SPC MD 1552

MD 1552 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR EXTREME NORTHEAST WY…EXTREME SOUTHEAST MT…AND WESTERN SD

MESOSCALE DISCUSSION 1552
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT MON JUL 27 2015

AREAS AFFECTED...EXTREME NORTHEAST WY...EXTREME SOUTHEAST MT...AND
WESTERN SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 272050Z - 272215Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SEVERE WEATHER THREAT IS EXPECTED TO INCREASE ACROSS
EXTREME NORTHEAST WY AND EXTREME SOUTHEAST MT INTO WESTERN SD THIS
AFTERNOON INTO THE EVENING...WITH A SEVERE WEATHER WATCH ISSUANCE TO
BE COORDINATED SOON FOR THIS REGION AND LOCATIONS FARTHER NORTH AS
DISCUSSED IN MCD 1551.

DISCUSSION...TRENDS IN LIGHTNING DATA...GOES-R CLOUD-TOP COOLING
PRODUCT AND RADAR IMAGERY INDICATED A RELATIVELY RAPID INCREASE IN
TSTM INTENSITIES WITH STORMS TRACKING TO THE NNE ACROSS FAR NE WY
AND FAR WRN SD IN VICINITY OF A COLD FRONT IN FAR ERN WY AND A N-S
ORIENTED PRE-FRONTAL BOUNDARY.  THE PRESENCE OF STEEP MIDLEVEL LAPSE
RATES AND STRONG INSTABILITY NEAR AND EAST OF THESE BOUNDARIES
FAVORS SUSTAINED/STRONG UPDRAFTS...WHILE STRENGTHENING BULK SHEAR
WILL ENHANCE THE LIKELIHOOD FOR ORGANIZATION.  THE RECENT INCREASE
IN STORM INTENSITIES IS LIKELY INDICATING THE LEADING EXTENT OF
STRONG FORCING FOR ASCENT SPREADING ACROSS THE NORTHERN PLAINS THIS
AFTERNOON WITH THE APPROACH OF THE UPSTREAM...PROGRESSIVE SHORTWAVE
TROUGH.

..PETERS/GOSS.. 07/27/2015

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

ATTN...WFO...BIS...LBF...UNR...CYS...BYZ...

LAT...LON   44350564 45970428 46010238 44710180 43830196 42970203
            43020385 43530438 43590516 44350564 

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from SPC Mesoscale Discussions http://1.usa.gov/1fB5aOE