Severe Thunderstorm Warning 123, NWS Aberdeen, SD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
942 PM CDT MON JUL 25 2011

.UPDATE...
LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY WEST OF THE MISSOURI
RIVER WILL CONTINUE TO PUSH EASTWARD THROUGH THE OVERNIGHT HOURS.
HAVE MADE SOME ADJUSTMENTS TO POPS TO ACCOUNT FOR THE TRACK AND
TIMING. DOES NOT LOOK LIKE THERE WILL BE MUCH IN THE WAY OF SEVERE
WEATHER...BUT CANNOT RULE OUT SOME SMALL HAIL AND WINDS GUSTS UP
TO 40 MPH OR SO. OTHERWISE...NO CHANGES MADE TO THE CURRENT
FORECAST. NEW AVIATION DISCUSSION BELOW.

&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
ISOLATED THUNDERSTORMS HAVE FORMED IN HIGH CAPE/UNIDIRECTIONAL
SHEAR ENVIRONMENT ACROSS THE SOUTHEASTERN CWA. SO FAR...STORMS
HAVE SUCCUMBED TO A COMBINATION OF LACK OF FORCING AND DRY
ENVIRONMENT ALOFT...THOUGH ORGANIZATION/INTENSIFICATION STILL
POSSIBLE ALONG A STALLED FRONT PARALLEL TO HIGHWAY 212. H7
TEMPERATURES ARE ABOUT 2C WARMER IN THE WESTERN CWA...SO
ADDITIONAL UPSTREAM STORM ENVIRONMENT WILL BECOME MORE FAVORABLE
LATER THIS AFTERNOON. LOSS OF DAYTIME HEATING WILL KILL OFF ANY
CONVECTION PRIOR TO LOW LEVEL JET DEVELOPMENT AS SUPPORT ALOFT
REMAINS WELL WEST OF THE CWA.

50KT LOW LEVEL JET FORCING IN PHASE WITH H7/H5 TROFS WILL SUPPORT
CONVECTION ACROSS THE WESTERN DAKOTAS TONIGHT...TRACKING INTO
MISSOURI VALLEY COUNTIES BY TUESDAY MORNING. UPPER LEVEL WINDS OF
50 TO 60KTS SUGGEST STORM MOTION/DECREASED PRECIPITATION
EFFICIENCY WILL LIMIT HEAVY RAIN THREAT.

FOCUS THEN SHIFTS TOWARDS TUESDAY AFTERNOON. WITH H7/H5 TROF OVER
THE CENTRAL DAKOTAS...WILL SEE HIGH CAPE/HIGH SHEAR ENVIRONMENT
SET UP ACROSS THE EASTERN HALF OF THE STATE. LINCHPIN FOR SEVERE
THREAT RESTS ON IMPACT OF NOCTURNAL CONVECTION ON THE PRE STORM
ENVIRONMENT. THIS ALSO ADDS UNCERTAINTY TO HIGH TEMPERATURE
FORECAST...WITH THE COMBINED HEAT/HUMIDITY PUSHING HEAT ADVISORY
THRESHOLD FOR A FEW HOURS IN THE AFTERNOON.

FOR THE REMAINDER OF THE FORECAST PERIOD...SOUTHWEST FLOW ALOFT
WITH WEAKLY EMBEDDED WAVES WILL RESULT IN CONTINUED LOW POPS AS
WELL AS TEMPERATURES CLOSE TO CLIMO.

.LONG TERM...THURSDAY THROUGH MONDAY
MOST OF THE EXTENDED PORTION OF THE FORECAST WILL BE DOMINATED BY
ZONAL FLOW ACROSS THE NORTHERN CONUS. AS USUALLY WITH ZONAL
FLOW...SEVERAL HARD TO TIME SHORT WAVES WILL TRACK OVER THE
REGION WITH EACH ONE BRINGING AT LEAST A SLIGHT CHANCE FOR
THUNDERSTORMS. BECAUSE OF TIMING ISSUES AMONG MODELS WILL ONLY
MAKE SLIGHT ADJUSTMENTS TO THE PREVIOUS FORECAST AND HPC GUIDANCE.
MODELS ARE SHOWING INCREASING HEIGHTS TOWARD THE TAIL END OF THE
PERIOD WHICH SHOULD RESULT IN ABOVE NORMAL TEMPERATURES FOR THE
WEEKEND.

&&

.AVIATION...
TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

A LINE OF SHOWERS AND THUNDERSTORMS WILL TRACK FROM WEST OF THE
MISSOURI RIVER ACROSS THE REST OF THE CWA THROUGH THE OVERNIGHT
HOURS. BRIEF PERIODS OF IFR/MVFR CONDITIONS WILL OCCUR WITH THE
THUNDERSTORMS. OTHERWISE...VFR CONDITIONS UNDER HIGH CLOUDS AOA
15K FEET WILL PREVAIL.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

UPDATE...PARKIN
SHORT TERM...CONNELLY
LONG TERM...SD
AVIATION...PARKIN

WEATHER.GOV/ABERDEEN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
408 AM CDT MON JUL 25 2011

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-260915-
TRAVERSE-BIG STONE-CORSON-CAMPBELL-MCPHERSON-BROWN-MARSHALL-
ROBERTS-WALWORTH-EDMUNDS-DAY-DEWEY-POTTER-FAULK-SPINK-CLARK-
CODINGTON-GRANT-HAMLIN-DEUEL-STANLEY-SULLY-HUGHES-HYDE-HAND-JONES-
LYMAN-BUFFALO-
408 AM CDT MON JUL 25 2011 /308 AM MDT MON JUL 25 2011/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MINNESOTA...CENTRAL SOUTH DAKOTA...NORTH CENTRAL SOUTH DAKOTA AND
NORTHEAST SOUTH DAKOTA.

.DAY ONE...TONIGHT

THUNDERSTORMS ARE POSSIBLE OVERNIGHT TONIGHT...MAINLY ALONG AND
WEST OF THE MISSOURI RIVER. A FEW STORMS COULD BECOME SEVERE AND
PRODUCE LARGE HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THUNDERSTORMS ARE FORECAST TUESDAY AFTERNOON THROUGH TUESDAY
NIGHT. LARGE HAIL...DAMAGING WINDS AND TORRENTIAL RAINFALL COULD
ACCOMPANY THUNDERSTORMS TUESDAY AFTERNOON AND NIGHT.

ADDITIONALLY THUNDERSTORMS ARE FORECAST THROUGHOUT MUCH OF
THE AREA WEDNESDAY AND WEDNESDAY NIGHT...THURSDAY AND THURSDAY
NIGHT...AND SATURDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED LATER TONIGHT ACROSS THE
MISSOURI RIVER VALLEY.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
859 PM CDT MON JUL 25 2011

SDZ033-260230-
STANLEY-
759 PM MDT MON JUL 25 2011

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR CENTRAL STANLEY
COUNTY UNTIL 830 PM MDT/930 PM CDT/...

AT 754 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 5 MILES NORTHWEST OF WENDTE...OR 18 MILES WEST OF
FORT PIERRE...MOVING EAST AT 25 MPH.

A LOCATION IN THE ADVISORY INCLUDE CHANTLER CREEK REC AREA.

SMALL HAIL...AND WINDS AROUND 40 TO 50 MPH ARE EXPECTED WITH THIS
STORM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. IF YOU CAN HEAR
THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

&&

PARKIN