Severe Thunderstorm Warning 182, NWS Des Moines, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
310 AM CDT TUE JUN 12 2001

FORECAST CHALLENGES WITH CAP AND THEREFORE EXTENT OF CONVECTION ACRS
CWA DURING THE NEXT 48 TO 60 HOURS.  CURRENTLY...CONVECTION RIDING
ALONG SFC BOUNDARY CONTINUES TO PRESS TO THE EAST WITH BEST LOW
LEVEL INFLOW.  ANOTHER AREA OF TSRA HAVE DEVELOPED ACRS SW NEBRASKA
WHERE LOW LEVEL CONVERGENCE HAS INCREASED ALONG FRONTAL BOUNDARY.
OTHERWISE...STRONG CAP HAS HELD ACRS THE SOUTHERN TWO-THIRDS OF THE
CWA TONIGHT WITH TEMPS IN THE MID TO UPPER 70S AND RATHER HIGH
DEWPOINTS.

STALLED BOUNDARY ACRS THE CWA WILL BEGIN TO MOVE NORTH DURING THE
DAY WITH INCREASING WAA.  MODELS INDICATE THAT CONVECTION WL ONCE
AGAIN FIRE ACRS N IA ON THE EDGE OF THE CAP DURING THE DAY AS LOW
LEVEL FLOW BACKS.  ANY SUNSHINE THIS MORNING WL LEAD TO RAPID
DESTABILIZATION AND SEVERE CONVECTION REMAINS A DISTINCT
POSSIBILITY.  FARTHER SOUTH...CAP SHOULD HOLD IN THE WARM SECTOR WITH
WARM TEMPS INTO THE 90S AGAIN.

STATE TO BE IN WARM SECTOR OVERNIGHT WITH ONLY CHANCE OF CONVECTION
IN THE NORTH WITH CAP HOLDING ELSEWHERE.  LOWS TO REMAIN QUITE WARM
WITH READINGS IN THE 70S.  NEXT CHANCE FOR PCPN SHOULD COME LATER ON
WEDNESDAY AS COOLER MID LEVEL TEMPS MOVE INTO IA WITH UPPER LOW
PULLING INTO NORTHERN PLAINS.  EXPECT TEMPS TO BE NEAR 90 WITH
HUMID CONDITIONS CONTINUING.  FRONTAL BOUNDARY MOVES SLOWLY ACRS ON
WEDNESDAY NIGHT WITH CONVECTION BECOMING MORE LIKELY.  NO CHANGES TO
EXTENDED AT THIS TIME.

.DSM...NONE

COGIL

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
555 AM CDT TUE JUN 12 2001

A STALLED FRONT EXTENDED FROM SOUTHWEST INTO NORTHEAST IOWA EARLY
THIS MORNING.  THIS FRONT WILL BEGIN TO MOVE NORTH TODAY AS WARM AND
MOIST AIR SURGES NORTHWARD ACROSS IOWA.  INSTABILITY SHOULD ONCE
AGAIN BE HIGH WITH TEMPERATURES APPROACHING 90 AND DEWPOINTS AROUND
70.  A CAP IS EXPECTED TO BE IN PLACE ACROSS SOUTHERN IOWA AND
SHOULD INHIBIT CONVECTION SOUTH OF HIGHWAY 92.  FARTHER NORTH...THE
CAP WEAKENS WITH THE DEVELOPMENT OF CONVECTION REMAINING POSSIBLE
THROUGHOUT THE DAY.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>006-015-016-023-024-033-034-131100-
CALHOUN-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO
ALTO-POCAHONTAS-SAC-WINNEBAGO-
INCLUDING THE CITIES OF...ALGONA AND ESTHERVILLE
517 AM CDT TUE JUN 12 2001

* EVENT TIMING...  10 AM THROUGH 10 PM

* THREAT CATEGORIES...
     TORNADO.......... LOW
     DAMAGING WINDS... MODERATE
     LARGE HAIL....... MODERATE
     FLASH FLOODING... MODERATE

* SPOTTER ACTIVATION OUTLOOK... MODERATE

* MISCELLANEOUS INFORMATION - THERE MAY BE A PERIOD OF THUNDERSTORMS
LATE THIS MORNING AS THUNDERSTORMS MOVE EAST OUT OF NEBRASKA.  THEN
ANOTHER ROUND OF THUNDERSTORMS COULD DEVELOP LATER THIS AFTERNOON AS
A WARM FRONT PUSHES THROUGH NORTHERN IOWA.

