686 
fxus63 kdmx 052325 
afddmx 


Area forecast discussion...updated for aviation 
National Weather Service Des Moines Iowa 
625 PM CDT Sat Jul 05 2008 


Discussion... 
unsettled pattern setting up across the region over the next few 
days...as upper ridge in place over the last few days flattens into 
more of a zonal flow pattern. Surface low/trough axis situated along the 
Front Range into SC Canada...to move east slowly...with trough axis 
stretching from near Hudson Bay southwestward through Iowa into the 
southern High Plains as upper ridge flattens. Surface cool front to 
slide into northern Iowa Sunday...and linger over the area into Monday 
and Monday night before moving south Tuesday. Models indicating 
convection developing this afternoon in vicinity of the front to 
develop into an mesoscale convective system and progress southeastward through northern Iowa late 
tonight into early Sunday morning. Moisture transport vectors 
directed into the state late tonight through Monday night...with 
dewpoints slated to rise into the upper 60s to lower 70s Sunday. 
Precipitable water values also increase to around 2 inches for Sunday as well. 
Therefore expecting continued chances for heavy rain with any 
development over the next few days. Hard to nail down exact timing 
of thunderstorm development...with stream of weak impulses 
continuing to push through the state in the near zonal flow pattern. 
However models keying on the mesoscale convective system late tonight...although shear is 
minimal so may end up being more of a heavy rain threat. As surface 
boundary slowly sinks through the area Sunday into Monday...bulk 
shear increase to around 40 kts Sunday...and to near 50 kts Monday. 
With the increasing moisture...cape values still in the range of 
around 3000 to 4000 j/kg with better directional shear coming Monday 
night as surface low moves through the central/southern portion of the 
state. With all that being said...went with more of a broadbrush 
with probability of precipitation through Monday night. Depending on lingering precipitation 
Sunday morning...may end up limiting some of the activity for later 
Sunday...so will have to monitor. Otherwise as for the remainder of 
the long range...pattern remains tricky with a broad upper ridge 
trying to develop into the central US. Ec keeps more of a cooler 
wetter pattern...with the GFS remaining drier and warmer. Went with 
more of a blend...but did opt to keep the forecast mainly dry for 
now. 850 mb temperatures climbing into the 20s celsius which should send 
temperatures into the upper 80s to low 90s into next weekend. 


&& 


Aviation...06/00z 


Can expect VFR conditions for a good portions of this evening into 
the overnight hours...however the potential for thunderstorms and rain and MVFR/IFR 
conditions increases significantly from 09-15 UTC. Thunderstorms are 
likely along a surface trough that is forecast to enter the area 
during this timeframe. Atmosphere set up for potential of very heavy 
rain so have foreast prob30...with lower cielings in the MVFR 
catergory with IFR visbys. 


&& 


Dmx watches/warnings/advisories...none. 


&& 


$$ 


Short term...Kinney 
aviation...Russell 
long term...donavon