River Flood Warning 24, NWS Des Moines, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
422 PM CDT FRI MAR 14 2008

.SHORT TERM...TONIGHT THROUGH SUN
SEVERAL ISSUES TO DEAL WITH IN THE SHORT TERM.  FIRST IS THE STRATUS
BARRELING DOWN OUT OF MN THAT THE MODELS HAVE NOT CAUGHT ON TO AND
THE SECOND IS THE SYSTEM TO OUR SOUTH THAT THE MODELS DO HAVE A
DECENT HANDLE ON.  I PREFERRED THE NAM OVER THE GFS FOR THIS
SYSTEM. THE GFS HAS BETTER PLACEMENT OF QPF BUT BASED ON RADAR
RETURNS...IS MUCH TOO HOT ON QPF.  PLUS A COLD FRONT PUSHING DOWN
ACROSS OUR CWA HAS DEWPOINTS SLIGHTLY COOLER THAN THE MODELS ARE
THINKING SO ONSET OF PRECIP SHOULD BE A LITTLE LATER AND QPF VALUES
SHOULD NOT BE AS HIGH AS PREVIOUSLY THOUGHT. THE SYSTEM IS RATHER
SLOW MOVING AS PRECIP HAS REMAINED OVER SRN NEB/NRN KS THE
ENTIRE SHIFT.  IT IS FINALLY SPREADING INTO NW MO AND HEDGING
TOWARDS SRN IA NOW.  EXTRAPOLATED TIMING OF THE PRECIP INTO SRN IA
ABOUT 23Z.  AS FOR THE STRATUS...THIS WILL BE AN AVIATION HEADACHE.
HAVE ADJUSTED SHORT TERM CLOUD TRENDS IN GRIDS AND TAFS TO ACCOUNT
FOR THE FASTER ONSET OF LOWER CLOUDS BEHIND THE COLD FRONT.  TEMPS
FOLLOWED PERSISTENCE WITH SOME MINOR TWEAKS FOR THE LOWER CLOUD
COVER.  PCPN SHOULD LINGER INTO SAT MORNING WITH PCPN TYPE GRADUALLY
SWITCHING TO SNOW.  LITTLE OR NO ACCUMS ANTICIPATED.  HIGH PRESSURE
THEN SETTLES INTO MS VALLEY WITH ATTENTION TURNING TO DEVELOPING WRN
CONUS TROUGH.

.LONG TERM...SUN NIGHT THROUGH FRI
MAIN CONCERN IN THIS PERIOD WILL BE THE WEEKEND SYSTEM AND PRECIP
TRENDS.  ECMWF HAS HAD BETTER RUN TO RUN CONSISTENCY...STEADILY
DEPICTING LESS PHASING THAN DOMESTIC SOLUTIONS...SO IT ALONG WITH
UKMET/GEM WILL BE PREFERRED SOLUTIONS.   GFS/GEFS/DGEX ALL SEEM
OVERDONE WITH DEEPENING LOW FROM SRN PLAINS INTO GREAT LAKES.
STRONG THETA-E ADVECTION IS IN PLACE EARLY MON NORTH OF MO WARM
FRONT FOLLOWED BY DPVA SURGE MON NIGHT.  12Z ECMWF HAS NOW BOOSTED
QPF TO NEAR AN INCH  MON SO THIS WILL HAVE TO BE WATCHED FOR HYDRO
CONCERNS.  CONVERGENCE ALONG FRONTAL BOUNDARY TO THE SOUTH MAY ROB
SOME MOISTURE...BUT SYNOPTIC SCALE LIFT IN RIGHT ENTRANCE REGION OF
GREAT LAKES JET COULD CERTAINLY AID WIDESPREAD UVM.

&&

.AVIATION...14/18Z
THERE ARE A COUPLE OF FORECAST PROBLEMS TODAY.  FIRST IS THE STRATUS
SHIELD PUSHING DOWN OUT OF MN THAT THE MODELS DONT SEEM TO HAVE A
HANDLE ON. I HAVE EXTRAPOLATED THE LEADING EDGE OF THIS STRATUS
FIELD BRINGING IT INTO THE TAF SITES ACCORDINGLY.  TO COMPLICATE
MATTERS FURTHER...WE HAVE A WEAK SYSTEM PUSHING ACROSS THE SOUTHERN
PLAINS WITH AN ATTENDANT FRONTAL BOUNDARY.  THIS FEATURE WILL LIFT
OFF TO THE NE BRINGING A CHANCE OF RAIN OR SNOW TO THE SOUTHERN
ROUTES MAINLY LATE THIS EVENING AND OVERNIGHT.  HOW THAT WILL BE
AFFECTED BY OR AFFECTING THE STRATUS SHIELD REMAINS TO BE SEEN.
BOTTOM LINE...MVFR/IFR COND WL EXIST ACROSS THE NORTHERN TAFS
BEGINNING AFTER 21Z.  VFR/MVFR COND ACROSS THE SOUTHERN TAF SITES IN
-RASN MIX THIS EVENING WILL GIVE WAY TO MVFR/IFR COND AFT 05Z.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

BSS/FAB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
344 PM CDT FRI MAR 14 2008

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-152045-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-
BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-
POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-
CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-
APPANOOSE-DAVIS-
344 PM CDT FRI MAR 14 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ALL OF CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A FEW RIVERS CONTINUE TO REMAIN AT OR ABOVE FLOOD STAGE. CONTINUED
SNOW MELT AND POTENTIAL ICE JAMS...COULD CAUSE ADDITIONAL FLOODING.
FOR ADDITIONAL INFORMATION PLEASE REFER TO THE NATIONAL WEATHER
SERVICE WEBSITE AT WEATHER.GOV/DESMOINES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE THREAT OF FLOODING WILL CONTINUE THROUGH EARLY NEXT WEEK AS
THE SNOW SLOWLY MELTS. A WEATHER SYSTEM ON MONDAY AND TUESDAY
WILL PRODUCE ADDITIONAL RAINFALL WITH SOME SNOW POSSIBLE DURING
THE NIGHT TIME HOURS CAUSING THE POTENTIAL FOR MORE PROBLEMS. AT
THIS TIME THE AMOUNT OF ANY ACCUMULATING SNOW IS HARD TO PINPOINT
BUT NORTHERN IOWA WOULD HAVE TO BETTER POTENTIAL FOR THAT.

FOR ADDITIONAL INFORMATION PLEASE REFER TO THE NATIONAL WEATHER
SERVICE WEBSITE AT WEATHER.GOV/DESMOINES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED...HOWEVER ANY REPORTS OF ICE
JAMMING OR FLOODING WOULD BE GREATLY APPRECIATED.

FAB