IAZ007-017-025>028-035>039-044>050-057>062-131100-
AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CARROLL-CERRO
GORDO-CRAWFORD-DALLAS-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HARDIN-
JASPER-MARSHALL-POLK-POWESHIEK-STORY-TAMA-WEBSTER-WORTH-WRIGHT-
INCLUDING THE CITIES OF...AMES...BOONE...CARROLL...DENISON...DES
MOINES...FORT DODGE...GRINNELL...IOWA FALLS...MARSHALLTOWN...MASON
CITY...NEWTON...PERRY...WATERLOO...WAVERLY AND WEBSTER CITY
517 AM CDT TUE JUN 12 2001

* EVENT TIMING... THROUGH 9 AM AND THEN AGAIN FROM 2 PM TO 10 PM.

* THREAT CATEGORIES...
     TORNADO.......... NONE
     DAMAGING WINDS... LOW
     LARGE HAIL....... MODERATE
     FLASH FLOODING... LOW

* SPOTTER ACTIVATION OUTLOOK... LOW

* MISCELLANEOUS INFORMATION - THUNDERSTORMS ACTIVITY IS MOST LIKELY
THROUGH MID MORNING THEN AGAIN THIS AFTERNOON.

IAZ070>075-081>086-092>097-131100-
ADAIR-ADAMS-APPANOOSE-CASS-CLARKE-DAVIS-DECATUR-LUCAS-MADISON-
MAHASKA-MARION-MONROE-RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN-WAYNE-
INCLUDING THE CITIES OF...ATLANTIC...CENTERVILLE...CHARITON...
CRESTON...INDIANOLA...KNOXVILLE...LAMONI...OSKALOOSA...OTTUMWA AND
PELLA
517 AM CDT TUE JUN 12 2001

* EVENT TIMING... 2 PM THROUGH 10 PM

* THREAT CATEGORIES...
     TORNADO.......... NONE
     DAMAGING WINDS... LOW
     LARGE HAIL....... LOW
     FLASH FLOODING... NONE

* SPOTTER ACTIVATION OUTLOOK... LOW

* MISCELLANEOUS INFORMATION - THE ATMOSPHERE SHOULD REMAIN CAPPED
OVER SOUTHERN IOWA...THEREFORE THUNDERSTORM ACTIVITY IS NOT EXPECTED.

-------------------------------------------------------------------

THREAT KEY:
    TORNADO.......... ANY TORNADO OCCURRENCE
    DAMAGING WINDS... WINDS >= 58 MPH
    LARGE HAIL....... HAIL >= 3/4 INCH DIAMETER
    FLASH FLOODING... FLOODING CAUSED BY HEAVY RAINS WITHIN 6 HOURS
                      OF RAIN EVENT. POSES THREAT TO LIFE OR
                      PROPERTY.

THREAT CATEGORY KEY:  PROBABILITY OF THREAT OCCURRING WITHIN 25
                      MILES OF POINT WITHIN FORECAST AREA
    NONE....... NOT EXPECTED.  LESS THAN 5% ( 2% FOR TORNADOES)
    LOW........ 5-15% (2-15% FOR TORNADOES)
    MODERATE... 25-35%
    HIGH....... 45% OR GREATER

SPOTTER ACTIVATION OUTLOOK KEY:
    NOT EXPECTED
    LOW........ ACTIVATION POSSIBLE BUT NOT LIKELY
    MODERATE... POSSIBILITIES ABOUT 50-50
    HIGH....... ACTIVATION LIKELY

FOR MORE INFORMATION ON PROBABILISTIC SEVERE WEATHER OUTLOOKS...GO
TO THE STORM PREDICTION CENTKER WEBSITE AT
WWW.SPC.NOAA.GOV/PRODUCTS/OUTLOOK/PROBINFO.HTML .

COGIL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
601 AM CDT TUE JUN 12 2001

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0534 AM    1 S MARSHALLTOWN          IA   .75 INCH HAIL
06/12/01   MARSHALL                       REPORTED BY STORM
                                          SPOTTER.

0555 AM    MARSHALLTOWN              IA   .75 INCH HAIL
06/12/01   MARSHALL                       REPORTED BY STORM
                                          SPOTTER.