Severe Thunderstorm Warning 155, NWS Aberdeen, SD

707 
WWUS53 KABR 031937
SVSABR

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
237 PM CDT FRI AUG 3 2012

SDC041-031946-
/O.CAN.KABR.SV.W.0155.000000T0000Z-120803T1945Z/
DEWEY SD-
137 PM MDT FRI AUG 3 2012

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN DEWEY COUNTY IS
CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED OR MOVED OUT OF THE
WARNED AREA.

LAT...LON 4547 10045 4568 10063 4591 10038 4561 9995
TIME...MOT...LOC 1936Z 240DEG 19KT 4560 10038

$$

SDC021-031-129-031945-
/O.CON.KABR.SV.W.0155.000000T0000Z-120803T1945Z/
CORSON SD-CAMPBELL SD-WALWORTH SD-
237 PM CDT FRI AUG 3 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHWESTERN
WALWORTH...SOUTHWESTERN CAMPBELL AND SOUTHEASTERN CORSON COUNTIES
UNTIL 245 PM CDT/145 PM MDT/...

AT 235 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING PING PONG BALL SIZE HAIL...
AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
MOBRIDGE...MOVING NORTHEAST AT 20 MPH.

IN ADDITION...QUARTER SIZED HAIL WAS REPORTED IN 2 MILES NORTHWEST 
OF MOBRIDGE WITH THIS STORM.

THIS SEVERE THUNDERSTORM WILL AFFECT MAINLY RURAL AREAS OF
NORTHWESTERN WALWORTH...SOUTHEASTERN CORSON AND SOUTHWESTERN CAMPBELL
COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

&&

LAT...LON 4547 10045 4568 10063 4591 10038 4561 9995
TIME...MOT...LOC 1936Z 240DEG 19KT 4560 10038
WIND...HAIL 60MPH 1.50IN

$$
SD

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1242 PM CDT FRI AUG 3 2012

.UPDATE...
SEE BELOW FOR AN UPDATED AVIATION DISCUSSION FOR THE 18Z TAFS.

STILL WATCHING COLD FRONT WHICH WILL MOVE THROUGH THE REGION
TODAY...LIKELY PRODUCING STRONG TO SEVERE STORMS LATER THIS
AFTERNOON OVER THE EASTERN HALF OF THE CWA. MADE SOME CHANGES TO
SKY GRIDS BASED ON CURRENT SATELLITE TRENDS. MOSTLY SUNNY SKIES
THIS MORNING BUT CLOUDS WILL INCREASE THROUGH THE DAY...ESPECIALLY
OVER NORTHERN SD WHERE LOW CLOUDS ARE ALREADY STREAMING INTO
CORSON COUNTY WITHIN LOW LEVEL COLD AIR ADVECTION. REMOVED POPS
FOR THE LATE MORNING HOURS AS IT APPEARS ANY ACTIVITY WILL HOLD
OFF UNTIL THE AFTERNOON HOURS. CURRENT HIGHS APPEAR ON TRACK BUT A
LOW CONFIDENCE FORECAST IN ACTUAL NUMBERS. WITH LOWER CLOUDS AND
COLD AIR ADVECTION OVER THE NORTHWEST COUNTIES...TRICKY FORECAST
HERE. NICE WARM UP STILL EXPECTED OVER THE EASTERN CWA...BUT IF
STORMS FIRE BY MID TO LATE AFTERNOON...CLOUD COVER FROM THIS
ACTIVITY COULD KEEP TEMPS DOWN A TOUCH. WILL LIKELY NEED
ADDITIONAL FORECAST UPDATES THROUGH THE DAY AS THINGS EVOLVE.

&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SUNDAY
EXPECT ELEVATED SHOWERS AND THUNDERSTORMS TO CONTINUE ACROSS THE
SOUTHEAST CWA THIS MORNING AND INCREASE IN AREAL COVERAGE DUE TO
STRONG WARM AIR ADVECTION AND SHORTWAVE ENERGY AHEAD OF THE MAIN
UPPER TROUGH. TEMPERATURES WILL BE TRICKY TODAY WITH CLOUD COVER
ACROSS THE REGION. 850 TEMPS WILL RISE TO 20 C OR GREATER ACROSS
THE SOUTHERN AND EASTERN CWA...BUT EXPECT CLOUD COVER WILL LIMIT
TEMPERATURE RISE THIS AFTERNOON.

THE MAIN FORECAST CHALLENGE WILL COME THIS AFTERNOON AS THE MAIN
UPPER TROUGH WILL MOVE INTO THE REGION WITH A 90 KT JET STREAK
ROUNDING THE BASE OF THE TROUGH. THE COLD FRONT WILL WORK ITS WAY
ACROSS THE CWA DURING PEAK HEATING HOURS TODAY. THERE ARE STILL
MINOR MODEL DIFFERENCES IN TIMING OF THE FRONT...BUT THE CENTRAL
AND EASTERN CWA WILL HAVE THE BEST CHANCE FOR SEVERE STORMS. STEEP
MID LEVEL LAPSE RATES...ML CAPE VALUES IN THE 2000-3000 J/KG RANGE
/PERHAPS SLIGHTLY OVERDONE WITH AREA CLOUD COVER/...0-6 KM SHEAR
VALUES OF 40 TO 50 KTS...AND 0-1 KM SHEAR VALUES 20 TO 30 KTS
ACROSS THE NORTHEAST...WILL BE A VERY FAVORABLE ENVIRONMENT FOR
SEVERE STORMS WITH LARGE HAIL...STRONG WINDS...AND TORNADOES
POSSIBLE. ALONG WITH ALL OF THIS...PWAT VALUES WILL BE IN THE 1.5
TO 2.0 INCH RANGE...WARRANTING A MENTION OF HEAVY RAIN AS WELL.
EXPECT THAT THE FRONT AND MAIN PRECIPITATION CHANCES WILL BE OUT
OF THE REGION BY 06Z.

