MESOSCALE PRECIPITATION DISCUSSION 0176
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 AM EDT SAT JUN 06 2015
 
AREAS AFFECTED...NORTH CENTRAL WYOMING...EASTERN MONTANA...WESTERN
NORTH DAKOTA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 060621Z - 061221Z
 
SUMMARY...CONTINUATION OF MPD 174 AS FLASH FLOOD THREAT CONTINUES
THOUGH SLOWLY REDUCING IN TIME

DISCUSSION...WELL DEVELOPED MCS ACROSS EAST CENTRAL MONTANA
SHOWING SOME SIGNS OF WEAKENING WITH REDUCTION OF AVAILABLE
INSTABILITY...WITH MUCAPES BETWEEN 500-1000 J/KG.  STILL STRONG
DEEP MOISTURE CONVERGENCE ALONG THE EASTERN SIDE OF THE CONVECTIVE
LINE FROM SOUTHEASTERN MONTANA INTO NORTHWEST NORTH DAKOTA
MAINTAINS CONVECTIVE DEVELOPMENT FROM 40-45KT 85H SOUTHEASTERLY
LOW LEVEL JET.  UPPER LEVEL SUPPORT ALSO REMAINS STRONG WITH
EXCELLENT DIFFLUENCE ALOFT FROM INFLUENCE OF EXITING SHORTWAVE
OVER SASKATCHEWAN AS WELL AS NORTHERN EXTENSION OF THE APPROACHING
JET FROM UTAH.... UPDRAFT STRENGTH SHOULD BE MAINTAINED WITH A
GOOD PROBABILITY OF BACKBUILDING CELLS ACROSS THE SOUTHWEST
PORTION OF THE LINE.  FORECAST VEERING OF THE LOW LEVEL FLOW PER
HI-RES GUIDANCE SUITE WILL SHIFT FOCUS  FURTHER NORTH INTO
NORTHEAST MONTANA/NORTHWEST NORTH DAKOTA...INCREASING FORWARD
PROGRESSION INTO CENTRAL NORTH DAKOTA BY 13-14Z.  STILL WITH SOME
REMAINING INSTABILITY AND TOTAL PWATS IN THE 1.25-1.4" RANGE...
RATES OF 1.5-2"/HR ARE LIKELY TO PERSIST WITH A BROAD AREA OF
1.5-2" TOTALS ACROSS ND WITH POSSIBLE FLASH FLOODING FOR ANY HUNG
UP CELLS OR MORE PRONE TERRAIN.  

OVER NORTH CENTRAL WYOMING/ACROSS MONTANA BORDER...THE COL IN MID
LEVEL FLOW ACROSS IDAHO...ALLOWS FOR IDEAL CONTINUATION FOR
BACKBUILDING OF CONVECTION PARTICULARLY FURTHER SOUTH AND EAST
WITH VERY LIGHT WINDS... STATIONARY CELL MOTIONS OVER NORTH
CENTRAL WYOMING AND PVA FROM APPROACH OF SHORTWAVE EXITING THE
UNITAS CONTINUES THE THREAT FOR CONVECTIVE GROWTH EVEN WITH
LIMITED INSTABILITIES OF AROUND 500 J/KG AND MOISTURE
TRANSPORT...THE LOCAL ENVIRONMENTAL PROFILES ARE LIKELY SATURATED
BY ONGOING CONVECTION...ALLOWING FOR INCREASED EFFICIENCY IN THE
NEAR TERM WITH .75-1.0"/HR RATES....THOUGH COVERAGE SHOULD BE
REDUCED HERE. 

GALLINA

ATTN...WFO...BIS...BYZ...GGW...RIW...

ATTN...RFC...MBRFC...NCRFC...

LAT...LON   48950390 48939997 46870178 45740511 44720738 
            44540919 45550921 47840672