Flooding in Indiana, July 16 to 21, 2017

Area Forecast Discussion
National Weather Service Paducah KY
225 AM CDT Sun Jul 16 2017

.SHORT TERM...(Today through Tuesday night)
Issued at 205 AM CDT Sun Jul 16 2017

The surface high will settle across the entirety of the Ohio river
valley today, and we think that will suppress the ridge topping
energy diving down the base of the mean trof aloft from activating
showers/storms this far south. Low level wind flow fields show
relative uniformity w/o convergence, dew points start to nudge
upward but remain in the 60s, and H7 temps hold AOA 10C, all
furthering support for no audible pop mention today. Similarly,
for tonight (this evening), with loss of diurnal fueling, we'll
refrain from mentioning Pops, while acknowledging a silent Pop
around 10-14 percent is warranted for a rogue updraft/cell
developing possibility, with some upstream boundaries possibly in
play and offering an activation parameter by then.

For Monday, particularly the pm hours, the boundary laid out is
modeled to hover across the lower Ohio river vicinity, as the trof
energy spills across the area in more earnest. Models show H7
temps are affected with a 1-2C drop in the cap, and that should
be enough to activate by then dew points souping toward 70F for
some widely scattered heat of day storms to develop. We'll not
argue with the blended modeling of slgt chance mentions for the
area.

Tuesday sees the upper ridge building in, with upwards of a net
+60 DM H5 height rise strengthening the cap to 10-12C at H7, and
that should be enough to suppress mentionable Pops again. The
continued bulk up in temp and humidity will lead to areally
increasing pixels of 100 Heat Index from Monday into Tuesday.

.LONG TERM...(Wednesday through Saturday)
Issued at 205 AM CDT Sun Jul 16 2017

Improved confidence in the extended as models come into better
agreement.

The GFS has come into much better agreement with the ECMWF and the
ensembles. This would place the upper level high over the region for
the entire extended. There are no significant surface features
except on Friday there appears to be a weak trough that rotates
through the region. This could ignite a few storms but coverage
would be sparse at best...however any storms that do get going
could be strong with LI's negative 4 to -5 surface and aloft.
CAPE's 1500 to 2k j/kg. Wind profiles are rather benign. So may
have to carry at least a slight chance toward the end of the week
and into the weekend but will be limited to max heating time in
the afternoon. In addition could not absolutely rule out an
isolated storm through most of the week but the chances and
coverage are too low to include at this time. Otherwise the main
threat will be excessive heat and its longevity. Will likely see
heat index values in the 100 to 105 range at least over parts of
the area throughout the extended...and especially on Wednesday and
Thursday. May end up with an advisory due to the longevity of the
heat more so than the extremity. Will see what collaboration
yields concerning this scenario.

&&

.AVIATION...
Issued at 205 AM CDT Sun Jul 16 2017

Patchy fog early may yield restricted vsbys at all terminals, but
should dissipate quickly after sunrise. Otherwise just anticipate
scattered VFR bases around 4K FT AGL through the heat of the day,
with any isolated storm development likely avoiding terminal
vicinity.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

Hazardous Weather Outlook
National Weather Service Paducah KY
357 AM CDT Sun Jul 16 2017

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-171000-
Jefferson-Wayne IL-Edwards-Wabash-Perry IL-Franklin-Hamilton-
White-Jackson-Williamson-Saline-Gallatin-Union-Johnson-Pope-
Hardin-Alexander-Pulaski-Massac-Gibson-Pike-Posey-Vanderburgh-
Warrick-Spencer-Fulton-Hickman-Carlisle-Ballard-McCracken-Graves-
Livingston-Marshall-Calloway-Crittenden-Lyon-Trigg-Caldwell-
Union KY-Webster-Hopkins-Christian-Henderson-Daviess-McLean-
Muhlenberg-Todd-Perry MO-Bollinger-Cape Girardeau-Wayne MO-Carter-
Ripley-Butler-Stoddard-Scott-Mississippi-New Madrid-
357 AM CDT Sun Jul 16 2017

This Hazardous Weather Outlook is for portions of southern
Illinois, southwest Indiana, western Kentucky, and southeast
Missouri.

.DAY ONE...Today and Tonight

No hazardous weather is expected.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Other than a sporadic slight chance of thunderstorms during
mainly the afternoon heating hours, the main hazard during this
time period will be increasing heat and humidity, with heat
indices reaching 100 to 105 each afternoon Tuesday through
Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.