Tornado Warning 6, NWS Des Moines, IA

IAZ004>007-015>017-023>028-033>039-044>049-057>062-070>075-081>086-
092>097-162100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1038 AM CDT SUN JUN 16 1996

HAZARD...THUNDERSTORMS WITH HEAVY RAINFALL OF 2 TO 3 INCHES AND
ISOLATED AMOUNTS UP TO 4 INCHES. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS PRODUCING HAIL UP TO DIME SIZE AND WIND GUSTS TO 60 MPH.

AREA OF CONCERN...ALL OF CENTRAL IOWA. THE THREAT OF BORDERLINE SEVERE
THUNDERSTORMS IS SOUTH OF HIGHWAY 30 AND WEST OF INTERSTATE 80.

TIMING DETAILS...SCATTERED THUNDERSTORMS WILL CONTINUE TO MOVE
NORTHEAST ACROSS IOWA THIS AFTERNOON AND TONIGHT. THE STRONGEST
DEVELOPMENT WILL BEGIN OVER SOUTHEAST NEBRASKA AFTER 200 PM AND THEN
MOVE ACROSS IOWA TONIGHT. THE THREAT OF SEVERE WEATHER IN SOUTHWEST
IOWA WILL END AFTER SUNSET...BUT THE HEAVY RAIN THREAT WILL CONTINUE
FOR MOST OF THE NIGHT.
                                                                     .
METEOROLOGICAL COMMENTS...A WARM CORE UPPER LOW CENTER WILL DRIFT FROM
CENTRAL NEBRASKA INTO IOWA TONIGHT. THIS SYSTEM HAS DRAWN MOISTURE
FROM THE TROPICAL CARIBBEAN SEA AND FUNNELED IT INTO IOWA. THIS
"TROPICAL CONNECTION" IS A NOTORIOUS HEAVY RAIN PRODUCER. WARM CORE
SYSTEMS ARE ALSO TROPICAL IN NATURE AND ALLOW EFFICIENT HEAVY RAIN
PRODUCTION. SATELLITE SHOWS SOME BREAKS IN THE CLOUD COVER OVER
SOUTHEAST NEBRASKA. THOSE BREAKS WILL DESTABILIZE THE ATMOSPHERE AND
CAUSE AN ORGANIZED AREA OF THUNDERSTORMS TO DEVELOP...WHICH WILL THEN
MOVE SLOWLY INTO IOWA TONIGHT. AS THESE STORMS MOVE INTO THE SOUTHWEST
BY LATE AFTERNOON...A COUPLE MAY BRIEFLY EXCEED SEVERE LEVELS....BUT
BECAUSE THE ATMOSPHERE IS SO SATURATED...WIDESPREAD SEVERE WEATHER IS
NOT LIKELY.

A FLASH FLOOD WATCH HAS BEEN ISSUED FOR SOUTHWEST IOWA THIS AFTERNOON
AND TONIGHT. IF THE STORMS MAINTAIN INTENSITY AND GET CAUGHT
UNDERNEATH THE WARM CORE LOW AS IT MOVES INTO IOWA TONIGHT...THIS
FLASH FLOOD WATCH MAY NEED TO BE EXPANDED.

PRECAUTIONS...THIS COULD BECOME A SERIOUS SITUATION IF THUNDERSTORMS
BEGIN TO TRAIN OR REDEVELOP REPEATEDLY OVER THE SAME AREAS. SPOTTER
ACTIVATION MAY BE NEEDED FOR A TIME IN SOUTHWEST IOWA DUE TO THE
ISOLATED SEVERE WEATHER THREAT..d.BUT THE PRIMARY CONCERN THROUGH
MONDAY MORNING WILL BE THE INCREASING THREAT OF FLOODING. STREAM
LEVELS AND LOW LYING AREAS SHOULD BE CLOSELY MONITORED.

PYTLAK

IAZ004>007-015>017-023>028-033>039-044>049-057>062-070>075-081>086-
092>097-162100-

CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRRECTION
NATIONAL WEATHER SERVICE DES MOINES IA
1038 AM CDT SUN JUN 16 1996

HAZARD...THUNDERSTORMS WITH HEAVY RAINFALL OF 2 TO 3 INCHES AND
ISOLATED AMOUNTS UP TO 4 INCHES. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS PRODUCING HAIL UP TO DIME SIZE AND WIND GUSTS TO 60 MPH.

AREA OF CONCERN...ALL OF CENTRAL IOWA. THE THREAT OF BORDERLINE SEVERE
THUNDERSTORMS IS SOUTH OF HIGHWAY 30 AND WEST OF INTERSTATE 35.

