Severe Thunderstorm Warning 199, NWS Sioux Falls, SD

031 
WWUS53 KFSD 282037
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
337 PM CDT THU JUL 28 2011

IAC193-282047-
/O.EXP.KFSD.SV.W.0199.000000T0000Z-110728T2045Z/
WOODBURY IA-
337 PM CDT THU JUL 28 2011

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL WOODBURY COUNTY WILL
EXPIRE AT 345 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.

LAT...LON 4245 9580 4222 9581 4226 9626 4244 9625
TIME...MOT...LOC 2037Z 281DEG 15KT 4233 9602

$$

JM

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
300 PM CDT THU JUL 28 2011

.DISCUSSION...
MAIN AREA OF LIGHT RAINFALL ACROSS SOUTHEAST SOUTH DAKOTA IS
BEGINNING TO PUSH OFF TO THE EAST THIS AFTERNOON...AS UPPER LEVEL
SUPPORT SHIFTS NORTHEAST OF THE AREA. THESE SHOWERS WILL DISSIPATE
AS THEY LOSE LOW LEVEL SUPPORT...AND SHOULD NOT RESULT IN MUCH
ACCUMULATION. ADDITIONAL DEVELOPMENT IS BEGINNING IN AREAS OF BROKEN
CLOUD COVER ACROSS NORTH CENTRAL NEBRASKA...WHICH WILL START TO
SLIDE UP ALONG THE SOUTHERN BORDER OF THE FORECAST AREA THROUGH THE
AFTERNOON AND EVENING. EXPECT MOST OF THE SHOWER AND THUNDERSTORM
ACTIVITY TO FOCUS ALONG THE SOUTHERN EDGE OF THE THICKEST CIRRUS
SHIELD BY LATE AFTERNOON...WHICH ALSO COINCIDES WITH THE POSITION OF
A LOW LEVEL BOUNDARY ALONG THE MISSOURI RIVER VALLEY... INTO PARTS
OF NORTHWEST IOWA. WITH BREAKS IN THE CLOUD COVER BEGINNING TO
APPEAR ACROSS NORTHWEST IOWA...COULD SEE SOME INSTABILITY SHOWERS
POP UP OVER THE NEXT SEVERAL HOURS...WHICH WILL MELD INTO ANY
ONGOING PRECIPITATION ALONG THE FRONTAL BOUNDARY LATER THIS EVENING.
BY EARLY MORNING...THE BOUNDARY SHOULD SHIFT SOUTH OF THE FORECAST
AREA...TAKING ANY MEASURABLE PRECIPITATION OUT OF THE CWA. COULD SEE
SOME FOG DEVELOP UNDER BROAD SURFACE HIGH PRESSURE TONIGHT...AS
DEWPOINTS WILL REMAIN FAIRLY HIGH. /LAFLIN

HIGH PRESSURE SETTLES IN OVER THE FORECAST AREA ON FRIDAY...WITH
LIGHT WINDS EXPECTED THROUGH THE DAY.  COULD SEE SOME PATCHY FOG
EARLY IN THE DAY...PARTICULARLY ACROSS OUR EASTERN HALF...OTHERWISE
EXPECT SEASONAL TEMPERATURES IN THE 80S AND MOSTLY SUNNY SKIES.
SOUTHERLY WINDS INCREASE LATE FRIDAY WHICH WILL BEGIN TAPPING INTO
SOME MOISTURE AND BRING DEWPOINTS BACK INTO THE LOWER 70S FOR MUCH
OF THE AREA.

SOME WARM AIR ADVECTION WILL BOOST TEMPERATURES SLIGHTLY ON
SATURDAY...MAINLY IN THE JAMES RIVER VALLEY WHERE LOW TO MID 90S
WILL BE  POSSIBLE.  GENERALLY EXPECT MOSTLY SUNNY TO PARTLY CLOUDY
SKIES WITH ACCAS FORMING IN THE AFTERNOON HEAT.  MIGHT SEE A FEW
THUNDERSTORMS FORM ALONG AN ILL DEFINED COLD FRONT WHICH WILL SAG
ALONG OUR NORTHERN BORDER SATURDAY NIGHT.  WITH STRONG RIDGING IN
PLACE HOWEVER...FRONT MAY STRUGGLE TO REACH OUR FORECAST AREA...AND
THEREFORE HAVE KEPT THUNDERSTORM CHANCES LOW AND FOCUSED ACROSS THE
NORTH IN THE MEANTIME.  IF STORMS DO REACH THE CWA...STRONG
INSTABILITY AND MODERATE SHEAR COULD SPELL SOME POTENTIAL SEVERE
STORMS SATURDAY NIGHT.

