Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 230457
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1156 PM CDT SAT AUG 22 2015
Updated aviation section for 06z taf issuance
We continue to watch an upper level disturbance moving across the
CWA which is aiding in the development of showers and
thunderstorms. Earlier, a batch of very heavy rain formed over
parts of extreme southeast MO near Cape Girardeau...over to
southwest IL. This batch has now weakened and is impacting
locations further east and we should see some rain move into parts
of the Wabash Valley/SW IN over the next few hours. Only isolated
to scattered activity remains over SEMO and W KY...and we should
see that continue this evening. After midnight...most of the
activity, if any is left, should be confined to eastern parts of
the CWA. An incoming front will lead to increasing pops overnight
mainly in SEMO.
.SHORT TERM...(This evening through Monday)
Issued at 222 PM CDT SAT AUG 22 2015
Upper level trof continues to slowly move east across the middle
Mississippi/lower Ohio River valleys this afternoon. Scattered
showers/thunderstorms have broken out in association with this
feature and the heat of the day. These showers will try to move
east across the MS River early this evening...but coverage will
likely decrease as we lose low lvl heating.
Cold front still expected to approach the region late
tonight/early Sunday. Decent instability is progged to form ahead
the the front by late morning/early afternoon along/ahead of the
front over se IL/wrn KY/sw IN. SB CAPES could be running up around
3000 J/KG by 18z. Limiting factor for organized severe threat may
end up being the relatively weak wind profiles. SFC-6KM bulk shear
only progged to be running in the 25-30 kt range. Mid lvl support
should also be weak. However, cannot rule out some isolated
marginal severe if enough instability can be generated. Scattered
storms will move east of the region by late in the day as the
front departs. Much drier and unseasonably cool conditions will
then filter in behind the front Monday and Monday night as high
pressure pushes se through the Plains.
.LONG TERM...(Monday night through Saturday)
Issued at 222 PM CDT SAT AUG 22 2015
Under a highly amplified flow pattern aloft, high sfc pressure will
dominate across the midsection of the country for most of the
extended period. Nnwrly flow aloft will persist over the PAH
forecast area, tending to keep deep layer cool dry Canadian air
flowing into our region.
Late next week, the med range models are in good agreement that the
mid/upper pattern will begin to deamplify as substantial shrtwv
energy moves into srn Canada and the Great Lakes region. This will
result in a weak flow pattern to the east of the persistent swrn
CONUS ridge aloft, and thus over our region. By Sat (Day 7), as
deeper moisture increases somewhat, an isold shower or tstm appear
possible during the heat of the day in nwrn parts of our region near
mid level shrtwv energy (and possibly a sfc reflection?) on the ern
periphery of the swrn CONUS ridge. Otherwise a rain-free mostly
clear forecast is in play.
Expect pleasant weather, with below average temps through the
extended period, and a slow warming trend.
Issued at 1156 PM CDT SAT AUG 22 2015
Areas of stratus and fog appear likely to form late tonight,
especially where rain moistened the ground in the past 12 hours.
Some patchy ifr cigs have already formed at kcgi before midnight.
Both kcgi/kpah will likely experience ifr cigs and/or vsbys late
tonight and especially around sunrise. Lower dew points and lack of
recent rain at kevv/kowb suggest only mvfr vsbys there.
Widespread cumulus cloudiness will develop Sunday morning and last
through the day. Cigs will start out mvfr in the morning and then
gradually increase during the day. Winds will shift into the west to
northwest in the afternoon as a cold front passes. Clearing appears
likely after sunset as stabilization takes place.