Severe Thunderstorm Warning 46, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
205 PM CDT MON JUN 16 2003

...CONVECTIVE CHANCES THROUGH THE PERIOD ARE THE MAIN CONCERN...

SYNOPSIS...12Z SUBJECTIVE UPPER AIR ANALYSIS INDICATED MAIN BRANCH
OF THE POLAR JET ACROSS SRN CANADA. SVRL SHRTWVS WERE VISIBLE ACROSS
THE CONUS AT H5. THE FIRST WAS OVR SE WY/SW SD WITH THE NEXT
UPSTREAM SHRTWV OVR CNTRL MT. STRNG SHRTWV WERE MOVING INTO SRN CA
AND PAC NW. CDFNT AT H85 WAS LOCATED FM NRN MN SWWD INTO THE NEB
PANHANDLE. ATMO ACROSS THE NRN PLAINS CONT TO MOISTEN UP WITH H85
DPS OF +10. LATEST OBJECTIVE SFC ANAL INDICATED SVRL OUTFLOW
BOUNDARIES FM ONGOING AND NOCTURNAL CONVECTION ACROSS THE NRN
PLAINS. KFSD/KUNR/KABR 88-D RADARS ARE INDICATING TRW DVLPNG ALONG
SVRL OF THESE BOUNDARIES.

FORECAST...ATMOSPHERE ACROSS THE CWA HAS CONT TO MOISTEN UP THIS
AFTERNOON WITH SFC DPS IN THE LOWER/MID 60S. LATEST LAPS DATA
INDICATE SBCAPE AROUND 1500-2500 J/GK WITH WK CIN. WK CONVERGENCE
AXIS FM KSUX TO KMML WILL CONT TO FIRE SCT TRW INTO EARLY EVENING
HOURS BEFORE WEAKENING WITH SUNSET. OUTFLOW BOUNDARY FM KATY TO KHON
TO K9V9 WL ALSO BE A FOCUS FOR TRW DVLPMNT. ADDITIONAL ACTIVITY IS
ALSO DVLPNG WITH WRN SD/SRN ND WITH ASSOCIATED WY/SD SHRTWV. WITH H6
TO SFC THETA-E DIFF OF >20 C AND WEB BULB HEIGHTS AROUND 10 K...AN
ISO SVR STORM IS POSSIBLE THIS EVENING. ALSO WITH VRY SLOW STORM
MOVEMENT...VERY LOCALIZED HEAVY RAIN POSSIBLE WRN CWA AND ALONG LINE
FM KSUX TO KMML AND IN WRN CWA WITH PWATS OF 1.5 INCHES. WL GO WITH
LIKELY POPS WRN CWA TONIGHT WHERE SUSTAINED CONVERGENCE ALONG MAIN
SYNOPTIC BOUNDARY MAY CONT ACTIVITY INTO THE NIGHT. MDL DIFFS CONT
WITH SPEED OF CDFNT INTO WED AND WL GENERALLY FOLLOW THE GFS WITH
THE VRY WK UPPR LVL FLOW. ANY TRW ONGOING AT THE BEGINNING OF WED WL
QUICKLY DISSIPATE...BUT WE ARE EXPECTING REDEVELOPMENT BY EARLY
AFTERNOON AGAIN WITH HEATING OF THE DAY AND FRONTAL BOUNDARY IN THE
AREA. AGAIN...NOTHING ORGANIZED BY ISO HEAVY RAIN/SVR STORM
POSSIBLE. WL CARRY POPS THRU THE NIGHT IN THE SRN CWA. THURS/FRI
CONT TO LOOK DRY.

EXTENDED...MEDIUM RANGE MDLS CONT TO BRING IN SIG HEIGHT FALLS TO
THE WRN CONUS BY LATE IN THE WEEK. THIS SHLD START STRNG WAA BY SAT
AND SOME ACCUS TRW NOT OUT OF THE QUESTION...BUT WL NOT INCLUDE IN
THE FORECAST AT THIS TIME DUE TO UNCERTAINTY. AS STRNG LO PRES DVLPS
OVR WRN HI PLAINS SIG MOISTURE RETURN EXPECTED BY LATE SAT
AFTERNOON. GFS NOW SLOWER WITH THE FRONT...AND BRINGS IT INTO THE
CWA SUN AFTERNOON. GIVEN THE SHEAR INSTABILITY AND UPPER
SYSTEM...SVR WX SEEMS POSSIBLE. FRONT FINALLY CLEARS CWA BY MON AND
WL GO WITH A DRY FORECAST. WL GO ABOVE MEX GUIDANCE FOR HIGHS MORE
ALONG WITH H85 TMPS.

.FSD...NONE

BOUSTEAD

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-IAZ001>003-
012>014-020>022-031-032-NEZ013-014-171200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
127 PM CDT MON JUN 16 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 THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS
AFTERNOON INTO EARLY THIS EVENING WEST OF THE JAMES RIVER...AND
OVER NORTHWEST IOWA AND SOUTHWEST MINNESOTA.  SOME OF THESE
THUNDERSTORMS COULD PRODUCE STRONG WIND GUSTS UP TO 45
MPH...ALONG WITH LOCALLY VERY HEAVY RAIN.  THERE IS A SLIGHT
CHANCE THAT THUNDERSTORMS COULD DEVELOP THIS AFTERNOON BETWEEN
THESE AREAS...OVER THE REMAINDER OF SOUTHEAST SOUTH DAKOTA.

WHILE THE ACTIVITY IN NORTHWEST IOWA SHOULD DIMINISH TOWARD
SUNSET... ANY THUNDERSTORMS ALONG AND WEST OF THE JAMES VALLEY
WILL LIKELY CONTINUE INTO THE OVERNIGHT HOURS.	THE CHANCE FOR
THUNDERSTORMS WILL ALSO SPREAD INTO THE BROOKINGS AND MARSHALL
AREAS AFTER MIDNIGHT TONIGHT. THE CHANCE FOR SEVERE WEATHER WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING...BUT LOCALLY HEAVY
RAIN IS STILL POSSIBLE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A CHANCE OF THUNDERSTORMS WILL SPREAD EAST OVER SOUTHEAST SOUTH
DAKOTA...SOUTHWEST MINNESOTA...NORTHWEST IOWA AND EXTREME
NORTHEAST NEBRASKA ON TUESDAY. THE THUNDERSTORMS WILL THEN BE
ENDING FROM THE NORTHWEST TUESDAY NIGHT. BY WEDNESDAY ONLY A
SMALL PART OF FAR SOUTHEAST SOUTH DAKOTA...NORTHWEST IOWA AND
EXTREME NORTHEAST NEBRASKA WILL HAVE A SLIGHT CHANCE OF
THUNDERSTORMS. NO SEVERE WEATHER IS EXPECTED AT THIS TIME WITH
THE THUNDERSTORMS.

.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.