Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 260508

Area Forecast Discussion
National Weather Service Paducah KY
1207 AM CDT THU MAY 26 2016

Issued at 1207 AM CDT THU MAY 26 2016

Updated aviation discussion.


Issued at 905 PM CDT Wed May 25 2016

The last of the rains is just now exiting our far eastern counties,
and the remainder of the evening should be dry throughout the area.

We are looking back to Kansas for our next potential MCS. Latest
HRRR data brings this area in one form or another right to the
northwest periphery of our area around sunrise. So, will keep the
entire area dry into the overnight hours, and then ramp them up to
low chance levels in the northwest toward 12Z.

SPC still has us in an Enhanced outlook for this activity, so a
wind and hail threat cannot be ruled out, but locally heavy
rainfall and lightning will be the primary concerns if anything
reaches the area.

Another concern overnight is the potential for fog formation
where skies clear, especially where we have received heavy
rainfall earlier today. The latest short term guidance keeps
significant wind through the night, so fog may be hard to get even
under clear skies. Did not insert any fog to the forecast at this
time, but will keep an eye on it.


.SHORT TERM...(Tonight through Friday night)
Issued at 250 PM CDT Wed May 25 2016

Very disorganized areas of convection have continued to move
east/northeast across the region today. None of these areas have
been well-predicted by any of the models, including the high
resolution convection-allowing (CAM) models. A deep-layer
southwest flow of moist air has enabled convective systems to
develop with little forcing evident in observations or models.
This pattern will continue through the short term, making pops and
qpf a real challenge.

As for tonight, there should be a diminishing trend in precip
coverage this evening. This trend is based primarily on the
experimental SSEO (Storm-Scale Ensemble of Opportunity), which
incorporates a range of high-res models into an ensemble-based
forecast. Nocturnal stabilization and satellite trends upstream
across western Missouri support this trend. Until then, some very
heavy rain will continue with clusters of storms. Overnight lows
will be mainly in the upper 60s under the influence of southerly
winds and moist dew points.

The forecast for Thursday is complicated by a lack of well-defined
synoptic scale features. A broad southwest flow aloft will likely
contain more impulses, any of which could generate convection.
Convectively induced MCV`s may emanate from convective complexes
over the southern Plains or Ozarks. A continuation of chance pops
is in order for Thursday. High temps are a challenge as well. Will
keep mid 80s in the forecast, but this may be on the warm side if
convection becomes widespread.

For Friday and Friday night, rain chances will be on the increase
as a 500 mb shortwave trough lifts out of the southern Rockies and
toward the central Plains. The strongest forcing will pass north
and west of the Ohio River, and this is where pops will be in the
likely category. Continued moist southwest flow could result in
more pockets of heavy rainfall. High temps will likely be coolest
in the Ozark foothills, probably staying below 80 there.

.LONG TERM...(Saturday through Wednesday)
Issued at 250 PM CDT Wed May 25 2016

Warm and humid conditions will continue through the long term. The
main forecast challenge continues to lie with precipitation chances.
Deep-layer southwest flow Saturday will decrease over the remainder
of the holiday weekend as mid level ridging takes place over the
eastern part of the country. The flow pattern will become weak and
non-descript by Memorial Day. There will likely be a corresponding
decrease in convective coverage over the holiday weekend as the flow

Precipitation coverage, for the most part, will be dependent on
mesoscale features such as outflow boundaries and/or convectively-
induced vorticity centers. Given the lack of model skill at longer
time ranges with such features, the forecast will continue with
generally 20 to 40 percent chance pops, with the lower chances being
Sunday and Memorial Day. Given the moist environment and rather high
PWAT values, locally heavy rain is likely in any thunderstorms that
do manage to form.  Even small doses of sun should be enough to push
highs into the mid 80s, which the models have consistently been
forecasting through the long term period.


Issued at 1207 AM CDT Thu May 26 2016

Initially VFR cigs overnight are expected to drop to MVFR levels,
with the possibility of transient cigs below 2 kft shortly after
midnight at the eastern terminals (KEVV/KOWB). Southerly winds are
expected to generally stay 4 kts or more overnight. Therefore, low
level moisture should turn into the lower cigs, instead of causing
significant vsby restrictions due to fog.

During the day Thursday, the cigs and cig heights may be highly
variable, depending on the presence (or not) of scattered
shower/tstm activity, which is not currently mentioned in the TAFs.
South southwesterly winds AOA 10 kts will subside by nightfall.


.PAH Watches/Warnings/Advisories...


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