Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/25/22

Area Forecast Discussion

National Weather Service Louisville KY

 1003 PM EDT Mon Oct 24 2022

.Forecast Update...
Issued at 955 PM EDT Mon Oct 24 2022

Minor update to the dewpoints to reflect the lower values currently
observed, which differences were between 2-6 degrees. Also, AMDAR
observation at SDF around 25/00Z depicts a deep dry airmass
extending from the surface to the mid levels. Therefore, moisture
recovery in the next 24 hours will be slow while any attempt of
precipitation overnight should evaporate before reaching the ground.
Rest of the forecast remains on track.

&&

.Short Term...(Tonight through Tuesday evening)
Issued at 315 PM EDT Mon Oct 24 2022

...Strong Winds Tuesday...
...Rain Showers Arrive Tue Afternoon/Evening...

A compact mid/upper level low and robust PV maxima is spinning ESE
over New Mexico this afternoon, within a broader trough reaching
into the northern Plains and Canada. The upper level low is forecast
to swing east across the southern Plains tonight and then pivot
northeast into the Mid-MS Valley on Tuesday. The approaching wave
will bring good diffluence aloft and strengthening S to SW flow
aloft on Tuesday.

Favorable upper level divergence will support a deepening sfc low
moving from eastern OK to southern MO overnight. In central
KY/southern IN, we will see partly to mostly cloudy skies with
plenty of cirrus streaming overhead. The low to mid levels will
remain quite dry into early Tuesday. Expect dry weather, a steady SE
sfc wind, and lows ranging through the 50s. The coolest low-lying
spots in the Bluegrass and Lake Cumberland regions should again dip
into the 40s for a short time.

Sfc low pressure is forecast to move northeast into central IL by
Tuesday evening. There is generally good agreement amongst hi-res
CAMs in a band of showers lifting northeast across central KY and
southern IN Tuesday afternoon and evening. Arrival time is somewhat
late in the day - most places should remain mainly dry into mid-
afternoon. Strong convection develop as a QLCS over portions of TN
and MS by early afternoon, with convection likely to weaken in
intensity as it moves northeast into central KY and southern IN.

Strengthening southerly flow will provide a good moisture fetch from
the Gulf, and sfc dewpoints may be able to creep into the lower 60s,
especially west of I-65. This could support a narrow ribbon of very
weak (< 200 J/kg MLCAPE) instability ahead of the line of
showers/pre-frontal trough. Forcing and shear are quite strong, so
an isolated storm is certainly possible. Overall, the risk for
severe weather remains very marginal. For a significant portion of
the CWA, instability is nil. For any robust line segment, however,
the primary threat would be damaging winds. Given the strength of
the low-level flow and helicity, a brief tornado cannot be ruled
out. However, instability may be too weak to support even small/weak
tornadoes.

For areas south of the Ohio River and west of a line from Fort Knox
to Glasgow, winds are forecast to become quite gusty beginning mid-
morning Tuesday. Dry low-level air and mixing up to at least 925 mb
will support downward momentum transfer of the strong LLJ.
Therefore, after coordination with PAH and OHX, will issue a Wind
Advisory for these areas for 40+ mph wind gusts. The window for
these gusts should be fairly short, with non-thunderstorm wind gusts
diminishing as lower clouds and rain push in from the southwest.

Read below in the Long Term section for more details on storm total
rainfall amounts. However, areas west of I-65 could see around a
half inch of rainfall in 3 hours prior to 00z Wednesday.

&&

.Long Term...(After midnight Tuesday night through Monday)
Issued at 301 PM EDT Mon Oct 24 2022

At the start of the long term the deep, nearly vertically stacked
low will be positioned near Saint Louis and will proceed to near
Detroit overnight. A narrow corridor of increased atmospheric
moisture ahead of the incoming cold front will support a band of
showers and possibly a few rumbles of embedded thunder. A robust low
level jet initially reaching from Alabama to Michigan will weaken as
it translates eastward, and what very little instability we may be
able to realize ahead of the front will weaken as well, resulting in
a downward trend in rainfall rates as the showers move through the
region. Plenty of low level helicity may lead to some rotational
signatures Tuesday evening, but updraft strength will be very weak
with extremely limited buoyancy. Can`t rule out a stray enhanced gust
of wind early in the evening given the strong flow off the surface.

A few wrap-around showers may scoot through southeast Indiana and
the Kentucky Blue Grass region Wednesday morning, but any rain that
does form would be light. Storm totals by the time the system
completely pulls away will likely be in the 1/2-1" range along and
west of I-65, with amounts around 1/3-1/2" to the east.

A north-south ridge of high pressure over the Plains will strengthen
as it pushes east to New England, giving us dry weather and typical
late October temperatures for the remainder of the work week.

An upper low over the southern Plains late this week will slowly
drift eastward, possibly opening up into a trough this weekend over
the Southeast. This feature may bring scattered showers to the Ohio
Valley. Rain amounts will be light, though heavier amounts would be
possible east and southeast of the low, so the track of the system
will play a role in just how much rain we get. At any rate, we may
get two or three days of increased cloud cover, increased moisture,
patchy rain, and light winds, which would at least slow the progress
of any advancement or development of drought.

&&

.Aviation...(00Z TAF Issuance)
Issued at 745 PM EDT Mon Oct 24 2022

Impacts/Confidence:
- High confidence on LLWS tonight at HNB and BWG. Medium confidence
for SDF
- High confidence on windy conditions tomorrow afternoon
- Increasing probability of MVFR with frontal passage

Discussion...VFR conditions are expected for most of this forecast
cycle although MVFR is possible towards the last portion of it due
to a cold front passage. Tonight, high clouds will keep building
from the west as the core of the low-level jet moves eastward
through the Mid Mississippi. As a result, continued mentioning
impactful wind shear for HNB and BWG while, after coordinating with
CWSU, decided to also include SDF given the latest model guidance.
For tomorrow, anticipate wind gusts to ramp up quickly through the
morning with windy conditions in the afternoon. As previously
mention, rainshowers are in store for the afternoon along and ahead
of the frontal line. MVFR conditions will be associated with the
heaviest showers and where storms realize since instability will be
limited and greatest towards BWG. Beyond TAF time, looks like that
post-frontal low-level cloud deck might bring MVFR/IFR ceilings.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Wind Advisory from 10 AM to 8 PM EDT Tuesday for KYZ023>028-
     061>063-070>074.

IN...None.

&&

$$

Update...ALL
Short Term...EBW
Long Term...13
Aviation...ALL