National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KLMK 190712
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
312 AM EDT Fri Apr 19 2024

.KEY MESSAGES...

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

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 312 AM EDT Fri Apr 19 2024

Synopsis...Fast zonal flow aloft and near-neutral upper height
anomalies will be present over the Lower Ohio Valley as upper low
over the Upper Great Lakes/southern Canada lifts to the northeast
and mid-level ridging stretches across the southern half of the
CONUS. At the surface, cold front will clear the region during the
morning hours with high pressure ridging nosing in from the west
late this afternoon and evening.

Today...Earlier severe threat has substantially decrease and latest
HRRR Neural Network and SSCRAM guidance barely give single-digit
probabilities of damaging winds before sunrise with ongoing
disorganized convection. This goes in line with the lack of
instability and effective bulk shear with stable conditions at the
surface, as shown in SDF ACARS. Therefore, heavy rainfall and
lightning will be the main hazards before convection departs to the
east early this morning. Otherwise, surface observations analyze the
cold front extending approximately from southern Illinois to central
Indiana at the time of this writing. Expect dry but still cloudy
conditions shortly after sunrise along and behind the frontal
boundary. Furthermore, winds will shift to the west and west-
northwest while gusting between 20 to 30 mph. Partly to mostly
cloudy skies will linger into the afternoon, which in combination
with cooler air advection, will yield for highs in the 60s.

Tonight...Quiet weather continues tonight as high pressure continues
advecting a dry and cool airmass to the region. Northerly winds will
become weaker after sunset and a near-surface inversion develops.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 312 AM EDT Fri Apr 19 2024

Saturday through Monday...

High pressure and zonal flow aloft will allow for dry and seasonable
conditions this weekend. High temperatures on Saturday will be in
the mid 60s. Ample atmospheric mixing may bring some momentum aloft
to the surface resulting in gusts up to 25mph. Saturday night, a
shortwave moving through the southeast US may brush the southern
tier of counties with some light showers. Otherwise, a stratus deck
will be the main feature with this system. Stratus deck will move
east of the region with the 850mb trough Sunday night. As clouds
clear and surface high pressure leads to light winds, there is a
potential for frost over the Bluegrass region and southern Indiana
Monday morning. Low temperatures will be in the low-mid 30s. Monday
will remain dry with high pressure over the region and high
temperatures in the mid-upper 60s.

Monday Night through Thursday...

A shortwave will move through southern Canada before sinking south
into the Midwest and Great Lakes. As this trough swings through, a
low pressure system will deepen and send a cold front south into the
Ohio Valley. Ahead of this system, a WAA regime will set up over the
region leading to moisture return via southwesterly flow and warming
temperatures. Showers and storms are possible along and ahead of the
front, which is likely to move through Tuesday night into Wednesday
morning.

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 141 AM EDT Fri Apr 19 2024

Impacts/Confidence:
- High confidence in MVFR/IFR ceilings this morning and slowly
improving this afternoon.
- High confidence in gusty W to NW winds today

Discussion...Pre-frontal rain and storms are currently moving
through the TAF area and although activity has let down in the last
hour, there might still be a chance for heavy rain to negatively
impacts BWG/RGA/LEX. Further upstream, surface observations locate
the cold front along southern IL and central IN while satellite
shows low-level cloud layer along and ahead of the frontal boundary.
For the next couple of hours, anticipated shower/storm to eject
eastward while winds turn to the west-northwest with ceilings
lowering to MVFR conditions. Given model support and upstream
observations, decided to indicate predominant IFR ceilings for good
part of the morning and slowly lifting to MVFR/VFR during the
afternoon. Winds, on the other hand, will become gusty in the wake
of the front with weakening trend the second half of the afternoon.

&&

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

&&

$$

SHORT TERM...ALL
LONG TERM...SRM
AVIATION...ALL