Hail in South Dakota, May 25, 2013

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1007 AM MDT SAT MAY 25 2013

.UPDATE...
ISSUED AT 1005 AM MDT SAT MAY 25 2013

WATER VAPOR SHOWS DISTINCT SHORT WAVE MOVING THROUGH FAR ERN WY
WITH SOME CONVECTION...STILL MOSTLY ELEVATED IN
NATURE...DEVELOPING FROM THE THE NRN BLKHLS INTO SERN MT/NWRN SD.
ANOTHER WAVE IS NOTED MOVING THROUGH ERN UT AND WILL ARRIVE LATER
THIS AFTERNOON. CAP IS STILL IN PLACE...BUT WILL ERODE IN THE NEXT
HOUR OR TWO AROUND THE NRN BLKHLS WHERE SURFACE BASED CONVECTION
IS EXPECTED TO INTENSIFY. CAP IS THEN EXPECTED TO QUICKLY ERODE
ON THE PLAINS AROUND NOON OR SHORTLY THEREAFTER. CONVECTIVE
PARAMETERS WILL POINT TOWARDS SVR POTENTIAL WITH LARGE HAIL THE
MAIN THREAT INITIALLY...WITH WIND ALSO BECOMING A THREAT LATER
TODAY AS STORMS PUSH THROUGH THE WRN/CNTRL SD PLAINS. A TORNADO OR
TWO ALSO CANNOT BE RULED OUT GIVEN LO LEVEL SHEAR AND LOW LCL'S.
LITTLE CHANGE NECESSARY TO CURRENT FORECAST...AND THE FORECAST FOR
THE NEXT COUPLE DAYS STILL LOOKING ON TRACK AND LITTLE OVERALL
CHANGES ARE EXPECTED.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 233 AM MDT SAT MAY 25 2013

08Z SURFACE ANALYSIS HAD LOW OVER EASTERN CO WITH BOUNDARY/LEE
TROUGH INTO CENTRAL MT. WARM FRONT EXTENDED FROM THE LOW INTO
NORTHEAST NE...LIKELY WHERE THE CONVECTION OVER NORTHERN NE IS
BEING FOCUSED. WATER VAPOR SHOWED UPPER RIDGE EAST OF THE AREA
WITH SOUTHWEST FLOW ALOFT FROM CA INTO THE DAKOTAS. EMBEDDED
SHORTWAVES NOTED...WITH THE ONE MOST LIKELY TO AFFECT TODAY/S
WEATHER OVER UT.

TODAY/TONIGHT...UPPER AIR PATTERN CHANGES LITTLE AS SHORTWAVE ENERGY
WORKS INTO WY/WESTERN SD THIS AFTERNOON. LEE TROUGH DEEPENS AHEAD OF
SHORTWAVE WITH GRADIENT/ISALLOBARIC FORCING RESULTING IN
BREEZY/WINDY SOUTHEAST WINDS OVER THE CWA EAST OF THE BOUNDARY. TD/S
WELL INTO THE 50S TO PERHAPS LOWER 60S WILL POOL ALONG WARM FRONT AS
IT SLOWLY LIFTS NORTH DURING THE DAY. MLCAPE INCREASES TO AT LEAST
2KJ/KG WITH 0-6KM BULK SHEAR RISING TO 20-25M/S. HODOGRAPHS NORTH OF
WARM FRONT FROM SOUTHEAST MT INTO CENTRAL SD DEVELOP PRONOUNCED LOW
LEVEL CURVATURE. AS UT SHORTWAVE MOVES THROUGH CWA...EXPECT SEVERE
THUNDERSTORMS TO ERUPT...INITIALLY OVER THE CONVERGENCE REGION ON
THE NORTH SIDE OF THE BLACK HILLS. A FEW SUPERCELLS AT FIRST...BUT
THEN STORMS SHOULD MERGE INTO A LARGE SCALE COMPLEX LIKELY TURNING
INTO A SQUALL LINE/MCS OVER FAR EASTERN REACHES OF THE CWA
TONIGHT...ESPECIALLY AS LOW LEVEL JET KICKS IN. VERY LARGE HAIL IS
EXPECTED WITH THE STRONGEST SUPERCELLS. ISOLATED TORNADOES MAY OCCUR
GIVEN FORECAST SOUNDINGS/HODOGRAPHS. THREAT WILL THEN TURN TOWARD
DAMAGING WINDS LATER THIS EVENING. LOCAL WRF AS WELL AS SOME
CONVECTIVE ALLOWING MODELS SUPPORT THIS SCENARIO. PRECIPITABLE
WATERS WILL BE 100-150 PERCENT OF NORMAL...BUT MEAN WIND IS AROUND
20KTS AND SUPERCELL MOTION IS 10-15KTS. TEMPERATURES WILL BE NEAR
GUIDANCE.

