Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 132345
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
745 PM EDT Wed Mar 13 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

* Near record high temps on Thursday.

* There is a marginal risk for severe storms Thursday afternoon
  through Friday morning. The best chances for storms will be during
  the overnight hours. Potential impacts of strong damaging wind
  gusts, severe hail and isolated spin up tornado.

* Unseasonably cooler early next week.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 329 PM EDT Wed Mar 13 2024

Another very anonymously warm and dry March day has unfolded across
the region thanks to broad southerly to southwesterly flow. Compared
to yesterday, low level moisture has increased quite a bit (18z obs
from BWG, for example, are about 15 degrees higher with Td vs 24
hours ago). This low level moisture should gradually push
northeastward through the remaining afternoon hours.

The overnight hours are shaping up to be dry in most spots, save for
some low chances (~20%) across our southern Indiana counties. The
best forcing for storms will be along a warm frontal boundary to our
west, and more than likely the low level inversion over our neck of
the woods will be too great to overcome for storm/shower initiation.
Overnight temps will be on the mild side thanks to light but steady
southerly flow.

Tomorrow`s forecast will be largely influenced by what happens and
develops overnight. Models generally take convection over the Plains
and Midwest that forms overnight and gradually pushes it eastward
into the upper Ohio Valley during the day tomorrow. Models vary on
the southward extent of the convection as it traverses eastward,
with some clipping our northern counties (southern IN and northern
KY) while others keep it north of the CWA. Most PoP probabilities
generally favor us being dry vs wet during the day tomorrow, which
is what the going forecast reflects. As a result of that, forecast
temperatures are very warm, and could even get near record values.
For more on that, see the Climate portion of the AFD.

Should we see storms develop over the region tomorrow, ample shear
and instability would support an organized strong to severe threat
with wind/hail hazards. With the capping that models have in place,
think any activity that would develop during the day on Thursday
would be isolated in nature.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 329 PM EDT Wed Mar 13 2024

Focus at the start of the long term will be the potential for strong
to severe storms Thursday night into Friday morning. As was
mentioned in the previous AFD and current short term section, the
threat of convection at the start of period is conditional on what
develops along the boundary to the north across central IN and how
far south any outflow induced convection develops during the late
afternoon/early evening of tomorrow. This would likely be ongoing
across southern IN and northern KY as we start the long term portion
of the forecast. Model soundings continue to keep a capping
inversion in place over most of the area through the first part of
the evening hours. If there are any ongoing convection, it would
remain isolated to a few clusters with wind/hail hazards.

Late Thursday night/early Friday morning, attention turns to the
advancing sfc boundary to our west and north as a cold front. This
will be the main forcing mechanism for additional convection across
the area towards early Friday morning. Trend in the hi-res CAMS is
to push the second wave of convection into our CWA along and ahead
of the cold front sometime between 04z to 13z Friday. Models start
to diminish instability overnight but keep fair amount of shear over
the region. Convection looks to set up in a broken QLCS kind of
cluster with various northern and southern segments. This continues
to be highlighted in the hi-res CAMS developing a stronger linear
QLCS feature working from the Missouri Bootheel through western KY
then diving southeast into western and middle TN in the pre-dawn
hours on Friday. This looks to clip our far southwestern CWA
counties including Bowling Green. Keep in mind this is just one
potential scenario but feel that the SPC Day 2 convective outlook of
a marginal risk of severe storms along and west of I-65 looks well
placed for now with damaging winds being the main hazard, with hail
and an isolated spin-up tornado not out of the question. QPF looks to
range from a third to around three quarters of an inch of rain but
locally higher amounts that could lead to isolated hydro/flooding
concerns from heavier showers/storms as well as some potential
training ahead and long the front as it moves through Friday
morning.

Showers and storms will push through and diminish across the area
from the northwest to the southeast during the day Friday as the
cold front works across the Common Wealth. Drier and cooler air will
follow behind as the upper pattern becomes more amplified across the
CONUS for the weekend into early next week. Rex Block across the
western US will develop a deepening trough across the Great Lakes
into the northeastern US for the weekend. A series of shortwave
troughs embedded in the northwest flow will work across the Ohio
Valley as sfc high noses in from the Central Plains from the west.
Temperatures will go from the 70s on Thursday to the 60s on Friday
and Saturday with mid/upper 50s on Sunday. Even with the passing of
a few upper shortwaves, we look to remain dry through the weekend.

Upper trough over the east will deepen over the eastern US by the
start of next week with temperatures 10-15 degrees below seasonal
normals with Monday being the coldest day with highs in the 40s and
morning lows near to slightly below freezing across northern KY into
southern IN. The coldest morning will be Tuesday with mid 20s for
lows causing a hard freeze for vegetation that may have already
started to bloom early. It looks to be mainly dry through the rest
of the period with highs returning into the mid/upper 50s by the
middle of next week.

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 745 PM EDT Wed Mar 13 2024

Tonight the middle Ohio Valley will be well within the warm sector
of a large Plains storm system. Thunderstorms erupting over the
central Plains and Midwest tonight are expected to remain to the
northwest of the TAF sites, with scattered high clouds and a light
south breeze here. Can`t completely rule out a rogue pre-dawn shower
at HNB, but chances are too small for inclusion in the TAF.

On Thursday low pressure over MCI will slide eastward to between ORD
and STL, keeping us in the warm sector well ahead of the system`s
cold front stretching from Missouri to Texas. SSW winds will pick up
as mixing increases, with gusts of 20-25kt possible, especially in
the afternoon. Widely scattered storms may develop in the afternoon,
but the greatest chance for the most widespread convection will
arrive Thursday night as the surface low passes by to our north and
the cold front approaches from the west.

&&

.CLIMATE...
Issued at 329 PM EDT Wed Mar 13 2024

================== Potential Record Temperatures ==================

             Thursday 3/14/2024
          Max T Fcst/Record (Year)

Louisville:       76/82     (2012)

Bowling Green:    79/82     (2012)

Lexington:        77/81     (1973)

&&

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

&&

$$

SHORT TERM...DM
LONG TERM...BTN
AVIATION...13
CLIMATE...DM


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