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Area forecast discussion 
National Weather Service Des Moines Iowa
633 am CDT Friday Apr 18 2014

..updated aviation discussion...

issued at 316 am CDT Friday Apr 18 2014

High pressure ridge over Iowa will drift off to the east as low
pressure over the northern rockies will move east and minor out as
negative tilted trough lifts northeast into Canada. A stronger
system is poised to move into the central U.S. For the middle and
end of next week.


Short term /today/...
issued at 316 am CDT Friday Apr 18 2014

Surface high will move east over the Great Lakes region
today and winds are expected to shift and increase out of the
southeast through the afternoon. Main concern today is with
lingering fog across the north this morning and maximum temperatures.
Leaned slightly warmer that the 18.00z NAM as the GFS/ECMWF/sref seem
a bit too cold. Plus...the NAM did slightly better with respect to to maximum
temperatures on Thursday. Have patchy fog mentioned through 14z this
morning in the northeast as winds should increase and sunshine
should dissipate it rather quickly.

Long term /tonight through Thursday/...
issued at 316 am CDT Friday Apr 18 2014

Southerly flow will increase tonight and Saturday. The strongest
Theta-E advection will be to the north of the County Warning Area so warm air advection thunderstorms and rain
development is not favored. Will slow down the precipitation further with
this package with systems moving slower than even the slower European model (ecmwf)
indicated yesterday. Instability is a little higher today with k
indices in the 30 to 35 c range with 700 to 1500 j/kg of cape
available Sun afternoon and evening. Expect widespread thunderstorms and rain by Sun
afternoon and evening as the cap weakens and eventually is broken.
Severe potential is reduced by the distance from the parent low
and the overall system weakening as shortwave well to the northwest

Attention turns to the next system. Upper air shows a full
latitude trough moving into the western U.S. Early in the week and
making slow progress to the east after that. Cape values are
higher with this system and excepted to see a period of
thunderstorm activity extending from Tuesday through the rest of the
forecast period. Potential for stronger storms with this system.
Deeper moisture will be available as well with surface dew points
rising to around 60 ahead of the cold front on Wed, and over the
east Thursday.


issued at 630 am CDT Friday Apr 18 2014

Once the early morning fog dissipates by around 13-14z this
morning across northern Iowa...VFR conditions will prevail through
Saturday morning.


Dmx watches/warnings/advisories...none.



Synopsis...MS Apr 14
short term...podrazik
long term...MS Apr 14