000
FXUS63 KPAH 150744
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
144 AM CST Sun Dec 15 2013

.SHORT TERM...(This Evening through Monday Night)
ISSUED AT 200 PM CST SAT DEC 14 2013

.Short term (Today through Monday Night)

Main shortwave/sfc low pressure system impacting the area this
morning swung rapidly northeast by 18Z today. The last area of
rain/drizzle/fog took most of the morning to move out of the region.
However, another upper level shortwave was waiting in the wings
behind it and will move through the area this evening/overnight, but
no precipitation is expected with this feature.

Colder air filters in for tonight with high pressure at the sfc.
When to clear out clouds will be tricky to forecast but it appears
we could see partial clearing sometime later tonight/early Sunday
morning. However, we do tend to clear out clouds too quickly in
these winter time regimes, so will be rather conservative with any
partial clearing. Depending on how much clearing we do receive,
will dictate how low temperatures will drop. Right now, lower 20s
looks reasonable.

With the approach of the aforementioned secondary upper wave for
Sunday/Sunday night, more clouds look to be in the offing,
especially later in the day, which will keep high temperatures down
as well, but at least no precipitation is expected. Highs in the
upper 20s/lower 30s appear likely Sunday depending on cloud cover.

We remain in northwest flow aloft Sunday night through Monday night
with waves upper level energy passing by...which will produce some
cloudiness, thickest in our northern/northeastern counties. Right
now, any precipitation is expected to remain to our north. In
addition, upper level heights will be rising and so should
temperatures, as sfc/low levels winds shift to southwesterly.
Highs on Monday should reach the upper 30s north to mid 40s south,
depending on the amount of cloud cover.

.LONG TERM...(Tuesday Night through Saturday)
ISSUED AT 127 AM CST SUN DEC 15 2013

We start the long term with good model agreement upon surface high
pressure moving to and ridging to our east and nwlys aloft. This
means at least one more night (tue night) of cold with 20s
commonplace.

Southerlies develop Wed, beginning a warming trend, as the upper
level flow backs to westerlies. This will help bump highs back
into the 40s Wed and 50s for Thursday, as night time lows nudge
upwards similarly from 30s to 40s. Dry weather looks to hold til
Thursday.

By 00z Friday, low pressure in the Plains develops, and the
consistent fetch of s-swlys allows dew point temps to increase to
near 50F. Time/height cross sections and forecast model soundings
show the upper profile moistening, and some light shower activity
possibly developing, mainly along and just off to our north/west
CWA periphery.

The warming/moistening trend kicks in with earnest Thursday night-
Friday. While model differences begin to develop in the signal in
how low pressure evolves/tracks, there is good agreement that dew
point temps at the surface rise through the 50s and may even flirt
with 60F by Friday pm as a frontal boundary makes its way into the
FA. Elevated instability parameters such as the K index offer
support for a mention of thunder Thu night-Friday. 850mb winds
increasing to near 50Kts further support its mention.

Friday night-Saturday, the models diverge. The 00z GFS suggests
the moisture pushes on out with the boundary and the profile
pretty much stays warm in a more or less westerly flow pattern.
The ECMWF keeps the boundary in our neck of the woods as the srn
Plains trof deepens, resulting in west-southwerlies continuing for
us along with continued pops. The contrasting surface temps then
offer a changeover chance pop mainly for our northern half of the
region through the time in question. We`ll keep such mention in
the either/or chance category with these model hints of
warmer/drier starting to be included in the ensemble, though not
enough yet to influence the blend. To be watched.

&&

.AVIATION...
ISSUED AT 127 AM CST SUN DEC 15 2013

MVFR cigs will persist before clearing from the northwest between
16z and 20z. MVFR vsbys and brief IFR cigs are possible through
11z, especially at KEVV and KOWB. Mid level clouds will spread
across the area from the northwest after 20z. Northwest winds
around 10 kts with some higher gusts will continue, becoming west
at 6 to 12 kts after 16z.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$