Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 080017

Area Forecast Discussion
National Weather Service Paducah KY
617 PM CST Wed Dec 7 2016

Issued at 617 PM CST Wed Dec 7 2016

Updated aviation discussion.


.SHORT TERM...(Tonight through Friday night)
Issued at 158 PM CST Wed Dec 7 2016

Satellite shows clouds overspreading the region this pm, and obs
show some flurries/light snow from western MO/eastern KS. Models
continue to really squeeze out this pcpn and basically eliminate
it by the time the source zone of mrh moves overhead, effectively,
tonight. We`ll still carry the inherited/collaborated slgt chance
mention of a non measurable flurry (or sprinkle early).

After that, the cold air ushers in its arrival, with teens still
slated for tmrw and Fri nights. Fri night may be the slightly
cooler night with the surface High moved overhead by then. Both
Thu-Fri daytime highs will struggle their way toward/around the
freezing mark.

.LONG TERM...(Saturday through Wednesday)
Issued at 158 PM CST Wed Dec 7 2016

The main weather concern for the weekend will be a low pressure
center tracking to our north and west. There is good model agreement
on a low track from the central Plains northeast to the Great Lakes
region. Cloudiness will thicken on Saturday ahead of the system.
Precipitation will overspread our region from the southwest
Saturday night, mainly after midnight.

Precip type is still a concern for Sat night into Sunday morning.
There will be a lot of dry air to overcome before precip reaches the
ground. Evaporational cooling will play into precip type. The 12z
gfs indicates wet bulb zero profiles will be entirely below freezing
at kpah until 09z-12z Sunday, which is when the column becomes
saturated. At kevv, the wet bulb zero profile remains entirely below
freezing for a few hours after the column saturates. Based on the
gfs, there would be an inch or two of snow at kevv. However, the
ecmwf has been consistently slower to saturate the column. Based on
the 12z ecmwf, precip would not start until around 12z Sunday. By
that time, the ecmwf indicates enough warm air for primarily rain
everywhere. The forecast will reflect a blend of the two, with pops
around 50 percent Sat night and then likely on Sunday. Since most of
the precip will occur after the warmer air arrives on Sunday
morning, any snowfall amounts should be very minor. The official
forecast will include a small accumulation along the Interstate 64
corridor, mainly below one-half inch.

Precip will taper off from northwest to southeast Sunday night in
the wake of a cold front. There may be a brief change to snow before
it ends, but no impacts are anticipated.

Weak high pressure will bring dry and chilly air for early next
week. Highs Monday and Tuesday will be around 40, with lows in the
upper 20s.

An arctic cold front will likely arrive by the middle of next week.
The 12z gfs is the slow outlier. The forecast will follow a 12z
ecmwf/gfs ensemble blend. The latest model 850 mb temps suggest next
week`s air mass will be at least as cold as the air mass tomorrow
and Friday. There may also be a weak clipper disturbance, which
could bring some light snow. This light snow currently appears to be
mainly along and north of Interstate 64, but the models are going to
vary between now and then.


Issued at 617 PM CST Wed Dec 7 2016

The arrival of a new air mass overnight will result in VFR
cloudiness. The atmosphere is rather dry below 5 kft, making snow
flurries in any significant quantity unlikely near the surface.
Winds aob 10 kts will back 20 to 30 degrees overnight. Winds will
increase to around 12 kts with higher gusts Thu morning in
southeastern IL/southwestern IN/northern KY, but should be less




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