SUNDAY...DEPENDING ON WHERE TODAY/S CONVECTION ENDS UP...LEFTOVER
LEE TROUGH/WARM FRONT/SURFACE BOUNDARY WILL BE STRETCHED ACROSS CWA.
SOUTHWEST FLOW ALOFT WILL CONTINUE. DAYTIME INSOLATION WILL RESULT
IN 2-3KJ/KG MLCAPE...BUT SHEAR WON/T BE QUITE AS PRONOUNCED AS
TODAY. SLIGHT RISK OF SEVERE THUNDERSTORMS LOOKS REASONABLE GIVEN
THERMODYNAMICS PRESENT. TEMPERATURES WILL BE NEAR GUIDANCE.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 233 AM MDT SAT MAY 25 2013

PERSISTENT TROF ACROSS THE PACIFIC NORTHWEST WILL KEEP
THE NORTHERN PLAINS UNDER ACTIVE SOUTHWEST FLOW THROUGH THE MIDDLE
OF NEXT WEEK. DAILY CHANCES FOR TSTMS WILL CONTINUE AS LIGHT EAST TO
SOUTHEAST BOUNDARY LAYER FLOW CONTINUES TO BRING MOIST AIR INTO THE
REGION...AND WEAK ENERGY EJECTS OUT OF THE WESTERN TROF INTO THE
NORTHERN PLAINS. A STRONGER SHORTWAVE IS PROGGED TO CROSS THE AREA
ON MONDAY...LEADING TO THE POTENTIAL FOR STRONG TO POSSIBLY SEVERE
STORMS DURING THE AFTERNOON AND EVENING HOURS. LONGER RANGE GUIDANCE
IS STILL SUGGESTING A STRONG NEGATIVELY TILTED UPPER TROF WORKING
THROUGH THE NORTHERN PLAINS MID TO LATE NEXT WEEK...WHICH COULD
PROVIDE WIDE SPREAD SIGNIFICANT RAINFALL. TEMPERATURES WILL REMAIN
ABOVE AVERAGE...WITH HIGHS GENERALLY IN THE 70S AND LOWER 80S ACROSS
THE AREA THROUGH THE MIDDLE OF NEXT WEEK...WITH SOME COOLING
EXPECTED TOWARDS THE END OF THE WEEK AS THE UPPER TROF MOVES INTO
THE NORTHERN PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1005 AM MDT SAT MAY 25 2013

SCT/NMRS TSRA ARE EXPECTED THIS AFT/EVE WITH SOME LINGERING
OVERNIGHT BRINGING MVFR/IFR VIS IN HEAVIER PRECIP. SOME TS MAY
BECOME SEVERE WITH LARGE HAIL/STRONG GUSTS. SOME LOW CIGS MAY
DEVELOP OVERNIGHT OVER PTNS OF THE SD PLAINS...BRINGING AREAS OF
MVFR/IFR CIGS. OTHERWISE...VFR CONDITIONS ARE EXPECTED.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

UPDATE...JOHNSON
SHORT TERM...HELGESON
LONG TERM...15
AVIATION...SCHILD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
539 AM MDT SAT MAY 25 2013

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-261300-
BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-
HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK-
NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS-
NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-
SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS-
SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-
WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH-
539 AM MDT (639 AM CDT) SAT MAY 25 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND
NORTHEASTERN WYOMING.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHEAST
WYOMING AND WESTERN SOUTH DAKOTA THIS AFTERNOON AND THIS EVENING.
STORMS WILL LIKELY START AROUND LUNCHTIME NEAR THE BLACK HILLS AND
THEN SPREAD OVER THE PLAINS. VERY LARGE HAIL WILL BE POSSIBLE ALONG
WITH DAMAGING WINDS. ISOLATED TORNADOES ARE ALSO POSSIBLE LATE THIS
AFTERNOON AND EARLY THIS EVENING.

IN ADDITIONAL TO THE SEVERE WEATHER...LOCALLY HEAVY RAINFALL MAY
OCCUR.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED THUNDERSTORMS ARE EXPECTED SUNDAY THROUGH NEXT WEEK. THERE
IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA SUNDAY AND MONDAY. LARGE HAIL AND DAMAGING
WINDS WILL BE THE MAIN THREAT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY.

&&

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER DETAILS OR UPDATES...
OR CHECK OUR WEB SITE AT WEATHER.GOV/RAPIDCITY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
1208 PM MDT SAT MAY 25 2013

SDZ001-012-251900-
BUTTE SD-HARDING SD-
1208 PM MDT SAT MAY 25 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BUTTE AND SOUTHEASTERN
HARDING COUNTIES UNTIL 100 PM MDT...

AT 1207 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 7 MILES NORTH OF HOOVER...OR 28 MILES SOUTHEAST
OF BUFFALO...MOVING NORTH AT 35 MPH.

HAIL UP TO THE SIZE OF PENNIES IS EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  REVA...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 4568 10331 4555 10295 4508 10323 4517 10347
TIME...MOT...LOC 1808Z 200DEG 31KT 4522 10330

SCHILD

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
127 PM MDT SAT MAY 25 2013

SDZ012-025-252030-
BUTTE SD-NORTHERN FOOT HILLS SD-
127 PM MDT SAT MAY 25 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN LAWRENCE AND CENTRAL
BUTTE COUNTIES UNTIL 230 PM MDT...

AT 125 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR DOWNTOWN BELLE FOURCHE...MOVING NORTHEAST AT
25 MPH.

WIND GUSTS UP TO 45 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH
FREQUENT DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  FRUITDALE...
  BELLE FOURCHE RESERVOIR...
  CASTLE ROCK...

&&

LAT...LON 4513 10353 4490 10328 4452 10377 4463 10397
TIME...MOT...LOC 1926Z 224DEG 23KT 4465 10378

CLARK