Severe Thunderstorm Warning 177, NWS Sioux Falls, SD

000 
WWUS53 KFSD 312200
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
500 PM CDT THU AUG 31 2006

SDC067-312215-
/O.CON.KFSD.SV.W.0177.000000T0000Z-060831T2215Z/
HUTCHINSON SD-
500 PM CDT THU AUG 31 2006

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT 
FOR SOUTHERN HUTCHINSON COUNTY...

AT 500 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL. 
THIS STORM WAS LOCATED 5 MILES WEST OF OLIVET...OR ABOUT 31 MILES
NORTHWEST OF YANKTON...MOVING SOUTHEAST AT 5 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
   OLIVET AROUND 515 PM CDT...

THIS STORM WILL PRODUCE LARGE HAIL. GO INSIDE A STURDY BUILDING AND
STAY AWAY FROM WINDOWS.

LAT...LON 4332 9764 4331 9788 4319 9785 4320 9761

$$

CJ

000 
WWUS53 KFSD 312213
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
513 PM CDT THU AUG 31 2006

SDC067-312223-
/O.EXP.KFSD.SV.W.0177.000000T0000Z-060831T2215Z/
HUTCHINSON SD-
513 PM CDT THU AUG 31 2006

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN HUTCHINSON COUNTY 
EXPIRES AT 515 PM CDT...

THE STORM IS NO LONGER SEVERE.

LAT...LON 4332 9764 4331 9788 4319 9785 4320 9761

$$

CJ

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
345 PM CDT THU AUG 31 2006

.DISCUSSION...
INIT ACTVTY THIS EVE HAS PRBLMS MOVG EWD INTO MORE STABLE AMS...AND
IN FACT FOR THAT REASON THE FAR ERN OR AT LEAST THE FAR SERN PART OF
FCST AREA IN NWRN IA SHUD AVOIND PCPN TNGT. AS SFC/LO LVL BOUNDRY
TRIES TO MOVE EWD...WITH LIMITED SUCCESS...A FOCUS FOR A LTL BETTER
CVRG OF SHWRS AND TSTMS SHUD DVLP LATR TNGT FROM SSW TO NNE OVER
CNTRL PART OF FCST AREA. STILL...CVRG OF ACTVTY IS IN QSTN AND WILL
KEEP POPS AT 40 PCT TOPS TNGT. LESSER CHC TO WNW AND ESE IN FCST
AREA. INITIATG MECHANISM HARD TO FIND XCP FOR A LTL CURNT SEMI
HEALTHY ACTVTY SE OF MHE THAT SEEMS TO BE HELPED BY PERSISTENT WEDGE
OF CLR SKIES AND HEATG FROM PKS TO YKN. IN ANY EVENT SHUD BE NOTHING
TO BIG AND BAD TNGT. LOW TEMPS WITH CLD CVR AND DEWPTS WHERE THEY
ARE...SHUD BE A LTL ABV GUIDNCE TNGT.

THEN THE FORECAST BECOMES VERY CHALLENGING FOR FRIDAY INTO THE
WEEKEND.  CURRENT WATER VAPOR IMAGE SHOWS WELL THE NEXT SYSTEM TO
EFFECT OUR REGION...THAT BEING AN UPPER LEVEL TROUGH PRESENTLY
SWINGING INTO THE NORTHERN ROCKIES. THE NAM LOOKS TO BE THE OUTLIER
WITH REGARD TO THE HANDLING OF THIS SYSTEM...DIGGING THE TROUGH MUCH
DEEPER INTO THE NORTH CENTRAL U.S. THAN OTHER MODELS WITH A STRONGER
UPPER LEVEL JET FEEDING INTO THE BACKSIDE OF THE TROUGH.  IN
ADDITION...IT IS FASTER THAN THE OTHER MODELS IN PUSHING THE FEATURE
OUT FOR THE END OF THE WEEKEND.  IN LIGHT OF THIS...AND THE FACT
THAT IT SEEMED TO HAVE SOME INITIALIZATION PROBLEMS WITH REGARD TO
PLACEMENT OF CERTAIN SYNOPTIC FEATURES OVER THE NATION...I PRETTY
MUCH DISREGARDED THIS MODEL.  AT THE SAME TIME...THE GFS IS NOT
EXACTLY PERFECT EITHER...SEEMING TO WIND UP THE WEEKEND SYSTEM A
LITTLE TOO MUCH OVER OUR REGION.  WHAT THIS MEANS IS THAT I DID USE
THE GENERAL PLACEMENT AND TIMING OF THE GFS WITH REGARD TO THE
FEATURE...BUT BLENDED ELEMENTS FROM OTHER MODELS.

