Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 282340

530 PM CST Sun Dec 28 2014


For aviation section only.

.SHORT TERM...(Tonight through Tuesday night)
Issued at 1237 PM CST SUN DEC 28 2014

Clearing line working slowly east across MO. Light precip has
stayed south of the area all day. Maybe some drizzle close to the
KY/TN line near KHOP. Expect the decreasing higher cloud cover to
continue working east into the evening. The low level clouds are
forecast to decrease as well, but this is a lower confidence call.

Arctic high pressure will slowly become more expansive east of the
Rockies through mid week. Low amplitude pattern with SW flow to
become more W with time across our region. Variable cloud cover
expected in this progressive pattern, but it should stay dry.
Temperatures will be a bit below normal.

.LONG TERM...(Wednesday through Sunday)
Issued at 132 PM CST SUN DEC 28 2014

The embedded circulation that is forecast to develop into the
closed low in California was located just topping the Eastern
Pacific based upper ridge. It was located east of the State of
Alaska, south of the Beaufort Sea, along the border of the Yukon
and Northwest Territories in Canada around 12z Sunday. The GEM
(Canadian) numerical guidance had the best position of this
system, followed by the GFS/ECMWF guidance. Overall, the ECMWF
handled the translation of this system well. However, from a
thermal profile perspective, the GFS guidance has been slightly
warmer aloft. This has been critical in determining the longevity
and type of wintry precipitation late Thursday night into Friday.

As alluded to yesterday, it will take sometime for Top-Down
saturation of parcels, as the vast majority of the moisture
initially remains above 10kft AGL, where temperatures and lift are
relatively good for ice crystal and dendritic snow growth. It
looks like temperatures below 10kft AGL will increase under decent
warm air advection during this period also, further slowing the
onset of precipitation. This will also aid in the development of a
rain/snow or rain/sleet mix early on, changing to all rain by dusk
on Friday.

At this point, anticipate the first onset of wintry mix reaching
the surface will be between 03-09z Friday over Southeast Missouri
(west of the Mississippi river), then 06z-15z Friday east of the
Mississippi River.

Will continue to make a general mention of a wintry mix late
Thursday night into Friday morning for the benefit of post holiday

The GFS apparently saturates and intensifies the entire layer by
Friday evening through daybreak Saturday. Am a little skeptical
about this scenario since this has not been consistent from run to
run of the model guidance. Regardless, there should at least be
some persistent rain into early Saturday.


Issued at 530 PM CST SUN DEC 28 2014

MVFR cigs around 1500 ft will last into early evening, but should
clear from nw to se 01Z-06Z. Expect generally clear conditions
thereafter. Should be too much dry air just off the surface to
preclude anything appreciable fog development.




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