Dense Fog in Illinois, August 8, 2019

Area Forecast Discussion
National Weather Service Paducah KY
602 PM CDT Wed Aug 7 2019

.SHORT TERM...(Tonight through Friday night)
Issued at 300 PM CDT Wed Aug 7 2019

Once we get rid of the afternoon convection out over portions of
se MO, much of the region should remain rainfree the rest of the
night tonight. SPC HREF CAMs suggest another MCS type system to
get going out over MO during the overnight into early Wed, but
most of the members keep the storms just west of out forecast
area.

The next feature to bring an increase in shower/storm chances will
be another weak cold front easing south Thursday within the ever-
persistent nw flow aloft regime. A weak disturbance may interact
with this feature later in the day, but bulk shear remains
meager, and low level convergence along sfc front looks weak at
best. Thus, even with CAPES possibly in the 2000-3000 J/KG range,
we are not anticipating a very high severe storm potential. Heavy
downpours within a high PWAT environment appear more likely with
any thunderstorm.

It may take awhile for the weak surface front to clear the region
Friday, and therefore will need to keep scattered POPs in the
forecast. Once again, locally heavy rainfall would be the higher
concern, and much of the activity should be limited to the heat of
the day.

If the front does manage to ease south of the region Friday
night, we may actually get some mid 60s dew points to filter down
into much of the forecast area. Would feel noticeably less humid
come the start of the weekend. We shall see...

.LONG TERM...(Saturday through Wednesday)
Issued at 300 PM CDT Wed Aug 7 2019

The weather pattern looks to stay rather active, even though August
is climatologically the driest month of the year. The mean
summertime 500 mb ridge will be anomalously strong and far south for
August, which is in line with CPC forecast trends in recent weeks.
This means the belt of mid-level westerlies will be rather strong
and far south for August.

On Saturday, surface high pressure will be centered over
Indiana/Illinois. This high will provide our region with mainly dry
conditions, despite the rather strong northwest flow around the
southern Plains upper-level high. Highs will be in the upper 80s
with lows around 70.

On Sunday, a slow eastward drift of the surface high will allow
summertime heat and humidity to creep eastward. Highs will be near
90 with dew points rising well into the 70s. Given the fairly strong
flow aloft (for August) atop the hot and moist low levels, a slight
chance of storms seems prudent.

Monday into Tuesday, southwest flow will increase in the low levels
ahead of a cold front. The models are forecasting 850 mb temps to
climb into the lower 20s, which usually translates to surface highs
in the lower or mid 90s. Dew points will be in the mid 70s. There
are slight variances in the models, but it appears westerly flow
aloft will be sufficiently strong for a convectively active period
until the frontal passage.

The ensemble means of the gfs/ecmwf have been consistently
indicating a slight southward suppression of the 500 mb high about
mid-week. This should be enough to force a weak cold front south
across our region. Forecast highs Wednesday will be in the mid 80s
with lowering dew points.

&&

.AVIATION...
Issued at 601 PM CDT Wed Aug 7 2019

VFR conditions will dominate the 00z Thursday WFO PAH TAF
issuance. Surface high pressure will be maintained over the TAF
sites through the period, with the main weather disturbances
(MCS's - Mesoscale Convective Systems) being shunted westward into
parts of southwest Missouri, northern Arkansas, west Tennessee,
and the lower Mississippi Valley. There should be minimal general
aviation impact associated with the TAFs this period.

Main adjustments to the forecast groups were driven by wind
direction and speed and the existence of cloud bases vs. ceilings
and/or significant ceiling height changes.

&&

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

SHORT TERM...GM
LONG TERM...MY
AVIATION...Smith

Hazardous Weather Outlook
National Weather Service Paducah KY
346 PM CDT Wed Aug 7 2019

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-082100-
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-
346 PM CDT Wed Aug 7 2019

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

.DAY ONE...Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Off and on isolated to scattered thunderstorms will be through
much of the period, especially during the heat of the day. The
best chances appear to be on Friday and then again on Tuesday,
near and ahead of approaching cold fronts. Strong storms are
possible with the Tuesday storms.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated at this time.