Dense Fog in Illinois, April 19, 2017

Area Forecast Discussion
National Weather Service Paducah KY
252 AM CDT Wed Apr 19 2017

.SHORT TERM...(Today through Friday night)
Issued at 252 AM CDT Wed Apr 19 2017

Increasing confidence in the short term as models begin to come into
better agreement.

Small chances for showers and a couple of elevated thunderstorms
mainly this afternoon over the southern Pennyrile region of western
Kentucky as weak upper level energy taps into lingering lower
tropospheric moisture there.

Tonight with the region being in the warm sector and plenty of
convective inhibition, it should remain dry. Chances for showers and
storms enter the forecast again on Thursday with the approach and
passage of a cold front. The combination of the front, surface
dewpoints in the lower to mid 60s, and 0-6 KM bulk shear of 40-50
knots may produce a severe thunderstorm or two. The main limiting
factor will be lack of upper support.

The front is forecast to become quasi-stationary just south of our
region Thursday night, and with weak upper level energy passing
across the area, chances for showers and storms continue. Chances
for showers and storms steadily increase Friday into Friday night as
a storm system lifting northeast out of the southern plains takes
aim on the lower Ohio valley. Models are slightly different on the
timing and track of this system, but any of the current solutions
will make for a wet introduction to the weekend.

Temperatures will remain well above normal through the period.

.LONG TERM...(Saturday through Tuesday)
Issued at 252 AM CDT Wed Apr 19 2017

Models are now indicating a more southerly track to our early
weekend system which means severe weather chances should be mainly
to our south.

At 12Z Saturday, the sfc low is situated over NW Arkansas
and then shifts east during the day into west TN. Models have not
honed in on the where the best chances for convection will be during
the morning hours but good chances for rain will exist across the
entire region. However, by Saturday afternoon, the highest chances
will be in parts of western KY, as the sfc low moves into central TN
by 00Z Sunday. Some hefty QPF amounts are being advertised in parts
of west KY as well. Right around 00Z Sunday is when the dry slot
will be impacting parts of our region, although models are still not
exactly in agreement on how far north it makes it. Whatever lull
there may be in the action late afternoon or early evening, will be
replaced by additional shower chances during the rest of the evening
as the upper level low associated with this system moves overhead.

After midnight, rain chances will decrease substantially and be
confined to mainly western KY. By Sunday morning, only a small
chance for rain will linger in the southern Pennyrile region of west
KY with decreasing cloudiness from northwest to southeast occurring
with sunny conditions everywhere by afternoon.

Given the more southerly track of this system, the better sfc
moisture stays to our south. Dewpoints barely reach into the mid 50s
across our southern areas. Highs on Saturday will struggle to reach
the mid 50s up north and creep into the low 60s across southern MO
and west KY. Have trimmed thunder chances to just out southern
areas. Instability parameters are just not as impressive up in our
area as they are further south. Will continue to watch however.

High pressure settles over the area on Monday which means dry
conditions, light winds and actually warmer conditions as upper
level heights rise. Dry weather and highs in the low to mid 70s
look to stay with us through the early part of the new work week.

&&

.AVIATION...
Issued at 1151 PM CDT Tue Apr 18 2017

Not much change from the previous forecasts. Still not confident
about low cloud/fog forecast overnight into Wednesday. There are
some scattered clouds around 2500ft near KOWB, so played the MVFR
ceiling there, but went with MVFR fog elsewhere. Low clouds would
seem to be a better bet farther south through Kentucky, so KPAH
would be the next most likely place to see a low ceiling in lieu
of fog. The forecasts are all MVFR. A thick cu field is still
expected through the afternoon, but the clouds should be at VFR
levels regardless of whether they are scattered or broken. South
winds will kick in by midday and some gusts into the teens are a
decent bet, especially where the cu field is not so thick.

&&

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

SHORT TERM...JP
LONG TERM...CW
AVIATION...DRS

Hazardous Weather Outlook
National Weather Service Paducah KY
326 AM CDT Wed Apr 19 2017

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-201000-
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-
326 AM CDT Wed Apr 19 2017

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

.DAY ONE...Today and Tonight

Isolated thunderstorms are possible mainly over the southern
Pennyrile region of western Kentucky this afternoon. Lightning and
locally heavy rainfall will be the primary hazards.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms are possible over the entire outlook area Thursday
and Thursday night. At this time widespread severe weather is not
expected but a severe thunderstorm or two is not out of the
question mainly Thursday afternoon and early evening with damaging
winds and large hail being the primary hazards. Otherwise,
lightning and locally heavy rainfall will be the primary hazards.

Thunderstorms are also possible over all or part of the outlook area
Friday, Friday night, and Saturday. Lightning and locally heavy
rainfall will be the primary hazards.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required Thursday afternoon and early
evening.

JP/CW

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
335 AM CDT Wed Apr 19 2017

ILZ075-076-080>082-084>086-088>090-MOZ076-086-087-191400-
JEFFERSON-WAYNE IL-PERRY IL-FRANKLIN-HAMILTON-JACKSON-WILLIAMSON-
SALINE-UNION-JOHNSON-POPE-PERRY MO-BOLLINGER-CAPE GIRARDEAU-
INCLUDING THE CITIES OF MOUNT VERNON, FAIRFIELD, PINCKNEYVILLE,
WEST FRANKFORT, MCLEANSBORO, CARBONDALE, MURPHYSBORO, HERRIN,
HARRISBURG, JONESBORO, VIENNA, GOLCONDA, PERRYVILLE, MARBLE HILL,
CAPE GIRARDEAU, AND JACKSON
335 AM CDT Wed Apr 19 2017

...Patchy dense fog possible early this morning...

If you are traveling across southern Illinois or southeast
Missouri this morning, you may run into patches of locally dense
fog with visibilities dropping to one quarter mile or less at
times over short distances.

Be sure to use low beams or fog lights should you encounter
reduced visibility due to the fog. Signal any lane changes well
enough in advance so that drivers around you can react in time.

Conditions should begin to improve starting shortly after
sunrise.

JP