955 
fxus63 klmk 240114 
afdlmk 


Area forecast discussion 
National Weather Service Louisville Kentucky 
914 PM EDT Wednesday Jul 23 2008 


Evening update (overnight)... 


Currently...surface high pressure drifting through the region. This 
feature will keep skies clear tonight along with light winds. 
Combination of recent rains and light winds should result in a good 
radiational fog production overnight. Current forecast is good 
shape...but will add in patchy fog to the zone forecast product. 


Updated products/grids/digital products will be available by 930 PM 
EDT. 


Short term (tonight and thursday)... 


High pressure to slowly build in from the northwest with mostly 
clear skies in place through tonight and Thursday. Lower relative 
humidities and cooler temperatures will be around as well with lows 
tonight generally in the upper 50s to lower 60s and highs tomorrow 
in the middle 80s. Some patchy fog may develop early Thursday morning 
in locations that received some precipitation earlier today as well 
as other fog favored locations...though fog should not be very 
widespread and will keep mention out of the grids at this time. 


Long term (thursday night through wednesday)... 


Typical summertime weather this period with warm afternoons and 
scattered thunderstorm chances. 


A stubborn upper trough over southeast Canada near the Great Lakes 
combined with ridging across the southern United States will keep US 
in a northwest/west-northwest flow regime through the forecast period. 


At the surface...low pressure will organize over Kansas Friday 
morning and remain nearly stationary...acting as an anchor for a 
cold front dropping from the upper plains into the Midwest. Saturday 
morning low pressure will be over Hudson Bay with the cold front 
reaching south into Illinois and then west to the Kansas low. The 
front then weakens and slowly settles into the Ohio Valley Saturday 
and Sunday. This is a somewhat slower solution than 
previously...which makes some sense as cold fronts this time of year 
typically do slow down and get hung up in the Ohio and Tennessee 
valleys...plus the front will become more parallel with the upper 
flow. 


It appears an mesoscale convective system will develop in vicinity of Iowa Thursday night and slide 
southeast towards our region. For that reason we will have chance 
probability of precipitation in the northwest after midnight Thursday night into Friday 
morning...and then probability of precipitation everywhere on Friday as leftover boundaries 
may help to fire some additional convection. Could see a couple of 
strong storms in the heat of the afternoon. Locally heavy downpours 
will be possible too with precipitable waters  over 2 inches expected. 


Over the weekend rain chances increase as that front settles in. 


While the models are in fair agreement with the large-scale features 
through the weekend...they fall into some disarray for the first 
half of the new work week. The GFS ensemble and Gem ensemble seem to 
be the most in agreement. Going with those solutions...high pressure 
attempts to build southward into the Great Lakes and Ohio Valley as 
the cold front weakens significantly. Cannot rule out isolated pop 
up afternoon and evening thunderstorms through the 
period...especially over southern Kentucky...as often happens this 
time of year. However without a good signal to hang our hat on right 
now will keep Monday through Wednesday primarily dry in the zones 
rather than having 20 percent chances for several consecutive 
periods. 


&& 


Aviation (00z tafs)... 


High pressure will drift southeast across the area overnight brining 
clear skies and light winds. While prevailing VFR conditions are 
expected at the terminals overnight...there still is the possibility 
of visibility dropping into the MVFR Cat during the 07-12z time frame. At 
this time...main terminals that would be affected by this would be 
klex and kbwg. Thus...will maintain a MVFR time-frame at those site 
during the overnight hours. Ksdf terminal is forecast to remain VFR all 
night. 
&& 


Lmk watches/warnings/advisories... 
Kentucky...none. 
In...none. 
&& 


$$ 
Weather.Gov/Louisville 


Update.......mj 
short term...maczko 
long term....13 
aviation.....Mj