Severe Thunderstorm Warning 503, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
900 PM CDT SUN AUG 22 2004

.DISCUSSION...
HAVE ALREADY SENT OUT GRID AND ZONE UPDATE. TSTMS DEVELOPED SOUTH OF
COLD FRONT OVER NRN NE THIS EVENING. CONVERGENCE WAS NOT GREAT AND
WITH THE LOSS OF DAYTIME HEATING THEY WEAKENED AND DID NOT FORM EAST
ALONG THE FRONT INTO OUR CWA OVER NERN NE AND NW IA. AT 02Z BOUNDARY
IS HUNG UP ALONG THE SD-NE BORDER AND SHWRS/TSTMS CONTINUE OVER NRN
NE. DID LEAVE A LOW POP CHC OF TSTMS IN SRN PART OF CWA NEAR
BOUNDARY THIS EVENING. HOWEVER LOOKS LIKE BEST CHC OF ELEVATED TSTMS
WILL BE LATER TONIGHT...MAINLY AFTER MIDNIGHT AS UPPER WAVE MOVES UP
FROM SW PUSHING FRONTAL BOUNDARY BACK TO THE NORTH. CONSIDERABLE
HIGH LEVEL CLOUDS SPREADING SLOWLY NORTH FROM TSTMS OVER NEBRASKA
BUT OVERALL SHOULD BE PARTLY CLOUDY TONIGHT. EARLIER FORECAST LOWS
LOOK REASONABLE. TSTMS MOVING NE OUT OF CWA MONDAY MORNING AS WAVE
MOVES THRU...BUT TSTMS REDEVELOPING AGAIN IN THE WEST LATE AFTN AND
SPREADING OVER AREA WITH TROF AHEAD OF COLD FRONT.

&&

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

&&

WB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1136 AM CDT SUN AUG 22 2004

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-231200-
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-
1136 AM CDT SUN AUG 22 2004

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON AND
THIS EVENING OVER NORTHWEST IOWA ALONG A SLOW MOVING FRONTAL
BOUNDARY. AN ISOLATED SEVERE STORM IS POSSIBLE DUE TO SUFFICIENT
INSTABILITY AND SHEAR. LARGE HAIL AND DAMAGING WIND ARE THE MAIN
THREAT THIS EVENING. ADDITIONAL THUNDERSTORMS WILL DEVELOP OVER
CENTRAL SOUTH DAKOTA THIS EVENING AND WILL MOVE EAST INTO
SOUTHEAST SOUTH DAKOTA AND SOUTHWEST MINNESOTA AFTER MIDNIGHT.
ISOLATED SEVERE WEATHER IS POSSIBLE WITH THESE STORMS WITH LARGE
HAIL BEING THE MAIN THREAT AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ON MONDAY WEST OF
A BROOKINGS TO YANKTON LINE. ISOLATED THUNDERSTORMS MAY DEVELOP
LATE MONDAY AFTERNOON ALONG A TROUGH OF LOW PRESSURE FROM NEAR
HURON TO WAGNER. THESE THUNDERSTORMS ARE EXPECTED TO MOVE TO THE
NORTHEAST ON MONDAY NIGHT...INTO NORTHEAST SOUTH DAKOTA AND WEST
CENTRAL MINNESOTA. LARGE HAIL AND DAMAGING WIND WILL BE POSSIBLE
WITH THESE STORMS.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ON TUESDAY.
THUNDERSTORMS ARE ONCE AGAIN EXPECTED TO DEVELOP ALONG A TROUGH
OF LOW PRESSURE OVER SOUTHEAST SOUTH DAKOTA. THESE THUNDERSTORMS
WILL MOVE INTO SOUTHWEST MINNESOTA AND EXTREME NORTHWEST IOWA
DURING THE LATE EVENING. LARGE HAIL AND DAMAGING WIND WILL BE
POSSIBLE WITH THESE STORMS.

THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
THE REMAINDER OF THE WEEK. THE INTENSITY AND TIMING FORECAST OF
THESE THUNDERSTORMS WILL BE BETTER DEFINED IN LATER OUTLOOKS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE POSSIBLE AFTER 3 PM IN PARTS OF
NORTHWEST IOWA...AND AFTER MIDNIGHT ALONG AND NORTH OF A LINE
FROM WAGNER SD TO MARSHALL MN.

&&

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