Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 130014
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
714 PM CDT Sat Apr 12 2014
Issued at 704 PM CDT SAT APR 12 2014
For aviation section only.
.SHORT TERM...(Tonight through Monday night)
Issued at 132 PM CDT SAT APR 12 2014
Breezy conditions will persist this afternoon with diurnal cu and
some high clouds present. Some variation of this coverage should
continue tonight, although cu should diminish. Mild overnight as
south winds stay up. Most of Sunday will be dry and breezy.
Increasing chances of convection by afternoon across the Ozark
Foothill region ahead of an approaching mid level s/wv forecast to
eject NE from the southern Plains.
The wave will move NE through the evening, resulting in increased
convective coverage. Best chance PoPs through midnight will be
over the west 1/2, then east of there after midnight. Instability
and shear parameters most favorable for isolated strong to severe
storms is west of the Mississippi River. Looks like a marginal
chance at best. Locally heavy rain possible, but not enough to
cause problems (very local, minor if anything). In the wake of the
lead s/wv, at the surface a front will move through, with the
trof`s at h8/h7 lagging just behind late Sunday night into Monday.
Surface temps should drop slowly post front through the day
Monday. Meanwhile, with the main upper trof to our west at 18z
Monday, and abundant low level moisture still present, cannot rule
out lingering light showers, or drizzle (light rain).
Monday evening, as the main upper trof moves through, chance of
showers/rain will move west to east across the area, best chances
east 1/2, departing the area by about 12z Tue.
.LONG TERM...(Tuesday through Friday)
Issued at 315 PM CDT SAT APR 12 2014
There may be some lingering showers in the srn Pennyrile region at
the beginning of the extended forecast period (after sunrise Tue).
Otherwise, a sfc ridge of high pressure will invade the PAH forecast
area during the day Tue, under wnwrly mid level flow. This will
ensure dry weather for the mid week period, as the flow aloft
gradually transitions to wswrly. Frost is possible Tue night with
light erly winds in place, then temps are expected to undergo a
gradual warm-up through at least Fri.
Some return flow should get started Thu as high sfc pressure moves
ewd and is replaced with srly low level flow over our area. It is at
this time frame that the med range models begin to differ a bit in
The models showed a developing shrtwv in the mid levels across the
Plains during the day Thu, but the 00Z ECMWF showed the feature to
be shallower/weaker and therefore had less sfc reflection. This also
means that the low level pressure gradient and moist fetch is shown
to be much more robust by the GEM and GFS. The 12Z ECMWF showed some
improvement in the intensity of the system, but still did not depict
a closed sfc low over the upper Midwest by Fri morning, and
therefore lacked deeper moisture ahead of an approaching cold front.
The ECMWF depicted sfc low pressure was shown generally over the PAH
forecast area Fri morning.
The initialization blend did provide a better signal among the med
range models for a pcpn event (with some possibility of thunder) on
primarily Fri, then back to dry for Sat (Day 7). This scenario
seemed to be supported by the GEFS/ECENS/NAEFS ensemble means. The
post-frontal air mass will be of a mild Pacific origin.
Issued at 704 PM CDT SAT APR 12 2014
Expect VFR conditions through most of the TAF period. The main
weather factor will likely come with the southerly wind flow.
winds will subside to around 10 kts or so tonight, but 30-40 kts
just off the surface may pose some LLWS concerns. Gusty sfc winds
up around 30 kts will commence aft 14-15z as low lvl heating
allows vertical mixing to ensue.