PAH issues Area Forecast Discussion (AFD) at Jan 3, 10:39 PM CST
891
FXUS63 KPAH 040439
AFDPAH
Area Forecast Discussion
National Weather Service Paducah KY
1039 PM CST Fri Jan 3 2025
.KEY MESSAGES...
- A major winter storm system comes calling this weekend
starting late Saturday night and continuing into Monday
morning. It will bring a mix of rain, freezing rain, sleet,
and snow.
- Significant ice, sleet, and snow accumulations are possible
across most of the Quad State.
- The coldest air so far this season settles in behind this
system as temperatures plummet to start next week. Wind chill
values may drop to single digits or below zero next week.
&&
.DISCUSSION...
Issued at 259 PM CST Fri Jan 3 2025
We have already made two adjustments to the Winter Storm Watch.
We have expanded it south to include Scott county Missouri, the
rest of southern Illinois, and Ballard, McCracken, Marshall and
Trigg county eastward in Kentucky. This was done to account for
a southern shift in much of the available guidance. The second
change was to extend the Watch through 18Z Monday to allow the
deformation zone snowfall to push east out of the area.
Yesterday, guidance was in pretty good agreement in the storm
track this weekend, but that agreement has dissolved since. Last
night the ECMWF and CMC kept the surface low track along or
south of the border, and their 12Z runs have done the same
thing. The 12Z NAM came in similar to them, but the GFS
continues to push the surface low up near Paducah. The impact on
the surface freezing line is significant, as the GFS continues
to push it northwest through much of the region by Sunday
evening, while the others struggle to bring it much past Cairo,
Paducah, and Owensboro. Obviously this will have significant
impacts on the location of the freezing rain belt, which may now
be farther south in the region than previous expected.
The upper-level low track is also trending farther south across
the Quad State. That could limit the northward extent of the
warm nose aloft, allowing for more snow accumulation along I-64,
especially in southern Illinois. It also would allow the
deformation zone snow Sunday night into Monday morning to impact
the entire Quad State rather than just the northern half.
Given all of the uncertainties, we decided to not upgrade to a
warning with this forecast.
Much of west Kentucky may need a Winter Weather Advisory or a
Winter Storm Warning Sunday morning when freezing rain could
create treacherous driving conditions and close to a quarter
inch of icing. Assuming the freezing line does lift into/across
west Kentucky in the afternoon and evening, we would likely be
able to cancel any headlines in the afternoon and evening.
The area of greatest concern and most varied potential outcomes
is northwest Kentucky into southwest Indiana, where
temperatures may or may not reach freezing. If they climb above
freezing presumably any icing would melt before the final belt
of sleet/snow arrives overnight into Monday morning. If it
doesn't, there could be some huge ice totals, well over a half
inch, with a couple inches of snow on top.
At this time, the zone from Cape Girardeau and Carbondale
eastward through Evansville, Henderson, and Owensboro have the
best shot at a bonafide, dangerous ice storm. Areas to the
north of that zone should see more sleet and snow, and areas to
the south will likely see only a brief concern for icing Sunday
morning.
WPC QPF is still averaging 1.5-1.75", so there is a lot of
precipitation to account for in those areas that never climb
above freezing. Winds are expected to be sustained at 10-20 mph
through most of the event, and with the moderate to heavy rain
expected, ice accretion on power lines and tree limbs should be
an inefficient process. However, the stronger winds will tend
to make it easier to knock down ice-laden limbs and power
lines. Power outages are a strong bet somewhere in the zone
mentioned above, but just how widespread and where they will be
is impossible to narrow down at this time.
Looking at the snow/sleet potential, with the potential southern
shift of the storm track, the Interstate 64 corridor could see a
half foot or more, with little or no freezing rain. Also, the
entire area could see an inch or two of snow late Sunday night
into Monday morning before the system completely exits the
region.
The Quad State will remain in northwest flow through Thursday,
and surface high pressure will eventually build over the region
Wednesday and Thursday. Temperatures are not expected to climb
above freezing until possibly next Friday, and then just barely
over the far south and southwest portions of the region. Any
snow an ice accumulations will be difficult to get rid of and
may cause travel difficulties through much of the week. The
coldest air will be early Wednesday and Thursday. Wind chill
readings will bottom out in the single digits below zero in the
north and in the single digits above zero in the south.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1037 PM CST Fri Jan 3 2025
Another set of VFR TAF's ahead of the late weekend weather
system. High level clouds will continue to overspread the area
with gradually lowering ceilings throughout the day and into the
night. Winds will be light around 5 kts or less.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Winter Storm Watch from late Saturday night through Monday
morning for ILZ075>078-080>094.
MO...Winter Storm Watch from late Saturday night through Monday
morning for MOZ076-086-087-100-107-111.
IN...Winter Storm Watch from late Saturday night through Monday
morning for INZ081-082-085>088.
KY...Winter Storm Watch from late Saturday night through Monday
morning for KYZ004-005-007-008-010>022.
&&
$$
DISCUSSION...DRS
AVIATION...AD
Source: PAH issues Area Forecast Discussion (AFD) at Jan 3, 10:39 PM CST (https://mesonet.agron.iastate.edu/p.php?pid=202501040439-KPAH-FXUS63-AFDPAH)
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