000
ACUS11 KWNS 232348
SWOMCD
SPC MCD 232347
MTZ000-WYZ000-240115-

MESOSCALE DISCUSSION 0787
NWS STORM PREDICTION CENTER NORMAN OK
0647 PM CDT THU MAY 23 2013

AREAS AFFECTED...FAR SOUTH-CENTRAL MT

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 232347Z - 240115Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED BOUTS OF SEVERE HAIL/GUSTY WINDS WILL BE POSSIBLE
THROUGH EARLY/PERHAPS MID-EVENING ACROSS PORTIONS OF
SOUTH-CENTRAL/SOUTHEAST MT...POTENTIALLY INCLUDING PARTS OF THE I-90
CORRIDOR/BILLINGS VICINITY.

DISCUSSION...SCATTERED TSTMS WILL LIKELY CONTINUE TO MOVE GENERALLY
NORTHWARD FROM THE MT/WY BORDER VICINITY/BIGHORNS INTO PARTS OF
SOUTH-CENTRAL/NEARBY SOUTHEAST MT THIS EVENING. WHILE CAPE IS NOT
ROBUST /MLCAPE 500-800 J PER KG OR LESS/ AMID 40S F SURFACE
DEWPOINTS...STEEP LAPSE RATES ALOFT AND STRONG/DEEP
SOUTH-SOUTHWESTERLY FLOW /ON PERIPHERY OF PACIFIC NORTHWEST TROUGH/
ATOP LIGHTER NEAR-SURFACE WINDS WILL SUPPORT SOME SUSTAINED
UPDRAFTS/SMALLER SUPERCELL STRUCTURES CAPABLE OF SEVERE HAIL TO
AROUND 1 INCH IN DIAMETER. THIS DEVELOPMENT MAY REACH PORTIONS OF
THE I-90 CORRIDOR/BILLINGS VICINITY TOWARD 01Z. THE PERCEIVED
MARGINAL/ISOLATED NATURE OF THE SEVERE RISK WILL LIKELY PRECLUDE A
WATCH ISSUANCE.

..GUYER/THOMPSON.. 05/23/2013

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

ATTN...WFO...BYZ...RIW...

LAT...LON   45140787 44940884 45130956 45770975 46510904 46040783
            45140787