957 
fxus63 kind 061819 
afdind 


Area forecast discussion 
National Weather Service Indianapolis in 
219 PM EDT Monday Oct 6 2008 


Discussion... 


Forecast focus is on chances for rain Tue-Thu. 


At 18z an upper trough was across the Southern Plains with an upper ridge 
across the forecast area /fa/. High clouds were across the forecast area with 
temperatures in the 70s. 


Models are in better agreement...although differences remain in 
strength and location of upper low for middle week. GFS still looks too 
strong with upper low compared to other models. However per National 
model discussion NAM had some initialization issues...so do not 
completely trust the NAM either. Thus believe reality will be 
somewhere in between and thus took a blend of their solutions. 


Expect some middle and high clouds around tonight...thickening some 
toward morning as upepr system begins its move to the east. Thus partly cloudy 
or becoming partly cloudy looks good for skies tonight. Higher dewpoints 
are moving into the area as well. A blend of met/mav temperatures reflects 
these conditions and looks good. 


Clouds will continue to increase on Tuesday but still expect some sun 
and warm advection to boost temperatures to near the similar mav/met 
numbers. NAM/GFS bring precipitation well into the forecast area by 00z but NAM precipitation 
has a bulls-eye that looks out of place. Short range ensembles 
/srefs/ are slower than the NAM/GFS. Given this and the fact that 
the atms will need a little time to moisten up will not go quite as 
high as mav probability of precipitation. However given trend of speeding up this system and 
the fact that the 850 jet looks to impact the area by 00z will 
expand smaller chance probability of precipitation farther east. 


As the system moves east across the forecast area Tuesday night precipitable water 
values are well over an inch. Good isentropic lift will occur and 
q-vector convergence plots indicate additional forcing as well. Thus 
feel that the categorical probability of precipitation continue to be warranted. Instability 
not impressive so will go with just scattered thunderstorms with the occasional rain. 


System will be slow to exit the area and enough forcing will be 
around to probably get some measurable precipitation on Wednesday...especially 
early. So will continue likely probability of precipitation on Wednesday. 


Trend has been to speed up the exit of the system so have removed 
probability of precipitation for Thursday. High uncertainty exists on the evolution of the 
pattern for the weekend and early next week. Will keep things dry 
for now. 


&& 


Aviation...discussion for 18z tafs. 


Upper level ridge of high pressure will slide across the area tonight 
keeping VFR conds at the taf sites through 18z Tuesday. Surface winds will 
slowly veer from straight east to southeast through 18z Tuesday. 


Conds will quickly deteriorate after 18z Tuesday as strong moisture 
advection and lift arrive so ceilings and visible conds will drop at least 
into the MVFR range by 00z Wednesday as rain and possible thunderstorms 
arrive. 


&& 


Ind watches/warnings/advisories...none. 


&& 


$$ 


Aviation...Colorado 
public...cs