TIMING DETAILS...SCATTERED THUNDERSTORMS WILL CONTINUE TO MOVE
NORTHEAST ACROSS IOWA THIS AFTERNOON AND TONIGHT. THE STRONGEST
DEVELOPMENT WILL BEGIN OVER SOUTHEAST NEBRASKA AFTER 200 PM AND THEN
MOVE ACROSS IOWA TONIGHT. THE THREAT OF SEVERE WEATHER IN SOUTHWEST
IOWA WILL END AFTER SUNSET...BUT THE HEAVY RAIN THREAT WILL CONTINUE
FOR MOST OF THE NIGHT.
                                                                     .
METEOROLOGICAL COMMENTS...A WARM CORE UPPER LOW CENTER WILL DRIFT FROM
CENTRAL NEBRASKA INTO IOWA TONIGHT. THIS SYSTEM HAS DRAWN MOISTURE
FROM THE TROPICAL CARIBBEAN SEA AND FUNNELED IT INTO IOWA. THIS
"TROPICAL CONNECTION" IS A NOTORIOUS HEAVY RAIN PRODUCER. WARM CORE
SYSTEMS ARE ALSO TROPICAL IN NATURE AND ALLOW EFFICIENT HEAVY RAIN
PRODUCTION. SATELLITE SHOWS SOME BREAKS IN THE CLOUD COVER OVER
SOUTHEAST NEBRASKA. THOSE BREAKS WILL DESTABILIZE THE ATMOSPHERE AND
CAUSE AN ORGANIZED AREA OF THUNDERSTORMS TO DEVELOP...WHICH WILL THEN
MOVE SLOWLY INTO IOWA TONIGHT. AS THESE STORMS MOVE INTO THE SOUTHWEST
BY LATE AFTERNOON...A COUPLE MAY BRIEFLY EXCEED SEVERE LEVELS....BUT
BECAUSE THE ATMOSPHERE IS SO SATURATED...WIDESPREAD SEVERE WEATHER IS
NOT LIKELY.

A FLASH FLOOD WATCH HAS BEEN ISSUED FOR SOUTHWEST IOWA THIS AFTERNOON
AND TONIGHT. IF THE STORMS MAINTAIN INTENSITY AND GET CAUGHT
UNDERNEATH THE WARM CORE LOW AS IT MOVES INTO IOWA TONIGHT...THIS
FLASH FLOOD WATCH MAY NEED TO BE EXPANDED.

PRECAUTIONS...THIS COULD BECOME A SERIOUS SITUATION IF THUNDERSTORMS
BEGIN TO TRAIN OR REDEVELOP REPEATEDLY OVER THE SAME AREAS. SPOTTER
ACTIVATION MAY BE NEEDED FOR A TIME IN SOUTHWEST IOWA DUE TO THE
ISOLATED SEVERnE WEATHER THREAT...BUT THE PRIMARY CONCERN THROUGH
MONDAY MORNING WILL BE THE INCREASING THREAT OF FLOODING. STREAM
LEVELS AND LOW LYING AREAS SHOULD BE CLOSELY MONITORED.

PYTLAK
CORRECTION TO AREA OF CONCERN

IAZ004>007-015>017-023>028-033>039-044>049-057>062-070>075-081>086-
092>097-170000-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
315 PM CDT SUN JUN 16 1996

HAZARD...THUNDERSTORMS WITH HEAVY RAINFALL OF 2 TO 3 INCHES AND
ISOLATED AMOUNTS UP TO 5 INCHES. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS PRODUCING HAIL UP TO DIME SIZE AND WIND GUSTS TO 60 MPH.

AREA OF CONCERN...THE THREAT OF BORDERLINE SEVERE THUNDERSTORMS IS
SOUTH OF HIGHWAY 30 AND WEST OF INTERSTATE 35. THE THREAT OF HEAVY
RAIN EXISTS OVER ALL OF CENTRAL IOWA.

TIMING DETAILS...THE BORDERLINE SEVERE WEATHER THREAT WILL LAST UNTIL
SUNSET...WITH THE HEAVY RAINFALL THREAT CONTINUING THROUGH EARLY MONDAY
MORNING.
                                                    .
METEOROLOGICAL COMMENTS...THE ATMOSPHERE WAS PRIMED FOR A SIGNIFICANT
RAINFALL EVENT. TROPICAL MOISTURE CONTINUED TO FEED INTO IOWA WITH
SURFACE DEWPOINTS IN THE LOWER 70S. THE ATMOSPHERE HAS ALSO
DESTABILIZED THIS AFTERNOON DUE TO A LITTLE SUNSHINE. A STATIONARY
FRONT WILL REMAIN IN PLACE NEAR HIGHWAY 20...WHILE A COLD FRONT
ADVANCES SLOWLY EAST ACROSS THE STATE. BOTH OF THESE BOUNDARIES WILL
FOCUS THUNDERSTORM DEVELOPMENT TONIGHT...WITH THE HEAVIEST RAIN
EXPECTED NEAR THE INTERSECTION OF THE TWO BOUNDARIES. A FEW STORMS IN
THE SOUTHWEST COULD BRIEFLY EXCEED SEVERE LEVELS WHERE INSTABILITY
WILL BE GREATEST THROUGH SUNSET. HOWEVER...THIS THREAT WILL END AS THE
STORMS CONSOLIDATE INTO A THUNDERSTORM COMPLEX. BECAUSE ALMOST THE
ENTIRE DEPTH OF THE ATMOSPHERE WILL BE SATURATED TONIGHT...THE RISK
FOR HEAVY RAIN WILL BE MUCH HIGHER THAN THE RISK OF SEVERE WEATHER.

PRECAUTIONS...FLASH FLOOD WATCHES HAVE BEEN EXPANDED TO INCLUDE MOST OF
THE STATE TONIGHT. THE HEAVY RAINS EARLIER TODAY HAVE SATURATED THE
GROUND...AND THE ADDITIONAL RAIN WILL MAINLY RUN OFF INTO STREAMS AND
RIVERS. WATER SYSTEMS WILL HAVE TO BE MONITORED CLOSELY TONIGHT. LOCAL
LAW ENFORCEMENT IS STRO NGLY ENCOURAGED TO RELAY ANY REPORTS OF FLOODED
CREEKS OR ROADS TONIGHT AS THE HEAVY RAINS MOVE IN.

PYTLAK