Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 231830

Area Forecast Discussion
National Weather Service Paducah KY
130 PM CDT Tue May 23 2017

.SHORT TERM...(Tonight through Thursday night)
Issued at 116 PM CDT Tue May 23 2017

Scattered showers were developing in the mid pm, mainly over
SEMO/SW IL. Both the short res and med range models have been
picking up on that, and continue that trend into the early evening
hours. Short res modeling suggests it will take awhile longer for
height falls to reach the still ridging eastern parts of the FA,
and by then, then sun will be down, so slgt chance mentions, or
less, have been applied for our eastern counties this pm.

Pops do expand area-wide and peak in the likely range tonight, as
the evolving upper trof drives a cold front across the region. The
threat of thunder will diminish overnight, as diurnally aided
instability is lost.

Pops remain high tmrw, and actually peak again in the likely cat in
the pm across our east, with diurnal instability enhancement and
the upper Low still over scntl MO. Then they`ll diminish and end
overnight Wed night, as the Low moves east of the Tennessee

Temp forecast has little change with today`s 70s/50s supplanted by
the Low`s cool air/60s tmrw, before returning to 70s for Thursday.

.LONG TERM...(Friday through Tuesday)
Issued at 116 PM CDT Tue May 23 2017

Confidence has improved slightly for the extended as the models
slowly merge a little closer with their solutions.

There are some minor discrepancies in the model solutions which is
not unusual for summer type convection scenarios. Starting Friday
models do indicate a weak perturbation in the flow during the day.
However the ECMWF does not indicate this and holds the ridging in
place during the day. It does however bring the pulse through Friday
night...a little slower than most of the models. Either way none of
the models show much in the way of qpf for Friday. Although the
ECMWF places higher qpf but keeps it south of us over AR and TN. I
do believe we will have at least a chance of a storm Friday but
the cap is very impressive at about 750mb which would be a
mitigating factor even with a warm front lifting through the area.

Saturday we will be in the warm sector with the warm front to our
north and a cold front to our northwest. This strong cap is
expected to persist through Saturday which would be a mitigating
factor for storms at that time. In contrast any storms that break
through the cap would have very little competition for fuel. The
instability will be substantial with the GFS forecast soundings
yielding Li`s approaching double digits and CAPE`s 2-3k j/kg2.
Again like the last few runs the ECMWF is not nearly as unstable.

Finally the cold front should move into the area Saturday night
and by Sunday it should bisect the area from northeast to
southwest by sunrise...or along the Ohio river. This should be our
best chance of storms. With all this considered most of the time
we have mainly low level moisture as the Gulf is open near the
surface but cut off aloft. The models continue to indicate a
mainly dry Monday in the wake of the cold front. There is a weak
signal of a weak cold front to move through Monday night into
Tuesday which may require a pop. Temperatures are expected to be
slightly above normal in the mid 80s through the weekend then fall
slightly below normal in the cold fronts wake early next week.


Issued at 116 PM CDT Tue May 23 2017

We still have scattered to broken mid and high level
clouds/bases in the warm sector, but a deterioration toward MVFR
restrictions of CIGS/VSBYS can be expected tonight as an Upper
Low drifts in and a cold front drives across the flight terminals.
The front`s passage will shift winds to the west or northwest, as
Pops or vicinity showers linger into the planning period. VSBYS
should improve to VFR with the rising sun, but MVFR restricted
CIGS may be slower to improve, as the upper Low remains to the
west of the terminals thru the valid portion of the forecast.




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