000
FXUS63 KPAH 190458
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1158 PM CDT Tue Jul 18 2017

.UPDATE...
Issued at 1158 PM CDT Tue Jul 18 2017

Updated aviation section for 06z TAF package.

&&

.SHORT TERM...(Tonight through Thursday night)
Issued at 224 PM CDT Tue Jul 18 2017

Isolated weak convection lined up across central sections of the
CWFA in an area of enhanced CU, max instability. 500-300mb flow is
weaker than yesterday, as is DPVA aloft. Also noted are slightly
lower values of DCAPE. The only parameter similar is surface
based instability. Thus, intensity of convection overall likely
to be less than yesterday, though one or two storms could flare up
to a decent level. After this afternoon, no PoPs in the forecast
through Thursday, as mid level heights rise and the ridge expands
across the area.

As far as the Excessive Heat Watch, coordinated with SGF and LSX,
and the decision was made to go with an extended period Heat
Advisory for Wednesday through Sunday. Some areas will be
borderline 105F, maybe a couple of degrees less. Other locales at
or just above 105F. The result will be a consistent headline
message. Will strengthen the wording a bit in the Advisory product
given the duration aspect.

.LONG TERM...(Friday through Tuesday)
Issued at 224 PM CDT Tue Jul 18 2017

The upcoming heat wave continues to be the main concern in the
extended, along with increasing thunderstorm chances, mainly late in
the weekend and early next week.

As far as the heat, little change is seen in the latest patterns or
guidance. Have tweaked the max temps up a degree for Friday and
Saturday in closer agreement with neighboring offices. Max temps are
still a couple degrees below WPC guidance but at or just above MOS
guidance. Heat indices will peak out near 105 degrees in most areas
Friday through Sunday, thus the Heat Advisory headlines thru Sunday.

A cold front still looks on track to advance south toward the FA
Sunday and into the FA by Sunday evening. However, the 500mb ridge
begins to break down enough by Saturday allowing for small
thunderstorm chances mainly east and north. The better chance of
thunderstorms will arrive Sunday through Monday with the cold front
in the vicinity of the FA. It is questionable of the front`s
southern progression and thus the extent of the lower temps and
dewpoints for the first of the week. For now we will continue to
forecast the modified air mass with HI values lowering into the
90s Monday and Tuesday.

&&

.AVIATION...
Issued at 1158 PM CDT Tue Jul 18 2017

VFR conditions expected through the TAF period except for MVFR
fog possible between 09z-13z. FEW050 cu possible between 18z-01z.
Winds will be light variable to calm overnight, becoming west to
southwest around 5kts after 13z, then becoming calm after 00z.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from noon Wednesday to 7 PM CDT Sunday for
     ILZ075>078-080>094.

MO...Heat Advisory from noon Wednesday to 7 PM CDT Sunday for MOZ076-
     086-087-100-107>112-114.

IN...Heat Advisory from noon Wednesday to 7 PM CDT Sunday for INZ081-
     082-085>088.

KY...Heat Advisory from noon Wednesday to 7 PM CDT Sunday for
     KYZ001>022.

&&

$$


AVIATION...RST