Severe Thunderstorm Warning 246, NWS Des Moines, IA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1010 PM CDT SAT JUN 16 2001

WILL UPDATE FORECAST TO REFLECT BETTER TIMING OF TSTM DVLPMNT
OVRENIGHT AND LOCATION.  WITH FOCUS OF LLJ AND LKLY ELEVATED PCPN
SRN TWO TIERS OF COUNTIES IN LINE FOR DVLPMNT AFTER MIDNIGHT WITH
PSBL HVY RAINS AS HI MOISTURE PLUME CONCENTRATES IA/MO BORDER. LTST
RUC APPEARS TO HAVE BEST HANDLE ON OVRNGT DYNAMICS.  UPPER TEMPS
ABIT NI THE SOUTH WITH CLDS CVR AND INCRSG DWPOINTS.

.DSM...NONE

FORSTER

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1010 PM CDT SAT JUN 16 2001

A SURFACE WARM FRONT OVER NORTHERN MISSOURI...ALONG WITH DECENT WIND
CONVERGENCE ALONG THE FRONT...WILL ALLOW FOR CONTINUED THUNDERSTORM
DEVELOPMENT INTO SOUTHERN IOWA OVERNIGHT. ALSO AN INCREASING LOW
LEVEL JET OF AIR MOVING NORTH ACROSS KANSAS AND MISSOURI WILL PUMP
MOISTURE INTO THESE THUNDERSTORMS. THE COMBINATION OF THE FRONTAL
FORCING AND AVAILABLE MOISTURE COULD PRODUCE SOME ISOLATED HEAVY
RAINS WHICH MAY LEAD TO FLASH FLOODING. IN ADDITION TO THE
POSSIBILITY OF HEAVY RAINS...WIND SHEAR AND COOL AIR ALOFT WILL
PROVIDE THE NECESSARY INGREDIENTS FOR THE DEVELOPMENT OF ISOLATED
LARGE HAIL.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ081>086-092>097-171100-
ADAMS-APPANOOSE-CLARKE-DAVIS-DECATUR-LUCAS-MONROE-RINGGOLD-TAYLOR-
UNION-WAPELLO-WAYNE-
INCLUDING THE CITIES OF...CENTERVILLE...CHARITON...CRESTON...LAMONI
AND OTTUMWA
952 PM CDT SAT JUN 16 2001

* EVENT TIMING...NOW THROUGH 6 AM

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

* SPOTTER ACTIVATION OUTLOOK...LOW

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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 CENTER WEBSITE AT
WWW.SPC.NOAA.GOV/PRODUCTS/OUTLOOK/PROBINFO.HTML .

KNOLLHOFF