Damaging Winds in Wyoming, July 11, 2011

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
153 PM MDT MON JUL 11 2011

.DISCUSSION...19Z SURFACE ANALYSIS HAD RIDGE FROM CENTRAL CANADA
INTO CENTRAL NE. SURFACE BOUNDARY WRAPPED AROUND RIDGE FROM
CENTRAL MT INTO CENTRAL WY AND THEN INTO WESTERN NE. SHORTWAVE
ENERGY NOTED OVER CENTRAL WY...LIFT AHEAD OF THIS WAVE
RESPONSIBLE FOR ELEVATED CONVECTION OVER MUCH OF THE CWA THIS
AFTERNOON. LATEST MESOANALYSIS HAD TONGUE OF 1-2KJ/KG MLCAPE ALONG
BOUNDARY IN NORTHEASTERN WY...WITH LITTLE MLCIN. MLCIN INCREASES
AS YOU MOVE EAST ONTO THE SD PLAINS. APPEARS SURFACE BASED CONVECTION
WILL CONTINUE TO DEVELOP OVER NORTHEASTERN WY. DRIER SURFACE AIR
BEING FUNNELED INTO AIR MASS OFF SURFACE RIDGE WITH MIXING DRYING
OUT HIGHER ELEVATIONS. SHEAR SUFFICIENT FOR SUPERCELLS...SO WOULD
EXPECT STRONG/SEVERE THUNDERSTORMS IN THE WEST INTO THE EVENING
HOURS. FURTHER EAST...SURFACE BASED ACTIVITY LIMITED BY CAP.
SCATTERED TSRA WORDING FOR TONIGHT LOOKS GOOD AS TEMPERATURES DROP
TO NEAR GUIDANCE.

TUESDAY/WEDNESDAY...UPPER LEVEL RIDGE OVER THE CENTRAL US WITH
UPPER TROUGH OVER NORTHWEST US. SOUTHWEST FLOW ALOFT OVER THE CWA
WITH A SERIES OF EMBEDDED SHORTWAVES EXPECTED TO PASS THROUGH.
SURFACE HIGH SHIFTS INTO THE MIDWEST AS BOUNDARY/TROUGH SHIFTS
EAST TO BISECT THE CWA. IT SHOULD BE THE FOCUS FOR TSRA
ACTIVITY...ESPECIALLY DURING PEAK HEATING. INSTABILITY/SHEAR WILL
BE SUFFICIENT FOR STRONG/SEVERE STORMS ESPECIALLY OVER THE WESTERN
2/3RDS OF THE CWA. TEMPERATURES WILL BE NEAR GUIDANCE.

EXTENDED...AN UPPER RIDGE WILL BUILD OVER THE AREA THROUGH THE
EXTENDED PERIOD. A FEW WEAK WAVES MAY MOVE THROUGH THE RIDGE
THURSDAY THROUGH SATURDAY BRINGING A FEW THUNDERSTORMS...WHILE DRY
WEATHER IS EXPECTED TO START NEXT WEEK. TEMPERATURES WILL CLIMB TO
ABOVE AVERAGE BY LATE THIS WEEK...AND REMAIN WARM INTO EARLY NEXT
WEEK.

&&

.AVIATION...SCATTERED THUNDERSTORMS ARE EXPECTED ACROSS THE AREA
THROUGH THIS EVENING...WITH A FEW STORMS POSSIBLY LINGERING INTO
TUESDAY MORNING. ANY STRONGER STORMS MAY PRODUCE BRIEF MVFR/IFR
CONDITIONS. PATCHY FOG MAY DEVELOP LATE TONIGHT AND LINGER INTO
TUESDAY MORNING OVER SWRN SD AND FAR NERN WY...BRINGING LCL IFR VIS.
OTHERWISE...VFR CONDITIONS ARE EXPECTED.

&&

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

HELGESON/SCHILD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
632 AM MDT MON JUL 11 2011

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-121300-
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-
632 AM MDT (732 AM CDT) MON JUL 11 2011

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING...
WITH A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEAST WYOMING
AND MUCH OF WESTERN SOUTH DAKOTA. LARGE HAIL AND DAMAGING WINDS WILL
BE THE MAIN THREAT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH MUCH OF THE
WEEK...WITH A DAILY CHANCE OF THUNDERSTORMS. THERE IS A SLIGHT RISK
OF SEVERE THUNDERSTORMS ACROSS NORTHEAST WYOMING AND SOUTHWEST SOUTH
DAKOTA TUESDAY AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.