Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 012252
AFDPAH

AREA FORECAST DISCUSSION
National Weather Service Paducah KY
452 PM CST MON FEB 1 2016

.UPDATE...
Issued at 449 PM CST MON FEB 1 2016

Updated Aviation discussion for 00Z TAF Issuance.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 214 PM CST MON FEB 1 2016

Main forecast challenge in the short term continues to lie with
the severe weather potential coming up on Tuesday across much of
the region.

Vigorous mid/upper level low is still slated to eject ne through
the Plains and into the Midwest Tuesday/Tuesday evening. Associated
pre-frontal surface trof will be approaching the mid MS River
Valley by early afternoon...and will cross srn IL/wrn KY/sw IN
during the afternoon and early in the evening. Moisture levels
will also be increasing ahead of the front Tuesday afternoon, with
some guidance now surging sfc dew points into the lower 60s prior
to trof passage. Wind profiles/shear progs are practically off
the charts, suggesting a decent severe storm potential, depending
on the amount of instability that can be generated. Much of the
operational model guidance suggests MU CAPES 400-800 J/KG forming
ahead of the front on Tuesday, and if sfc dew points make it into
the 60s, then I do not believe instability will be an issue as
long as we can break a fairly strong capping inversion aloft.

If so, a QLCS type of event would be in order, with a squall line
possibly developing late morning/midday over far se MO, then
transversing east across the remainder of the forecast region Tue
afternoon into the early evening. Though damaging wind gusts with
bowing segments appears to be the most likely risk with this type
of regime, isolated/brief tornado spin-ups cannot be ruled out. It
should also be noted that extremely highly sheared environments
have been know to rip convection apart due to the highly tilted
nature of the storms, so the extremely high shear could be a
mitigating factor, along with the capping aloft. It is still
looking as though the higher svr risk will be over wrn KY, where
high dew points/instability may lie. However, still would not be
surprised if much of the region ends up in some type of SPC watch
box Tuesday afternoon/evening.

.LONG TERM...(Wednesday night through Monday)
Issued at 214 PM CST MON FEB 1 2016

A wavy mid/upper pattern will continue across the CONUS in the
extended period. However, measurable pcpn is not expected until Day
7.

Early in the period, lack of any low level moist return flow should
preclude measurable rainfall associated with a mid level shrtwv
moving through on Thursday. Through Friday, the PAH forecast area
will be on the nrn periphery of of a sfc high pressure area, which
the models show moving off to the ese by early in the weekend.
Initial nwrly sfc winds are expected to turn srly/swrly by Friday
and should remain that way through the end of the extended period.

A nrn stream shrtwv is progged to drag a dry weak cold front through
our region Saturday. The only effects the boundary should have is an
increase in cloud cover and a subtle wind shift.

Dry conditions should continue until Monday, when a large-scale
mid/upper level trof and attendant sfc cold front will be in our
vicinity, providing low level forcing, upper dynamics, and improved
moisture return for at least some shower activity to be generated.
At this time, it does not appear that forecast temps will result in
any wintry pcpn on Day 7.

&&

.AVIATION...
Issued at 449 PM CST MON FEB 1 2016

Incoming storm system will introduce restricted cigs by tmrw
morning with storms onset by late morning or early pm. Thunder
with restricted vsbys are anticipated as the system sweeps thru.
Gradient winds will strengthen in the warm sector and gust to 30
kts during the pm hours.

&&

.PAH Watches/Warnings/Advisories...
IL...Wind Advisory from 6 AM Tuesday to midnight CST Tuesday night
     for ILZ081>083-085>094.

MO...Wind Advisory from 6 AM Tuesday to midnight CST Tuesday night
     for MOZ087-108>112-114.

IN...Wind Advisory from 6 AM Tuesday to midnight CST Tuesday night
     for INZ081-082-085>088.

KY...Wind Advisory from 6 AM Tuesday to midnight CST Tuesday night
     for KYZ001>022.

&&

$$


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