Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 161759

1259 PM CDT Sat Aug 16 2014

Issued at 1259 PM CDT SAT AUG 16 2014

The AVIATION section has been updated for the 18Z TAF issuance.


.SHORT TERM...(Today through Monday night)
Issued at 243 AM CDT SAT AUG 16 2014

Model isentropic fields about all that`s useful for determining
where the light rain edging into the area may continue into the
morning, utilizing low pdef values. Will keep some PoPs in for
light showers early on, then back off into the afternoon as the
isentropic lift is forecast to weaken. Fair amount of debris
clouds may affect the area today. Thus will not stray too far from
guidance. Raw model output may be accounting for this a bit
better. Will incorporate as well.

Upper system will be over east central MO by 12z Sunday with
increasing rain/thunder chances from the NW tonight, especially
after midnight. Will bring in likely PoPs after midnight west
half, staying chance or slight chance over toward the Pennyrile
area of west KY.

The system will continue its southeast track Sunday. There been
talk of strong storms Sunday/Sunday evening etc. Highly conditional
on existing cloud cover and ongoing convection. Even NAM which is
its typical worse case scenario with instability, suggests other
parameters such as mid level lapse rates and deep layer shear, are
typically marginal and August like. So overall, yea a strong storm
or two maybe, pushing severe if enough instability can develop.
Nothing to be overly concerned about.

Should be more concerned with heavy rain potential given PWAT
values are forecast top 2 inches, which reaches the 99th
percentile for August. Highs Sunday will be tricky as well, highly
dependent on convection and cloud cover.

As the system eventually passes east Sunday night through Monday,
will gradually taper off PoPs from west to east.

.LONG TERM...(Tuesday through Friday)
Issued at 243 AM CDT SAT AUG 16 2014

Heights do try and rise in the long term. However, the 00z GFS
will be thrown out, building the ridge north into the area as
aggressively as it does. This does not agree with prior 12z
ensemble means, and goes against the general pattern tendency.
Will stay closer to the 12z/00z ECMWF ops runs, and prior ensemble
mean depictions. On and off chances of thunderstorms will
continue, though it certainly will not rain the entire time.
Certainly looks as though we will see some hot humid weather
especially by Wednesday into Friday.


Issued at 1259 PM CDT SAT AUG 16 2014

Some light rain or light showers will flirt with KEVV and KOWB for
the first few hours of the period, but they should be of little
impact to aviation concerns. There is a strong signal for convection
to impact much of the region mainly overnight tonight, as a compact
upper-level storm system drifts southeast into the region. Not
confident enough to go with prevailing, so just made some minor
timing adjustments to the PROB30s at all sites. Could definitely see
convection affecting much of the area well into Sunday morning.
Cannot really see any non-VFR conditions outside of convection
through this forecast period.




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