Area Forecast Discussion
Issued by NWS Paducah, KY

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221
FXUS63 KPAH 171828
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
128 PM CDT Sun Sep 17 2017

.SHORT TERM...(Tonight through Tuesday night)
Issued at 125 PM CDT Sun Sep 17 2017

Active convection today is largely diurnally influenced, and
should wane with sunset, but not necessarily go away altogether.
The synoptic scale cold front is closeby, currently stretched from
near the the WI/IL border, where it is more baroclinically
oriented, and trailing into Missouri, where it becomes more difuse
and parallel with the upper flow. Out ahead of the front, in our
FA, surface based Capes ranged from generally, 1300-2300 J/KG.
These heat of day showers/storms will be primarily heavy rainers,
although there is a correlated lightning threat, with detection
instrumentation displaying this is more sporadic and strictly
concentrated in northwest most ptns FA.

Overall, the short term forecast requires little adjustment. The
front, already showing signs of distolysis, will continue to be
lifted northeasward, and its southern-most ptn here will continue
its identity loss in that process. Surface high pressure in the
Great Lakes, behind the front, will offer a relative pause in wx
later tonight-early tmrw, before another piece of energy aloft
moves within the now zonal flow pattern across the mid Mississippi
river valley, and activates the still summer like airmass, perhaps
on any lingering boundary/outflows, for small shower/storm chances
thru the remainder of the short term. This will too be most
pronounced with the diurnal aid of daytime heating, and largely
wane if not altogether with loss of that fuel come nightfall.

.LONG TERM...(Wednesday through Sunday)
Issued at 125 PM CDT Sun Sep 17 2017

A stagnant weather pattern is expected during the long term. A
narrow mid level ridge (700 to 500 mb layer) will extend from the
southern Plains northeast across the Ohio Valley to the eastern
Great Lakes. This ridge will provide warm and mainly dry conditions
through the period. Daytime highs will be mostly in the mid 80s with
lows in the mid to upper 60s.

At the surface, high pressure will be quasi-stationary along the
Appalachian Mountains. This high will produce a light southeast to
south wind flow of humid air. A few isolated showers or storms could
not be ruled out, mainly in southern parts of the region. The lack
of organized forcing precludes more than a slight chance during any
given period.

&&

.AVIATION...
Issued at 125 PM CDT Sun Sep 17 2017

Any ceiling or visibility restrictions today will be associated
with scattered convection, whose mention is vicinity at this
writing. Otherwise low VFR cigs will prevail, with some
improvement with loss of diurnal fuel this evening. Overnight,
patchy fog is again possible, although gridded time/height cross
sections show ample moisture in the 700-850 mb layer to support
clouds perhaps conducive to minimizing expanse of fog development,
relative to previous nights, and this is reflected in some of the
mos guidance. Tmrw should be similar to today, with diurnal cu
developing by mid morning after any patchy F/low cloud that
develops dissipates.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$



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