Area Forecast Discussion
Issued by NWS Paducah, KY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
FXUS63 KPAH 141734

Area Forecast Discussion
National Weather Service Paducah KY
1134 AM CST Tue Nov 14 2017

Issued at 1132 AM CST Tue Nov 14 2017

For aviation section only.

UPDATE Issued at 530 AM CST Tue Nov 14 2017

Updated for 12Z aviation forecast discussion.


.SHORT TERM...(Today through Thursday night)
Issued at 243 AM CST Tue Nov 14 2017

Early this morning, surface high pressure was sprawled out from the
lower to mid Mississippi River Valleys up into the Ohio valley and
into the eastern Great Lakes. The cold front that is expected to
reach us Wednesday was situated just east of the Rocky Mountains.

High pressure will be slowing moving east and out of the region
today. Winds will become more southeasterly with time but remain
light. The main area of return flow resulting in cloudiness and
precipitation will remain out to our west today, so we will stay
dry. The shield of high clouds over the area at this time will
continue to slowly move southeast this morning. However, another
area of low to mid clouds to our west will slowly migrate
eastward and lead to an increase in clouds over southeast MO and
southwest IL through the day. This cloud deck will continue
sliding eastward into the night tonight as the cold front moves

By 12Z Wednesday, the cold front will be situated from central WI,
into central MO and into TX. We could see some rain sneaking into
the northwestern tier counties of southeast MO and southwest IL
prior to 12Z. Otherwise, as the front makes its way east, expect
chances for rain and isolated storms to trek eastward across the
area throughout the morning. By Wednesday afternoon, western
portions of the CWA will likely be seeing the rain ending with the
bulk of the precipitation impacting southwest IN and west KY
during the afternoon hours. By 00Z Thursday, most of the area
should be dry but left a lingering slight chance POP in the far
eastern areas for the evening hours. Rainfall amounts should stay
in the 0.15- 0.25 inch range on average for the event.

High pressure will build in Wednesday night and dry us out and will
keep us dry through Thursday. After seeing highs today and Wednesday
in the lower to mid 50s (some upper 50s possible in SEMO on Wed.),
temperatures will drop back down on Thursday behind the front, with
some locations only reaching the upper 40s near and north of I-64.

High pressure starts pulling away from the area Thursday afternoon
into the evening hours. Later on in the evening, we should see
moisture returning, but any chances for rain should hold off until
after 06Z Friday and be confined to mainly southeast MO.

.LONG TERM...(Friday through Monday)
Issued at 243 AM CST Tue Nov 14 2017

Confidence in the long term portion of the forecast starts off lower
than average with persistent model variability around the system
slated to impact the region late in the week. Forecast confidence
improves somewhat later in the weekend and early next week--mainly
due to a lack of significant weather concerns.

Shortwave energy progged to enter the Pacific Northwest Thursday
night is forecast to move swiftly east across the Plains into the
Mississippi Valley Friday night and Saturday. At the surface, low
pressure is forecast to develop in the lee of the Rockies early in
the period before reaching the Great Lakes region sometime Saturday.
A cold front accompanying this low is expected to pass through the
forecast area late Friday night into Saturday. As this occurs, the
potential for showers and even some thunderstorms will exist until
the front makes passage.

Unfortunately, exactly how all this unfolds is still quite uncertain
at this time. Timing differences persist among the models, with the
GFS some 12 hours faster than the ECMWF on frontal passage, and the
CMC leaning in the direction of the slower ECMWF. One reason for the
slower timing of the ECMWF may be its less amplified upper level
solution, which is an outlier compared to the GFS and CMC. Given the
model uncertainty, prefer to stick with an overall model blend at
this point. The end result is the potential for showers from Friday
through Saturday, with some thunderstorms also possible Friday night
into Saturday. We should be able to narrow down that window of
greatest potential once models come into better agreement in the
coming days.

With such a dynamic system, the potential for severe weather is also
of interest--particularly Friday night into Saturday. Similar to
what happened the first weekend of November, models are suggesting
the presence of a fairly strong mid level capping inversion through
Friday, though some weakening is expected as the front and mid level
system approach Friday night. Models are also signaling a westerly
component to the low level flow as the front approaches, which would
tend to favor convection of a linear nature. However, exactly how
things pan out remains uncertain at this time with so many unknown
variables. Nonetheless, it is something to keep an eye on in the
coming days.

Once the system shifts east of the area, a return to dry and cooler
weather is forecast late in the weekend into early next week. The
magnitude of this cold snap will largely depend on which model has
the best handle on the depth of the northwest flow behind the
system. The initialized blend appears to provide a good starting
point as its temperatures are largely cooler than the climatology-
trending MOS guidance from Sunday onward.


Issued at 1132 AM CST Tue Nov 14 2017

VFR conditions from mid morning through Tuesday night with
mid clouds becoming thicker with time from west to east. Light
winds becoming east-southeast aob 5-6 kts. Winds will turn more
south-southwesterly aft 12z Wed AOB 10 kts as cigs lower to low
VFR in light rain showers.




AVIATION...GM is the U.S. government's official web portal to all federal, state and local government web resources and services.