Severe Thunderstorm Warning 53, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1030 AM CDT SAT JUN 21 2003

GOING FORECAST...INCLUDING GRIDS...IN GOOD SHAPE.  WELL DEFINED
SHORT WAVE ROTATING NORTHEAST OUT OF NEBRASKA THIS MORNING WILL
PRODUCE SCATTERED SHOWERS AND A FEW TSTRMS ACROSS CWA THROUGH MID
AFTERNOON.  THIS DEPICTED QUITE WELL ON LATEST MESOETA RUN.
SHORTWAVE PASSING THRU AT DIURNALLY A POOR TIME FOR CONVECTION SO
SEVERE THREAT MINIMAL.  ABUNDANT MID CLDS MAY TEMPER AFTERNOON
HEATING...BUT STILL EXPECT TO REACH FORECASTED HIGHS LATER IN DAY AS
SHORTWAVE PASSES AND SKIES BEGIN TO CLEAR.  AIRMASS BECOMES QUITE
UNSTABLE BY LATE AFTERNOON WEST OF THE JAMES RIVER...AND THIS
ALSO PRIME AREA FOR POOLING OF LOW LEVEL MOISTURE IN ADVANCE OF
APPROACHING FRONT.  DEW PTS ALREADY IN MID 60S ACROSS WESTERN
PORTION OF CWA.  THIS SHOULD BE THE FOCUS AREA FOR EARLY EVENING
THUNDERSTORM DEVELOPMENT AS NEXT UPPER LEVEL DISTURBANCES
APPROACHES.  SOME STORMS MAY BE SEVERE OVER WESTERN PART OF CWA THIS
EVENING WITH HIGH CAPE AND INSTABILITY.  GOING HWO COVERS THIS WELL
AND WILL CONTINUE THEME IN LATE MORNING UPDATE.   ONCE
GENERATED...STORMS SHOULD CROSS CWA OVERNIGHT...WITH RISK OF SEVERE
WX SPREADING EAST.  SEVERE WX THREAT AGAIN SUNDAY WITH ANOTHER
SHORTWAVE...FRONTAL BOUNDARY...AND UNSTABLE AIRMASS IN THE AREA.

.FSD...NONE

HARMON

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-IAZ001>003-
012>014-020>022-031-032-NEZ013-014-221200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1101 AM CDT SAT JUN 21 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA...
SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CROSS THE AREA
THROUGH MID TO LATE AFTERNOON.	ONLY BRIEF PERIODS OF LIGHT TO
MODERATE RAIN WILL OCCUR WITH THIS ACTIVITY AND SEVERE WEATHER IS
NOT EXPECTED THROUGH 5 PM.

THUNDERSTORMS ARE EXPECTED TO REDEVELOP EARLY THIS
EVENING...ALONG AND WEST OF THE JAMES RIVER VALLEY...INCLUDING
THE HURON...MITCHELL AND CHAMBERLAIN AREAS.  LARGE HAIL AND
ISOLATED TORNADOES WILL BE POSSIBLE WITH THE STRONGER STORMS.

THIS ACTIVITY WILL SPREAD EAST OVER THE REMAINDER OF SOUTHEAST
SOUTH DAKOTA...INTO SOUTHWEST MINNESOTA AND NORTHWEST IOWA
OVERNIGHT.  THE THREAT OF SEVERE WEATHER SHOULD DIMINISH
OVERNIGHT AS THE STORMS MOVE EAST...HOWEVER LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED THUNDERSTORMS MAY LINGER OVER PARTS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA INTO SUNDAY MORNING.  AFTER THIS
ACTIVITY DECREASES... AND AS TEMPERATURES CLIMB THROUGH THE
DAY...THUNDERSTORMS ARE AGAIN EXPECTED TO REDEVELOP BY LATE
SUNDAY AFTERNOON.

EXACT TIMING AND LOCATION OF REDEVELOPMENT IS DIFFICULT TO
PINPOINT...AS IT WILL LARGELY DEPEND ON THE EXTENT OF
THUNDERSTORMS EARLIER IN THE DAY.  HOWEVER AT THIS TIME THERE
APPEARS TO BE A MODERATE RISK OF WIDESPREAD SEVERE WEATHER SUNDAY
AFTERNOON AND EVENING...ESPECIALLY OVER NORTHWEST IOWA AND
EXTREME NORTHEAST NEBRASKA...INTO PARTS OF SOUTHWEST MINNESOTA
AND SOUTHEAST SOUTH DAKOTA.  TORNADOES AND LARGE HAIL WILL BE
POSSIBLE SUNDAY AFTERNOON AND EVENING...WITH THE PRIMARY SEVERE
WEATHER THREAT TRANSITIONING TO DAMAGING WINDS AND HEAVY RAIN
DURING THE OVERNIGHT HOURS.

THE THREAT FOR SEVERE WEATHER AND HEAVY RAIN WILL CONTINUE INTO
MONDAY AND MONDAY NIGHT...AS NUMEROUS LOW LEVEL BOUNDARIES
RESULTING FROM THE WEEKEND THUNDERSTORM ACTIVITY ARE EXPECTED TO
PERSIST OVER THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED ALONG AND WEST OF THE JAMES
RIVER THIS EVENING.

&&

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

 HARMON