Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 140652
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
152 AM CDT Mon Apr 14 2014

.SHORT TERM...(Today through Wednesday)
Issued at 139 AM CDT MON APR 14 2014

Active/Ongoing convection is the primary near term challenge. The
first prefrontal line of storms is just departing the FA to the
east at this writing. It contained generally 35 mph wind
gusts...though we outlooked its potential for 40 to 50 mph gusts
through the area. One spotter report suggested such but a nearby
same time measured mesonet gust (Cadiz) did not confirm the higher
gust.

Another/secondary convective line is now bearing down on PAH. It
too may produce winds gusting 30 to 40 mph. With both lines,
locally heavy rains could produce ponding of water on roadways. In
general, the svr/convective parameters are lessening with
time/eastward progression. The new swody1 shifts the slgt risk svr
significantly south of our area. Ltg plot shows CG strikes have
all but disappeared, even within the otherwise high dbz/narrow
secondary line moving in on western Ky.

Will continue high PoP today with the upper trof axis making
passage after the surface front does this morning. Thunder risk
will be mainly attendant to along/ahead of the front, i.e. mainly
early this morning, although it may continue into/thru the pm in
our farthest southeastern counties/wky.

The next challenge then becomes the consistently forecast freezing
or sub freezing temps for Tue night-Wed morning. Given this
consistency, and a plethora of nearby offices issuing Freeze
Watches, we`ve decided to join the bandwagon for this event. Site
reference shows local input as either/or and user input as a
positive, so net sum leans toward headline, esp considering we`d
anticipate anothe degree or two lowering in projected low temps
forecast next couple runs. Add to this the already expected frost
and the watch headline seems appropriate (it is a WATCH).

.LONG TERM...(Wednesday through Sunday)
Issued at 258 PM CDT SUN APR 13 2014

After a frosty morning, a sfc ridge of high pressure will be in the
process of moving off to the ne on Wed, as the mid level flow turns
swrly. This will allow low level return flow (sfc to 850 mb) to pick
up a srly direction by sunset. Sfc temps are expected to rise into
the middle 60s. The PAH forecast area should remain rain-free
through Thu evening as a mid level shrtwv and sfc frontal system
develops in the central Plains. The med range deterministic models,
particularly the ECMWF, have come into better agreement with
solutions for this system, though some differences in the location
of the sfc low (to our north) and forward speed of the system
remain.

Overnight Thu night, rain showers are expected to move into mainly
the wrn half of the region as the sharp trof continues to approach
from the west. Friday looks rather wet, with at least a quarter inch
of rainfall over the region, and up to a half inch possible in the
srn half of the region on average. Due to limited instability, tstms
may occur, but at this time we will forecast slight chance/isold
coverage. The GFS continues to be aggressive with the sharpness of
the mid level trof and the strength of the sfc low/ pressure
gradient. There is too much uncertainty in the predicted moisture
return/instability to speculate on severe wx potential. Fropa will
probably occur late Fri, bringing an end to any lingering showers
Fri night.

Uncertainty among the deterministic models increased after Fri. The
GFS continues to really wrap up shrtwv energy in the nrn stream flow
right behind the system, unlike the GEM/ECMWF and the GEFS/ECENS/
NAEFS ensemble means. This would put the PAH forecast area under
cyclonic, then zonal flow aloft, while the ECMWF insists on a brief
period of ridging aloft Fri night through Sat night. It should be
dry nonetheless. The next possibility of pcpn in mainly the nwrn
third of the region might be on Sun, as the GFS/ECMWF depicted
another mid level shrtwv arriving out of the Pacific Northwest.

Air masses behind these fronts appear to be of Pacific origin,
therefore temps are expected to remain mild through Day 7.

&&

.AVIATION...
Issued at 139 AM CDT MON APR 14 2014

Mix of low VFR cigs/vsbys with convectively induced IFR conditions
will continue thru the early morning hours, as convective bands
move thru the terminals. Daylight should see a see-saw from MVFR to
VFR cigs/vsbys, with continued fairly high probability pcpn
chances until front and upper trof axis swings thru. Gusty winds
will shift from southerlies to west/northwest over the course of
the day as the aforementioned boundaries make their passage.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...FREEZE WATCH from late Tuesday night through Wednesday morning
     FOR ILZ075>078-080>094.

MO...FREEZE WATCH from late Tuesday night through Wednesday morning
     FOR MOZ076-086-087-100-107>112-114.

IN...FREEZE WATCH from late Tuesday night through Wednesday morning
     FOR INZ081-082-085>088.

KY...FREEZE WATCH from late Tuesday night through Wednesday morning
     FOR KYZ001>022.

&&

$$






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