Severe Thunderstorm Warning 237, NWS Des Moines, IA

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-292100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1038 AM CDT MON JUN 29 1998

HAZARD--SCATTERED TO NUMEROUS THUNDERSTORMS...SOME PRODUCING SEVERE
WEATHER INCLUDING DAMAGING WINDS...LARGE HAIL AND TORNADOES.

AREA OF CONCERN AND TIMING DETAILS--WEST OF A WAVERLY--FORT DODGE--
CRESTON LINE THROUGH 200 PM...THEN SPREADING EAST THROUGHOUT THE REST
OF IOWA DURING THE MID TO LATE AFTERNOON.

METEOROLOGICAL COMMENTS--A FRONTAL BOUNDARY IS BECOMING MORE
ESTABLISHED FROM NEAR DECORAH TO NEAR SIOUX CITY TO A LOW PRESSURE
CENTER IN SOUTHWEST NEBRASKA.  ISOLATED SEVERE THUNDERSTORMS WERE
ALREADY DEVELOPING IN NORTHEAST NEBRASKA...WEST OF SIOUX CITY.
OTHER STORMS WERE EXPANDING OVER NORTH CENTRAL AND NORTHWEST IOWA
WHICH ARE EXPECTED TO INTENSIFY.  PLENTIFUL MOISTURE AND
INSTABILITY IS AVAILABLE FOR STRONG STORM UPDRAFTS.  STORM-
RELATIVE WIND SHEAR IS QUITE FAVORABLE FOR THE DEVELOPMENT AND
MAINTENANCE OF SUPERCELL THUNDERSTORMS WITH ROTATION...THUS THE
ISOLATED TORNADO THREAT.  AS TEMPERATURES HEAT UP OVER CENTRAL
IOWA...INSTABILITY WILL CONTINUE TO INCREASE WITH CAPE VALUES UP TO
5000 JOULES PER KILOGRAM.

PRECAUTIONS--SPOTTER GROUPS WILL LIKELY BE NEEDED THIS AFTERNOON.  A
SEVERE WEATHER WATCH IS BEING CONSIDERED FOR MUCH OF THE AREA OF
CONCERN ALSO IN THE NEXT 1 OR 2 HOURS.  KEEP ABREAST OF FURTHER
UPDATES AND PAY ATTENTION TO NWS SHORT TERM FORECASTS FOR ADDITIONAL
INFORMATION.

KULA

IAZ004>007-015>017-023>026-033>034-291930-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
125 PM CDT MON JUN 29 1998

THE FOLLOWING COUNTIES OF TORNADO WATCH NUMBER 699 HAVE BEEN
CLEARED FROM THE WATCH...

EMMET - KOSSUTH - WINNEBAGO - WORTH - PALO ALTO - HANCOCK - CERRO
GORDO - POCAHONTAS - HUMBOLDT - WRIGHT - FRANKLIN - SAC - AND CALHOUN.

THE REMAINDER OF THE WATCH REMAINS IN EFFECT UNTIL 500 PM.  IN ADDITION
TORNADO WATCH NUMBER 700 REMAINS IN EFFECT UNTIL 500 PM FOR THE REST
OF SOUTHERN AND EASTERN IOWA.

THUNDERSTORMS WILL CONTINUE OVER THE CLEARED COUNTIES...HOWEVER THE
THREAT OF SEVERE WEATHER HAS PASSED TO THE SOUTH.