Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/02/23

Area Forecast Discussion

National Weather Service Louisville KY

 920 PM EDT Sat Apr 1 2023

.Forecast Update...
Issued at 920 PM EDT Sat Apr 1 2023

Satellite imagery continues to show low/mid stratus over most of
north-central KY and all of southern IN. KLVX was showing very light
returns over the northern and northeastern parts of the CWA
including most of southern IN, Louisville Metro and the Bluegrass.
While most of this activity was not reaching the ground a few
locations reported light rain so decided to include silent PoPs and
the mention of sprinkles in the grid for the next couple of hours.
Clouds are still on track to clear overnight into tomorrow morning
as high pressure currently over MO builds in over the Ohio Valley.
Winds have already begun to diminish and will become light and
variable by morning. Only made a few tweaks to the going forecast
and updated products will be updated shortly.

Issued at 515 PM EDT Sat Apr 1 2023

Wind advisory has been allowed to expire but decided to issue a
special weather statement as winds will continue to gust between 25
to 35 mph with a few isolated gusts approaching 40 mph at times but
will continue to see winds diminish through the evening and then
becoming light after midnight. Also cleaned up and updated some of
our weather grids for Sunday Night into Monday morning.

&&

.Short Term...(This evening through Sunday)
Issued at 315 PM EDT Sat Apr 1 2023

Synopsis...Progressive mid-level flow will turn more zonal as the
current upper trough departs to the east and weak positive height
anomalies build in from the blocking high over the far Caribbean
Sea. At the surface, post-frontal airmass will quickly transition
through the lower Ohio Valley as an elongated high pressure migrates
from the Ozark Plateau to the Ohio Valley tonight and continues to
the Eastern Seaboard on Sunday.

Rest of the Afternoon...Area wide wind gusts have started to lessen
at this time as the primary LLJ core have moved to the easternmost
corner of Kentucky (per SPC Mesoanalysis) and the approaching cloud
deck lowers mixing heights, as seen in the last couple of hours in
the SDF ACARS soundings. As a result, the High Wind Warning will be
set to expire at 19Z with a Wind Advisory still effective until 21Z
to account for the chance of isolated 30-40 mph gusts that continue
happening across the CWA. Otherwise, there is a very low possibility
of sporadic light rain showers with no accumulations whatsoever
while temperatures continue falling from north to south under CAA.

Tonight...A fresh west-northwesterly breeze will be present at the
beginning of the night, but flow will turn light and variable by
midnight, or shortly after, given the incoming high pressure and
attendant subsidence. At the same time, clouds will clear from the
southwest to the northeast as the surface high pressure and
shortwave ridge build into the area. Last but not least,
temperatures are forecast to go down to the low to mid 30s which
combined with clear skies and light winds will promote areas of
frost by sunrise.

Sunday...After a frosty morning, mostly sunny conditions with light
southerly wind will remain for the rest of the day. Weak warm air
advection component will take highs back to the low 60s with
dewpoints barely in the mid 30s, so it will be a pleasant day.

.Long Term...(Sunday night through Saturday)
Issued at 305 PM EDT Sat Apr 1 2023

The long-term period begins with a relatively zonal flow across the
region, save for a shortwave impulse riding through across the Deep
South Sunday night. This system may bring some light rains across
the region, after a dry weekend forecast, but still just have a 20
PoP for any measurable QPF. The work week actually has several
chances for rain in it, with Tuesday night through Wednesday night
still looking like the focus for the heaviest amounts.

That midweek period comes as a large upper low moves out of the
Rockies and into the Upper Midwest. As it does so, it`ll drag a cold
front across the MS River Valley early Wednesday before it
slows/stalls out somewhere in our vicinity Wednesday night. Latest
guidance from CMC/GFS/Euro all get that front far enough through
though that we should both cool down and dry out for Thu/Fri, though
our Lake Cumberland counties stand the best chance for a comeback of
precip as another disturbance crosses the Deep South sometime next
weekend...still some model discrepancy in timing of those features.

Of note by many in the meteorology community with the midweek system
has been the available fuel, CAPE, for storms. We have a peak in
CAPE values Tuesday afternoon, with Grand Ensemble means...notably
weighted higher by the GEFS...of around 1000 J/kg. Pulling the GEFS
out and we have more solutions around 500 or less. Matching with
deterministic models, the GFS has plenty of QPF around, whereas the
Euro and CMC are drier. Thus like the idea of going a little drier
for pops during the day. At night, the cold front moving through
should be able to take advantage of the instability that is there to
bring in some soaking rains in the Ohio Valley vicinity. Model
guidance has a swath in southern Indiana, and that lines up well
with the NAEFS and EPS ESAT vapor transport and 850 mb jet axes
Tuesday night. As the front does shift eastward, those rains will
move into our area Wednesday.

Outside of the precip forecast mentioned above, expect above normal
temperatures for the first half of the work week...even on our wet
day Wednesday...then we return to around normal to close out the
week and start the weekend.

&&

.Aviation...(00Z TAF Issuance)
Issued at 725 PM EDT Sat Apr 1 2023

Satellite imagery shows a low to mid stratus deck over southern IN
and north central KY. This will linger at the start of the forecast
period where SDF/LEX could see a brief period where CIG drop into
MVFR levels. Other than those locations, flight categories will be
VFR and skies will clear as we go into tomorrow thanks to high
pressure building in from the plains.

The gusty winds from today will linger but diminish after 04z and
become light and variable for tomorrow morning. Winds will then
shift and become more southerly tomorrow afternoon as the high
pressure shifts east of the area.


&&

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

$$

Update...BTN
Short Term...ALL
Long Term...RJS
Aviation...BTN