199 
fxus63 kpah 070443 
afdpah 


Area forecast discussion 
National Weather Service Paducah Kentucky 
1143 PM CDT Monday Oct 6 2008 


Update... 
updated for 06z aviation package. 


&& 


Discussion... 
going forecast has things handled pretty well. Nudged probability of precipitation just 
a tad eastward after 06z...a little farther into west Kentucky 
and southern Illinois...but not by much. Minor adjustments were 
made to temperature and cloud trends...more cosmetic than anything. 


&& 


Previous discussion... /issued 225 PM CDT Monday Oct 6 2008/ 


Main issues this forecast package revolve around the upcoming 
system tonight through midweek and another system over the 
weekend. 


Models still in OK good agreement with the evolution of 
precipitation over the next 48 to 60 hours. An upper level 
trough/surface frontal system currently in the Central Plains...will 
continue to move east toward US. This system is producing some 
pretty good rain across Kansas...central Nebraska and eastern 
Oklahoma/western Arkansas early this afternoon. The GFS and NAM 
differ on precipitation onset...with the GFS faster...and bring 
rain into the Ozark foothills prior to 06z. Looking at the latest 
National radar...the activity is already into western Arkansas...so 
would not be surprised if portions of southeast Missouri get wet 
later this evening...with the best chances during the overnight 
hours. GFS is showing showalter values around -1 over semo...so 
we could see some thunderstorms...but backed off to slight chance 
for thunder. 


It appears that the front associated with this system will be 
knocking on our western counties by Tuesday 12z...and very slowly 
move east...and be over the Ozarks by 00z Wednesday. Showers and storms 
will begin overspreading the entire area from west to east 
throughout the day on Tuesday. While models differ on amounts and 
location of the greatest rainfall...the potential exists for an 
inch to two inches of rainfall in some areas. Soundings show 
precipitable water values ramping up rapidly over the next 24 to 
36 hours...so there will be lots of moisture to work 
with...eventually. The latest from Storm Prediction Center indicates that severe 
storms are not probable due to the weak thermodynamics in the 
atmosphere. 


By Tuesday night...the GFS develops a h50 closed low over Missouri 
and moves it southeast into west Tennessee by 18z Wednesday. The 
NAM develops a closed low...but over Arkansas and moves it into 
central Mississippi by that time. The European model (ecmwf) seems somewhat in 
between...with a low over central Illinois and another near 
Memphis by 12 Wednesday. The difference in these models will make the 
forecast somewhat difficult for Tuesday night and into Wednesday. 
But it does appear as though the better chances for precipitation 
will be in our eastern counties. By Wednesday night...the 
rain...if it is still around...should definitely be confined to 
eastern portions. Whichever way the upper low decides to head...we 
should be dry by Thursday. 


As most surrounding wfo's weighted the extended toward the 00z Monday 
European model (ecmwf) solution. Still not buying into the 06z GFS scenario with low 
overhead early in the weekend. The 12z Monday GFS coming in now and 
keeps area mainly dry Saturday. Thus...followed suit and kept dry 
Sat but did see a chance Sunday as warm air advection gets a little better. Also agree 
with slower frontal passage into next week. Thus kept temperatures and relative humidity up into 
Monday then start to taper as we head into Tuesday. Also introduced 
a few minor gusts for the weekend in response to the synoptic scale 
features. 


As for temperatures...after a warm day today...clouds and 
precipitation will keep temperatures down tomorrow and Wednesday...with 
readings moderating back into the upper 70s by the weekend. 


&& 


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. 
&& 


$$