Severe Thunderstorm Warning 197, NWS Sioux Falls, SD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
300 PM CDT MON AUG 7 2000

GENERALLY USED A BLEND OF THE NGM AND META FOR THIS FORECAST.  LOTS
OF PARAMETERS POINTING TO THUNDERSTORMS ACROSS THE CWA TONIGHT WITH
SEVERE STORMS EXPECTED. MESO SCALE FEATURES WILL ULTIMATELY
DETERMINE THE WORST OF THE SEVERE WEATHER...BUT FOCUS SHOULD BE
ALONG THE WARM FRONT FROM CENTRAL SD TO THE SOUTHWESTERN MN BORDER.
WILL INCLUDE MENTION OF SEVERE STORMS IN THE ZONES...EXCEPT FOR THE
SIOUX CITY AND ADJACENT IA CWA COUNTIES WHERE THE POPS WILL BE KEPT
A BIT LOWER WITH BEST ACTION TO THE NORTH OF THEM.  FOR NOW I WILL
NOT INCLUDE ANY POPS FOR THE FAR EASTERN CWA TUESDAY MORNING...BUT
DEPENDING ON THE SPEED OF THE SHORTWAVE THERE MAY BE SOME LINGERING
SHOWERS.  OTHERWISE...THE CWA WILL BE DRY TUESDAY AND WEDNESDAY.  NO
LARGE DEPARTURES FROM THE FWC TEMPERATURES.

MOST OF THE EXTENDED PERIOD WILL BE DRY. I DROPPED THE EARLIER
MENTION OF A CHANCE OF THUNDERSTORMS IN SD FOR FRIDAY AS THE AREA
WILL STILL BE CAPPED WITH THE H5 RIDGE. FOR NOW I WILL INCLUDE A
CHANCE OF THUNDERSTORMS IN THE WESTERN CWA FOR FRIDAY NIGHT AND
SATURDAY.  I WENT A FEW DEGREES WARMER THEN THE FMR GUIDANCE FOR MAX
TEMPERATURES.

.FSD...NONE
  UMLAND

SIGNIFICANT WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1115 AM CDT MON AUG 7 2000

*** THIS SIGNIFICANT WEATHER OUTLOOK FROM THE NATIONAL WEATHER SERVICE
PERTAINS ONLY TO CONDITIONS ASSOCIATED WITH THUNDERSTORMS. ***

.SYNOPSIS...EXPECT A RAPID EVOLUTION INTO A SIGNIFICANT SEVERE
WEATHER THREAT SITUATION TONIGHT ACROSS PORTIONS OF THE TRI STATE
AREA.  THE FOCUS FOR THE MOST SIGNIFICANT WEATHER WILL BE A SURFACE
WARM FRONT WHICH WILL LIFT INTO EAST CENTRAL SOUTH DAKOTA AND
SOUTHWEST MINNESOTA THIS AFTERNOON.  THE PRESENCE OF ELEVATED
THUNDERSTORMS ACROSS THE REGION LATE THIS MORNING REVEALS THE
ATMOSPHERE IS ALREADY CHARACTERIZED BY A STEEP MID LEVEL LAPSE RATE.
LOW LEVEL MOISTURE WILL POOL THROUGH THE AFTERNOON ALONG THE SURFACE
BOUNDARY...INCREASING THE POTENTIAL INSTABILITY AS TEMPERATURES HEAT
INTO THE LOWER TO MID 90S SOUTH OF THIS BOUNDARY. LIFT IS EXPECTED TO
INCREASE LATE THIS AFTERNOON AND EVENING AHEAD OF A SHARP UPPER LEVEL
IMPULSE MOVING OUT OF WYOMING AND MONTANA. SCATTERED STORMS SHOULD
FIRST DEVELOP OUT IN WESTERN AND CENTRAL SOUTH DAKOTA THIS
AFTERNOON...WITH A FEW ALSO ALONG THE WARM FRONT THIS EVENING.
INITIAL STORM TYPE APPREAS FAVORED FOR SUPERCELLULAR...WITH THE MAIN
TORNADIC THREAT FOCUSED IN THE EVENING ALONG THE LOCATION OF THE WARM
FRONT.  AT THE EVENING PROGRESSES...THUNDERSTORMS SHOULD EVOLVE INTO
A ORGANIZED CONVECTIVE SYSTEM ALONG AND NORTH OF THE FRONTAL BOUNDARY
...AND WITH THE ABUNDANCE OF DRY AIR AVAILABLE OFF THE SURFACE...
EXPECT A LIKELIHOOD OF WIDESPREAD DAMAGING WINDS...ESPECIALLY ACROSS
SOUTHWEST MINNESOTA AND ADJACENT AREAS.

