Flash Flood Warning 4, NWS Sioux Falls, SD

000 
WGUS73 KFSD 042326
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
625 PM CDT WED JUN 4 2008

SDC135-042335-
/O.EXP.KFSD.FF.W.0004.000000T0000Z-080604T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
YANKTON SD-
625 PM CDT WED JUN 4 2008

...THE FLASH FLOOD WARNING WILL EXPIRE AT 630 PM CDT FOR SOUTHERN
YANKTON COUNTY...

LIGHT SHOWERS WILL CONTINUE THROUGH 8 PM IN THE YANKTON COUNTY 
AREA...BUT ADDITIONAL RAINFALL TOTALS ARE EXPECTED TO BE ONE QUARTER 
OF AN INCH OR LESS. NO FURTHER FLASH FLOODING IS EXPECTED.

LAT...LON 4282 9723 4285 9724 4286 9731 4286 9741
      4284 9745 4286 9753 4284 9759 4286 9764
      4290 9764 4292 9752 4299 9751 4299 9717
      4279 9717
TIME...MOT...LOC 2325Z 270DEG 14KT 4287 9692

$$

MG

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1059AM CDT WED JUN 4 2008

.DISCUSSION...
VERY ACTIVE 36 HOURS COMING UP AS A POTENT UPPER LEVEL WAVE DIVES
INTO THE FOUR CORNERS REGION TODAY. FOR TODAY...PRECIPITATION SHOULD
CLEAR OUT OF MOST AREAS...BUT WITH WEAK UPPER LEVEL SUPPORT AND A
MOIST PROFILE...CANNOT RULE OUT ADDITIONAL SHOWERS AND ISOLATED
THUNDERSTORMS THROUGHOUT THE DAY. IN FACT...SOME OF THIS UPPER LEVEL
SUPPORT MOVING ONTO THE WESTERN HIGH PLAINS AND COULD SEE SOME OF
THIS PRECIPITATION MOVE INTO THE WESTERN CWA THIS AFTERNOON. WILL
TAKE OUT THREAT OF TORNADOES/LAND SPOUTS FOR THIS AFTERNOON AND
EVENING WITH THE LACK OF A DECENT BOUNDARY AND LACK OF
HEATING...ESPECIALLY NOW THAT THE CLOUD COVER IN THE WEST IS
EXPANDING PRETTY RAPIDLY.

OTHERWISE...HEADING INTO TONIGHT...PRETTY GOOD CHANCE THAT A FLOOD
WATCH WILL NEED TO BE ISSUED FOR MOST OF SOUTHEAST SOUTH DAKOTA AS
MODELS CONTINUE TO CONVERGE ON A SOLUTION THAT BRINGS HEAVY RAIN
INTO CENTRAL/SOUTHEAST SOUTH DAKOTA TONIGHT INTO THURSDAY
MORNING...WITH ADDITIONAL DEVELOPMENT LIKELY ON THURSDAY AFTERNOON
AND EVENING. SEVERE THREAT TONIGHT PRETTY MUCH JUST HAIL AND MAINLY
LATE. BETTER CHANCES FOR SEVERE SHOULD BE SOUTH OF THE CWA.

08

&&

AVIATION...
SHOULD REMAIN PRETTY MUCH LOW END MVFR TO OCCASIONAL IFR IN FOG
AND THUNDERSTORMS FOR THE NEXT 24 TO 36 HOURS.

&&

.PREV DISCUSSION...
ADVECTION SHOWERS WITH EMBEDDED THUNDER SPREADING EWRD EARLY THIS
MORNING. LOOKS LIKE MUCH OF THE CWA SHOULD BE ABLE TO SQUEEZE OUT
MEASURABLE PRECIP. SHOULD DRY OUT FOR A TIME LATER THIS MORNING
INTO THE EARLY AFTERNOON AS BEST MID LEVEL FORCING SLIDES EAST OF
THE AREA...HOWEVER CONVOLUTED MOIST WRLY FLOW MAKES IT HARD TO
COMPLETELY DISCOUNT SHOWERS ANYWHERE DURING THE REMAINDER OF THE
DAY. NOT ANTICIPATING MUCH IN THE WAY OF SUNSHINE TODAY AS SFC
HEATING WOULD MOSTLY BE SELF DESTRUCTIVE PROVIDED THE ABUNDANCE OF
SFC MOISTURE...WITH THE EXCEPTION POSSIBLY IN THE WEST.

