871 
fxus63 kpah 202336 aaa 
afdpah 


Area forecast discussion...updated 
National Weather Service Paducah Kentucky 
636 PM CDT Sat Mar 20 2010 


Update... 
discussion for 00z Sunday routine taf issuance. 


&& 


Discussion... 
/previously issued 1243 PM CDT Sat Mar 20 2010/ 
17z frontal position on northwest doorstep of forecast area...separating 60s/near 70 
across forecast area from 30s over much of MO/behind front. The NAM has a 
good grip on the near term conditions including precipitation. It models 
probability of precipitation in very slow tonight...with a dry evening for all but western 
semo...most probability of precipitation coming in late tonight/after midnight. In the far 
east...arguably the probability of precipitation hold off until tomorrow...but collab 
consensus may be to ride a 20 or so there...will monitor through 
press time before final call. 


Sun is a cloudy/cool/wet day. All models rotate upper/surface lows 
across MS valley with categorical probability of precipitation. Only elevated instability 
indices support thunder...but with Storm Prediction Center swody2 and inherited slight 
chance T...cant argue enough to take it out...though did taper it to 
mainly eastern 1/2 region (e of MS river) Sunday...and will 
monitor this too through press time before final call. 


Monday S/b mainly an early day pop as we wash out the crud on the 
back side of the low. Do not believe lower tropospheric temperatures 
support frozen precipitation at this time...so keeping all liquid as did 
predecessors. 


After that...middle week drying is followed by late week return probability of precipitation. 
Both GFS/ec move it on through...though ec is a little more high amplify 
with the pattern and as such is slower with tracking the open wave 
across the area...still doing so prior to weekend onset though. 


Favored NAM/therefore met MOS short term temperatures/dew points with slight 
collab adjustments. 


&& 


Aviation... 
evolution of the deepening closed low along the Red River /aloft/ 
and eastern Arkansas /surface/ will continue to delay the lowering of VFR 
ceilings east of the Mississippi River until after 06z Sunday. 
Between 06z and 12z Sunday...local IFR ceilings will move into 
kcgi as the surface low moves into southeast MO...working toward 
kpah before 18z Sunday. Broken IFR ceilings should move into the 
kevv/kowb taf sites after 17z...as any remnant of the impinged 
ridge axis ahead of the closed low disappears and the atmospheric 
layer becomes quickly saturated with time. Despite the 
saturation toward the surface...visibilities should remain in the 
MVFR category through 00z Monday. 


&& 


Pah watches/warnings/advisories... 
Kentucky...none. 
MO...none. 
Illinois...none. 
In...none. 
&& 


$$ 


Smith