000
FXUS63 KPAH 041055 CCA
AFDPAH

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE PADUCAH KY
423 AM CST Wed Dec 4 2013

.SHORT TERM...(Today through Friday night)
ISSUED AT 423 AM CST WED DEC 4 2013

Will maintain our Winter Storm Watch as is. Significant winter
weather impacts remain likely. Model preferences included an even
blend of the GFS/NAM given very comparable thermal profiles sfc-H8
Thur-Fri eve. QPF was a 75 percent GFS/ECMWF 25 percent GEM/NAM
blend with weight given to HPCs output as well. Running the
numbers, generally 2 inches of snow NW of a Owensboro KY, to New
Madrid MO line, 3-4 inches with spot 5 inch amounts across
portions of southeast Missouri, southern Illinois, and southwest
Indiana. Sleet may play havoc with some of the totals resulting in
a slight reduction. Over the rest of the area, 1-2 inches
possible, again with antecedent conditions and sleet, making
accumulations still difficult to pin point down.

Looking at an overall 0.20-0.33" ice accumulation potential average
in an area generally south of a line from KPOF and KCGI to KPAH,
Madisonville, and areas south toward the AR/TN state lines. Cannot
rule out amounts around 0.50". Given the transitional nature of
the precip, and antecedent conditions, including very warm conditions
today, temps not falling until tonight, and still above freezing
air through the day Thursday, we could see a more gradual downward
process of accretion from elevated surfaces toward the ground, thus
tempering slightly higher end amounts.

Precipitation is still forecast to come in two waves, a late Thur
into Thur night surge from SW to NE, with a second surge bringing
appreciable QPF to the SE 1/2 of the area Friday. Expect all rain
Thursday, except toward sunset over the far west part of our CWFA.
Then, you can infer the predominant forecast precip types given the
above forecast amounts and areal coverage. Again, this is subject to
change should newer model data adjust one direction or the other.
This signal has been monitored for 5 days now, and has remained very
persistent, in that winter weather impacts will likely occur.

In the meantime, for early today, dealing with areas of fog, at
times dense over southern IL. Moisture through the day remains
shallow. So other than some early morning light drizzle, or maybe
sprinkles later in the morning, not expecting much. Tonight, a
wave lifts NE and brings convection to especially the SE 1/2 of
the CWFA. Cannot rule out isolated TSRA, but not a big deal.
Unseasonably warm today, then the arctic front will progress
from west to east across the fa tonight, clearing the KHOP
area Thursday morning.

.LONG TERM...(Saturday through Tuesday)
ISSUED AT 423 AM CST WED DEC 4 2013

The primary concern in the extended portion of the forecast is with
another chance of wintry precipitation primarily Saturday night
through Sunday night. Our attention then turns to bitterly cold air
to start the new week.

On the heels of the significant late week system, dry and very cold
conditions will prevail on Saturday as cold arctic high pressure
builds south from Canada. Highs on Saturday will likely remain below
the freezing mark across the entire forecast area, after morning
lows in the upper single digits to lower teens.

The upper level flow pattern will remain southwesterly through the
weekend as a longwave trough progresses east into the Plains. A
couple perturbations in the upper flow pattern will contribute to
the development of large scale forcing for upward motion as the area
becomes positioned beneath the divergent right entrance region of a
strong 100+ knot H5-H3 jet core. At the surface, an inverted trough
(stalled frontal boundary) will become established from the lower
Ohio Valley and Tennessee Valley into the Deep South by Sunday. Low
pressure is forecast to develop along the Gulf Coast and ride
northeast along the front. The low should reach Kentucky by Sunday
evening.

With the aforementioned dynamics in place and increasing moisture
from the Gulf, a wintry mix of precipitation is forecast to spread
across the region Saturday night and continue through Sunday into
Sunday night. Through this event, the best combination of moisture
and lift will exist over western Kentucky, where the highest
precipitation totals are expected. Lighter precipitation amounts are
forecast further north and west.

Model forecast soundings indicate that temperatures will be cold
enough to support primarily snow and sleet at the onset Saturday
night. As temperatures warm aloft, the precipitation will gradually
become mixed with and change over to freezing rain and sleet Sunday
morning. By Sunday afternoon, surface temperatures across much of
western Kentucky may be just above freezing, which would transition
everything over to all rain. While all of this is preliminary and
subject to change, this system is certainly worth a close watch as
travel conditions may be impacted again late in the weekend.

Most of the precipitation will come to an end Sunday night as the
system shifts to the east. Bitterly cold arctic air will pour into
the area early next week. Much of the temperature forecast will of
course be driven by the amount of snowpack. However, current
indications are that temperatures may struggle to reach the 20
degree mark in some locations by Tuesday, with lows Tuesday night
perhaps well into the single digits. It would appear that winter is
here to stay for a while...

&&

.AVIATION...
ISSUED AT 1143 PM CST TUE DEC 3 2013

As mentioned with the 00Z Wednesday aviation TAF discussion,
subtle large scale lift within the boundary layer appears to be
enough to support the development of VFR/MVFR ceilings and lowered
visibilities. With the broad baroclinic leaf of cirrus clouds
moving into the area, ceilings and visibilities are dropping
again. The timing of this drop in ceilings and visibilities were
forecast about 1-2 hours too soon with the 00z Wednesday
issuance.

For now, kept the trend of lowered ceilings and visibilities in
place, but improving visibilities Wednesday afternoon and evening
as winds pick up sharply and turn southwest in advance of the
approaching cold front.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WATCH from Thursday evening through Friday
     afternoon FOR ILZ075>078-080>089-092-093.

     WINTER STORM WATCH from late Thursday night through Friday
     afternoon FOR ILZ090-091-094.

MO...WINTER STORM WATCH from Thursday evening through Friday
     afternoon FOR MOZ076-086-087-100-107>111.

     WINTER STORM WATCH from late Thursday night through Friday
     afternoon FOR MOZ112-114.

IN...WINTER STORM WATCH from Thursday evening through Friday
     afternoon FOR INZ081-082-085-086.

     WINTER STORM WATCH from late Thursday night through Friday
     afternoon FOR INZ087-088.

KY...WINTER STORM WATCH from late Thursday night through Friday
     afternoon FOR KYZ001>022.

&&

$$

SHORT TERM...Noles
LONG TERM...RJP
AVIATION...Smith