Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 220248
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
848 PM CST Wed Jan 21 2015
Issued at 848 PM CST WED JAN 21 2015
Made some minor adjustments to the public forecast, mainly for
cloud trends and resultant impact on temperatures. The low clouds
in the north have broken up considerably since sunset, though a few
batches of them will still skirt along and north of I-64 through
midnight. High clouds will try to advance northeast over the
region through the night. They may become thick enough to help
temper radiational cooling over southeast Missouri, as winds die off
later this evening and overnight. Increased lows a bit in
southeast Missouri and southwest Kentucky, and lowered them a bit
in the Pennyrile where radiational cooling will be most effective.
UPDATE Issued at 548 PM CST Wed Jan 21 2015
Updated aviation discussion only.
.SHORT TERM...(Tonight through Friday night)
Issued at 223 PM CST WED JAN 21 2015
Main focus in the short term, is the system, that will likely
bring snowfall to portions of west KY Friday afternoon and evening.
The "all or nothing" line seems to set up from New Madrid MO, to
Paducah, KY to Owensboro, KY. The area with the best chances of
accumulation will be south of that line, and especially from
Mayfield and Murray, east across the Lakes area toward
Hopkinsville. Freezing levels are forecast to be low enough for
snow, though early on, before intensity increases, some rain may
mix in or fall exclusively. We should see dynamic cooling and
lowering temps from above through the column as 700-500mb QG
forcing increases over the aforementioned area during the
afternoon, pushing east through the evening, coincident with
respectable low trop frontogenetical forcing. The main element
that will create uncertainty with respect to snowfall accumulations
will be surface temps. It does look like it readings will fall
into the lower 30s, and if rates are enough, it should accumulate,
especially on grassy and elevated surfaces. Slick spots on roads
certainly possible as well. Straight up QPF conversions suggest
1-3" likely, highest closer to the TN border (higher QPF area).
However, amounts will also be determined by antecedent conditions,
surface temps and rate of fall. Saying 1 to maybe 2 inches is
reasonable for now as a general introduction. The activity will
end over the Pennyrile during the evening. North of the Ohio,
chances drop off considerably to essentially none. The "track"
seems to have stabilized. However, we cannot rule out minor
adjustments on how far the north the snows will extend. Stay
tuned. Adjustments may still be required.
Otherwise, until then high pressure in control. A few more clouds
Thursday with a system passing to our south. Temps initially will
be a blend of MOS and base model output. Friday into Friday
night, utilized more in the way of the NAM 12 km output, as it
seems to capture best the lowering afternoon temps across west KY.
.LONG TERM...(Saturday through Wednesday)
Issued at 223 PM CST WED JAN 21 2015
The long term appears mainly dry as the northwest flow pattern
continues. A little light rain or snow is possible Sunday afternoon
into Monday morning, mainly east of the Mississippi River. This
precip will be associated with a clipper type system that will move
southeast across the Ohio Valley.
As far as the daily details...
Saturday and Saturday night will be dry and milder as winds become
southwest ahead of the clipper type disturbance. Clouds will begin
to increase on Saturday night.
Sunday into Sunday night...the models have trended further northeast
with the path of the system, especially the 12z gfs. All models are
in good agreement that the surface low will track southeast across
Ohio. The models have backed off on pops and qpf. In fact, southeast
Missouri will have a dry forecast for the entire long term period.
The best chance of precip will be over sw Indiana Sunday night, but
even there it should be rather spotty. Temps will fall from the 40s
Sunday into the mid and upper 30s Sunday night.
On Monday and Monday night...dry conditions are expected as weak
high pressure moves east from the Plains to the Mississippi Valley.
Highs will be mainly in the lower 40s with lows in the 20s.
Tuesday through Wednesday will continue dry with not much change in
temps. Another clipper type system appears likely, but once again
the path and strength of the system would need to be ideal to
generate precip in such a dry air mass.
Issued at 548 PM CST WED JAN 21 2015
As a ridge of high sfc pressure expands into the region, winds will
remain out of the north/nw aob 6 kts through the next 24 hours.
Airports in swrn IN and adjacent parts of srn IL and nrn KY may
develop a VFR cig from about sunrise to early afternoon. Cannot rule
out an MVFR cig, but the model signal was not strong enough to
include in the TAFs at this time.