SEVERE THUNDERSTORM THREAT NON EXISTENT THROUGH THE EARLY
AFTERNOON...BUT MAY HAVE TO WATCH WRN AREAS LATER THIS AFTERNOON
AND EARLY EVENING. MOISTURE AND TEMPERATURE ADVECTION IN THE LOWEST
LEVELS AND SOME OF DRYING IN THE 700 TO 500 MB LAYER SHOULD
DESTABILIZE THE ATMOSPHERE ENOUGH BY LATE AFTERNOON FOR THUNDERSTORM
DEVELOPMENT...ESPECIALLY IN PLACES WHICH DO SEE A BIT OF SUNSHINE.
SHOULD TIMING BE RIGHT WITH S/WV PASSAGE...ENHANCEMENT OF CONVECTION
CAN BE EXPECTED. NAM AND GFS DIFFER ON THE EXTENT OF CAPE WITH THE
GFS YIELDING MORE ROBUST MU CAPE VALUES THIS AFTERNOON...ALTHOUGH ML
CAPES ARE SOMEWHAT SIMILAR IN THE 800 TO 1400 J/KG RANGE BY 00Z THIS
EVENING IN THE JAMES VALLEY WEST. DEEP LAYER DIRECTION SHEAR DOES
SUPPORT THE POTENTIAL FOR SUPERCELL THUNDERSTORMS IN THESE AREA LATE
TODAY INTO EARLY EVENING...HOWEVER BUFKIT SOUNDINGS INDICATED TALL
SKINNY CAPE...WHICH DOES NOT SUPPORT VIGOROUS UPDRAFTS. SO...MAINLY
THINKING MARGINAL SEVERE STORMS POSSIBLE WITH THE POTENTIAL FOR HAIL
IN THE LOW END SEVERE RANGE. ONE OTHER THING TO WATCH WILL BE THE
POTENTIAL FOR LANDSPOUTS WITH THESE STORMS. PROGGED 2 KM VGP VALUES
IN THE .1 TO .4 RANGE AND LAPSE RATES AROUND 7 DEG/KM. SHOULD THERE
BE ENOUGH SURFACE HEATING...WHICH REMAINS A QUESTION AT THIS
TIME...THEN A FEW LANDSPOUTS ARE CERTAINLY A POSSIBILITY.

BETTER CHANCES FOR SEVERE THUNDERSTORM WILL BE LATER TONIGHT AND
THEN AGAIN LATE THU AFTERNOON INTO THU EVENING. STRONG ELEVATED WARM
FRONT WILL MOVE NORTH ACROSS THE CWA AFTER MIDNIGHT TONIGHT.
THUNDERSTORMS ARE ANTICIPATED TO DEVELOP ALONG THIS FRONT WITH SOME
STORMS LIKELY BECOMING SEVERE. MAIN SEVERE THREAT WITH THESE
ELEVATED STORMS WILL HAIL TO THE SIZE OF GOLF BALLS...AND POSSIBLY
LARGER. THESE STORM SHOULD MOVE FROM THE SRN CWA AROUND
MIDNIGHT...TO THE NRN EXTEND OF THE CWA TOWARDS SUNRISE. THEN
GENERALLY SHOULD SEE A BREAK IN THE THUNDERSTORM ACTIVITY LATER IN
THE MORNING AND INTO MID AFTERNOON. SET UP FOR LATE THU
AFTERNOON/EVENING IS A POTENTIALLY VOLATILE ONE. SEVERE THREAT WILL
LARGELY DEPEND ON PLACEMENT OF UPPER TROUGH AND SFC WARM FRONT.
MODELS HAVING DIFFERENT IDEAS ON PLACEMENT AND TIMING BUT LIKELY
THERE WILL BE HIGH THREAT OF SEVERE WX ALONG AND EAST OF I29 AND
POSSIBLY AS FAR WEST AS THE WRN CWA BORDER. VERY LARGE
HAIL...DAMAGING WIND GUSTS...AND STRONG TORNADOES WILL BE POSSIBLE.
THE MAIN TORNADO THREAT WILL BE ALONG THE SFC WARM FRONT...WHICH AT
THIS TIME IS EXPECTED TO BE DRAPED ACROSS SE SD AND SW MN. WILL ALSO
HAVE TO MONITOR THE FLOOD POTENTIAL WITH THUNDERSTORMS TONIGHT AND
AGAIN TOMORROW.

