Area Forecast Discussion
Issued by NWS Louisville, KY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLMK 262341
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
741 PM EDT Tue Mar 26 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

* Gusty winds and a low-end chance of a isolated strong to severe
  storm (north of I-64) through the evening hours.

* Dry and mild rest of the work week. Warmer temperatures and
  increasing shower and storm chances later this weekend.

&&

.UPDATE...
Issued at 610 PM EDT Tue Mar 26 2024

Across the region at this hour, a cold front is analyzed just west
of the I-65 corridor. Evidence of the front`s position can be seen
from an agitated cu field, with SPC mesoanalysis indicating a few
hundred joules of CAPE in the immediate vicinity of the front. This
modest instability, combined with support from the left exit region
of a transient mid-level jet core, has provided enough lift for
isolated showers and thunderstorms to develop along the front. All
of the convection has been sub-severe thus far, as meager
instability is offset from the axis of greatest shear and other
dynamic support. Hi-res guidance shows these showers and storms
continuing eastward along with the front over the next few hours,
gradually fizzling out as diurnal instability abates.

Additionally, wind speeds and gusts have gradually decreased over
the past few hours as the low-level jet core lifts into the Great
Lakes region. Accordingly, the Wind Advisory has been allowed to
expire at 22Z. Sustained winds of 15-20 mph with gusts of 25-35 mph
will continue over the next few hours before subsiding after sunset.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 325 PM EDT Tue Mar 26 2024

Early afternoon satellite imagery shows the dry slow working into
the western third of KY.  Ongoing shower activity continues over the
eastern half of the state with widespread rain showers in areas east
of a line from Allen county to Franklin county.  Within these
showers, we`re still getting some gusty winds as the we`re mixing
down some of the remaining low-level jet core that continues to push
east.  Just after noon we had some 45-50 mph wind gusts in the
Bluegrass region, but with the core of the jet transitioning east,
there has been a noticeable downtrend in the wind gusts via the KY
Mesonet data.  Temperatures across the reign were in the upper 50s
east of I-65 with lower 60s confined to areas west of I-65.  Within
the dry slot temps have warmed into the 65-66 degree range out just
west of Owensboro with dewpoints in the lower 50s.

SPC mesoanalysis shows about 100-250 J/kg of SBCAPE out that way and
recent GOES imagery shows some agitated Cu going up along the
boundary.  However, this Cu field has been struggling a bit,
probably due to the lack of sufficient moisture.  Ongoing cloud
cover in the I-65 corridor is likely to continue for the next hour
or two where we`d normally see the highest insolation of the day. If
this turns out to be the case, temps maxing out in the low-mid 60s
with dewpoints in the upper 40s/lower 50s would not yield all that
much CAPE for storms.  On the other hand, environmental shear
remains favorable with 25-30kts available.  Latest high res models
suggest a band of showers and possible storms may develop in the
vicinity of the I-65 corridor.  However, this is somewhat
conditional based on how long cloud cover stays in place.  Based on
wind profiles, the veered flow near the surface looks to very much
limit the tornado threat.  However, gusty winds and perhaps some
small hail in the strongest cores would be the main severe weather
hazards.  The higher risk of severe weather looks to remain to our
north across east-central IN and west-central OH and up into lower
MI.  For now, plan on keeping a slight chance of showers/storms in
the forecast through the evening.  Outside of storms, once areas get
into the dry slot, surface wind gusts may come up a little bit more.
Based on current obs upstream, wind gusts of 25-30 mph will be
possible before winds slacken off toward sunset.

By early evening, the cold front will push through the I-65 corridor
and then push into the I-75 corridor by late evening.  This will end
the storm threat and winds will shift to the west and eventually
northwest. Skies are expected to clear out overnight with lows in
the mid-upper 30s by Wednesday morning.

For Wednesday, looks like we`ll start off with some low stratus
across the region during the morning hours, but clearing looks to
take place in the afternoon.  Highs will be on the cool side with
lower-mid 50s west of I-65 and highs in the upper 50s east of I-65.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 325 PM EDT Tue Mar 26 2024

Heading into the long-term, the axis of the upper trough will sit
just west of the Mississippi Valley as it continues it progression
eastward. At the surface, high pressure centered near Oklahoma and
Kansas stretches east through the Ohio Valley. Cold air advection
even with mostly clear skies will drop temperatures into the 30s
Wednesday night before temperatures reach to near normal with highs
in the upper 50s to low 60s on Thursday.

Thursday night, the surface high begins passing the CWA to the
south. Return flow initiates warm air advection as a limitedly
amplified upper ridge begins to enter the Lower Ohio Valley.
Temperatures reach the upper 60s to near 70 on Friday before the low
to mid 70s on Saturday.

Heading into the weekend, upper flow becomes more zonal as a
baroclinic zone sets up along the Ozarks and Lower Ohio Valley. As
moisture flows around a surface high over the Southeast along the
front, precipitation chances will begin increasing. Keeping low
chance PoPs during this period because model guidance currently
shows good agreement overall, but details of timing and placement
remain uncertain. Much of this time will likely remain dry as the
front drifts back and forth, but currently the best area for
precipitation looks to be central and southern Indiana.

By early next work week (Monday - Tuesday), good model agreement has
a strong cold front shifting the pattern to one of deep layer
northwest flow. This will bring convection and cooler midweek
temperatures to southern Indiana and central Kentucky.

&&

.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 740 PM EDT Tue Mar 26 2024

The first feature of interest in the current TAF period is a wind
shift associated with a cold front currently along a line from SDF
to BWG which will continue east over the next several hours. Winds
will shift from southerly ahead of the front to westerly behind the
front, and could briefly be gusty, though winds will generally be
decreasing through the nighttime hours tonight. Once the front
passes through LEX/RGA later tonight, winds should be fairly
consistent out of the W/NW through much of the current forecast
period.

Secondly, an expansive area of MVFR stratus currently resides across
the Middle and Upper Mississippi Valley, and will creep closer to
the region over the next 6-12 hours. Initially, obs suggest ceilings
around 4-5 kft within the stratus, though CIGs decrease to 2-3 kft
further into the stratus. With the low pressure system lifting north
later tonight, there is low-medium forecast confidence in how far
east the MVFR stratus gets. Have kept most sites VFR given limited
confidence except for a brief period Wednesday morning where there
is the best signal for MVFR ceilings. Cloud bases should lift and
begin to scatter out from west to east late tomorrow morning, with
high confidence in a return to VFR conditions by the end of the
current TAF period.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...MJ
LONG TERM...KDW
AVIATION...CSG


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.