Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/26/21

Area Forecast Discussion

National Weather Service Louisville KY

 1006 PM EDT Tue May 25 2021

.Forecast Update...
Issued at 1005 PM EDT Tue May 25 2021

Current surface analysis displays area of high pressure over the
southeastern CONUS and a surface low centered over Ontario with a
cold front extending southwest through the Upper Midwest and into
the south-central Plains. Satellite imagery reveals mostly clear
skies over the area at the moment, with earlier afternoon cu having
dissipated. Only a few stray showers were able to develop this
afternoon and evening, with little in the way of rainfall being
observed. Temperatures remain in the 70s to lower 80s currently,
with overnight lows expected to be rather warm in the mid 60s to
lower 70s. As we move towards dawn, expect increasing cloud coverage
to begin pushing into the area with showers and storms arriving
after sunrise. Overall, the forecast remains on track and only
minor edits have been made to the grids.

&&

.Short Term...(This evening through Wednesday)
Issued at 222 PM EDT Tue May 25 2021

Temperatures have gotten quite toasty this afternoon as many places
are reporting readings in the upper 80s at this hour. Visible
satellite reveals a well established cu field across southern IN and
central KY, but convection has struggled to take off mainly due to
warm air around and above 700mb (per AMDAR soundings) and dry air
entrainment in the mid-levels. We may see a couple of isolated
showers or storms develop by late afternoon, but they should be
relatively weak and short lived given the unfavorable environment.

Cu field should dissipate by sunset and skies will turn clear with
occasional cirrus spilling in from the southwest. Showers and storms
that form across the Midwest and Missouri Valley ahead of a cold
front will begin trekking toward the region overnight, but won`t
arrive until after sunrise tomorrow. High-res CAMs vary on the
evolution of this line of showers and storms, with some weakening it
significantly as it moves into southern IN and central KY during the
morning hours, and others showing it maintaining some strength and
then gradually becoming stronger as it pushes eastward. Models
generally show weak instability and shear ahead of the line, so
think the solutions of a weaker/more subdued line of showers and
convection seems plausible, at least through late morning. By early
to mid afternoon, we may see enough instability build ahead of the
line to support a couple stronger or marginally severe storms. SPC
Day 2 Outlook highlights this potential with a marginal hail/wind
threat.

Additional showers and storms may fire off along the true cold front
to our north and spill into northern portions of the region... but
confidence in that happening remains low and will be largely
dependent on how much clearing we get in the wake of the first round
of precipitation.

.Long Term...(Wednesday night through Tuesday)
Issued at 300 PM EDT Tue May 25 2021

Anticipated cold front will be passing through the region Wednesday
evening to begin the long term forecast. Will carry slight chc PoPs
for primarily our Kentucky counties for a few hours Wednesday night
as the katafront pushes through. For Thursday, upper flow becomes a
bit more zonal, with sfc temps expected to exceed convective temps
(low 80s) and max out in the mid-upper 80s. SREF plumes have an
ensemble mean of MLCAPE at BWG around 900 J/kg, with lower
instability the further north you go. There should be enough
instability to support at least isolated-scattered showers and
storms, but weak shear and meager lapse rates should limit
convective organization. The better chances for PoPs come Thursday
night and into Friday, when a large convective complex expected to
initiate over the Plains and track ESE across the Midwest and into
the Ohio Valley.

By Friday morning, a deep sfc low will be located just to our north
and across IN/IL. Continued convection is possible for Friday as we
will be located within the warm sector. Trailing cold front and NW
flow will eventually come by Friday evening, resulting in cooler
temps for Friday night and into Saturday. Expect Saturday`s temps to
remain in the upper 60s to low 70s.

We stay dry for the remainder of the Holiday weekend, with temps
staying in the upper 70s for Sunday and low 80s for Monday.

&&

.Aviation...(00Z TAF Issuance)
Issued at 720 PM EDT Tue May 25 2021

IMPACTS: Expect CIGs to begin lowering into MVFR range Wednesday
morning as showers and storms begin to push into the area. Brief
reductions in visibility will also be possible in any heavier
rainfall.

DISCUSSION: Overnight period should be relatively quiet with mostly
clear skies and winds out of the SSW generally around 5 - 10 kts. As
we approach dawn, cloud cover will begin to increase ahead of an
approaching system. Shortly after sunrise, expect showers and storms
to begin pushing in from the northwest and progressing southeast
across KY throughout the day. Precipitation should then be exiting
east of LEX/BWG towards the end of the TAF period with CIGs also
lifting back into VFR range. Winds during the day Wednesday will
take more of a SW/W direction with speeds generally around 10 kts. A
few gusts to 20 kts will also be possible.


&&

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

$$

Update...JML
Short Term...DM
Long Term...CJP
Aviation...JML