611 
fxus63 kjkl 240645 
afdjkl 


Area forecast discussion 
National Weather Service Jackson Kentucky 
245 am EDT Thursday Jul 24 2008 


Short term.../today through Friday night/...updated 


Upper trough over the eastern Great Lakes will shift north over the 
next 48 hours leaving the region in northwest flow aloft. Surface 
high pressure will shift eastward across the Bluegrass state today 
ending up over North Carolina by the end of the period. 


A pleasant and dry airmass will continue to advect into the region 
today with light northeasterly low level flow. The airmass has 
proved too dry to allow for much fog development tonight as of 
yet... although our river valleys will no doubt have at least patchy 
dense fog through the early morning hours. Plenty of sunshine is 
then anticipated today with a very dry airmass in place (pwats 
around 0.75 inch). 


The airmass will gradually begin to moisten up as the low level flow 
turns more southerly and eventually southwesterly by Friday. A weak 
cold front will be pushing through the upper Midwest late Friday and 
models continue to hint that mesoscale convective system activity will develop upstream. As 
one would expect... there is considerable uncertainty with regards 
to timing and movement of this system though with the current model 
consensus being a late Friday night arrival into eastern Kentucky. 
Backed off probability of precipitation for Friday with that in mind and will continue to 
focus highest probability of precipitation late Friday night into the day on Saturday. Still 
only low chance probability of precipitation seem prudent given the uncertainty. 


Temperatures through the period will feature a warming trend and 
have generally followed the warmest guidance numbers. This is 
especially true on Friday where temperatures were raised a few 
degrees with less cloud cover anticipated. The dry airmass in place 
today will promote a rapid cool down in our valleys tonight with middle 
50s anticipated once again in the cooler spots. The Mercury should 
remain in the 60s Friday night though as the airmass modifies. 


Long term.../Saturday through Wednesday/ 


A front is prognosticated to move into eastern Kentucky on Saturday and all 
indications are that it will stall and hang around through most if 
not all the period. The overall pattern...weakly amplified northwest 
flow in the summertime...could yield both afternoon convection and 
some nocturnal mesoscale convective system activity so only a slight increase in afternoon 
probability of precipitation was depicted in the grids through the extended. Could not find a 
single day to omit precipitation chances and we basically have chance 
probability of precipitation throughout. 


The HPC temperatures looked reasonable throughout the period and we 
stayed pretty close. The only adjustments made to the previous 
forecast were to bump overnight temperatures up a couple degrees as 
moisture should be rather plentiful. 


&& 


Aviation.../06z to 06z/ 


VFR conditions will prevail for most of the forecast period...except 
for a brief drop in visibility just before dawn due to fog. Plenty of 
rainfall earlier today...combined with clear skies/calm winds tonight 
will provide the ingredients for some MVFR/IFR fog in most 
locations...especially east. As higher pressure begins to work its 
way in will keep ksme only in the MVFR visibility range tonight. T/dew point 
spread is around 8 degrees with much drier air just to the west in 
middle Kentucky. Kloz and kjkl should see a temporary drop to IFR visibility as 
T/dew point spreads are around 6 degrees and are behind the Daniel Boone 
National Forest ridge. Have pushed onset of fog back at all taf sites 
as well since latest guidance and current trends seem to hint at T/dew point 
spread not coming together till near sunrise. VFR conditions prevail 
after fog lifts tomorrow morning with a few cumulus around 6 k feet in the 
afternoon. 


&& 


Jkl watches/warnings/advisories...none. 


&& 


$$ 


Short term...Abe 
long term...Johnstone 
aviation...dusty