HIGH PRESSURE MOVES IN FOR THE REMAINDER OF THE PERIOD. WITH
COOLING TEMPERATURES ALOFT...STEEP LAPSE RATES WILL ALLOW FOR
SHOWERS ACROSS THE NORTHERN AND NORTHEASTERN CWA SATURDAY. HIGH
TEMPERATURES WILL BE MUCH COOLER SATURDAY...BUT WILL RISE TO NEAR
NORMAL ON SUNDAY.

.LONG TERM...MONDAY THROUGH FRIDAY

FROM WHAT CAN BE GLEANED FROM AVAILABLE MODEL DATA...IT APPEARS
THAT LITTLE TO NO CHANGE IS NEEDED RIGHT NOW FOR THE EXTENDED. THE
UPPER LEVEL RIDGE AXIS STARTS OUT POSITIONED WEST OF THIS CWA BACK
OVER THE ROCKIES AND ALONG THE FRONT RANGE. OVER A SEVERAL DAY
PERIOD...THE RIDGE AXIS IS FORECAST TO GRADUALLY SHIFT EAST TOWARD
THE WESTERN/CENTRAL DAKOTAS BY THE END OF THE PERIOD.

HOWEVER...WITH THE CWA POSITIONED ON THE BACKSIDE OF THE RIDGE
AXIS /NW FLOW ALOFT/...IT DOES APPEAR THAT A COUPLE OF BACKDOOR
COLD FROPAS AND ASSOCIATED WEAK-TRANSIENT SHORTWAVE TROFS TRY TO
WORK DOWN FROM THE NORTH/NORTHWEST...ONE MONDAY/MONDAY NIGHT AND
THEN A SECOND FROPA TRIES TO WORK DOWN INTO THIS AREA THURSDAY
NIGHT/FRIDAY. WILL TRY AND MIGRATE POPS TO THOSE TIME PERIODS AS
MUCH AS POSSIBLE.

TEMPERATURE-WISE...THE COOLEST READINGS DO APPEAR TO SHOW UP
EARLIER IN THE PERIOD...AND THEN GRADUALLY TREND WARMER RIGHT
THROUGH MID-WEEK. HOWEVER...WHENEVER THE SECOND /ILL-TIMED/ COLD
FROPA GETS DOWN THROUGH THIS CWA LATE IN THE WEEK...IT SHOULD
BRING A BIT OF RELIEF TEMPERATURES WITH SLIGHTLY COOLER/DRIER AIR
SLOWLY SINKING INTO THE CWA. TEMPERATURES IN THE OUT PERIODS WILL
VARY FROM NEAR NORMAL TO SEVERAL DEGREES ABOVE NORMAL THROUGHOUT
THE PERIOD.

&&

.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PREVAIL. SHOWERS AND THUNDERSTORMS WILL
DEVELOP ALONG AND AHEAD OF A COLD FRONT TRACKING ACROSS THE
AREA...MAINLY THIS AFTERNOON AND INTO THE EVENING. SUB-VFR CIGS
AND VSBYS ARE POSSIBLE WITH THE STRONGER STORMS...WITH THE BEST
CHANCE FOR STRONG TO SEVERE STORMS OVER THE EASTERN HALF OF THE
AREA...INCLUDING KABR AND KATY. HEAVY RAIN...RATHER LARGE
HAIL...DAMAGING STRONG WINDS AND PERHAPS EVEN A TORNADO OR TWO
COULD OCCUR NEAR OR WITHIN AIRPORT AIRSPACE. SOUTHERLY WINDS AHEAD
OF THE COLD FROPA WILL INCREASE INTO THE 15 TO 25 MPH
RANGE...WHILE WINDS BEHIND THE FROPA SHIFT AROUND TO THE
NORTHWEST.

&&

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

UPDATE...TMT
SHORT TERM...SERR
LONG TERM...DORN
AVIATION...DORN

WEATHER.GOV/ABERDEEN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
414 AM CDT FRI AUG 3 2012

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-040915-
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-
414 AM CDT FRI AUG 3 2012 /314 AM MDT FRI AUG 3 2012/

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

.DAY ONE...TODAY AND TONIGHT
A STRONG LOW PRESSURE SYSTEM AND COLD FRONT WILL MOVE ACROSS THE
REGION THIS AFTERNOON. THERE IS THE CHANCE FOR SHOWERS AND
THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT EARLY ON...BUT SEVERE
STORMS ARE MOST LIKELY ACROSS NORTH CENTRAL AND EASTERN SOUTH
DAKOTA...AS WELL AS WEST CENTRAL MINNESOTA THIS AFTERNOON AND
EVENING. LOCALLY HEAVY RAIN...LARGE HAIL...STRONG WINDS...AND
TORNADOES ARE POSSIBLE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
A FEW RAIN SHOWERS ARE POSSIBLE ON SATURDAY...BUT OTHERWISE HIGH
PRESSURE AND DRY CONDITIONS WILL PREVAIL THROUGH EARLY NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON.

SERR