054
FXUS63 KLMK 092329
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
729 PM EDT Thu May 9 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Very isolated shower or storm possible this afternoon and
    evening, mainly north of I-64. Brief gusty winds and small hail
    are possible.

*   Widely scattered storms possible north through east of
    Louisville Saturday afternoon.

*   Active pattern next week with daily chances of showers and
    storms Monday through Thursday. Severe weather is not expected
    through at least Tuesday. Strong storm chances may increase
    slightly by Wednesday-Thursday, but confidence is low.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 303 PM EDT Thu May 9 2024

A mid/upper level trough continues to drop southeast from the Upper
Midwest, with a mid-level speed max streaming east from Missouri
across the Ohio Valley this afternoon and evening. Sfc low pressure
will continue to move east-southeast across central IN and southern
OH this afternoon, dragging a cold front through the region. There
is still some low-level moisture available with sfc dewpoints still
in the mid 60s. Temperatures have struggled today beneath stratus,
however readings are quickly rebounding into the mid 70s as the low
clouds scatter out from west to east. Temperatures are still likely
to top out in the upper 70s to near 80 degrees by mid-afternoon.

The nearby sfc low and approaching cold front will provide modest
lift as the airmass destabilizes. Much of the precip will remain on
the cool side of the system, closer to I-70 and north. However, a
few isolated cells could develop across southern IN and northern KY.
There is some mid-level warm air to overcome still, as seen on
recent SDF ACARS soundings, and coverage will remain quite sparse.
Mainly dry weather is anticipated, but a few isolated showers and
storms will be possible north of I-64 into the evening hours. With
steeper low-level lapse rates and a dryer column, an isolated storm
or two could produce localized gusty winds. Effective bulk shear of
50+ kts is also more than sufficient for some organization, so there
may be very brief window for small to marginally severe hail.
However, confidence in a stronger storm is low due to very limited
coverage.

Tonight looks fairly quiet with mainly dry weather continuing. A
secondary sfc trough will drop south through the area into Friday
morning. Winds veer northerly in its wake, with a more notable surge
of cooler air. Stratus will blanket the region from north to south
early Friday morning, and cannot rule out a stray light shower or
sprinkle. Clouds will linger into the afternoon hours before partial
clearing late in the day. Highs will only reach the mid to upper 60s
in most places with a brisk north wind. A few spots will top out
near 70 F.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 303 PM EDT Thu May 9 2024

Stacked low pressure crossing the Great Lakes will swing a cold
front through the Ohio Valley around mid-day Saturday. Soundings
show a strong mid-level cap and very little moisture, so will keep
PoPs low and restricted to areas east of I-65 that will be ahead of
the front in the afternoon. There is a bit of instability below the
cap and the mercury should rise a few degrees above convective
temperatures so will include mention of thunder.

Sunday is still looking good as a small bubble of high pressure
crosses the Tennessee Valley. After a cool start in the mid 40s to
around 50, under mostly sunny skies temperatures will peak in the
70s in the afternoon, right at normal values for this time of year.

An active pattern develops next week with a 5H trough moving through
the region Tuesday and a stronger trough coming in from the west
late week. The Gulf will open up early in the week, allowing enough
moisture to include showery precipitation in the forecast. CAPE and
shear are weak Monday and Tuesday, so severe weather is not
expected, but there`s enough instability to include mention of
thunder.

Confidence is very low by mid/late week, but the general idea is for
an increase in moisture and instability, with shower and
thunderstorm chances ahead of an approaching Plains upper trough.
The main threats for severe weather look to be from the southern
Plains through the Southeast, but there are indications of a slight
uptick in strong storm chances in the Ohio and Tennessee Valleys by
Wednesday or Thursday.

High temperatures next week will primarily be in the 70s.

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 728 PM EDT Thu May 9 2024

Impacts/Confidence:
- High confidence in MVFR ceilings tonight and Friday morning
- Medium confidence in timing of VFR conditions
- High confidence in light northerly breeze on Friday

Discussion...Secondary surface front is currently moving into the
TAF area with spotty shower activity approaching the Bluegrass,
closer to the ejecting surface low. Given coverage and weakening
instability, decided to leave any VCSH/VCTS out of the forecast. For
tonight, winds will diminish substantially while turning to the
northwest. Furthermore, the stratus layer accompanying the post-
frontal airmass will promote MVFR ceilings after midnight and most
likely through the morning hours. There is a low chance of drizzle
close to sunrise, but confidence is not sufficient to mention any
impacts to VIS. Finally, ceilings will slowly improve Friday morning
with VFR returning after 10/16Z along with gusts around 15 knots.

&&

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

&&

$$

SHORT TERM...EBW
LONG TERM...13
AVIATION...ALL