Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 180825
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
225 AM CST Thu Jan 18 2018

.SHORT TERM...(Today through Saturday night)
Issued at 213 AM CST Thu Jan 18 2018

08Z surface map shows temps basically on track, already running
in single digits to low teens. The center of the surface high is
1038 mb, located close to Vicksburg, which is on track as well.
It ridges across the lower Mississippi and Tennessee river valleys
through the course of the short term forecast period. However, an
upper level Low develops overtop by day 3 and starts to close off
by day 3 night (Sat night). The net effect of this seems to be
tapping the gradually warming and moistening column, in the form
of overrunning/light rain chances by the end of the period. Other
than that, there will be alot of sunshine/warming and melting of
all the snow/ice pack. This will set the stage for soggy ground
conditions by the end of the period/and the pcpn event to come in
the 1st part of the long term portion of the forecast.

Forecast adjustments/Targets of opportunity and collaboration on
the short term yielded a blend of CONSALL for winds from 12Z today
thru 00Z Saturday, slightly higher than the model blend offered.
Also we continue to undercut guidance just a tad in the first 48
hours, particularly in the peak snow pack swath.

.LONG TERM...(Sunday through Wednesday)
Issued at 213 AM CST Thu Jan 18 2018

Main concern for this period will be a storm system impacting the
region later Sunday into the first part of Monday. Overall fairly
good model agreement, just some timing issues which is common at
this time range.

The period begins with an upper trough pushing east into the central
U.S. At the surface, low pressure will develop over Kansas and move
northeast into the upper Midwest/Great Lakes region on Monday. Some
timing issues exist with the speed of the upper trough and
associated surface low. The 00z operational GFS continues to be
around 6 hours faster than the 00z ECMWF and Canadian models. Thus
the GFS is faster bringing the precipitation into and exiting the
area. But the main timing of the precipitation looks to be in the
Sunday evening through Monday morning window.

Models are showing very marginal instability, but there are some
hints, especially elevated. Showalters are forecast to be 0 to
slightly negative, while K Index values are at or above 30. Thus
included slight thunder mention for Sunday evening/night across
mainly the southern half of the area. Ample wind shear will be
present, as is common this time of year. An 850mb jet is forecast to
strengthen over the region with upwards of 60+ kts Sunday night.
Will need to continue to monitor this system closely in the coming
days.

QPF amounts generally look to be in the range of a 1/3 inch east to
1 inch west at this time. This combined with the saturated ground
from snow melt could cause some flooding issues. Once this system
passes, the rest of the period looks to be dry.

As far as temperatures go, we look to be well above normal in the
50s on Sunday, possibly touching 60 in a few areas. Winds remain
west/southwest at the surface Monday and Tuesday, thus not expecting
a big push of cold air. In fact temperatures look to remain near to
slightly above normal much of next week, with highs in the 40s to
low 50s. A welcome change to the wintry scene we have endured lately!

The next precipitation event looks to arrive around the 26th/27th of
the month.

&&

.AVIATION...
Issued at 213 AM CST Thu Jan 18 2018

Clear skies will continue as surface high pressure ridges across
the lower Mississippi and Tennessee river valleys. Light
southwest winds will increase to around 10 kt during the day, then
decrease again around sunset.

&&

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

&&

$$



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