Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 181142 AAA

642 AM CDT Fri Jul 18 2014

Issued at 643 AM CDT FRI JUL 18 2014

Updated the aviation discussion for the 12Z TAF issuance.


.SHORT TERM...(Today through Sunday night)
Issued at 303 AM CDT FRI JUL 18 2014

Model agreement in the short term better than the last few nights,
so forecast confidence somewhat better.

Through most of the short term period our region will remain under a
broad long wave trough with a series of upper level disturbances
moving through the flow making it difficult to pin down track,
timing, and placement of systems.

The short term period starts out with a short wave that pulls a
surface low and associated inverted trough currently over the
southern plains across the deep south. This scenario will set up an
overrunning precipitation event primarily for the southern and
southeast sections of our CWA for the next couple of days. At the
time of this writing light precipitation has already begun to spread
east northeastward across the far southwestern and southern sections
of our CWA.

With the passage of these features precipitation chances will
migrate from the southwestern to southern to southeastern sections
of our CWA through Saturday. Not as confident with precipitation
chances over the eastern and southeastern sections for Saturday
night and Sunday but most of the models are still showing weak
troughing coincident with lingering deeper moisture.

Sunday night into Monday the aforementioned long wave trough shifts
slightly eastward allowing for weak ridging across the area. That
should shut precipitation chances down through the rest of the short
term period.

Some of our far northern sections may remain dry through the entire
period. Even though temperatures and dewpoints will moderate
somewhat in the short term, they will still remain below normal.

.LONG TERM...(Monday through Thursday)
Issued at 303 AM CDT FRI JUL 18 2014

The large model differences concerning the strength and location of
upper level troughing over the eastern states have narrowed with the
00z model suite. The 00z gfs and ecmwf are in reasonable agreement
now...and they are in line with the consistent ecmwf ensemble mean.
The 00z gfs ensemble mean is not part of the consensus of the other

Based on the 00z model appears that the western U.S.
ridge will expand eastward across the Plains and Ohio Valley on
Monday and Tuesday. The trend toward stronger upper level ridging
translates to higher temps and lower pops in the deterministic model
mos guidance. Some isolated afternoon convection is still possible
in the hot and unstable air mass...but overall Monday through
Tuesday should be mainly dry.

Wednesday and Wednesday night appears to be the time frame when a
500 mb shortwave will dig southeast across the Great Lakes into the
Ohio Valley. Both the 00z gfs and ecmwf are rather impressive with
the strength of this shortwave. Pops will be somewhat higher as this
shortwave approaches...but still only in the chance category.

On Thursday...the models indicate a cold front associated with the
shortwave will make it into the Lower Ohio Valley. There is quite a
bit of variability concerning the strength and timing of the front.
The forecast will keep the chance pops going into Thursday with
temps cooling off a few degrees.


Issued at 643 AM CDT FRI JUL 18 2014

Low pressure moving eastward out of the southern plains combined
with an upper level disturbance will produce VFR clouds today with
VCSH possible at KPAH from 17-02Z. As low level moisture increases
late in the period, MVFR cigs and/or vsbys are possible at
KPAH/KEVV/KOWB and LIFR conditions possible at KCGI. Calm to light
and variable winds will pick up out of the east southeast AOB 10
knots after 15Z, then back to calm or light and variable after 01Z.




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