Severe Thunderstorm Warning 157, NWS Des Moines, IA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1050 AM CDT WED JUL 26 2000

WILL UPDATE FORECAST TO REFLECT CURRENT TRENDS.  TSTMS NOW EXITING
CWA THO REDVLPMNT LKLY ASL HEATING TAKES PLACE.  LOOK AT LTST MSAS
SHOWS LI W CNTRL INTO CNTRL OF -4 TO -10 AMD GD THETA E ADVCTN.
MRNG UA SHOWS MORE S/W ON THE WAY IN MID AND HIER LVLS.  SVR WX NOT
OVER.

.DSM...NONE

FORSTER

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-271100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
610 AM CDT WED JUL 26 2000

HAZARDS--A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH PRIMARY
THREATS OF DAMAGING WINDS OF 65 MPH AND HAIL TO GOLF BALL SIZED.
THE THREAT OF AN ISOLATED TORNADO EXISTS...BUT IT REMAINS LOW.

AREA OF CONCERN--SOUTH AND EAST OF A LINE EXTENDING FROM BUFFALO
CENTER IN WINNEBAGO COUNTY TO SAC CITY IN SAC COUNTY.

TIMING DETAILS--BETWEEN 6 AM THIS MORNING AND AND 8 PM THIS EVENING

METEOROLOGICAL COMMENTS--A RATHER POTENT UPPER LEVEL WEATHER SYSTEM
OVER CENTRAL MINNESOTA WILL CONTINUE TO BE THE WEATHER MAKER FOR
THE AREA TODAY AND EARLY THIS EVENING. A COLD FRONT FROM WESTERN
WISCONSIN BACK INTO NORTHWEST IOWA WILL SLOWLY MOVE SOUTHEAST INTO
SOUTHEAST IOWA LATER TONIGHT. CAPE VALUES WERE AROUND 1500 JOULES
PER KILOGRAM THIS MORNING WITH MODERATE LOW TO MID LEVEL SHEAR. THE
SHEAR PROFILE WILL AID MID LEVEL ROTATION...HOWEVER THE INSTABILITY
WILL INHIBIT THE STRONG UPDRAFT NEEDED FOR LONG LIVED ORGANIZED
THUNDERSTORMS. IT APPEARS THE SEVERE WEATHER THREAT WILL BE LIMITED
TO HAIL UP TO GOLF BALL SIZE...AND POSSIBLE THUNDERSTORM OUTFLOW
WINDS TO AROUND 60 MPH. THE LOW LEVEL SHEAR IS ANTICIPATED TO WEAK
THIS AFTERNOON AS THE UPPER LOW MOVE BEGINS TO WEAKEN. INSTABILITY IS
EXPECTED TO INCREASE THIS AFTERNOON...HOWEVER WITH THE SHEAR
WEAKENING THE TREAT FOR SEVERE WEATHER WILL REMAIN SLIGHT.

PRECAUTIONS--BE PREPARED TO SEEK SHELTER INDOORS IF STORMS APPROACH
YOUR AREA.

SPOTTER ACTIONS--SPOTTER ACTIVATION MAY BE NEEDED THIS MORNING AND
THIS AFTERNOON IN THE AREA OF CONCERN. SKYWARN SPOTTER
GROUPS...EMERGENCY MANAGEMENT COORDINATORS AND LAW ENFORCEMENT
OFFICIALS SHOULD PAY ATTENTION TO SHORT TERM WEATHER FORECASTS AND
LATEST STATEMENTS FROM THE NATIONAL WEATHER SERVICE.

TC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
952 AM CDT WED JUL 26 2000

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

0640 AM    MELBOURNE                 IA   .75 INCH HAIL
07/26/00   MARSHALL                       EVENT DURATION 5
                                          MINUTES. REPORTED BY
                                          STORM SPOTTER.

0845 AM    AMES                      IA   .75 INCH HAIL
07/26/00   STORY                          REPORTED BY OFF-DUTY
                                          NWS EMPLOYEE.

