Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 241124
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
624 AM CDT Thu Apr 24 2014

.UPDATE...Updated aviation discussion

.SHORT TERM...(Today through Saturday night)
Issued at 303 AM CDT THU APR 24 2014

Active weather situation expected from late this afternoon into
the evening. A potent short wave is forecast to move across the area.

Initially today should be dry with mainly cirrus clouds from
thunderstorms over the plains. Overall, models have slowed down
the system by a couple hours from previous thinking.

Chances of storms increase over the west this afternoon as higher
dew points move in and air becomes more unstable. 850 winds and
bulk shear increase this afternoon over the west while an upper
trough sharpens and becomes slightly negatively tilted. Narrow
band of 60 degree dew points are expected to reach into the area
just ahead of the cold front. Storms should become more organized
during the afternoon. Models suggest some convection out ahead of
the cold front over SEMO and gradually then become more linear
during the evening as the system moves east. Instability continues
through the evening as cold front moves through. By 00z the front
is just entering the western sections and should reach the Ohio
River just prior to 06z.

Lingering showers possible til morning over the eastern sections.
A high pressure ridge sets up quickly Friday during the day and by
Saturday we are back into a decent southerly flow ahead of the
next system. At this point, keeping area dry through Saturday Night.

.LONG TERM...(Sunday through Wednesday)
Issued at 303 AM CDT THU APR 24 2014

Well, in a nutshell, the extended period looks quite complicated.
Much of the Sunday through Tuesday period looks unsettled, but there
is currently low confidence on day to day specifics.

The first issue that crosses my mind begins with the Sunday
aftn/night mid lvl impulse that should be ejecting ne (in a
negatively tilted fashion) from a vertically stacked system out
over the Central Plains. Models are in decent agreement as to the
timing of the h50 impulse. However, there is uncertainty as to
whether we actually get into the warm sector at the surface, or
whether the warm front remains draped across srn portions of the
forecast area. The 00z GFS/GEM seem to want to lift the sfc front
to our north, while the deterministic ECMWF keeps the front down
closer to the TN border through 12z Monday. The placement of the
front will likely be key in determining the sfc based instability
and low lvl shear across the region. However, no matter which
solution pans out, there looks to be a decent chance of some type
of severe risk as that short wave ejects ne late Sunday and Sunday
night.

As we get into next week, additional short waves will likely
pinwheel around the closed low out over the Plains. The 12z GFS has
us well into the warm sector by Monday afternoon, with LI`s -6 to -8
as the next impulse rotates into the Ms River Valley. The ECMWF
wants to keep the warm front draped down across the TN border, with
most of the region still in the cool sector. Once again, even though
storm mode and specific timing will be in question, the chance of
rain/thunderstorms looks relatively high early next week. Bust
potential on sfc temps will also be high early next week, depending
on where that warm front ends up. Will likely play a middle of the
road approach at this point, esp for Monday, as to minimize error.
As we head into the Tuesday/Wed time frame, there seems to be a bit
more confidence that H50 heights will be falling with the approach
of the upper low, and temps will be falling to below normal levels.
Overall, it looks to be quite unsettled until the blocking pattern
can break down. Will need to monitor this extended period not only
for the severe storm potential, but also the heavy rain potential
given the stagnant pattern that is expected to unfold.

&&

.AVIATION...
Issued at 622 AM CDT THU APR 24 2014

Mainly high cirrus with some cumulus developing this morning.
Winds will gust to around 22kts at both KCGi and KPAH with gusts
around 18kts at KEVV and KOWB. Thunderstorms should reach KCGI
around 00z, KPAH around 02Z, and KEVV/KOWB around 03z. MVFR
conditions with thunderstorms, then IFR conditions due to low cigs
after storms move east. Isolated showers will continue through
most of the night over most of the area.

&&

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

$$

SHORT TERM...PS
LONG TERM...GM
AVIATION...PS






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