660 
fxus63 kind 200659 
afdind 


Area forecast discussion 
National Weather Service Indianapolis in 
259 am EDT Sat Mar 20 2010 


Discussion... 


Forecast focus is on chances for rain into early next week along 
with temperatures. 


At 06z a cold front was across northwestern sections of central 
Indiana and was slowly sinking southeast. No precipitation was along 
the front...with nearest precipitation across far northwestern 
Illinois. 


Models are in decent agreement with the big picture. Will continue 
to use a blend of the operational models along with the ensembles. 


Today the cold front will continue to slowly move southeast. Not a 
lot of forcing along the front...although models are trying to 
develop something along it this afternoon in an area of low level 
frontogenesis. As can be seen currently...best chances for rain will 
be well behind the front...and this area of precipitation looks to 
remain mainly northwest of our area today. Given this...will go 
chance probability of precipitation across the northwest half of the forecast area 
today...with the highest probability of precipitation across the far northwest. Will go 
slight chance across much of the southeast to account for possible 
development along the front. Temperatures will be tricky with front 
across the area. Will go near mav numbers behind the front but 
warmer than mav ahead of the front /since mav has been too cool in 
that airmass/. Ensemble means are similar to this thinking as well. 


Tonight forcing weakens across the area as energy will be focused 
near the surface and upper lows well to the southwest. Will only go 
low chance or slight chance probability of precipitation. Mav looks good for low temperatures given 
low coverage of precipitation and mostly cloudy skies. 


Chances for rain will increase during the day on Sunday as the 
surface low moves to north through Tennessee during the day. Went 
likely or higher probability of precipitation all areas during the afternoon. Isentropic and 
qvector forecasts show forcing continuing Sunday night as the low 
moves through Kentucky...so continued the likely or higher probability of precipitation 
across the area. Chance probability of precipitation will linger through Monday as the 
system pulls off to the east. 


&& 


Aviation...discussion for 20/06z tafs. 
Cold front was south of ikk and just northwest of stl late this 
evening with leading edge of the thick VFR cumulus deck near the 
front. The front is expected to reach laf around 07z and slowly 
spread southeast and reach ind and huf after before becoming 
quasi-stationary. Expect ceilings to deteriorate to MVFR after 18z 
at laf and spreading southeast...but looks like showers will not 
either not be around or will be to isolated to mention until after 
02z at laf and 06z at ind. Light winds will become northeast behind 
the front and increase to near 15 knots behind the front. 


&& 


Ind watches/warnings/advisories...none. 


&& 


$$ 


Public...50 
aviation...mk