003
FXUS63 KPAH 042239 AAA
AFDPAH

Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
439 PM CST Wed Dec 4 2024

.KEY MESSAGES...

- A cold front moves through tonight, causing wind chill values
  to plummet into the single digits by Thursday morning.
  Temperatures will be 20 degrees below normal on Thursday.

- Warming trend begins this weekend into early next week,
  followed by another cold blast in the latter half of the
  week.

- The next storm system brings widespread rainfall Sunday
  afternoon into Sunday night. Rainfall amounts between 0.75 to
  1.50 inches are possible. Rain shower chances may linger
  through at least Tuesday ahead of the next cold front.

&&

.DISCUSSION...
Issued at 209 PM CST Wed Dec 4 2024

Split flow aloft will inhibit any impactful pcpn from impacting the
FA this evening as a cold front approaches from the NW. Water vapor
imagery now shows a shortwave trough digging into Illinois. At
700 mb, a vort max may provide just enough forcing for ascent
to trigger an isolated sprinkle or flurry tonight along I-64,
especially into portions of southwest Indiana. Otherwise,
gradient winds will remain elevated through tonight with wind
gusts up to 30 mph possible as winds shift from SW to NW after
fropa.

Robust CAA will quickly put an end to the more mild seasonable temps
today with minTs tonight plummeting into the lower 20s and even
upper teens. Combined with the wind, wind chill values are progged
to drop into the single digits by Thursday morning. In fact, maxTs
on Thursday will struggle to reach freezing in the upper 20s to low
30s with minTs Thursday night falling well into the mid teens. Kept
temps close to the NBM 75th percentile and MOS guidance as the NBM
this season has been decoupling the boundary layer too quickly
resulting in a cold bias. A 1032-1034 mb sfc high pressure does
build into the FA Thursday night causing the pressure gradient to
weaken, but does not settle directly over the FA until Friday
morning. In the end, temperatures will be 20 degrees below normal.

Southerly return flow on the backside of the sfc high pressure
quickly causes a warming trend heading into the weekend as 500
mb energy over the SW CONUS eventually ejects across the Plains
by Sunday night. Model guidance is in good agreement showing a
wave of moisture moving across the FA. Scattered rain showers
will begin to increase in coverage by Sunday afternoon before
developing into a steady rain Sunday evening into Sunday night
as a 60+ kt nocturnal LLJ supports greater moisture transport at
850 mb. From NW to SE, WPC QPF ranges from 0.75 to 1.50 inches,
with model ensembles in good agreement in supporting at least
up to an inch. Flooding issues are unlikely with stratiform
pcpn, as FFG over a 3 hour period remains above 2 inches.

As a positively tilted longwave trough digs across the Midwest with
another cold front mid-week, forecast confidence becomes lower as
there is uncertainty in how quickly a cold front will move through.
Previous deterministic model runs have shown a low pressure system
developing along a tight baroclinic zone in the vicinity of the FA
that would support another round of impactful pcpn. However, the
latest 12z runs have trended more progressive and east in line
with the ensembles, with the low developing too late to have
much of an impact beyond additional scattered rain showers.
Something to monitor as another transient cold airmass is
looking likely in the latter half of the week. At the very
least, daily rain shower chances remain possible through at
least Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 439 PM CST Wed Dec 4 2024

VFR conditions are forecast through the period. A cold front
will move in from the northwest tonight increasing winds. A few
clouds may get trapped along the inversion at 2500-3500 ft but
coverage should be limited. Winds are expected to remain fairly
gusty through late morning on Thursday.

&&

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

&&

$$

DISCUSSION...DW
AVIATION...JGG