955
FXUS63 KPAH 081936
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
136 PM CST Wed Jan 8 2025

.KEY MESSAGES...

- Bitter and dangerously cold conditions tonight.

- Winter storm impacts the region Friday with areas of heavy
  snow.

- Below normal temperatures continue behind this storm through
  the remainder of the next week.

&&

.DISCUSSION...
Issued at 135 PM CST Wed Jan 8 2025

Larger scale clouds have finally cleared off and been replaced
by scattered to broken convective clouds. These clouds are
producing light snow flurries. This will probably continue -
aided by sunshine - until late this afternoon. Tonight clear
skies and drier and colder air, being advected in from the
northwest will lead to exceptionally cold conditions across much
of the region. Minimum temps at Mt. Vernon and Evansville are
between -2 and 0 in the persisting snowpack. While temperatures
in the teens are expected elsewhere. Despite light winds
apparent temperatures will fall low enough, particularly
considering the ongoing power outages in the ice storm region
that we issued a Cold Weather Advisory for parts of the
northeastern CWA for tonight.

For our winter storm, a sharp trough over the southwest, which
has aided in creating an exceptional wildfire situation over
southern California today will start to move east through the
day Thursday. Broad height falls begin ahead of this trough with
light precip starting overnight. Higher resolution convection
allowing models start precip earlier and are quite uniform in
that assessment. It appears they are resolving a little bit of
early, shallow convective instability, that while certainly not
enough for "thunderstorm" type convection may help generate
some light precip earlier than what the global resolution
models indicate and reflected that in the new PoP/QPF forecast.

Our best large-scale ascent occurs Friday morning with the broad
height falls from the approaching trough, and a brief phasing
of the right rear and left front quadrant of jet maxima ahead of
the trough. There is also a fair amount of persistent
isentropic lift and some 700-850 mb frontogenetic forcing
indicated in the GFS/ECMWF/Canadian guidance. The bulk of this
more mid and lower level forcing however is further south along
the KY/TN border.

This area roughly from Fulton-Murray-Hopkinsville is where we
have our highest snowfall forecast, at about 3 to 6 inches.
Ensemble guidance members have about a 70-80% probability of
warning level snow in this corridor. Will hold on to a watch
east of the Lakes as we would still be about 36 hours or so out
there and it fits into the collaboration picture with LMK/OHX.
Ensemble members are a little less enthusiastic from
Greenville, MO east to Cape Girardeau, MO and Paducah for
warning snow. However even tamping down our QPF a bit with 12-13
to 1 snow ratios, which may be conservative, we hit 4 inches
there. Drier air working in from the northwest threatens totals
a little but it did appear to be kept at bay enough to prevent
significant impacts. The snowfall in the northern edge of this
warning area will probably be a little more inconsistent.

For the remainder of the area at least a couple of inches of
snow looks like a lock and worked with SGF/LSX to do a longer
than normal lead time advisory for snow. Particularly given the
ongoing recovery efforts from the recent ice storm.

Behind the storm cold temperatures remain, likely made more so
by any snowpack. A large westerly zonal jet maxima then works in
and keeps us in a west to northwesterly upper and lower level
flow. This should result in persistent below normal temperatures
with highs in the 30s.


&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1142 AM CST Wed Jan 8 2025

MVFR cigs, with some light snow, are moving through eastern
portions of the forecast area this afternoon. Behind it, skies
are clearing. Westerly to west-northwesterly winds of 7-9 kts
this afternoon become light overnight, then shift to southerly
tomorrow.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Cold Weather Advisory from 9 PM this evening to 6 AM CST
     Thursday for ILZ075>078-081>083.
     Winter Weather Advisory from midnight Thursday night to
     midnight CST Friday night for ILZ075>078-080>087-089>091-
     094.
     Winter Storm Warning from midnight Thursday night to midnight
     CST Friday night for ILZ088-092-093.
MO...Winter Weather Advisory from midnight Thursday night to
     midnight CST Friday night for MOZ076.
     Winter Storm Warning from midnight Thursday night to midnight
     CST Friday night for MOZ086-087-100-107>112-114.
IN...Cold Weather Advisory from 9 PM CST /10 PM EST/ this evening
     to 6 AM CST /7 AM EST/ Thursday for INZ081-082-085>088.
     Winter Weather Advisory from midnight CST /1 AM EST/ Thursday
     night to midnight CST /1 AM EST/ Friday night for INZ081-
     082-085>088.
KY...Cold Weather Advisory from 9 PM this evening to 6 AM CST
     Thursday for KYZ018.
     Winter Weather Advisory from midnight Thursday night to
     midnight CST Friday night for KYZ007-010-014-015-018-019.
     Winter Storm Warning from midnight Thursday night to midnight
     CST Friday night for KYZ001>006-008-009.
     Winter Storm Watch from late Thursday night through Friday
     evening for KYZ011>013-016-017-020>022.

&&

$$

DISCUSSION...JGG
AVIATION...ATL