Severe Thunderstorm Warning 109, NWS Des Moines, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
310 AM CDT TUE JUN 17 2003

FORECAST CONCERNS EXTEND THROUGH WEDNESDAY AS FRONT SLIDES THROUGH
IOWA.  CURRENTLY...TRANQUIL WEATHER ACRS THE CWA AS FRONT HOLDS
ACRS THE DAKOTAS INTO NEBRASKA.  NARROW RIBBON OF MOISTURE ADVECTING
NORTHWARD INTO SYSTEM IS EDGING INTO WESTERN IA...HOWEVER WINDS
REMAIN LIGHT IN WEAK GRADIENT.

THE FRONT WILL PROGRESS INTO THE STATE LATER TODAY AS A SHORTWAVE
TROUGH DROPS THROUGH SOUTHERN CANADA.  LIMITED CLOUDINESS SHOULD
ALLOW TEMPS TO RISE NICELY ACRS MUCH OF THE CWA THROUGH MIDDAY.
EXPECT HIGHS TO CLIMB TO SIMILAR READINGS REACHED ON MONDAY...
ESPECIALLY IN CENTRAL AND SOUTH WHERE CLOUDS SHOULD BE LIMITED FOR
MOST OF THE DAY.  THEREFORE HAVE GONE WITH WARMER MET/FWC GUIDANCE.
THE WARMING WILL ALSO HELP TO DESTABILIZE THE ATMOSPHERE BY MIDDAY
AS CAPES CLIMB OVER 1000 J/KG.  HOWEVER...SHEAR WILL REMAIN WEAK AS
WINDS NEVER REALLY PICK UP THROUGH THIS EVENING.  THEREFORE...
PARAMETERS NOT VERY FAVORABLE FOR SEVERE WEATHER WITH ISOLATED
REPORTS MOST PROBABLE.  SLOWER MOVEMENT OF STORMS MAY ALLOW SOME
RATHER RAPID RAINFALL ACCUMULATIONS IN A SHORT TIME AND WL MENTION
THIS POTENTIAL IN THE HWO.

FRONT MOVEMENT BECOMES MORE OF AN ISSUE IN TIME AS MODELS DIVERGE
WITH ETA REMAINING FASTER THAN GFS.  WL CONTINUE TREND OF PREVIOUS
FCST AND LEAN TOWARD THE SLOWER GFS SOLUTION WITH ONLY SLIGHT
MODIFICATIONS.  CHANCES FOR TSRA PROGRESS SOUTHEAST ACRS CWA TONIGHT
WITH LINGERING SHRA SOUTH ON WEDNESDAY.  THEREAFTER...PUSH OF DRIER
AND COOLER AIR WITH EASTERLY FLOW SETTING UP ACRS THE STATE.
EXTENDED FORECAST STILL IN DECENT SHAPE AS WESTERN TROF DEVELOPS BY
THIS WEEKEND.

.DSM...NONE

COGIL

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-181100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
545 AM CDT TUE JUN 17 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL MOVE ACROSS PORTIONS OF NORTHERN AND WESTERN IOWA
THIS MORNING AND EVENTUALLY SPREAD INTO CENTRAL IOWA BY THIS
AFTERNOON.  INSTABILITY IS EXPECTED TO INCREASE DURING THE DAY AS
TEMPERATURES CLIMB WELL INTO THE 80S.  HOWEVER...WIND SHEAR WILL
REMAIN WEAK...THEREFORE WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
ISOLATED SEVERE STORMS WILL BE POSSIBLE WITH MARGINALLY SEVERE
HAIL.  THE MAIN THREAT WILL COME FROM ISOLATED HEAVY RAIN WITH THE
STORMS TODAY AND TONIGHT AS THEY MOVE SLOWLY IN THE LIGHT WINDS OF
THE ATMOSPHERE.  ALTHOUGH WIDESPREAD HEAVY RAIN IS NOT
ANTICIPATED...THE STRONGEST STORMS MAY BE CAPABLE OF PRODUCING AND
INCH OR TWO OF RAIN WITHIN AN HOUR.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

CHANCES FOR THUNDERSTORMS WILL CONTINUE INTO WEDNESDAY FOR THE
SOUTHERN HALF OF CENTRAL IOWA.  NO SEVERE WEATHER IS EXPECTED AT
THIS TIME...HOWEVER THE THREAT OF ISOLATED HEAVY RAIN REMAINS.
THE NEXT CHANCE FOR THUNDERSTORMS IS EXPECTED ON SUNDAY AS A SYSTEM
APPROACHES THE MIDWEST.  AT THIS TIME...WIDESPREAD SEVERE WEATHER IS
NOT EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

&&

MORE INFORMATION CAN BE OBTAINED AT WWW.CRH.NOAA.GOV/DMX (ALL LOWER CASE).

COGIL