324 
fxus63 kpah 061910 
afdpah 


Area forecast discussion 
National Weather Service Paducah Kentucky 
208 PM CDT Sat Sep 6 2008 


Short term /tonight through Wednesday/... 
of immediate concern is the areas of light rain over western and 
south central Missouri depicted on ksgf radar at 18z. The 
NAM/GFS/sref quantitative precipitation forecast and probability of precipitation do not reflect this activity well...at 
least over south central MO. The primary lifting mechanism appears 
to be a 500 mb trough over the plains. 09z sref indicated a jet 
streak would intensify in the base of this trough tonight...then 
eject northeast with the trough late tonight and Sunday. As the 
trough ejects northeast...some of this light precipitation could brush southern 
Illinois and southeast Missouri tonight and Sunday morning. 


Weak high pressure will move east across the lower Ohio Valley 
Sunday afternoon and night...which will bring dry conditions. With 
less cloudiness and calm winds...there is a potential for fog late 
Sunday night. This potential will be greatest over the part of southeast 
Missouri and SW Illinois that was soaked by the remnants of Gustav. 


Low level winds will become southerly Monday in advance of a cold 
front over western and northern Missouri. With plenty of sun and dew 
points increasing into the lower to middle 60s...moderate instability 
should develop Monday afternoon. Sref indicates surface based convective available potential energy 
in the 1000 to 2000 range. Expect isolated to scattered storms to 
arrive late in the day along the northwest border of the County Warning Area. This 
activity will spread east across the remainder of the region Monday 
night. Highest coverage should be in the northern counties...closer 
to the 500 mb shortwave trough crossing the Great Lakes region. 


In the wake of the cold front...dew points will lower somewhat. 
Overnight lows will be cooler...and daytime highs will show little 
change. 


Long term /Wednesday night through Saturday/... 


Another 500 mb shortwave trough will move east across the northern 
states late in the week...associated with a surface cold front. 
Besides model differences regarding the speed of this system...there 
are also differences concerning whether moisture from tropical 
system Ike will be drawn northward ahead of the front. The consensus 
of the 12z GFS and 00z European model (ecmwf) is that the front will cross the 
forecast area Thursday night...too quickly for moisture to arrive 
from Ike. 


Since there is not a well established model trend yet...will keep 
probability of precipitation in the 20 to 30 percent range for Thursday through Friday. 
Generally dry conditions should follow for Friday night and 
Saturday. However...a slight chance pop will be kept over the khop 
area... closer to where the remnants of Ike could follow the exiting 
cold front. 


&& 


Aviation... 
remaining MVFR ceilings near the Mississippi River will quickly lift 
and scatter this afternoon. Winds should be near calm tonight 
throughout the area...as surface high pressure settles in. 
However...middle and high clouds are expected to increase over the area 
overnight. This may help keep any fog formation from becoming dense 
or very widespread. Knocked kcgi taf down to 1/2sm...as that area 
will be one of the last to mix out this afternoon. Also mentioned 
MVFR fog at kowb where less cloud and wind is expected compared to 
kpah and kevv. Clouds will increase 5kft and up Sunday...with light 
northwest winds. 


&& 


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


$$ 


Short term...my 
long term...my 
aviation...drs