259 
fxus63 kind 211909 
afdind 


Area forecast discussion 
National Weather Service Indianapolis in 
310 PM EDT Thursday Aug 21 2008 


Discussion... 


Forecast focus will be on rain chances next several days followed 
secondly temperatures Friday and Saturday. 


18z surface map shows large area of high pressure over southern New 
England which is keeping T.S. Fay from moving north. Upper air 
chart also shows an upper trough of low pressure over the middle 
Mississippi Valley and a much stronger trough over western Canada 
and the northwest U.S. Radar and satellite shows quite a bit of moisture 
streaming north across the Mississippi Valley. With the high 
pressure to our east moving little scattered showers and a few 
thunderstorms will continue across the west and northwest parts of 
our region while dry or only slight chance probability of precipitation occur in our east. 


NAM shows quite a bit of quantitative precipitation forecast just to our west...while GFS shows very 
little. For now will go with model blend concerning rain chances 
with best chances mainly in our northwest until Saturday night or Sunday. 
Models eventually move a weak cold front through our area Sunday as 
the western trough eventually moves into the Great Lakes. 


Cloud cover Friday will be similar as today and will go closer to 
met MOS temperatures which has lower maximum temperatures and warmer mins as they have 
verified much better today. 


In the extended precipitation chances will end Sunday night as weak front 
moves to our south. Models keep the remains of Fay well to our 
south...but GFS and European bring another short wave across our area 
towards the middle of next week. 


Looks like Monday and Tuesday will be dry and then will bring slight 
chance probability of precipitation across our region by middle of next week. 




&& 


Aviation...discussion for 18z tafs 


Area of rain looks to move across far western in and should impact huf 
early this afternoon. Heaviest rain should remain west of the site so have 
went with 6sm -shra for now. If a heavier shower moves across visibilities 
could drop to MVFR. Laf will be a little farther away so have kept 
just a vcsh for now. Only widely scattered rain showers will be around ind/bmg so 
coverage is too small to mention there. Ceilings will be VFR for the 
most part. 


As atms moistens up this afternoon and evening haze/br will be possible at 
laf/huf...and perhaps bmg. Have indicated this with a 6sm visibility 
group. Chances for rain diminish for a while this evening but 
increase once again across laf/huf late tonight. Have included a 
vcsh mention. Threat for rain showers continues into the day Friday...mainly at 
laf/huf. 


&& 




Ind watches/warnings/advisories... 
none. 
&& 


$$ 




Aviation...cs 
public...jh