Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 220434
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1134 PM CDT Thu Mar 21 2024

.KEY MESSAGES...

- Spotty showers are forecast mainly Friday into Friday night;
  best chance is in western Ky.

- Saturday will be brisk/cool with gusty north winds 15 to 30
  mph at times. Heightened fire danger Saturday afternoon is
  expected in the southeast MO Ozarks, due to the winds and
  relative humidity dropping to about 30%.

- Our next significant storm system arrives early next week.
  Strong gradient winds just shy of Advisory thresholds will
  precede its approach Monday, with the best chance for storms
  and heavy rains with its passage Monday night.

&&

.UPDATE...
Issued at 1133 PM CDT Thu Mar 21 2024

Updated aviation discussion for 06z TAFs.

&&

.DISCUSSION...
Issued at 130 PM CDT Thu Mar 21 2024

A cool surface high pressure system will move off to the east
tonight, giving way to an amalgamation of what will effectively
be low pressure trofing making its approach/passage here. It`ll
spread clouds with spotty showers over us, mainly tmrw
afternoon/evening, but qpf is overall scarce with surface dew
points only able to recover into the 40s and lacking convective
support. Northerlies return by late tmrw night as this system
too pushes off to the east, so after a brief return to near 70
degrees Friday, we dive back down into the 30s Friday night and
look at seasonally chilly 50s for highs Saturday. They`ll feel
esp chilly as brisk northerlies/gust 15-30 mph at times...which
with low dew points (around 30F) may heighten fire danger again
as RH values drop to near 30% in the Ozarks.

The new week begins with a powerful jet trofing the Desert SW
and opening up a difluent pattern aloft downstream, as far east
as the Mississippi Valley. This will induce broad, large scale
ascent over our neck of the woods, as the approaching jet
initiates cyclogenesis in the Plains. The models track that
initial cyclone into the Great Lakes over the course of the day
Monday, with a trailing cold front and 2ndary wave of low
pressure approaching us by evening. This metamorphosis helps
crank up gradient winds in the warm sector pretty good Monday,
with the NBM indicating some gusts just shy of Advisory
thresholds. Steepening lapse rates aloft, and broad albeit
fairly uniform (speed) shear, enhances the convective threat and
SPC draws a 15% risk for a line of storms to develop/move
across the lower MS Valley late Monday into Monday night. A
closer examination shows some negating factors here vs to our
south...0-1KM CAPE is limited and surface dew points struggle
thru the 50s. In addition, the H2 jet pieces off to our north
and south, so better drives convection to our south, hence where
the risk zone is centered. If dew points can over-achieve and
the system speed up just a little, we might see some of that
favor work into the lee of the SEMO Ozarks during peak heating,
but otherwise at this stage of the game we think a night-time
passage yields to more of a heavy rain with the line impact
hazard with a broad 1-2" average rainfall (locally higher
possible) expected...enough to support the MRGNL excessive
rainfall risk assessed by HPC.

That`s our main system to focus upon, with overall pops dwindling as
the seasonal air mass leftover produces upper 50s/lower half 60s for
highs and 30s/40s for lows finishing out the remainder of the mid
week period.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1133 PM CDT Thu Mar 21 2024

Mid-level clouds will thicken into Friday morning with a storm
system approaching from the south. As moisture increases Friday
afternoon, cigs will lower to around 5 kft AGL with the outer
extent of pcpn moving across the southeast. Model guidance is a
bit more suppressed and drier, but have maintained a PROB30 for
-SHRA at KOWB where a period of pcpn remains possible. E winds
 between 5-10 kts veer S by Friday afternoon.

Friday evening, the forecast becomes a bit more tricky. MVFR
cigs will start to spread across the region as a cold front
approaches from the northwest. This will cause a wind shift to
the N towards the end of the TAF period and breezy conditions.
Where winds remain light & variable ahead of the front, some
MVFR vsbys are also possible as the low-levels remain saturated.

&&

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

&&

$$

UPDATE...DW
DISCUSSION...DH
AVIATION...DW


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