STRONGER NORTHWARD PUSH OF THE RIDGE AND STRONG MOIST WARM AIR
ADVECTION WILL BRING TEMPERATURES NEAR THE CENTURY MARK ACROSS
CENTRAL SOUTH DAKOTA WITH THE 90S FORECAST AREA WIDE. DEWPOINTS ARE
EXPECTED TO BUILD INTO THE LOW TO MID 70S WHICH WILL COMBINE WITH
THE ABOVE NORMAL TEMPERATURES TO BRING HEAT INDICES INTO THE 100-110
RANGE ONCE AGAIN ON MONDAY. A LITTLE RELIEF ARRIVES ON TUESDAY WITH
THE HINT OF ANOTHER WEAK COLD FRONT SLIDING INTO THE FORECAST AREA.
WITH THE MAIN TROUGH OVER CENTRAL CANADA AND THE UPPER RIDGE HOLDING
STRONG...PRECIPITATION CHANCES APPEAR TO BE SLIM AND LIKELY FOCUSED
EAST OF I29.  FLOW TURNS MORE ZONAL FOR MID WEEK WITH SEASONAL
TEMPERATURES EXPECTED AND THE POTENTIAL FOR ISOLATED SCATTERED
THUNDERSTORMS WEDNESDAY AND THURSDAY AS A STALLED BOUNDARY SETS UP
IN THE REGION AND A FEW UPPER LEVEL WAVES PROVIDE SOME SUPPORT.

&&

.AVIATION...
SCATTERED LIGHT SHOWERS AND THUNDERSTORMS IN SOUTH CENTRAL SOUTH
DAKOTA WILL PUSH THROUGH SOUTHEAST SOUTH DAKOTA THIS AFTERNOON...
WITH THUNDERSTORM ACTIVITY EVENTUALLY BECOMING MORE FOCUSED ALONG A
LINE FROM KICR TO KSUX THIS EVENING...AND KSUX TO KSPW TONIGHT. MVFR
CONDITIONS FROM MODERATE RAIN AND WIND GUSTS OF 40 MPH WILL BE
POSSIBLE IN THUNDERSTORMS. SOME FOG MAY ALSO DEVELOP EARLY FRIDAY
MORNING WITH VERY LIGHT WINDS AND EXCESS LOW LEVEL MOISTURE. /LAFLIN

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
441 AM CDT THU JUL 28 2011

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-291200-
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-
441 AM CDT THU JUL 28 2011

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED THUNDERSTORMS ARE EXPECTED MUCH OF THE DAY SOUTHWEST OF
A LINE FROM HURON SOUTH DAKOTA TO JACKSON MINNESOTA. WHILE SEVERE
STORMS ARE NOT EXPECTED.  A FEW STORMS NEAR THE MISSOURI RIVER
MAY PRODUCE UP TO DIME SIZE HAIL AND WIND GUSTS TO 40 MPH DURING
THE AFTERNOON.

FLOODING...
MINOR FLOODING WILL CONTINUE ALONG LITTLE SIOUX RIVER THROUGH THE
END OF THE WEEK. MODERATE TO MAJOR FLOODING IS EXPECTED TO
CONTINUE ON THE JAMES RIVER UNTIL FURTHER NOTICE. HEAVY RAIN IN
THE BIG SIOUX BASIN WILL ALSO CAUSE MINOR FLOODING IN PORTIONS OF
LOWER BIG SIOUX RIVER LATER THIS WEEK.

HIGH RELEASES ALONG THE MISSOURI RIVER WILL CONTINUE INTO LATE
SUMMER. HIGH WATER LEVELS WILL CAUSE SIGNIFICANT IMPACTS BETWEEN
CHAMBERLAIN AND SIOUX CITY. THE HIGH FLOWS ON THE MISSOURI RIVER
WILL ALSO CAUSE FLOODING ON THE BIG SIOUX RIVER NEAR SIOUX CITY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

HOT AND HUMID CONDITIONS WILL RETURN ON SATURDAY. A HEAT INDEX
BETWEEN 100 AND 105 DEGREES WILL BE POSSIBLE SOUTHEAST OF A LINE
FROM HURON TO STORM LAKE. NORTHEAST OF THIS LINE...THERE WILL BE
A CHANCE OF THUNDERSTORMS SATURDAY NIGHT. A FEW OF THESE STORMS
COULD BE SEVERE.

TEMPERATURES IN THE 90S COMBINED WITH DEW POINTS OVER 70 DEGREES
ARE POSSIBLE SUNDAY THROUGH MONDAY. THIS COULD RESULT IN A HEAT
INDEX  FROM 100 TO 110 DEGREES BOTH DAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

&&

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

SCHUMACHER