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000
FXUS63 KLMK 230511
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
111 AM EDT Tue Apr 23 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Showers Tuesday night with rainfall around a quarter inch.

*   Lows in the 30s Wednesday night from southern Indiana into the
    northern Bluegrass region, and typical cold spots.

*   Warmer and more active weather late Friday through the weekend,
    but plenty of uncertainty in timing of any intervals of showers
    and thunderstorms.

&&

.UPDATE...
Issued at 917 PM EDT Mon Apr 22 2024

Sfc high pressure is centered over the Southeast and will slowly
drift eastward overnight. A cold front stretches south from a 997 mb
Canadian low across the Upper Midwest and southwest through the
central Plains. Between these two evolving features, the pressure
gradient tightens early Tuesday over the Ohio Valley. Expect a
light, but steady southerly wind overnight and partly cloudy skies.
SCT thin high clouds will continue to stream overhead. Temperatures
are forecast to bottom out in the upper 30s to mid 40s in most
places. A few of our coldest low-lying spots may dip into the mid
30s, which could result in very localized frost.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 320 PM EDT Mon Apr 22 2024

Sfc high pressure currently centered over the Lower Mississippi
Valley will slowly work eastward tonight and be off the southeast US
coast tomorrow. This will continue to keep weather quiet and dry.
Upper Pacific moisture associated with the system working across
southern Canada just north of the US border will increase high
clouds over the region along with warm air advection (WAA) ahead of
an approaching cold front associate with the system. While
temperatures will be cool overnight falling into the low/mid 40s (a
few locations could drop into the upper 30s) it won`t be as cold as
this morning so frost is not a concern.

As the sfc low works across the Great Lakes during the day tomorrow,
it will work the associated cold front southward across IL and IN
during the day. Pressure gradient will tighten over the Ohio Valley
allowing for winds to increase out of the southwest with gusts of 20
to 25 mph towards the afternoon. The bulk of the day will be dry and
with increased WAA, even with high clouds, temperatures are likely
to warm to near 70. With Td in the low 40s/upper 30s we will have
dry low levels. While we have precipitation chances increasing late
afternoon/early evening across southern IN, the dry air may cause
the shower activity to hold off until tomorrow night.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 320 PM EDT Mon Apr 22 2024

Still on track for a rainy Tuesday night as a progressive upper trof
moves through the Great Lakes, driving a cold front through the Ohio
Valley. Instability is nil and moisture supply isn`t great, so
expect a few hrs of showery light to moderate rain and little or no
chance of thunder. QPF will be around a quarter inch along and north
of the I-64 corridor, tapering down to a tenth or less across south
central Kentucky.

Dry and seasonably cool wx is expected Wed-Thu with sfc high
pressure over the Great Lakes and NW flow aloft. Wed night could see
some of our traditional cold spots, especially in the northern
Bluegrass region, drop into the 30s, and therefore bears watch for
frost potential.

Upper pattern shifts toward the end of the week trofiness digging
into the West and the Plains, and an amplifying ridge along the East
Coast. Overall trend will be toward warmer than normal temps as S-SW
flow deepens, but how much more active the pattern becomes will
depend on the trajectory of disturbances kicking out of the trof out
west. At this point, would expect intervals of rain chances, but the
timing is too uncertain to do more than a broadbrush 30-40% POP for
most of the weekend and into Monday. The more favorable spot for
severe wx still looks to be across the Plains, but we`ll need to
keep an eye on any eastward expansion of that threat. Temps this
weekend will be solidly above normal in the southerly flow,
especially at night when clouds, higher dewpoints, and a mixy
boundary-layer could keep us in the 60s, with 80 being in easy reach
in the afternoon.

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 110 AM EDT Tue Apr 23 2024

After uneventful weather during the pre-dawn hours, winds will pick
up today in a tight gradient between low pressure crossing the Great
Lakes and high pressure over Georgia and South Carolina. Winds
coming in from the southwest will gust 25-30kt, especially this
afternoon.

Tonight the low to our north will drag a cold front into the Ohio
Valley. Light rain and lower ceilings will accompany the front, but
flying conditions should prevail low-end VFR. The rain will only
last a few hours before the front pushes through, and winds will be
much lighter than what we will have seen during the day.

&&

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

&&

$$

UPDATE...EBW
SHORT TERM...BTN
LONG TERM...RAS
AVIATION...13