Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 200850

Area Forecast Discussion
National Weather Service Paducah KY
350 AM CDT Tue Mar 20 2018

.SHORT TERM...(Today through Thursday night)
Issued at 312 AM CDT Tue Mar 20 2018

Main forecast challenge in the short term comes today into this
evening as a mid/upper level level low moves east across the lower
Oh Valley. The low will likely generate an area of light
precipitation beginning over southeast MO this morning. The
precip will then traverse much of the forecast area today, though
there are confidence issues on precip types and impacts, if any
at all.

Firstly, progged thicknesses and thermal profiles suggest the
precip could fall in the form of wet snow, with blustery nw winds
gusting 20-30 MPH. However, surface temperatures are likely to
stay a couple to a several degrees above freezing, and much of the
precip will be light and fall during the daylight hours. In
addition, ground temperatures are quite warm. So, while the
chances of seeing snow in the air seem quite high today at many
locations, impacts are expected to be minimal unless the rates
somehow increase dramatically. If that were to occur, reduced
visibilities and some slushy roads could result. Will cover this
with a Special Weather Statement for this package, esp over sw IN
and the Pennyrile of western KY later in the day.

Conditions should improve some on Wednesday with the return of
some sunshine, but nw winds will keep temps well below normal, in
the upper 40s to mid 50s. Surface high pressure will then move
east through the Ohio Valley Thursday. This should keep things
rainfree, even though a weak upper level impulse may move
southeast through the mid MS Valley.

.LONG TERM...(Friday through Monday)
Issued at 312 AM CDT Tue Mar 20 2018

The long term period begins with above average confidence owing to
relatively good model agreement. However, confidence drops off over
the weekend into early next week with greater model variability.

An unsettled pattern will prevail from late this week into early
next week with multiple chances for showers. The period will start
with an upper level ridge centered over the Plains flanked by
troughs in the east and west. The ridge will translate eastward
through the weekend, placing the forecast area in southwest flow
early next week.

The first chance for showers arrives late Friday, Friday night, and
Saturday as energy over the Intermountain West tops the Plains ridge
and streams eastward into the Ohio Valley. At the surface, low
pressure over western Kansas late Friday is forecast to weaken as it
slides east along a baroclinic zone into the immediate forecast area
by Saturday evening. Rainfall amounts during this period are
forecast in the one quarter to one half inch range, with the higher
totals north of the front in closer proximity to Interstate 64.

By Sunday, the front is forecast to stall out south of the region.
Another low pressure system is forecast to develop over the Central
Plains and eventually lift the front north across the area as the
low moves northeast towards the Great Lakes. This will eventually
result in our next chance of precipitation, but how quickly all of
this transpires is unclear at this time. Both the ECMWF and GEM keep
dry conditions in place from Sunday through Monday evening with a
strong upper level ridge in place over the Southeast. Meanwhile, the
GFS is quicker to shift the ridge to the east and brings potentially
heavy precipitation into the area by Monday. Both the ECMWF and GEM
delay that potentially heavy precipitation until mid week. Given the
uncertainty, will stay close to the initialized model blend, which
keeps rain chances generally at or below 50 percent Sunday night and

A look at temperature guidance reveals a spread of as much as 15 to
20 degrees between the 00Z GFS and ECMWF MOS guidance late in the
weekend and early next week. The current forecast relies heavily on
a model blend, which smooths out the extremes from the individual


Issued at 1147 PM CDT Mon Mar 19 2018

MVFR to IFR cigs expected overnight, with more of the IFR at
KCGI/KPAH. Isolated light showers will continue near KEVV/KOWB
overnight. MVFR cigs expected after 12z, slowly improving to low
VFR by the afternoon. Included VCSH at KCGI/KPAH mainly during the
morning hours, and mainly during the afternoon hours at KEVV/KOWB.
Winds overnight will be from the northwest to north at 5 to 10
kts, increasing to 10 to 15 kts with gusts near 20 kts after 13z.




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