
potentially severe storms would be across extreme southwestern KY 
including the southwest corner of our CWA and most of 
western/central TN. That is where the Storm Prediction Center has a 
marginal risk of severe weather. The main threat with any storms 
that may develop will be heavy rain that could lead to localize 
flooding. strong gusty winds and as mentioned above the slight risk 
of an isolated spin up tornado. 

As the upper level closed low continues to move northward in MO, 
another mid level vort max will work across central KY from the 
south to north as a 25-35 kt LLJ develops over central and eastern 
KY. Going with likely PoPs across all of the CWA during the 
overnight hours. PWATs will remain around 1.60-1.70" so brief 
periods of heavy rain are once again likely.

&&

.Long Term...(Thursday through Tuesday)
Issued at 307 AM EDT Wed Oct 6 2021

Slow-moving upper low will rotate NNE over St. Louis on Thursday and 
open up to the northeast across the Great Lakes Friday into 
Saturday. At least scattered showers are likely to be ongoing at 12z 
Thursday. A moist airmass will remain in place along with deep 
southerly flow on the east side of the low. Southerly low-level 
jetting does lift north of the region during the day, so think 
coverage at any one hour will generally be scattered. However, 
confidence is high in scattered showers and a few storms as well. So 
will keep 6- and 12-hr PoPs quite high. Forecast soundings suggest a 
weak, skinny CAPE profile which should limit the threat for severe 
storms. Deep layer shear will be around 25-30 kts, but low-level 
shear is weaker relative to Wednesday. Overall, Thursday is showery 
at times with highs in the mid 70s. 

Precip coverage likely diminishes to isolated at best Thursday 
night. Drier air slowly, steadily works in from the south behind the 
departing upper low. The upper low rotates over Milwaukee on Friday, 
with the lingering upper trough draped over the lower Ohio Valley. 
Expect a drier day in general, but diurnal heating may help spark 
isolated showers. Look for partly to mostly sunny skies and highs in 
the mid to upper 70s. 

Strong upper level ridging replaces the upper level trough for the 
weekend, and summer warmth makes a return. Heights will continue to 
be pumped up through Sunday, downstream of a potent upper level wave 
over the Southwest US. Highs in the upper 70s to lower 80s should be 
common Saturday, with low to mid 80s possible Sunday. 

Mild weather continues into early next week. The aforementioned wave 
of low pressure appears likely to develop northeast from the 
southern Plains, eventually weakening over the Midwest early next 
week. However, model consistency and agreement on this system isn't 
great thus far. Confidence is fairly low on the exact evolution of 
the low and its attendant cold front. There is at least a low chance 
for showers and storms Monday into Tuesday.

&&

.Aviation...(06Z TAF Issuance)
Issued at 145 AM EDT Wed Oct 6 2021

IMPACTS: Prevailing VFR conditions with times of MVFR to IFR with 
areas of showers and even thunderstorms this afternoon and evening. 

DISCUSSIOn: Radar showing light showers streaming in from the south-
southeast this morning. Likely see showers around all TAF sites this 
morning. Most CIG will remain around VFR but there could be some 
MVFR conditions with showers this morning from BWG/HNB. 

Attention then turns to the afternoon where we could see areas of 
showers and even embedded thunderstorms work from the south to the 
north. These showers and storms likely will produce brief periods of 
heavy rain reducing VIS to MVFR/IFR levels. Another wave of showers 
and embedded storms will likely work from the south to the north 
again overnight with periods of MVFR/IFR conditions with heavy rain 
and reduced visibility. 

CONFIDENCE: medium on timing and conditions.


&&

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

$$

Short Term...BTN
Long Term...EBW
Aviation...BTN