MESO: Mesoscale Discussion 1545

ACUS11 KWNS 272327
SWOMCD
SPC MCD 272326
MTZ000-280200-

MESOSCALE DISCUSSION 1545
NWS STORM PREDICTION CENTER NORMAN OK
0626 PM CDT SAT JUL 27 2013

AREAS AFFECTED...PARTS OF N-CNTRL MONTANA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 272326Z - 280200Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A VERY ISOLATED SVR-THUNDERSTORM POTENTIAL MAY EVOLVE INTO
THE EVENING HOURS...THOUGH THE ISSUANCE OF A WW IS NOT ANTICIPATED.

DISCUSSION...THE INFLUX OF RELATIVELY MOISTER AIR SUCCEEDING THE
PASSAGE OF A SWD/SWWD-MOVING COLD FRONT BENEATH STEEP MID-LEVEL
LAPSE RATES ACCOMPANYING AN EML PLUME IS CONTRIBUTING TO MODERATE
BUOYANCY IN A SMALL PART OF N-CNTRL MT AROUND THE HI-LINE. THE
FRONT -- AS REFLECTED BY A FINE-LINE IN TFX BASE REFLECTIVITY -- HAS
ALREADY MOVED S OF CONRAD AND CHESTER. BEHIND THE FRONT...CUT BANK
DEWPOINTS HAVE RISEN INTO THE MIDDLE 50S AND SFC TEMPERATURES HAVE
REMAINED SUFFICIENTLY WARM IN THE PRESENCE OF INSOLATION TO MITIGATE
SUBSTANTIAL DEVELOPMENT OF CONVECTIVE INHIBITION. WITH THE
MOISTER/MORE UNSTABLE AIR HAVING BANKED UP AGAINST THE ROCKY
MOUNTAIN FRONT RANGE IN ASSOCIATION WITH SOME UPSLOPE FLOW
COMPONENT...A SMALL CONVECTIVE CELL DEVELOPED JUST NW OF CUT BANK --
THOUGH WEAKENING TRENDS HAVE RECENTLY BEEN NOTED WITH THIS
PARTICULAR CELL.

THE DEVELOPMENT OF ADDITIONAL CONVECTION CANNOT BE RULED OUT JUST E
OF THE NRN ROCKY MOUNTAIN FRONT TOWARD THE HAVRE AREA INTO EARLY
EVENING. HOWEVER...CONVECTIVE COVERAGE SHOULD BE VERY ISOLATED...AT
MOST...AS STRONGER DEEP FORCING FOR ASCENT RESIDES TO THE N IN
ALBERTA. IN FACT...IT IS COMPLETELY POSSIBLE THAT NO ADDITIONAL
CONVECTION DEVELOPS. HOWEVER...MODERATE MID-LEVEL FLOW AND
ACCOMPANYING DEEP SHEAR WOULD CONDITIONALLY SUPPORT AN ISOLATED
SUPERCELL POTENTIAL WITH LARGE HAIL AND DMGG WIND GUSTS
POSSIBLE...IF SUSTAINED CONVECTION CAN MATERIALIZE.

..COHEN/CORFIDI.. 07/27/2013

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

ATTN...WFO...TFX...

LAT...LON 47931216 48381278 48641295 48941273 49021162 48970982
48630964 48200998 47931110 47931216

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