Flash Flood Warning 17, NWS Des Moines, IA

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-240300-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
525 PM CDT TUE JUN 23 1998

HAZARD--SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS...LARGE HAIL AND EXCESSIVE RAINFALL RATES.  ISOLATED SUPERCELLS
CAPABLE OF PRODUCING A FEW TORNADOES ARE NOT OUT OF THE QUESTION.

AREA OF CONCERN AND TIMING DETAILS--NORTH OF INTERSTATE 80 AND WEST
OF INTERSTATE 35 BETWEEN 700 PM AND 1100 PM.  NORTH OF INTERSTATE 80
AND EAST OF INTERSTATE 35 AFTER 900 PM.

METEOROLOGICAL COMMENTS--PARTIAL SUNSHINE ACROSS IOWA THIS AFTERNOON
HAS LED TO AN INCREASINGLY UNSTABLE ATMOSPHERE ACROSS THE STATE.
ABUNDANT LOW LEVEL MOISTURE HAS BEEN STREAMING NORTHWARD INTO IOWA
AND SURROUNDING STATES ON SOUTHERLY WINDS OF 20 TO 30 MPH IN KANSAS
AND MISSOURI.  MEANWHILE...TWO WARM FRONTS WILL HELP TO PROVIDE ZONES
OF CONVERGENCE AND LIFT FOR THUNDERSTORM INITIATION THIS EVENING AS
AN UPPER LEVEL DISTURBANCE MOVES INTO THE AREA FROM WESTERN NEBRASKA.
THE FIRST WARM FRONT...EXTENDING FROM SOUTHEAST SOUTH DAKOTA INTO
WISCONSIN WILL PROBABLY BE WHERE MOST THUNDERSTORMS WILL BEGIN.
MEANWHILE...A SECOND WARM FRONT EXTENDING FROM SOUTHEAST NEBRASKA
INTO EXTREME SOUTHERN IOWA WILL SERVE AS THE SOUTHERN EXTENT OF
THUNDERSTORM ACTIVITY SINCE THE AIR ABOVE AND SOUTH OF THIS FRONT IS
TOO WARM TO ALLOW CONVECTION TO SUSTAIN ITSELF.  SO...THUNDERSTORMS
ARE EXPECTED TO BEGIN LATER THIS EVENING IN NORTHEAST NEBRASKA AND
SOUTHEAST SOUTH DAKOTA...AND MOVE NEARLY DUE EAST AT 20 TO 30 MPH.
SOME OF THE STORMS WILL BE SEVERE AND CAPABLE OF PRODUCING VERY HEAVY
RAIN OVER REPEATED AREAS LATER THIS EVENING AND INTO THE OVERNIGHT
HOURS.

PRECAUTIONS--SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS EVENING
INTO THE NIGHTTIME HOURS.  NOT ONLY IS SEVERE WEATHER POSSIBLE WITH
THESE STORMS...BUT HEAVY...FLOODING RAINFALL COULD ALSO OCCUR DUE TO
THEIR RELATIVELY SLOW AND REPEATED MOVEMENT OVER THE SAME AREA.
ADDITIONALLY...RECENT RAINS HAVE KEPT THE SOIL NEARLY SATURATED AND
RIVERS RUNNING ABOVE NORMAL.  A FLASH FLOOD WATCH IS IN EFFECT FOR
MUCH OF NORTHERN AND NORTHEAST IOWA TONIGHT. KEEP ABREAST OF THE
LATEST FORECASTS AND OTHER STATEMENTS THIS EVENING.

SEARCY

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-240300-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
525 PM CDT TUE JUN 23 1998

HAZARD--SCATTERED SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS...LARGE HAIL AND EXCESSIVE RAINFALL RATES.  ISOLATED SUPERCELLS
CAPABLE OF PRODUCING A FEW TORNADOES ARE NOT OUT OF THE QUESTION.

AREA OF CONCERN AND TIMING DETAILS--NORTH OF INTERSTATE 80 AND WEST
OF INTERSTATE 35 BETWEEN 700 PM AND 1100 PM.  NORTH OF INTERSTATE 80
AND EAST OF INTERSTATE 35 AFTER 900 PM.

METEOROLOGICAL COMMENTS--PARTIAL SUNSHINE ACROSS IOWA THIS AFTERNOON
HAS LED TO AN INCREASINGLY UNSTABLE ATMOSPHERE ACROSS THE STATE.
ABUNDANT LOW LEVEL MOISTURE HAS BEEN STREAMING NORTHWARD INTO IOWA
AND SURROUNDING STATES ON SOUTHERLY WINDS OF 20 TO 30 MPH IN KANSAS
AND MISSOURI.  MEANWHILE...TWO WARM FRONTS WILL HELP TO PROVIDE ZONES
OF CONVERGENCE AND LIFT FOR THUNDERSTORM INITIATION THIS EVENING AS
AN UPPER LEVEL DISTURBANCE MOVES INTO THE AREA FROM WESTERN NEBRASKA.
THE FIRST WARM FRONT...EXTENDING FROM SOUTHEAST SOUTH DAKOTA INTO
WISCONSIN WILL PROBABLY BE WHERE MOST THUNDERSTORMS WILL BEGIN.
MEANWHILE...A SECOND WARM FRONT EXTENDING FROM SOUTHEAST NEBRASKA
INTO EXTREME SOUTHERN IOWA WILL SERVE AS THE SOUTHERN EXTENT OF
THUNDERSTORM ACTIVITY SINCE THE AIR ABOVE AND SOUTH OF THIS FRONT IS
TOO WARM TO ALLOW CONVECTION TO SUSTAIN ITSELF.  SO...THUNDERSTORMS
ARE EXPECTED TO BEGIN LATER THIS EVENING IN NORTHEAST NEBRASKA AND
SOUTHEAST SOUTH DAKOTA...AND MOVE NEARLY DUE EAST AT 20 TO 30 MPH.
SOME OF THE STORMS WILL BE SEVERE AND CAPABLE OF PRODUCING VERY HEAVY
RAIN OVER REPEATED AREAS LATER THIS EVENING AND INTO THE OVERNIGHT
HOURS.

PRECAUTIONS--SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS EVENING
INTO THE NIGHTTIME HOURS.  NOT ONLY IS SEVERE WEATHER POSSIBLE WITH
THESE STORMS...BUT HEAVY...FLOODING RAINFALL COULD ALSO OCCUR DUE TO
THEIR RELATIVELY SLOW AND REPEATED MOVEMENT OVER THE SAME AREA.
ADDITIONALLY...RECENT RAINS HAVE KEPT THE SOIL NEARLY SATURATED AND
RIVERS RUNNING ABOVE NORMAL.  A FLASH FLOOD WATCH IS IN EFFECT FOR
MUCH OF NORTHERN AND NORTHEAST IOWA TONIGHT. KEEP ABREAST OF THE
LATEST FORECASTS AND OTHER STATEMENTS THIS EVENING.

SEARCY