THINGS DRY OUT ON FRIDAY AND STRONG COLD FRONT PUSHES EAST OF THE
AREA. MODELS HAVE SHIFTED UPPER LOW FARTHER NORTH...SO LOWER THE
CHANCES FOR POP FRI MORNING. RESIDUAL MOISTURE AND COOLER
TEMPERATURES ALOFT...COULD SEE SOME SHOWERS/ISOLATED THUNDERSTORMS
LATE IN THE DAY FRI. OTHERWISE OVERALL WET WX PATTERN TO CONTINUE
INTO THE FORESEEABLE FUTURE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

LIEBL/RYRHOLM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1128 AM CDT WED JUN 04 2008

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-051200-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA-
CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE-
DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON-
IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN-
LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN-
OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN-
SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON-
1128 AM CDT WED JUN 04 2008

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
RAIN AND THUNDERSTORMS ARE EXPECTED TO REDEVELOP OVER NEBRASKA
AND SOUTHERN SOUTH DAKOTA TONIGHT AND LIFT NORTHWARD. SOME OF THE
STORMS WILL BE CAPABLE OF PRODUCING HAIL TO THE SIZE OF
QUARTERS...ESPECIALLY LATE.

FLOODING...
THE LITTLE SIOUX RIVER FROM AROUND SPENCER TO LINN GROVE IS
EXPECTED TO CREST AT OR JUST SLIGHTLY ABOVE FLOOD STAGE BY LATE
THIS WEEK.

MINOR TO MODERATE FLOODING IS EXPECTED ALONG PORTIONS OF THE
VERMILLION RIVER THE NEXT FEW DAY. RAINS FROM THUNDERSTORMS ARE
EXPECTED OVER THE NEXT FEW DAYS...WHICH COULD BE CAUSE FOR
CONTINUED OR ADDITIONAL FLOODING.

HEAVY RAIN WILL MOVE INTO SOUTHERN SOUTH DAKOTA TONIGHT AND
CONTINUE INTO TUESDAY MORNING. RAINFALL AMOUNTS OF 1 TO 3 INCHES
WILL BE POSSIBLE...ESPECIALLY ALONG AND WEST OF THE JAMES RIVER
VALLEY. THIS COULD CREATE SOME LOCALIZED FLASH FLOODING ISSUES AS
WELL AS INCREASE THE THREAT OF ADDITIONAL FLOODING ON
CREEKS...STREAMS AND RIVERS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

HEAVY RAIN AND SEVERE THUNDERSTORMS WILL AGAIN BE POSSIBLE
THURSDAY AFTERNOON AND NIGHT. THE BEST CHANCE FOR SEVERE
THUNDERSTORMS SHOULD BE SOUTH AND EAST OF A BROOKINGS TO YANKTON
LINE WITH GOLF BALL SIZED HAIL...WIND GUSTS TO 70 MPH AND STRONG
TORNADOES ALL THREATS. HEAVY RAIN WILL ALSO BE A THREAT TO THE
WEST OF THIS LINE WITH AN ADDITIONAL ONE TO TWO INCHES OF RAIN
LIKELY ACROSS MUCH OF THE AREA THROUGH LATE THURSDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.
SPOTTER ACTIVATION WILL BE POSSIBLE AFTER
SPOTTER ACTIVATION WILL BE LIKELY AFTER

&&

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