MESO: Mesoscale Discussion 1028

ACUS11 KWNS 111805
SWOMCD
SPC MCD 111805
MTZ000-WYZ000-IDZ000-111930-

MESOSCALE DISCUSSION 1028
NWS STORM PREDICTION CENTER NORMAN OK
0105 PM CDT TUE JUN 11 2013

AREAS AFFECTED...CNTRL AND SRN MT...NRN WY

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 111805Z - 111930Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...A SEVERE THREAT IS EXPECTED TO DEVELOP THIS AFTERNOON
ACROSS PARTS OF CNTRL AND SRN MT. THE THREAT GRADUALLY SHOULD SHIFT
SEWD INTO NRN WY. ISOLATED LARGE HAIL AND WIND DAMAGE SHOULD BE THE
PRIMARY THREATS INITIALLY BUT A TORNADO THREAT COULD DEVELOP LATER
THIS AFTERNOON. WW ISSUANCE APPEARS LIKELY ONCE STORMS BEGIN TO
INCREASE IN COVERAGE.

DISCUSSION...THE LATEST SFC ANALYSIS SHOWS A SFC LOW OVER CNTRL WY
WITH AN INVERTED TROUGH EXTENDING NWD INTO ECNTRL MT. SFC DEWPOINTS
ALONG THE TROUGH ARE IN THE 50S F WITH A SMALL POCKET OF LOWER 60S F
DEWPOINTS IN SE MT EAST OF THE TROUGH. SFC TEMPS HAVE WARMED INTO
MID 70S F ACROSS MUCH OF THE MCD AREA RESULTING IN MODERATE
DESTABILIZATION WITH MLCAPE VALUES ESTIMATED IN THE 500 TO 1200 J/KG
RANGE. SFC-BASED THUNDERSTORMS ARE DEVELOPING IN PHILLIPS COUNTY MT
WITH OTHER STORMS EXTENDING SWWD TO NEAR THE ID-MT STATE-LINE. THIS
ACTIVITY SHOULD CONTINUE TO INCREASE IN COVERAGE THIS AFTERNOON AS A
SHORTWAVE TROUGH MOVES INTO THE REGION FROM THE SOUTHWEST. 0-6 KM
SHEAR VALUES ACROSS SRN AND CNTRL MT ARE ESTIMATED IN THE 30 TO 45
KT RANGE WHICH COMBINED WITH STEEP MID-LEVEL LAPSE RATES WILL BE
FAVORABLE FOR HAIL AS CELLS INTENSIFY. A POTENTIAL FOR SUPERCELLS
WILL EXIST AND THESE STORMS SHOULD BE ABLE TO PRODUCE ISOLATED LARGE
HAIL. A WIND DAMAGE THREAT WILL ALSO BE POSSIBLE ESPECIALLY IF A
LINE SEGMENT CAN ORGANIZE. THE SEVERE THREAT SHOULD GRADUALLY SHIFT
SEWD WITH TIME. A TORNADO THREAT MAY DEVELOP ONCE THE STORMS ACCESS
THE STRONGER INSTABILITY ACROSS SERN MT AND NRN WY LATER THIS
AFTERNOON.

..BROYLES/CORFIDI.. 06/11/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...UNR...BYZ...GGW...RIW...TFX...MSO...

LAT...LON 48390661 48020825 46901023 45981224 45301328 44781321
44581292 44731200 45161047 45210933 44530880 44030834
43710737 43700655 43830582 44230521 45030530 45470578
46250640 47060676 47240668 47730624 48080617 48390661

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