IN TERMS OF ACTUAL WEATHER...SURFACE BOUNDARY CURRENTLY LOCATED
THROUGH WEST CENTRAL SOUTH DAKOTA WILL BEGIN TO PUSH EASTWARD
THROUGH THE DAY ON FRIDAY...BRINGING SHOWERS AND SCATTERED
THUNDERSTORMS...MAINLY TO WESTERN AND CENTRAL AREAS DURING THE DAY.
SHOWERS WILL INCREASE OVER THE CWA ON FRIDAY NIGHT WITH THE APPROACH
OF THE UPPER TROUGH...AND HEAVIEST RAINFALL SHOULD OCCUR DURING THIS
TIME FRAME.  WITH THE UPPER LEVEL LOW LOCATED OVER OUR REGION
THROUGH THE WEEKEND...SCATTERED SHOWER ACTIVITY WILL CONTINUE
THROUGH THE PERIOD...BUT RAINFALL AMOUNTS ARE GOING TO BE DEPENDENT
ON TRACK AND INTENSITY OF THE LOW.  AS MENTIONED EARLIER...THE GFS
HAS A MUCH MORE WOUND UP SYSTEM OVER THE REGION...AND IF ITS
PLACEMENT WERE TO VERIFY...OUR AREA WOULD BE DRY SLOTTED LATER IN
THE DAY ON SATURDAY AND INTO SATURDAY NIGHT...WHICH WOULD OF COURSE
REDUCE OUR RAINFALL AMOUNTS.  THE NAM PROGS A MUCH MORE OPEN AND
SOUTHERLY TRACKING LOW...WITH A MORE GENERAL RAINFALL OVER THE
FA...AND PROGS WEEKEND QPF AMOUNTS IN EXCESS OF 2 INCHES THROUGH THE
EASTERN PORTIONS OF THE CWA.  BECAUSE OF ALL THE MODEL
UNCERTAINTIES...I DID NOT WANT TO FORECAST THE MUCH LOWER QPF
AMOUNTS PER THE GFS...SO WENT WITH MORE OF BLEND.  FIGURED THAT
WHILE THERE IS NO TROPICAL COMPONENT TO THE SYSTEM...WITH THE
SLOWNESS OF THE SYSTEM MOVING OUT OF THE REGION...WE COULD PICK UP
BETWEEN AN INCH TO TWO INCHES OF PRECIPITATION OVER A GOOD PORTION
OF THE CWA AFTER ALL IS SAID AND DONE ON SUNDAY NIGHT.

ALL THIS UNCERTAINTY WILL OF COURSE IMPACT TEMPERATURES...AS IT
COULD BE VERY COOL ON SATURDAY UNDER A NORTHERLY FLOW WITH CLOUDY
AND RAINY CONDITIONS...THOUGH IF WE WERE TO GET DRY SLOTTED IT WOULD
BE A LITTLE WARMER.  IN ANY EVENT...IT IS A PRETTY GOOD BET THAT
DAYTIME TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND.

UPPER LOW LOOKS TO PUSH INTO THE UPPER MISSISSIPPI VALLEY ON
MONDAY...WITH SHOWER ACTIVITY COMING TO AN END OVER OUR AREA.  THIS
WILL LEAD TO A DRIER PATTERN THROUGH THE MIDDLE OF NEXT WEEK WITH
TEMPERATURES WARMING SLIGHTLY THROUGH THE PERIOD.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

BW/JM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1116 AM CDT THU AUG 31 2006

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-011200-
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-
1116 AM CDT THU AUG 31 2006

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED THUNDERSTORMS WILL BE MAINLY NEAR AND WEST OF
INTERSTATE 29 THROUGH THIS AFTERNOON. THE THREAT OF THUNDERSTORMS
WILL SPREAD SLOWLY EAST TONIGHT...ALTHOUGH THE CHANCE IS STILL
FAIRLY SMALL TONIGHT AS FAR EAST AT THE WINDOM MINNESOTA TO STORM
LAKE IOWA AREA. SEVERE STORMS ARE NOT EXPECTED...ALTHOUGH SOME OF
THE STRONGER STORMS COULD PRODUCE SMALL HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SCATTERED THUNDERSTORMS WILL BE FOUND ACROSS THE AREA FRIDAY AND
FRIDAY NIGHT. THESE STORMS SHOULD BE BELOW SEVERE LIMITS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

&&

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

WILLIAMS