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000
FXUS63 KPAH 210446 AAB
AFDPAH

Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
1146 PM CDT Sat Apr 20 2024

.KEY MESSAGES...

- Below normal temperature and dry weather is expected through
  the remainder of the weekend.

- A few locations may see some patchy frost tonight while a more
  widespread frost is expected Sunday night.

- The next risk for rain arrives on Tuesday, with additional
  chances possible late week.

- The weather pattern turns even more active April 27-29th, when
  some stronger storms will be possible.

&&

.DISCUSSION...
Issued at 243 PM CDT Sat Apr 20 2024

The weekend will remain unseasonably cool with quasi zonal flow
aloft as a 130 kt jet max at 250 mb is currently located over the
Ohio Valley. As a 500 mb shortwave passes by well south of the FA
tonight with pcpn, clouds will thicken overnight. There will be
enough of a gradient on the leading edge of sfc high pressure over
Nebraska to keep winds elevated across most locations. The exception
is the far northwest counties in southern Illinois and southeast
Missouri where skies may clear in time for patchy frost to develop,
especially near Mount Vernon. MinTs are progged to fall into the mid
30s to lower 40s.

Sunday will be a few degrees cooler with maxTs generally in the low
60s. As a 1025 mb sfc high pressure builds south near the AR/MO
border, conditions will allow for radiational cooling Sunday night
with clear skies and calm winds. The setup is not only more
favorable for areas of frost to develop, but it is possible a few
cold spots reach the freezing mark with a 500 mb trough digging
south. Leaned colder with the NBM 50th percentile for minTs mainly
in the mid 30s as the probability for falling below 35 degrees is
over 60% across portions of the FA.

The synoptic flow remains more meridional on Monday as another 500
mb trough ejects out of Saskatchewan. Meanwhile, southerly return
flow on the backside of the sfc high pressure will allow for a
warming trend. By Tuesday, a shortwave associated with the
aformentioned trough will provide forcing for ascent on the synoptic
level as a weak sfc low moves east across Ontario with a trailing
cold front. QPF amounts look to be a few hundreths to a tenth of an
inch at most as a narrow axis of 700 mb moistures moves through
along the frontal boundary. However, the 12z GEFS remains the
wettest with over a quarter of an inch in some locations while the
EPS has shifted the higher amounts slightly south. With better 300
mb divergence located over southwest Indiana and southern Illinois,
locally higher amounts are certainly possible with the GEFS/EPS
indicating a 50-60% probability of exceeding a tenth of an inch.
More seasonable conditions with maxTs in the mid to upper 60s are
progged Monday and upper 60s to lower 70s on Tuesday.

By Thursday, an upper level ridge axis builds across the central
CONUS as a 500 mb low digs across the Rockies setting the stage for
a highly amplified pattern. In fact, a more potent trough quickly
enters the western CONUS. As a result, a few rounds of pcpn are
possible beginning late Thursday through Friday. Ensemble model
guidance favors April 27-29th in particular for when we will need to
watch for stronger storms as the GEFS indicates a 40-50% of
exceeding 2000 J/kg of SBCAPE by next Saturday. Unseasonably warm
conditions also look to return by Friday with a 50-70% probability of
exceeding 80 degrees.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1145 PM CDT Sat Apr 20 2024

Light to moderate north winds are expected through the night and
into the day Sunday. Those winds will ease up after sunset
Sunday evening. VFR conditions with sporadic high cloudiness are
forecast through the period.

&&

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

&&

$$

DISCUSSION...DW
AVIATION...JGG