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000
FXUS63 KLMK 201050
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
650 AM EDT Sat Apr 20 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Possible frost, especially locations in the Bluegrass Monday
    morning.

*   Showers and a few thunderstorms by Tuesday night into Wednesday

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 315 AM EDT Sat Apr 20 2024

Early this morning a small cluster of showers and thunderstorms is
advancing from northeast Arkansas through the Missouri Bootheel into
west Tennessee and southwest Kentucky. Dry low level air quickly
rushing in from the north will undercut these showers and as a
result not much is expected in south central Kentucky, but a few
showers and even a rumble or two of thunder can`t be ruled out
before sunrise in the southernmost one or two counties north of the
Tennessee line. The majority of the activity will remain to the
south in Tennessee.

The center of a strong dome of Canadian high pressure will sink from
Montana to Nebraska today, with ridging extending eastward into the
Ohio Valley. Northwest winds ahead of this high will bring cool and
dry low level air into the region. Given dry low level air on
soundings beneath a mixing height around 5000 feet, and looking
at surface dew points upstream yesterday, expect afternoon dew
points down into the low-mid 20s in southern Indiana this
afternoon, to the low 30s in the Lake Cumberland region.

We should have abundant sunshine today, though cirrus will swell
northeastward from Texas into the region by mid/late afternoon ahead
of an upper trough over the Four Corners. After cool early morning
temperatures in the 40s, there should still be enough April sunshine
to pull afternoon readings into the upper 50s in southern Indiana
and low-mid 60s in central Kentucky.

Tonight the Nebraska high will slip into Kansas with an arm of
ridging still reaching east into the Ohio Valley. Widespread high
clouds are expected to continue streaming into the area, with a
slight uptick in mid clouds possible after midnight ahead of an
upper trough over the Midwest and Great Lakes. These clouds plus a
steady surface breeze around 5 mph and borderline temperatures will
limit the chances of frost. The best shot at patchy frost will be in
sheltered rural areas of southern Indiana where there may be some
partial clearing of the clouds right around dawn, and where
temperatures may slip into the mid 30s. Even so, near-surface dry
air will further limit frost development. Lows in central Kentucky
will generally be in the upper 30s and lower 40s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 315 AM EDT Sat Apr 20 2024

Sunday - Monday Night...

On Sunday, another reinforcing shot of cool air will move into the
region along a shortwave trough aloft. This shortwave will lead to
increased shallow, low-level stratus overhead, which will also help
keep temperatures cooler in the upper 50s and low 60s on Sunday. As
the shortwave swings east of the region, low-level stratus will
follow, allowing for ample radiational cooling. Low temperatures on
Monday morning will be in the mid-upper 30s. High pressure will
build into the region, allowing winds to become light. These
ingredients may lead to frost potential on Monday morning. Greatest
chance for frost will be in the Bluegrass region.

Monday and Monday night will feature high pressure, mostly clear
skies, light winds, and slightly cooler than normal temperatures.

Tuesday - Tuesday Night...

A low pressure system currently situated over the Pacific NW will
travel across southern Canada and sink south into the upper Midwest
and Great Lakes region by Tuesday. This system will send a cold
front south into the Ohio Valley. Ahead of the cold front, high
pressure will move off to the east allowing for moisture to return
to the region via southwesterly flow. Showers and possibly some
storms will develop along and ahead of the cold front, being the
next chance for precipitation over the region. Cold front is still
progged to move through the region late Tuesday into Tuesday night.

Wednesday - Thursday Night...

The 850mb trough associated with the low pressure system will move
east of the region, and clouds will quickly begin to thin. High
pressure will build into the region, leading to mostly clear skies,
light winds, and temperatures near normal.

Late Next Week...

Southerly flow will return to the region as surface high pressure
moves off to the east, which will allow for increased moisture and
warming temperatures. A few systems will move over the Ohio Valley
bringing increased chances for showers and storms.

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 649 AM EDT Sat Apr 20 2024

High pressure building from the Prairie Provinces into the Plains
and ridging eastward into the Ohio Valley will keep our weather
quiet with VFR skies and vsbys. We`ll get a little mixy today with
plenty of sunshine, resulting in northwest breezes possibly gusting
to near 20kt in the afternoon. High clouds will begin to stream in
from the southwest by mid to late afternoon, becoming widespread
tonight with some mid-clouds possible as well.

&&

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

&&

$$

SHORT TERM...13
LONG TERM...SRM
AVIATION...13