Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 191146

545 AM CST Fri Dec 19 2014

Issued at 545 AM CST FRI DEC 19 2014

Revised aviation discussion for 12Z TAFs.


.SHORT TERM...(Today through Sunday)
Issued at 350 AM CST FRI DEC 19 2014

Main weather impact through the short term is the potential for
very light snow over the far southern part of the region tonight.

Of all the considerations we make in preparing a winter forecast,
perhaps the most critical factor in determining how much and what
type of precipitation any one location receives is storm track.
That is certainly the case with tonight`s weather system. It is
interesting to look back on how storm track impacted the forecast
in recent days. Once forecast models began to lock into the
synoptic situation earlier this week, they continued to shift the
track of the surface low further and further south of the region.
As a result, thermodynamic profiles cooled to the extent that what
was once rain forecast across our southern counties became snow.
And the chance for any accumulating snow slowly trickled to
nothing over our northern counties.

That trend has continued with tonight`s model runs--to the point
that I am rather doubtful that anyone within our forecast area will
even see measurable snow. All in all, tonight`s system looks very
minor and confined to far southern portions of western Kentucky. A
few flurries may be observed in communities north of there, but no
impacts are expected at this point.

Otherwise, the forecast is dry and seasonably cold--albeit with a
gradual moderation in temperatures--through the weekend. Partial
clearing is possible over northeastern sections of the area for a
time today. It will take time for clouds to begin to clear
Saturday, but more sunshine is anticipated on Sunday.

.LONG TERM...(Sunday night through Thursday)
Issued at 350 AM CST FRI DEC 19 2014

Forget about snow, all I want for Christmas is some sunshine!

The 00Z ECMWF and GFS are trending more amplified with the
large/deep low/trough aloft that will dominate the region through
the extended portion of the forecast. They both develop a closed low
over the upper Midwest by Monday, and then bring more energy
southward to the west of it heading into Tuesday. This results in
troughing from the northwest Gulf Coast all the way to the western
Great Lakes by the end of the day Tuesday.

Of course there are differences in the exact orientation and timing
of a cold front passage Monday night into Tuesday, which leads to
differences in timing and location of QPF. It does appear as though
there will be a nice swath of rain with the cold frontal passage,
whenever it moves through. After that, we will be under the
influence of deep cyclonic flow with the upper low not far north of
the area Tuesday night into Wednesday.

The ECMWF is deeper than the GFS and develops a nice swath of what
could be snow across the northeast half of the area Wednesday
afternoon and evening. The GFS has only faint QPF during this
period, but keeps the low farther north of the area. There is no
sign of a major influx of cold air at the surface, so accumulations
would not be likely. Will keep mainly lower chance PoPs in place
behind the cold front through Wednesday.

As for temperatures, high temperatures Monday will climb to slightly
above normal levels, and depending on the timing of the cold front,
Tuesday could be similarly warm as well. Wednesday will be below
normal with the upper trough in the vicinity. It should climb back
to normal levels Thursday. Lows will be relatively mild through the
period, with readings generally at or above freezing through the
period. The lone exception will be across the north on Wednesday
night, where some upper 20s will be possible.

It looks like sunshine will be difficult to find until Christmas


Issued at 1136 PM CST THU DEC 18 2014

VFR conditions will prevail through the forecast period. Much of the
area will be covered with VFR ceilings, but partial clearing is
possible over the KEVV and KOWB areas by late morning and afternoon.
Winds at all sites will be north to northeast at 5 kts or less.




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