University of Kentucky Agricultural Weather Center Serving Kentucky residents	On the World Wide Web at: http://wwwagwx.ca.uky.edu/

583 
FXUS63 KLMK 190147
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
947 PM EDT Thu Apr 18 2024

.KEY MESSAGES...

*   Strong to severe storms possible Thursday night. Highest risk of 
    severe storms will be generally west of I-65.

*   Much cooler weather this weekend. Next chance of rain arrives in 
    the Tuesday/Wednesday timeframe.

&&

.MESOSCALE...
Issued at 947 PM EDT Thu Apr 18 2024

A few discrete warms sector cells have been firing off ahead of the 
main convective line, which has been expected and picked up well in 
the earlier CAM runs. It appears these cells are popping up in an 
area of localized theta-e advection and deep moisture convergence 
axis, and underneath a pocket of positive vorticity advection. SPC 
Mesoanalysis suggest these storms are firing along a gradient of 
SBCAPE, but have struggled to become severe. Will keep an eye on 
these. 

Severe thunderstorm line is charging across eastern Illinois at this 
hour, and is noticeably accelerating as the cold pool pushes it 
further east. At this pace, believe the line will be arriving into 
Dubois County by 0230z. ACARS sounding out of SDF does show some 
SBCAPE lingering, but thinking MLCIN will help weaken the line as it 
approaches the I-65 corridor by 04-05z. HRRR 00z data supports this 
too, with low level stable layer expected to help weaken this 
convective line in a few hours. Will need to keep tabs on additional 
convection across south-central KY later tonight though, where there 
is potential to remain unstable within the warm sector prior to the 
cold front arrival.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 346 PM EDT Thu Apr 18 2024

Currently, satellite imagery is showing a warm front stretching to 
the northwest through southern Indiana and central Kentucky. This 
front arches to the west into a surface low in western Missouri. To 
the north of this front, dew points are in the 40s and 50s. To the 
south of the front, mid 60s, and as we head through the afternoon 
and evening hours, the surface low, part of a larger cold front 
extending to the north and south, will begin moving towards 
Indianapolis. This will cause the warm front and cold front to 
develop an inverted "V" look by 0z over southern Illinois, eastern 
Missouri and western Kentucky. Dew points over southern Indiana and 
central Kentucky will likely drop into the 50s as the region becomes 
better mixed. 

As 1-2z approaches, the surface low will be moving from Illinois 
into central Indiana. The area under the aforementioned inverted "V" 
will see dew points in the mid 60s. Again, this is the area in 
between the warm and cold fronts. On the leading edge, the warm 
front will likely kick off convection over western Kentucky and 
southward while the cold front running through Chicago arches 
southward through southern Illinois. As these two lines continue 
eastwards. The front line could become the dominate line for 
southern part of the cold front over Missouri and could combine with 
the northern half of the cold front, or it could remain as two 
separate lines and join with the cold front over southern Indiana. 
It doesn't make much of a difference, except some over central 
Kentucky could get one or two lines of convection. 

The timing is going to help us from a severe weather standpoint. 
Since the fronts won't move through until after sunset, an inversion 
is expected to develop and make any convection elevated. This will 
limit potential wind energy from reaching the ground. Overall shear 
is fairly weak. Think the current SPC outlook is a little bullish 
over our CWA.  

Winds tonight will remain out of the south to southwest around 5-10 
mph. A few gusts around 30 mph will be possible as the line of 
convection passes, and as the cold front begins to move through 
during the morning on Friday, winds will quickly veer towards the 
north-northwest increasing cold air advection into the area. Winds 
tomorrow will stay around 10 mph as they gust to 15-20 mph. 

WAA will keep temperatures warm tonight, only dropping into the 50s 
to low 60s. Tomorrow, the sun is expected to return, but CAA will 
limit temperatures to the 60s. A few in the Lake Cumberland region 
could hit the low 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 346 PM EDT Thu Apr 18 2024

Friday Night through Monday Night..

Dry conditions are expected Friday night and into Saturday as a 
surface high pressure system builds into the region with a dry zonal 
flow pattern aloft.  A southern stream system may graze the far 
southern part of KY Saturday night and Sunday morning, but the 
latest trends in the data suggests a drier forecast may end up 
prevailing.  Lows Friday night will dip into the upper 30s and lower 
40s.  Highs Saturday will be cool highs in the 60-65 degree range. 
Lows Saturday night should be a bit cooler with lows in the upper 
30s across much of the region.  Areas south of the Cumberland 
Parkway may only drop into the lower 40s.  Continued cool conditions 
are expected for Sunday with highs in the upper 50s to near 60. 
Depending on cloud cover conditions Sunday night, we could see some 
patchy frost in southern IN and the KY Bluegrass region as lows dip 
into the mid 30s.  Monday will see warmer conditions returning to 
the area with temps warming up into the mid-upper 60s.

Tuesday through Thursday...

Forecast confidence continues to increase in another chance of 
showers and storms coming into the region in the late Tuesday/early 
Wednesday time frame as a shortwave trough aloft moves through the 
region.  The previous forecast of solid PoP coverage still looks 
good here.  Temperatures through the period will warm into the upper 
60s to the lower 70s with overnight lows in the low-mid 40s.

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 744 PM EDT Thu Apr 18 2024

VFR conditions will deteriorate this evening as showers and 
thunderstorms approach the region ahead of a cold front. Expect 
impacts to ceilings and vis as thunderstorms roll through from west 
to east, first at HNB in the next few hours, and later tonight at 
LEX and RGA. The peak for convective activity will be from 02-09z 
tonight. After the storms pass, ceilings will lower to MVFR and 
likely below the 2k ft fuel alternate threshold near the pre-dawn 
hours. There appears to be a short window where ceilings could drop 
to IFR, so included a TEMPO group at all terminals for that as well. 
We'll gradually improve to VFR conditions again by late tomorrow 
morning or early afternoon, with post-frontal winds from the north.

&&

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

&&

$$

MESOSCALE...CJP
SHORT TERM...KDW
LONG TERM...MJ
AVIATION...CJP

Ag Weather Center, Department of Biosystems & Agricultural Engineering, University of Kentucky