MESOSCALE PRECIPITATION DISCUSSION 0512
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 AM EDT MON AUG 01 2016
 
AREAS AFFECTED...SOUTHEAST MT...SOUTHWEST AND CENTRAL ND...FAR
NORTHWEST SD 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 010745Z - 011245Z
 
SUMMARY...DEVELOPING CONVECTIVE COMPLEX TO EXPAND WITH SOME
POTENTIAL TRAINING/REPEAT CELL TRACKS OVER LOW FLASH FLOOD
GUIDANCE VALUES MAY POSE FLOODING CONCERNS EARLY THIS MORNING IN
SE MT/W ND. 

DISCUSSION...WV SHOWS DEVELOPING S/W  ENERGY ON SOUTH SIDE OF
80-90KT UL JET.  HEIGHT FALLS ARE FOSTERING SFC LOW DEVELOPING
ACROSS NE WY ATTM AS WELL AS STRENGTHENING NORTH AND NORTHEASTERLY
FLOW ALONG THE NORTH SIDE OF THIS LOW...FOCUSING LOW LEVEL
FRONTOGENESIS ACROSS NE MT AND W ND.  ADDITIONALLY IN THE WARM
SECTOR FLOW IS VEERING  TO SE IN THE WAKE OF EARLIER CLUSTER AND
OUTFLOW BOUNDARY ACROSS NW SD...AS EVIDENCE IN THE UDX VWP.  STILL
STRENGTHENING MST CONVERGENCE FROM BOTH SIDES OF THE FRONTAL ZONE
WITH HIGH 50 TO LOW 60 TDS AS WELL AS THE INCREASING DIVERGENCE
ALOFT SUPPORTS CONVECTIVE EXPANSION AND GROWTH WITH RESPECT TO THE
CLUSTER ADVANCING OUT OF  SE MT ATTM.  MOISTURE FLUX FROM MULTIPLE
CHANNELS HAS INCREASED TPW VALUES OVER 1.25" AND WITH HIGHER
FLUX/CONVERGENCE SHOULD SUPPORT EFFICIENT RAINFALL PRODUCTION
THOUGH WITH SOME LOSS TO HAIL GENERATION RATES UP TO 1.5"/HR ARE
PROBABLE. 

EXPECTATION IS FOR FURTHER EXPANSION OF CONVECTION NORTHEAST ALONG
THE FRONTAL ZONE OVER THE NEXT FEW HOURS INTO W ND. ORIENTATION OF
THE BOUNDARY ALONG WITH FORWARD PROPAGATION OF THE CLUSTER MAY
SUPPORT SOME TRAINING PROFILES IN THE SHORTER TERM.  AS THE
COMPLEX REACHES WESTERN ND AND THE APEX OF THE 500-1000MB
THICKNESS RIDGE...PROPAGATION VECTORS SLACKEN AND DIVERGE
SUPPORTING SOUTHEAST PROPAGATION INTO THE BEST 850MB MOISTURE
TRANSPORT WHILE CONTINUING EXPANDING NORTHEAST ALONG THE FRONT
INTO CENTRAL ND WITH TRAINING POSSIBLE.  OVERALL HI-RES GUIDANCE
MAINLY THE OPERATIONAL AND PARALLEL HRRR ALONG WITH THE ARW
PRESENT THIS SETUP WELL INCLUDING RAINFALL TOTAL IN THE 2-3" MAY
PRESENT FLASH FLOODING CONCERNS MAINLY GIVEN THE LOW FLASH FLOOD
GUIDANCE VALUES BELOW 2" IN 3HRS ACROSS THE VAST MAJORITY OF THE
DISCUSSION AREA. 

OF NOTE: ISOLATED DEFORMATION SHOWERS ACROSS NE MT INTO FAR NW ND
PRESENT SOME TRAINING ISSUES BUT LACK OF SUBSTANTIAL MOISTURE AND
LIMITED INSTABILITY SHOULD KEEP TOTALS AT OR JUST BELOW FFG IN THE
VICINITY BUT CANNOT RULE OUT ISOLATED THREAT IN ANY PRONE AREAS.  

GALLINA

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

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

LAT...LON   48480174 47899991 46779996 45990156 45610192 
            45070293 45310417 45550496 46180536 46940476 
            47850334 
A