798
FXUS63 KLMK 140529
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
129 AM EDT Tue May 14 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Active pattern with 2 storm systems bringing chances of showers
    and storms through Saturday.

*   Scattered showers and storms, especially during the afternoon
    Tuesday and Wednesday.

*   Main impacts from this activity will be gusty winds, small hail
    and heavy rain that could result in localized minor flooding.

*   Another similar system arrives for the end of the week and into
    the weekend with a chance of showers and a few embedded storms.

&&

.UPDATE...
Issued at 952 PM EDT Mon May 13 2024

At this hour, we`re watching two areas of light returns on radar,
one across southern IN and far northern KY, with another area
located between the Cumberland and Bluegrass Parkways across central
KY. The northern area of reflectivity appears to be associated with
an axis of higher 700 mb moisture, with some of the returns farther
east likely not reaching the ground with dry air still present from
the sfc-800 mb. This would also explain the near 30 mph wind gusts
we`ve seen on KY Mesonet sites over the past hour in the Bluegrass,
which could be due to downward momentum transfer within the
saturating air mass.

On the other hand, the southern area of radar returns looks to be
associated with a low-level southerly moisture fetch which will
continue to move across the region tonight into tomorrow. Have
reduced PoPs in the near term slightly given latest trends in model
guidance and obs; however, the expectation for isolated to scattered
rain showers overnight remains on track. Temperatures will remain
relatively mild, with lows only expected to fall into the upper 50s
and lower 60s.

Updated products will be published shortly.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 318 PM EDT Mon May 13 2024

Conditions remain dry early this afternoon with a few light showers
noted across western KY, SE MO, and TN. A nearly vertically-stacked
low pressure system is approaching Kansas City, with troughing
extending south across TX. This slow-moving low closes off as it
meanders eastward across Missouri this evening. Southerly to
southwesterly flow in the low to mid-levels will pull Gulf moisture
northward ahead of the low. Lingering dry air up through the mid-
levels will keep us mainly dry into the afternoon hours. A few
isolated light showers will be possible across the southern and
western parts of the forecast area by late afternoon and early
evening. Otherwise, expect a relatively quiet afternoon with
thickening clouds and temperatures topping out in the mid 70s to
near 80 degrees.

Tonight, moisture and lift deepen as the low rotates east across
Missouri. Moderate low-level moisture transport develops along a 25
kt LLJ. PW increases to 1.3+ inches with forecast soundings showing
a moist profile with limited instability. Scattered showers are
likely, and there is a slight chance (10-20%) for an isolated rumble
of thunder. Precipitation will be somewhat spotty, with more
widespread activity arriving Tuesday. Expect mild morning lows in
the upper 50s to lower 60s.

Numerous showers with scattered storms are expected Tuesday as the
low moves over the Lower Ohio Valley. While broad ascent is noted
along with deep, rich moisture, instability will be kept in check by
clouds and moist adiabatic lapse rates. Tall, thin SBCAPE developing
by the afternoon will support scattered storms capable of locally
heavy downpours, gusty winds up to 40 mph, and perhaps isolated
small hail. Deep-layer shear is only 20-25 kt, with stronger mid-
level winds remaining to our south across the Gulf Coast states.
This will significantly limit convective organization, and severe
weather is not expected. Rainfall amounts of 0.50-1.25" inches are
possible, with some locally convectively-enhanced totals not out of
the question. With a wet ground and above normal streamflow, might
result in some ponding and minor flooding issues in low-lying or
flood-prone areas. Temperatures will top out in the 70s Tuesday
afternoon.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 318 PM EDT Mon May 13 2024

Stacked system will slowly work across the Ohio Valley Tues night
through the day Wed. This will result in lingering clouds and wet
weather through at least Wed afternoon. Initially, any
showers/storms from Tues will diminish overnight due to a lack of
diurnal heating but with the sfc low slow to work eastward during
the day, another round of scattered showers and even a few embedded
thunderstorms. No organize severe threat is expected but models due
show amble instability with very low shear. Lapse rates per model
soundings don`t look very steep but with any activity couldn`t rule
out some gusty winds and small pea size hail. This will be
especially true during the afternoon as most of the activity will be
a result of diurnal heating. Lows Wed morning will be near 60 with
highs mid 50s on Wed.

Showers and any convection will diminish Wed evening as the system
works off the Delmarva Peninsula and upper ridging builds in over
the Ohio Valley along with an area of weak sfc high pressure.
Thursday will be drier and warmer for most of the day as high will
warm into the upper 70s to even a few 80s for the afternoon.

End of the week into the weekend the models continue to show a
second system working into the Ohio Valley but continue to show a
spread in solution both spacial and temporal between the
deterministic models. Expect to see an increase in non severe
shower/storm activity over the are for Friday into the weekend.
Given the differences in the deterministic kept the NBM Pops for
Friday into the weekend. Showers/storms could come in as early as
Thursday evening with the best chance during the day Friday. While
we have low all day PoPs for Saturday and Sunday, anticipate that
this will not be the case but confidence on timing and placement is
low so there remains a lot to be ironed out between now and then.
Highs will be in the upper 70s to near 80 on Friday but expected to
warm through the weekend with low 80s Saturday to the mid 80s on
Sunday.

&&

.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 128 AM EDT Tue May 14 2024

Surface low over Missouri early this morning will drift slowly into
the lower Ohio Valley over the course of this TAF period. With the
slow forward movement of the system, showers and scattered
thunderstorms can be expected through tonight, with the most likely
time for storms in the afternoon hours, and especially at BWG where
instability is expected to be strongest.

Low confidence in ceilings with cloud bases at several different
levels across the region at any given time. With models showing
quite a bit of low level moisture, satellite showing widespread
clouds, and surface observations reporting low ceilings, will
include 1-3K` cigs for much of the forecast period. Any storms today
will be capable of lower than prevailing cigs/vsbys.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...EBW
LONG TERM...BTN
AVIATION...13