112
FXUS63 KLMK 081346
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
946 AM EDT Mon Jul 8 2024

.KEY MESSAGES...

*   Very warm today with with slowly increasing humidity.

*   The remnants of Beryl will move into the region Tuesday into
    early Wednesday. Isolated strong to severe storms will be
    possible Tuesday afternoon and evening, with heavy rainfall,
    isolated damaging wind gusts, and brief tornadoes possible.

&&

.UPDATE...
Issued at 946 AM EDT Mon Jul 8 2024

Temperatures are starting to come up from morning lows though clouds
have slowed down heating in some areas. Our eastern-most counties
across the Kentucky Bluegrass have already climbed into the 80s
where clouds are at their thinnest, while our southwestern zones
(BWG metro area) have only climbed into the low/mid 70s with thicker
clouds overhead. Upstream observations do show some breaks in the
clouds across Tennessee so once that slides in we should see
temperatures respond more quickly. Forecast remains on track.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 322 AM EDT Mon Jul 8 2024

Early morning satellite imagery shows partly to mostly cloudy skies
across central Kentucky with mainly clear conditions across much of
southern Indiana.  Early morning temperatures were in the low-mid
60s in the valleys and the typical cooler mesonet locations.
Elsewhere temperatures ranged from the upper 60s to the lower 70s.
For the remainder of the overnight hours, no significant weather is
expected.

For today, we`ll remain in a southwest flow aloft with moisture in
the column continuing to increase. Partly cloudy skies are expected
and highs should be about 1-2 degrees higher than what we saw on
Sunday.  So we`ll be going with highs again in the upper 80s to the
lower 90s.  It will be a bit more humid today as dewpoints rise into
the mid-upper 60s.  Afternoon heat index values will likely top out
in the mid-upper 90s.

For tonight, stronger moisture advection will continue across the
region with skies becoming mostly cloudy.  Scattered showers/storms
may encroach on our western counties toward dawn Tuesday.  Lows will
be quite mild with readings mainly in the lower 70s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 322 AM EDT Mon Jul 8 2024

Tuesday through Wednesday Night...

An unusually active start to the extended forecast period is
expected Tuesday into Wednesday as the remnants of Tropical Cyclone
Beryl lift northeast from the mid-Mississippi Valley into the Ohio
Valley and Midwest. A pre-existing upper trough over the central
U.S. will interact with and ultimately absorb Beryl over the next 48
hours. There is still some dispersion in model guidance in the exact
track and speed of Beryl; however, the current consensus would take
the storm center from the ArkLaTex Tuesday morning to the Wabash
Valley by Wednesday morning before continuing to lift northeast away
from the region Wednesday afternoon. This track would take the bulk
of the precipitation shield associated with meso-alpha and synoptic
scale forcing (i.e., mid-level troughing, frontogenesis, and
convergence) on the NW side of the cyclone into IL/IN, with the bulk
of the precipitation over our area being driven primarily by
convection and forcing from meso-beta and smaller scale boundaries.

Immediately ahead of the remnants of TC Beryl, a stout moisture
surge will spread over the Tennessee and Ohio Valleys. EPS, GEFS,
and GEPS ensemble mean IVT approach model climo max values Tuesday
afternoon across western KY, with IVT in excess of the 90th
percentile of model climo spreading into central KY and southern IN
by Wednesday morning. This will help PW values surge to around or
just above 2" by Tuesday evening, which is also in excess of the
90th percentile of model climo. As a result, any showers and
thunderstorms which may develop Tuesday afternoon into early
Wednesday morning will have the potential to put down localized
swaths of heavy rainfall in a short amount of time. However, for the
reasons mentioned in the above paragraph, widespread heavy rainfall
should slide just northwest of our area.

With most of the forecast area expected to fall within the front
right quadrant of the sfc low track, the potential for gusty winds
and spin-up tornadoes will exist within convectively-driven bands
Tuesday afternoon into Tuesday night. While there are multiple
complicating factors associated with the amount of severe potential,
the amount of destabilization will be the main limiting factor.
First, convection southwest of the area on Tuesday may produce
widespread mid- and upper-level clouds. Also, a slower northward
progression of the system (as in the 03Z RAP) would delay the
northward surge of the greatest instability axis until overnight
Tuesday night, resulting in less overall instability for storms to
work with. However, if instability is sufficient to allow storms to
fire Tuesday afternoon, curved and elongated hodographs, as well as
enhanced SRH along an effective warm frontal boundary draped across
the CWA will lead to an elevated tornado and damaging wind threat.
Additionally, effective bulk shear around 40 kt would support some
supercells, adding additional tornadic potential. For now, given
continued uncertainties in the amount of instability, a Day 2
marginal (level 1/5) risk for severe weather exists, though SPC
notes the potential for an increased threat level depending on
trends in expected instability.

By Wednesday morning, drier westerly flow will begin to wrap around
the back side of the sfc low, bringing an end to the severe and
heavy rain threat. While isolated to scattered showers and storms
will be possible for the day on Wednesday, precipitation amounts
should be relatively light.


Thursday through next weekend...

In the wake of Beryl`s remnants, large scale upper troughing will
dissipate and gradually transition to ridging as we head into next
weekend. The return of positive height anomalies across much of the
central and eastern CONUS will bring warming temperatures, with
above normal temps likely next weekend. While an isolated shower or
storm cannot be ruled out at this amount of lead time, the lack of
any well-defined systems in medium-range guidance would suggest a
mainly dry period from Thursday into next weekend. Looking out to 10
days from now, an extended period of hot weather looks likely from
next weekend into the following week, as indicated by ensemble
guidance and CPC 6-10 day temperature outlook. This heat may lead to
worsening drought conditions if not accompanied by consistent
rainfall; fortunately, CPC`s precipitation outlook slightly favors
above normal precipitation during this period.

&&

.AVIATION /12Z TAFS THROUGH 18Z TUESDAY/...
Issued at 653 AM EDT Mon Jul 8 2024

Other than some light fog over at KHNB early in the period, VFR
conditions are expected through the upcoming TAF period at the
terminals.  Winds will start off light and variable this morning and
then pick up out of the southeast this morning.  The winds will then
shift to the south/southwest this afternoon, but speeds will
generally be less than 5 knots.  VFR conditions are expected tonight
and into the day on Tuesday.
southwest by afternoon.

&&

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

&&

$$

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