097 
fxus63 kdmx 202322 aaa 
afddmx 


Area forecast discussion 
National Weather Service Des Moines Iowa 
623 PM CDT Sat Mar 20 2010 


Short term /tonight/... 
low pressure consolidating over Arkansas will lift northeastward tonight. Bulk of the 
energy expected to remain the south of the County Warning Area. -Sn will brush the 
southeastern zones and went for an inch or less through the night with most of it 
before 06z. Clouds will linger through the night and that will keep temperatures 
from dropping much more than 5-7 degree. Nwia will be clear and went 
at or below MOS across most of the area. Winds will keep the bottom from 
falling out though. 


Long term /Sunday through Saturday/... 
high pressure to build into the area over the next couple of days. 
Along with that...foehn warming will take place across the northern 
plains as downslope winds commence there on Sunday. Looking at h850 
temperatures warm nicely into Monday and Tuesday. Despite that...little 
mixing taking place on Monday so rise in temperatures may be limited 
compared to a fully mixed scenario. For Sunday...will have to melt 
off the recent snow cover to fully appreciate the warmer temperatures aloft 
on Monday. This should be no problem for most of the region except 
for a few instances where the highest totals from fridays event 
occurred. By Tuesday...models all suggest Lee side troughing over 
the northern plains. This will slightly enhance mixing across the 
region and allow for highs to reach the upper 50s to lower 60s. 
Moisture return with the midweek system is rather limited...so am 
not looking at high probability of precipitation to return anytime soon. Weak convergence 
and some light Post frontal precipitation is possible for Tuesday 
night as the northern stream low tracks to the east. High pressure 
and a slightly cooler airmass will follow for Wednesday afternoon. For 
now...southern stream continues to be favored over the north as for 
storm development. As another low develops over the Southern Plains 
on Thursday...both Euro/GFS/Gem suggest that the system and its best 
forcing will pass south of the region with only a slight chance for 
some measurable precipitation across the south. Though the timing 
will be slower...a system arrives by late Saturday which may bring 
some light precipitation to the region as well. Likely timing will be on 
day 7 or beyond...so have left probability of precipitation under slight chance Cat for now 
and will let evaluate over a few more days. With southern storm 
track currently move favored...it is possible that the frontal 
boundary and forcing may become too sheared/weak to support any Post 
frontal precipitation later on Saturday or Sat night of next 
weekend. 


&& 


Aviation... 
21/00z...widespread VFR conditions are expected across much of Iowa as 
storm stays primarily to the south. Ceilings will remain at or above bkn120 
with unrestricted visibilities. Only exception will be near kotm in 
southeast Iowa where MVFR ceilings and visibilities will be possible tonight with 
some light snow in far southern Iowa. Entire forecast area will be VFR 
on Sunday. 


&& 


Dmx watches/warnings/advisories...none 


$$ 


Short term...MS March 10 
long term...rev 
aviation...cogil