478 
fxus63 kpah 070829 
afdpah 


Area forecast discussion 
National Weather Service Paducah Kentucky 
329 am CDT Tuesday Oct 7 2008 


Discussion... 
the precipitation event we have been waiting for is finally underway in the 
MO Ozarks this morning. No thunderstorms were seen yet in the pah forecast area... 
just showers. A sharp middle level trough across the central Continental U.S. Is 
prognosticated by the models to split into two troughs as it moves eastward. 
Accordingly...most models show two separate surface lows with weak surface 
boundaries that are expected to move eastward also. The southern low and front 
should be in our vicinity by late tonight as the parent middle level 
trough heads east-southeastward toward the deep south. 


Meanwhile...rainfall will be almost a certainty this morning for 
the western half of the region. Eastern parts of southwestern ind and the Kentucky 
pennyrile region may not get rain until evening as it will take a 
while for the relatively dry atmosphere to moisten up. At this time...it 
appears thunderstorm activity in Arkansas will eventually translate northward into 
mainly southeastern MO and part of The Purchase area of Kentucky this morning. 
Even in the afternoon...thunderstorm activity will be the most likely in southeastern 
MO/Purchase area of Kentucky/southwestern Illinois. This will be because of increased 
instability due to low level warm air advection ahead of the aforementioned surface 
low...and cooling aloft. In the late morning and early 
afternoon...bulk shear of more than 40 knots /0-6km/ could help a stronger 
thunderstorm or two kick out some small hail. Widespread precipitation and 
cloudiness should limit severe weather potential in our region. Precipitation 
during the day on Wednesday will be mainly light showers as the system 
departs. Some showers may linger into Wednesday evening in the deformation 
zone between the opening northern trough and the closed southern trough. 


Thursday on...the pah forecast area will be under a middle level southwesterly flow 
regime...meaning above normal temperatures...somewhat higher 
humidities...and mostly rain free conditions. The European model (ecmwf) hints at 
the slight possibility of some showers on Sunday. No changes were 
made after day 5 in this package. 


&& 


Aviation... 
VFR ceilings and visibilities will continue through the overnight hours. After 
11z...scattered -shra will be possible at kcgi and kpah...with rain showers and 
thunderstorms and rain becoming predominant after 14z. With the rain showers and thunderstorms and rain...MVFR 
ceilings and visibilities can be expected...with IFR visibilities possible at times. 
Scattered -shra will make it to kevv and kowb after 15z...with rain showers and 
thunderstorms and rain becoming widespread after 18z. Southeast winds at 3 to 6 kts 
overnight will become more southerly and increase to 6 to 12 kts 
after 12z. 


&& 


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


$$ 


Public...db 
aviation...rls