0845 AM    AMES                      IA   1 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

0850 AM    AMES                      IA   .88 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

0850 AM    AMES                      IA   .75 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

0918 AM    HUXLEY                    IA   1 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

0920 AM    MARSHALLTOWN              IA   1.75 INCH HAIL
07/26/00   MARSHALL                       REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

0930 AM    MARSHALLTOWN              IA   1.25 INCH HAIL
07/26/00   MARSHALL                       REPORTED BY STORM
                                          SPOTTER.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1028 AM CDT WED JUL 26 2000

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

0950 AM    COLLINS                   IA   .75 INCH HAIL
07/26/00   STORY                          REPORTED BY MEDIA.
                                          KCCI-TV

1000 AM    MAXWELL                   IA   1.75 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

1005 AM    MAXWELL                   IA   .75 INCH HAIL
07/26/00   STORY                          REPORTED BY EMERGENCY
                      Q                    MANAGEMENT.

1007 AM    MAXWELL                   IA   1.75 INCH HAIL
07/26/00   STORY                          REPORTED BY STORM
                                          SPOTTER.

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-271100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1031 AM CDT WED JUL 26 2000

HAZARD--SEVERE THUNDERSTORMS WITH HAIL TO BASEBALL SIZE...DAMAGING
WINDS TO 70 MPH...AND ISOLATED TORNADOES.

AREA OF CONCERN--SOUTHEAST OF A MASON CITY TO CARROLL LINE...WITH
PRIMARY CONCERN ALONG AND SOUTH OF CARROLL...AMES AND MARSHALLTOWN.

TIMING DETAILS--FROM NOW THROUGH 8 PM...WITH NEW THUNDERSTORM
DEVELOPMENT IN CENTRAL AND SOUTHWEST IOWA AFTER 1 PM.

METEOROLOGICAL COMMENTS--THE POTENTIAL FOR SEVERE THUNDERSTORMS WITH
VERY LARGE HAIL EXISTS THIS AFTERNOON AND EARLY EVENING.  A COLD
FRONT FROM ESTHERVILLE TO JUST SOUTH OF SIOUX CITY WILL SLOWLY MOVE
SOUTHEAST TO NEAR WATERLOO...FORT DODGE AND OMAHA BY LATE
AFTERNOON.  OUTFLOW FROM THUNDERSTORMS THIS MORNING EAST CENTRAL
IOWA...WILL BE ANOTHER FOCUS FOR ADDITIONAL THUNDERSTORMS THIS
AFTERNOON.  MOISTURE AND INSTABILITY ARE INCREASING IN SOUTHWEST AND
WEST CENTRAL IOWA...AS VERY COLD AIR ALOFT MOVES SOUTH FROM AN
UPPER LEVEL SYSTEM IN MINNESOTA.  THIS SETUP HAS ALREADY PRODUCED
LARGE HAIL STORMS THIS MORNING IN CENTRAL AND EAST CENTRAL IOWA.
A STRONG DIRECTIONAL AND WIND SPEED SHEAR PROFILE EXISTS...WHICH
WILL FAVOR SUPERCELL THUNDERSTORMS THIS AFTERNOON.  IF THESE STORMS
FORM ALONG THE COLD FRONT OR OUTFLOW BOUNDARY...THERE IS AN
ENHANCED POTENTIAL FOR ISOLATED TORNADOES.

PRECAUTIONS--THOSE OUTDOORS SHOULD TAKE SHELTER INDOORS AS THE
STORMS APPROACH.  PAY ATTENTION TO FUTURE SHORT TERM FORECASTS AND
POSSIBLE WARNINGS THIS AFTERNOON.

SPOTTER ACTIONS--SKYWARN AND LAW ENFORCEMENT SPOTTER GROUPS SHOULD
PREPARE FOR ACTIVATION THIS AFTERNOON AND EARLY EVENING.

KULA