Area Forecast Discussion
Issued by NWS Paducah, KY

Home | Current Version | Previous Version | Text Only | 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 39 40 41 42 43 44 45 46 47 48 49 50
764
FXUS63 KPAH 260402
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1102 PM CDT Tue Jul 25 2017

.UPDATE...
Issued at 1105 PM CDT Tue Jul 25 2017

Updated Aviation discussion for 06Z TAF Issuance.

&&

.SHORT TERM...(Tonight through Thursday night)
Issued at 302 PM CDT Tue Jul 25 2017

The main concern Wednesday will be a temporary resurgence of
hazardous heat indices, then thunderstorms will be a concern on
Thursday as a cold front arrives.

A nearly stationary frontal boundary extended from near kmdh to
khop early this afternoon. Isolated thunderstorms have been
increasing in coverage and intensity on the south side of this
boundary, where diurnal heating has boosted mixed layer capes to
near 4000 j/kg. Due to the slow movement of the storms and very
high precip water values, these storms will pose a risk of
isolated very heavy rainfall over the next few hours. Wind shear
values are very low, precluding organized severe potential.

The storms will diminish with loss of daytime heating around
sunset, but the boundary will not be going anywhere. Isolated
relatively weak showers or storms may persist overnight in the
vicinity of the frontal boundary, similar to what occurred last
night.

On Wednesday, the frontal boundary will make slow northeast
progress. Some isolated diurnal convection could occur along the
boundary, mainly from southwest Indiana and the Wabash Valley down
into the Pennyrile region of west Kentucky. With this in mind,
heat indices may be lower in that region. The upcoming Heat
Advisory will be for southeast Missouri, southwest Illinois, and
far western Kentucky, where storms are not expected. Although
high temps will not be especially hot for July (lower to mid 90s),
dew points are again forecast to be well up in the 70s. This
should once again push the heat index to around 105 in the
advisory area.

A bona fide cold front will approach from the northwest on
Thursday, bringing much higher thunderstorm chances. The 12z nam
is more than 12 hours faster than the gfs with this front. The
sref is a good compromise, and the forecast will basically match
the sref as far as frontal timing. The cold front will push across
our region on Thursday night, accompanied by scattered to numerous
thunderstorms. Depending on the timing of thunderstorm complexes
and associated outflow boundaries, some isolated severe storms are
possible. Storms could arrive as early as late Wednesday night,
which would impact instability parameters on Thursday.

.LONG TERM...(Friday through Tuesday)
Issued at 302 PM CDT Tue Jul 25 2017

The overall forecast confidence is high.

The ridge west, trough east pattern will amplify into the weekend. A
cold front should be south of the area by 12Z Friday, but the 12Z
GFS has come in slower, leaving QPF over west Kentucky through the
day. Tried to minimize the impact from the GFS, as its previous run
and the GEM and ECMWF kept the area virtually dry on Friday. The
best chance of thunderstorms on Friday should be in the far
southeast in the morning hours.

The cold front will bring an end to the heat and humidity for quite
awhile. Cooler and drier surface high pressure will dominate the
region over the weekend, as we remain in northerly flow aloft. High
temperatures will generally be in the lower half of the 80s with
lows in the lower half of the 60s.

Heading into next week there is some evidence in the models that the
troughing aloft may wobble back westward enough to bring some
showers or thunderstorms back to west Kentucky by Tuesday. Will
throw in some slight chances, but would prefer keep it dry until the
signal is a bit stronger and more persistent. Temperatures will
slowly modify, but remain below normal levels for the end of
July/beginning of August.

&&

.AVIATION...
Issued at 1105 PM CDT Tue Jul 25 2017

An isolated thunderstorm will continue to be possible as we
progress through the forecast. For now the chance is not high
enough to include mention 15% chance range. We would likely see
some fog in the morning mainly at CGI and PAH. Other than a few
hours of mvfr in the morning with fog and low clouds as it lifts
expect vfr conditions outside of any storms.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from noon to 8 PM CDT Wednesday for ILZ075-080-081-
     084-085-088-089-092>094.

MO...Heat Advisory from noon to 8 PM CDT Wednesday for MOZ076-086-087-
     100-107>112-114.

IN...None.
KY...Heat Advisory from noon to 8 PM CDT Wednesday for KYZ001>006.

&&

$$

SHORT TERM...MY
LONG TERM...DRS
AVIATION...KH



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