Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 132303

Area Forecast Discussion
National Weather Service Paducah KY
603 PM CDT Tue Mar 13 2018

Issued at 601 PM CDT Tue Mar 13 2018

Updated Aviation Discussion for 00Z TAF Issuance

UPDATE Issued at 545 PM CDT Tue Mar 13 2018

Minor sensible weather adjustments made for tonight and tomorrow.
Moved the precipitation potential a little further east from 7 to
9 pm CDT across the eastern sections of southwest Indiana and into
northwest Kentucky (generally east of a Princeton Indiana to
Calhoun Kentucky line). Kept the majority of the precipitation a a
trace mix of rain and snow. As the sub-cloud layer cools this
evening, anticipate some flurries before ending altogether.

Blended current forecast with the 3km HRR, SREF, 1 hour resolution
of the 20 km GFS, and 13km RAP guidance to reflect subtle changes
tonight into Wednesday.


.SHORT TERM...(Tonight through Thursday night)
Issued at 1243 PM CDT Tue Mar 13 2018

Upper level low pressure core associated with Noreaster
currently headed through New England will bring nwly flow to much
of the region this afternoon through tonight. Within this flow
may bring some 4kft cloud decks to mainly sw IN/nw KY, but any
precip should remain east of our forecast area. Not as much
cyclonic flow expected Wednesday, but still may be some afternoon
cumulus around/east of the MS River during the afternoon.

Main weather feature to take over the remainder of the short term
will be the development of a blocking mid/upper level Omega high
pressure system over the Continental Divide and and into the
western Plains by Thursday. This should allow for plenty of
sunshine and warming west to southwest winds, with temps finally
getting back above normal into the upper 50s to mid 60s. Should ne
a fairly nice afternoon for mid March.

.LONG TERM...(Friday through Tuesday)
Issued at 241 PM CDT Tue Mar 13 2018

The deterministic medium range models were in better agreement
currently than 24 hours ago. The general consensus is that there
will be two separate closed lows ejecting from persistent eastern
Pacific/CA shortwave energy, moving across the PAH forecast area in
the extended forecast period.

The forecast period will start out with a good signal for the
formation of a west-east surface boundary across the PAH forecast
area, ahead of the first impulse. Rain showers appear likely early
Fri as the front begins to push southward. At the same time, low
level moist fetch should be enabled, and this moisture will ride up
over the shallow wedge of cooler air that will be sustained by
easterly surface winds. This should result in the best QPF through
at least the morning hours Fri.

Isolated lightning strikes might occur near the AR/TN state lines
mainly Fri night under enhanced mid level positive vorticity
advection. As the impulse continues eastward, drier air should
eventually begin to move into our region from the southwest later,
limiting pcpn, but the timing of this is a bit uncertain (Fri
afternoon? Fri night?). This was dependent on the progged position of
the first tight, nearly stacked low pressure system moving out of
the central Plains (the CMC seemed to have a more unlikely, more
northerly path). There are signs that the low may begin to weaken as
it moves by just to the north of our region, thus the QPF should be
light for us into Sat, with conditions stable enough to
probably preclude thunder.

The latter half of the weekend appears dry at this time under quasi-
zonal flow aloft. The second impulse will approach our region from
the west Sun night, trailing a surface pressure trof/cold front
south of it. At this time, fropa is forecast to occur Mon afternoon
or Mon night. PoPs remain in the chance category for Tue (Day 7) due
to the possibility of the mid/upper low lingering in our region.

The trend lately has been toward cooler temps, staying in the
general vicinity of seasonable numbers.


Issued at 601 PM CDT Tue Mar 13 2018

Diurnally enhanced cu field in northeast (KEVV/KOWB) should
dissipate with loss of fuel, scattering mid (VFR) bases by mid
evening. Gusts may maintain until almost then, and then should
diminish as skies clear all sites. Nwlys will return tmrw, not as
gusty, then back during the day, with perhaps some scattered high
clouds at times.



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