MESOSCALE PRECIPITATION DISCUSSION 0186
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
549 PM EDT FRI JUL 11 2014
 
AREAS AFFECTED...CENTRAL AND EASTERN WY...SOUTHWEST SD...CENTRAL
AND WESTERN NE...EXTREME NORTHEAST CO 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 112145Z - 120345Z
 
SUMMARY...INCREASING THUNDERSTORM ORGANIZATION AND COVERAGE
EXPECTED OVER THE NEXT SEVERAL HOURS. CELL-MERGERS AND SLOW
MOVEMENT MAY SUPPORT SOME AREAS OF FLASH FLOODING THROUGH THE
EVENING.

DISCUSSION...THE LATEST IR SAT IMAGERY SHOWS COOLING CONVECTIVE
TOPS OVER MUCH OF WY IN RESPONSE TO A SHORTWAVE TROF ARRIVING FROM
NERN UT AND INTERACTING WITH A COLD FRONT AND AN ANOMALOUSLY MOIST
AND UNSTABLE BOUNDARY LAYER INVOF THE HIGHER TERRAIN AND ADJACENT
HIGH PLAINS NEAR THAT FRONT.

OVER THE NEXT FEW HOURS...SHOWER AND THUNDERSTORM ACTIVITY SHOULD
EXPAND IN COVERAGE AND INTENSITY OVER CNTRL AND ERN WY...AND
LIKELY ORGANIZING INTO AN MCS AFTER 00Z OVER THE WY/NE HIGH PLAINS
AND POSSIBLY FAR SWRN SD. THE AIRMASS ACROSS THIS AREA IS HIGHLY
UNSTABLE WITH SBCAPE VALUES OF NEAR 3000 J/KG AND LI/S AS PER
LATEST GOES-SOUNDER DATA OF -6 TO -8. THIS COUPLED WITH THE
ARRIVING SHORTWAVE TROF AND MOIST LOW LVL E/NELY FLOW INTO THE
HIGHER TERRAIN PROVIDING AN UPSLOPE FLOW COMPONENT SHOULD ENHANCE
THE POTENTIAL FOR ORGANIZED CONVECTION THROUGH THE EVENING.

THE LATEST HI-RES MODELS INCLUDING THE 18Z NAM-CONEST...12Z ARW
AND 12Z NMMB SUPPORT THIS SCENARIO...AND THEY SUGGEST POTENTIAL
FOR SEVERAL INCHES OF RAIN IN A SHORT AMT OF TIME...AND ESP AFTER
00Z WHEN THE CONVECTIVE ACTIVITY SHOULD BECOME NOTABLY MORE
ORGANIZED.

GIVEN A LIKELIHOOD FOR CELL-MERGERS AND RELATIVELY SLOW FORWARD
MOTION...EXPECT THERE TO BE SOME POTENTIAL FOR FLASH FLOODING
THROUGH THE EVENING...AND ESP NEAR AREAS OF HIGHER TERRAIN.

ORRISON

ATTN...WFO...LBF...UNR...BOU...CYS...RIW...

ATTN...RFC...CBRFC...MBRFC...

LAT...LON   40700258 40720386 41140566 41560700 42080806 42820886
            43460894 43890780 44070662 44130483 44000288 43440038
            42479985 41480034 40920146 40700258