MESO: Mesoscale Discussion 1401

ACUS11 KWNS 151952
SWOMCD
SPC MCD 151951
NDZ000-SDZ000-MTZ000-WYZ000-152115-

MESOSCALE DISCUSSION 1401
NWS STORM PREDICTION CENTER NORMAN OK
0251 PM CDT MON JUL 15 2013

AREAS AFFECTED...ERN MT...WRN ND...NE WY...NW SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 151951Z - 152115Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...A SEVERE THREAT APPEARS LIKELY TO DEVELOP LATE THIS
AFTERNOON OR EARLY THIS EVENING. THE MORE INTENSE STORMS SHOULD
CONTAIN A THREAT FOR LARGE HAIL...WIND DAMAGE AND POSSIBLY A FEW
TORNADOES. WW ISSUANCE WILL LIKELY BE NEEDED ONCE THE TIMING OF
INITIATION BECOMES MORE CERTAIN.

DISCUSSION...SFC ANALYSIS SHOWS A 1010 MB LOW NORTH OF GREAT FALLS
WITH BACKED WINDS TO THE SOUTHEAST ACROSS NRN AND ERN MT. A MOIST
AXIS IS LOCATED ACROSS WRN ND EXTENDING NWWD ACROSS NE MT.
MESOANALYSIS SUGGESTS THAT THE CAP HAS WEAKENED ACROSS ERN MT WITH
MLCAPE ESTIMATED FROM 1500 TO 2500 J/KG. THIS COMBINED WITH
INCREASING LARGE-SCALE ASCENT ASSOCIATED WITH A MINOR SHORTWAVE
TROUGH EVIDENT ON WATER VAPOR IMAGERY OVER NRN WY AND SE MT...SHOULD
ALLOW FOR CONVECTIVE INITIATION ALONG AND WEST OF THE INSTABILITY
AXIS LATE THIS AFTERNOON. CUMULUS IS ALREADY DEVELOPING NORTH OF
GLASGOW AND THE HRRR INITIATES STORMS AROUND 21Z FROM NEAR GLASGOW
SWD INTO NE WY. IF THIS OCCURS...THEN MODERATE INSTABILITY COMBINED
WITH 40 TO 50 KT OF 0-6 KM SHEAR AND STEEP MID-LEVEL LAPSE RATES
SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. A FEW HAILSTONES
OVER 2 INCHES IN DIAMETER WILL BE POSSIBLE WITH THE MORE DOMINANT
SUPERCELLS. A TORNADO THREAT MAY ALSO DEVELOP AS LOW-LEVEL FLOW
STRENGTHENS LATE THIS AFTERNOON INTO EARLY THIS EVENING. WIND DAMAGE
WILL ALSO BE POSSIBLE.

..BROYLES/CORFIDI.. 07/15/2013

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

ATTN...WFO...BIS...UNR...BYZ...GGW...

LAT...LON 44460319 45010291 46240326 47210309 48000256 48600240
48970255 49180279 49260393 49290554 49150696 48690754
48200748 46980633 46010580 45000558 44540525 44290469
44180420 44460319

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