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000
FXUS63 KPAH 130704
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
204 AM CDT Sat Apr 13 2024

.KEY MESSAGES...

- Warm weekend ahead with highs ranging from the mid 70s to
  lower 80s. The above normal temperatures continue much of
  next week with most days reaching 80.

- Active weather pattern sets up next week, with near daily
  chances for showers and thunderstorms. The highest chances
  appear to be late Tuesday into Tuesday night and again on
  Thursday or Thursday night. Severe storms may be possible with
  both of these systems.

- Significant cool-down appears increasingly likely next weekend
  (April 19-21). This may mean highs only in the 50s for a few
  days and lows possibly falling into the 30s.

&&

.DISCUSSION...
Issued at 204 AM CDT Sat Apr 13 2024

Warm, dry and pleasant weekend still looks on tap. We maintain a
very small pop Sunday afternoon for some warm air advection
related elevated showers but with convergence aloft still think
things will stay predominantly dry.

Main focus is on the Monday night through Wednesday period.
ECMWF/GFS have shifted quite a bit during the last 12-24 hours
with both camps now showing a cold front solidly through the
area by Wednesday afternoon. Before that things look fairly
similar with a closed low shooting off the Rockies Monday with a
broad jet maximum to its south and southeast wrapping around the
low. A broad low-level cyclone spins up over the Plains and
tightens our low level surface flow. This sends richer low level
moisture into the area Monday night into Tuesday.

Tuesday evening both GFS/ECMWF have the exit region of the upper
jet max over the area with a broadly diffluent flow region
overhead and increasing to the northwest. 850mb flow on the
ECMWF is about 50 kts, where it is up to 65 kts on the GFS
deterministic guidance. Dewpoints range from about 61 to about
67. Looking at the dewpoint fields over time though I do wonder
if the GFS isn`t overmixing parts of MS/AL a bit, resulting in
lower dewpoints into the area than what might end up happening.
GFS forecast soundings overnight Tuesday shows bout 500-700
J/kg of MLCAPE on 65 degree dewpoints with 6.5 C/km 3-6 km lapse
rates. Deep layer shear is 65-70 kts, with 35-40 kts of 0-1km
shear. 0-1km SRH is about 300 m2/s2. The wind direction/strength
do not really bring in a strong elevated mixed layer off the
Mexican Plateau until after 00z. This results in steepening
lapse rates, and significantly drying air aloft. This might make
dry air entrainment a factor in thunderstorm development given
the marginal instability if storms have not yet initiated, but
could add to the intensity of storms if they are already well
established. The broadly diffluent flow aloft initially present
over the area is then replaced by a west southwestward jet
maxima increasing to 110-120 kt. The surface cold front then
moves through Wednesday afternoon. Surface windfields will
support potentially advisory level winds ahead of and behind the
front.

The kinematic/synoptic environment deserves close attention over
the coming days. Shear parameters are extremely strong, and that
trend has held for the last 2-3 days of model runs. The
thermodynamics and moisture return still look a little
marginal, but we will need to monitor conditions to our
southeast to see if moisture might overachieve relative to the
latest guidance. If so, another supercell/QLCS system in the
overnight hours Tuesday appears entirely possible.

Behind the front things turn cooler and dry through the
remainder of the week. Frost/freeze type nights are at least
possible depending on small scale details once the drier and
cooler airmass gets into place. The current forecast verbatim
though is still a little too warm for that.


&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 1038 PM CDT Fri Apr 12 2024

VFR conditions expected through this TAF issuance as high
pressure builds across the Quad State. Gusty winds will diminish
after sunset this evening due to reduced mixing. The pressure
gradient will be much weaker Saturday, which should keep winds
fairly light through the day. A temperature inversion will set
up Saturday evening into Saturday night allowing for stronger
winds just off the surface, leading to LLWS at all the TAF sites
after sunset.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$

DISCUSSION...JGG
AVIATION...