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Area forecast discussion 
National Weather Service Paducah Kentucky
940 PM CDT Tuesday Jul 7 2015

Update...
issued at 939 PM CDT Tuesday Jul 7 2015

Just issued a middle-evening grid/tabular/text forecast update to
reflect transitional nature of the frontal zone overnight. Main
instability and more intense updrafts will remain south of the weather forecast office
pah forecast area for the rest of the night.

However...elevated (isolated) thunderstorms will still be possible
roughly south of a Perryville MO...Harrisburg Illinois...Evansville in
line overnight. This may provide locally higher amounts overnight.

Blended pop/weather/weather type/intensity grids with hrrr and
NAM-WRF guidance through 12z (7 am cdt) Wednesday. This will focus
the higher probability of precipitation along the southern edge of the weather forecast office pah forecast
area...with a gradual increase in probability of precipitation back into southeast Missouri
and southern Illinois between 7 am and 10 am CDT as the flow
changes and draws the frontal boundary back northeast over the
rain cooled boundary layer. This will shift the highest quantitative precipitation forecast
(rainfall amounts along and north crowley's ridge in southeast
Missouri and over southern Illinois (north of Route 13) between 7
am and 1 PM on wednesay.

The period between 1 am and 7 am CDT Wednesday will be a
transitional period with respect to quantitative precipitation forecast...with a sharp increase in
rain west of a Greenville...Poplar Bluff Missouri line...with a
secondary maximum in precipitation over the pennyrile region of
west Kentucky.

&&

Short term...(this evening through Thursday night)
issued at 125 PM CDT Tuesday Jul 7 2015

Boundary set up across pah forecast area is helping focus showers/storms
along it. High precipitable waters and efficient rain producing storms is adding
to predecessor rains to heighten flood concerns...collaborated for
flash Flood Advisory across entire forecast area through 00z Thursday.

Anticipate more or less continual pulsing of storms along boundary
and repeat training over same areas through tonite into tmrw...as
pieces of energy run along it with parallel flow atop it. This
will heighten the flooding concerns as well.

Beyond that...tapering chances as higher pressure builds aloft and
starts to squeeze out/disintegrate said boundary with time.
Clouds/convection to hold diurnal ranges down until then.

Long term...(thursday night through tuesday)
issued at 241 PM CDT Tuesday Jul 7 2015

An upper level high over the southeast U.S. Will keep the region in
a fairly dry and hot weather pattern Friday and into the early part
of the weekend. A few showers and storms may linger over our
northeast counties on Friday due to a weak upper level wave moving
across Illinois/Indiana. Kept some slight to low chance probability of precipitation across
southwest Indiana and adjacent areas of Illinois and northwest
Kentucky for Friday. Dry conditions are expected Friday night
through Sunday. Persistent southwest flow will help temperatures
climb to around 90 degrees Friday, and into the lower 90s Saturday
and Sunday. Dew points will also climb back into the lower 70s
Friday, and this moisture will remain in place through the weekend
into early next week. This moisture will help afternoon heat
indices reach the upper 90s to around 100 degrees through the
extended.

Sunday night into Monday, GFS and European model (ecmwf) show a surface low sliding
southeast out of the upper Mississippi Valley. The Canadian seems
to keep this feature farther north and northeast than the GFS and
European model (ecmwf). Though the GFS onset of precipitation in our region is a bit
slower than the ECMWF, overall they are in decent agreement and seem
a reasonable solution to follow. A small chance of showers and
thunderstorms will return to our northeast counties by Sunday night,
then chances will gradually increase from northeast to southwest
through Tuesday.

&&

Aviation...
issued at 657 PM CDT Tuesday Jul 7 2015

Primary challenges for the 00z Wednesday weather forecast office pah taf product
issuance will be handling changing wind direction with the
stalling...then northward shift of the frontal boundary through
the period. IFR ceilings will dominate and LIFR visibility
conditions will dominate in the 06-12z time period kpah/kcgi and
slightly later for kowb/kevv as boundary shifts northward. VFR
visibilities should dominate in the afternoon for all sites, but
broken upper IFR/lower MVFR ceilings will persist during the
latter half of the forecast period.



&&

Pah watches/warnings/advisories...
Illinois...Flash Flood Watch through Wednesday evening for ilz075>078-
080>094.

MO...Flash Flood Watch through Wednesday evening for moz076-086-087-
100-107>112-114.

In...Flash Flood Watch through Wednesday evening for inz081-082-
085>088.

Kentucky...Flash Flood Watch through Wednesday evening for kyz001>022.

&&

$$

Update...Smith
aviation...Smith

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