SDZ050-057>059-063-064-080500-
AURORA-BRULE-CHARLES MIX-DAVISON-DOUGLAS-GREGORY-
INCLUDING THE CITIES OF...CHAMBERLAIN...MITCHELL
1115 AM CDT MON AUG 7 2000

* FORECAST THROUGH MIDNIGHT:
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS SHOULD PERSIST THIS
AFTEROON...BUT EXPECT MORE SIGNIFICANT STORMS TO DEVELOP TOWARD
EVENING..AND END BEFORE MIDNIGHT.

* SIGNIFICANT WEATHER:
  SEVERE WINDS...GUSTS EQUAL TO OR GREATER THAN 58 MPH.

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION MAY BE NEEDED AFTER 4 PM CDT.

SDZ038-039-052>055-080500-
BEADLE-JERAULD-KINGSBURY-LAKE-MINER-SANBORN-
INCLUDING THE CITIES OF...HURON
1115 AM CDT MON AUG 7 2000

* FORECAST THROUGH MIDNIGHT:
WIDELY SCATTERED ELEVATED SHOWERS AND THUNDERSTORMS WILL ROAM SKIES
THIS AFTERNOON...BUT MORE SIGNIFICANT THUNDERSTORMS SHOULD ERUPT
AROUND DINNERTIME.

* SIGNIFICANT WEATHER:
  SEVERE WINDS...GUSTS EQUAL TO OR GREATER THAN 58 MPH.
  LARGE HAIL...DIME SIZE OR LARGER.
  TORNADOES POSSIBLE.

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION MAY BE NEEDED AFTER 5PM CDT.

SDZ040-056-MNZ071-072-080-081-089-090-097-IAZ003-080500-
BROOKINGS-MOODY-COTTONWOOD-JACKSON-LINCOLN MN-LYON MN-MURRAY-NOBLES-
PIPESTONE-DICKINSON-
INCLUDING THE CITIES OF...BROOKINGS...PIPESTONE...SLAYTON...
WORTHINGTON...SPIRIT LAKE
1115 AM CDT MON AUG 7 2000

* FORECAST THROUGH MIDNIGHT:
WIDELY SCATTERED ELEVATED SHOWERS AND THUNDERSTORMS WILL DEVELOP
DURING THE AFTERNOON HOURS.  HOWEVER...WIDELY SCATTERED SEVERE
CONVECTION MAY SPARK THIS EVENING ALONG A FRONTAL BOUNDARY...WITH
STORMS FEATURING A SUPERCELLULAR STRUCTURE...AND THREAT OF HAIL
OR TORNADOES.  THERE IS A HIGH LIKELIHOOD OF A ORGANIZED AND
SIGNIFICANT CONVECTIVE SYSTEM MOVING IN FROM THE WEST DURING THE
LATER EVENING HOURS...WHICH MAY THEN PRODUCE MORE WIDESPREAD DAMAGING
WINDS.

* SIGNIFICANT WEATHER:
  SEVERE WINDS...GUSTS EQUAL TO OR GREATER THAN 58 MPH.
  SMALL HAIL...PEA TO MARBLE SIZE.
  TORNADOES POSSIBLE.

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION IS LIKELY AFTER 6PM CDT.

SDZ060>062-066-067-MNZ098-IAZ001-002-012>014-021-022-080500-
HANSON-LINCOLN-MC COOK-MINNEHAHA-TURNER-ROCK-BUENA VISTA-CHEROKEE-
CLAY IA-LYON IA-O'BRIEN-OSCEOLA-SIOUX-
INCLUDING THE CITIES OF...SIOUX FALLS...LUVERNE...ROCK RAPIDS...
SIOUX CENTER...SPENCER...STORM LAKE
1115 AM CDT MON AUG 7 2000

* FORECAST THROUGH MIDNIGHT:
WIDELY SCATTERED HIGH BASED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE THIS AFTERNOON...BUT A MORE SIGNIFICANT THUNDERSTORM THREAT
WILL OCCUR FROM MID EVENING THROUGH SHORTLY AFTER MIDNIGHT.

* SIGNIFICANT WEATHER:
  SEVERE WINDS...GUSTS EQUAL TO OR GREATER THAN 58 MPH.
  LARGE HAIL...DIME SIZE OR LARGER.
  TORNADOES POSSIBLE.

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION MAY BE NEEDED AFTER 6PM CDT.

SDZ065-068>071-IAZ020-031-032-NEZ013-014-080500-
BON HOMME-CLAY-HUTCHINSON-UNION-YANKTON-IDA-PLYMOUTH-WOODBURY-DAKOTA-
DIXON-
INCLUDING THE CITIES OF...YANKTON...LE MARS...SIOUX CITY
1115 AM CDT MON AUG 7 2000

* FORECAST THROUGH MIDNIGHT:
SCATTERED THUNDERSTORMS WILL DEVELOP DURING THE EVENING HOURS.

* SIGNIFICANT WEATHER:
  SEVERE WINDS...GUSTS EQUAL TO OR GREATER THAN 58 MPH.
  SMALL HAIL...PEA TO MARBLE SIZE.

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION MAY BE NEEDED AFTER 7PM CDT.

CHAPMAN