Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/20/23

Area Forecast Discussion

National Weather Service Louisville KY

 801 PM EDT Mon Jun 19 2023

.Forecast Update...
Issued at 801 PM EDT Sun Jun 18 2023

Stacked low pressure is spinning over south-central KY this evening,
with bands of showers wrapping cyclonically around the low. The
atmosphere is very moist with SDF ACARS soundings and RAP
mesoanalysis data featuring PWATs around 1.7 inches. Mixed-layer
CAPE is decreasing thanks to rain-cooled air and approaching sunset.
Thunderstorms are now quite isolated, though visible satellite data
shows lingering convection near the low in south-central KY.
LightningCast probabilities are still elevated (50+% 60-min
lightning probability) in that region.

Instability will continue to weaken over the next few hours, and
coverage of showers will also begin to decrease in that time. Only
isolated to widely scattered showers are expected late tonight into
early Tuesday.

Stronger instability was present earlier this afternoon with MLCAPE
peaking near 1000 J/kg. CAPE and abundant moisture contributed to
very high rainfall rates in convection, which led to localized
excessive rainfall. Relatively slow-moving convective bands near the
pivot point produced 1-3 inches of rain, with 1-2 inches of that
falling in less than an hour over portions of Marion, Hardin,
Bullitt, and Jefferson counties. For example, 3.01 inches of rain
has fallen at the NWS Louisville office in South Louisville just
since 2 PM EDT. Very heavy rainfall rates did lead to localized
flooding, including some street flooding.

&&

.Short Term...(This evening through Tuesday)
Issued at 310 PM EDT Mon Jun 19 2023

Currently... The surface low pressure system is circulating over our
southern counties. This is leading to scattered-widespread showers
north of I-64 and scattered showers and storms south of I-64. Most
of the region has already seen about an inch of rainfall, however in
some localized areas we have seen around 2.0-2.5 inches of rain
during heavy downpours.

Tonight... Showers and scattered storms will continue into the
night, however they will begin to thin out. With high dew points, a
low cloud deck will likely develop tonight. This cloud deck will
prevent overnight cooling, so low temperatures Tuesday morning are
expected to be in the upper 60s and low 70s. Tonight will likely
feel muggy and misty.

Tomorrow... Scattered showers and storms are possible over the
region tomorrow morning and will increase in coverage in the
afternoon. Forecast soundings are similar to today with PWATs around
1.75-1.9 inches, and modest instability (1000-1500 J/kg MLCAPE).
Severe threat is low again tomorrow with the only concern being
heavy downpours with stronger storms. We could see another inch of
rain fall tomorrow over most of the area, and with stronger storms
we could see locally higher totals. Showers and storms will taper
off into the evening. With continued showers and storms, high
temperatures are likely to stay in the upper 70s and low 80s.

Overall... Showers and storms continue in the short term period
bringing much needed moisture into the region. Forecast confidence
is medium-high.

.Long Term...(Tuesday night through Monday)
Issued at 345 PM EDT Mon Jun 19 2023

The stacked low bringing our current rain showers is expected to be
to our south over the northern parts of the Alabama/Georgia border.
This is expected to give us a break from rainfall Tuesday night, but
as we head into Wednesday, expect an uptick in precipitation, mainly
during the afternoon and evening hours. Bands of showers are
expected to work from east to west around the circulation, so some
areas could see prolonged rainfall. Instability will be marginal,
and shear remains weak. This will lead to a mostly rain event with
no severe weather expected. Flooding isn`t expected, but will
continue to be monitored.

Wednesday night, the upper high just north of the Great Lakes will
begin to get pushed to the east. This will allow the aforementioned
low pressure system to work north towards the CWA. Expect enhanced
precipitation chances through Friday as more rounds of showers
traverse the Lower Ohio Valley. Instability and shear will remain
weak.

Friday night into Saturday, upper flow will finally start pushing
the decaying low pressure system eastward. This will begin to reduce
precipitation chances and increase sunshine for the weekend, but
high dew points and diurnally induced instability will increase the
likelihood of afternoon and evening convection.

Through the end of the work week, temperatures will remain fairly
mild with all the cloud cover keeping highs in the mid to upper 70s
during the day and only dropping into the low to mid 60s at night.
The weekend will see a return of mid and upper 80s.

&&

.Aviation...(00Z TAF Issuance)
Issued at 729 PM EDT Mon Jun 19 2023

Stacked low pressure is spinning over south-central KY this evening,
with scattered to numerous SHRA ongoing. Showers will diminish
somewhat in coverage and intensity after 03z Tue. Overall, drier
conditions are anticipated Tuesday morning. However, mist or
isolated light rain could occasionally limit visibility overnight.
Though, the main aviation concern will be IFR/low MVFR ceilings.

Low clouds and isolated SHRA will be the theme through Tuesday
morning, with SCT-NUM TSRA blossoming starting around 18z across
central and southern KY. Northeasterly winds of 5-10 kts will be
common through the period.


&&

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

$$

Update...EBW
Short Term...SRM
Long Term...KDW
Aviation...EBW