838 
fxus63 kdmx 211751 aaa 
afddmx 


Area forecast discussion 
National Weather Service Des Moines Iowa 
1249 PM CDT sun Mar 21 2010 


Short term /today/... 
a high pressure ridge currently over northwest Iowa early this 
morning will remain nearly stationary through the day as deep low 
pressure well to our south plods slowly east. Regional radar 
continues to show light returns southeast of a Corydon to Oskaloosa 
line in the northern periphery of deformation zone...but nothing has 
been reaching the surface thanks to a very dry sub cloud layer. 
Todays forecast is mainly one of temperature and dewpoint. A 
modifying cold airmass and full sunshine across the northwest half 
should allow temperatures to rise near or above the higher end of guidance. 
Over the southeast...kept temperatures closer to cooler end under the 
greater cloud cover. Soundings from the north into central areas 
indicate quite a bit of dry air aloft that could mix down during the 
late morning and afternoon...so have dropped dewpoints lower than 
guidance. 


Long term /Monday through Friday/... 
in general we stay in a zonal to northwest flow pattern aloft during 
the extended with a gradual warmup early in the week followed by a 
little cooler middle to late week. The system that models were 
depicting to affect central Iowa on Wednesday now looks like it will 
stay to our south and west. The GFS shifts the system furthest to 
the south while the Euro still hints at a weak wave rippling across 
central Iowa and at least a brief period of showers. However this 
is a drastic shift in that models thinking from yesterday and the 
Gem...which yesterday was a blend of the GFS and the Euro now also 
shifts the system further south. I removed probability of precipitation everywhere but the 
far southern counties where some threat for precipitation still exists but 
I am not expecting much out of this system. Little change to temperatures 
were needed except that I did bring highs down a touch late in the 
week and nudged temperatures higher for Tuesday. 


&& 


Aviation... 
21/18z...VFR conditions through the taf period. Hi pressure over northwest Iowa will 
drift slowly southeastward tonight and be southeast of Iowa Monday. Generally light winds 
with the exception of the kotm area which will be under the 
influence of the low to the southeast. Winds will become light southeast-southerly 
on Monday. 


&& 


Dmx watches/warnings/advisories...none 


$$ 


Short term/aviation...MS Mar 10 
long term...fab