MESOSCALE PRECIPITATION DISCUSSION 0374
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
557 PM EDT TUE JUL 21 2015
 
AREAS AFFECTED...SOUTHEAST WYOMING...NORTHEAST COLORADO...EXTREME
WESTERN NEBRASKA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 212156Z - 220256Z
 
SUMMARY...EFFICIENT RAINFALL PRODUCING SLOW MOVING CONVECTION
AHEAD OF SHORTWAVE ASSOCIATED WITH EX-TROPICAL CYCLONE DOLORES

DISCUSSION...PLEASE REFER TO CONCURRENT SPENES ISSUED AT 2120Z FOR
ADDITIONAL SYNOPTIC AND SATELLITE ANALYSIS SITUATION...

ACTIVE LINE OF CONVECTION DEVELOPED ALONG STRONG DEEP MOISTURE
CONVERGENCE ALONG A FRONTAL BOUNDARY RELATIVELY PARALLEL TO THE
FRONT RANGE.  WV LOOP SHOWS ELONGATED TROF ASSOCIATED WITH
NORTHERN STREAM SHORTWAVE OVER NORTHEAST WY EXTENDING BACK TO MORE
CONSOLIDATED SHORTWAVE ASSOCIATED WITH TROPICAL CYCLONE DOLORES
INTO NORTHWEST CO... WITH INCREASED MOISTURE THROUGH THE MID-LEVEL
SEEN BY COLDER TEMPS AS WELL AS INCREASED MOISTURE VALUES IN THE
700-500MB WITH .5-.8" THROUGH THAT DEPTH PER CIRA LAYERED TPW
LOOPS.  THIS HAS ALLOWED FOR LOWER LAPSE RATES THROUGH THE DEPTH
BUT WITH DAY TIME HEATING ALLOWED FOR INCREASED INSTABILITIES WITH
2000 J/KG FOR A NARROW SKINNY CAPE PROFILE INDICATIVE OF HIGHLY
EFFICIENT RAINFALL PRODUCTION AND REDUCED HAIL SIZES... FOR A MORE
NUMEROUS HAIL COVERAGE/DEPTH FOR INCREASED MELT AT SURFACE TO
COMPOUND HIGH RAINFALL TOTALS AS WELL. SURFACE/LOW LEVEL 20-30KT
SOUTHERLY FLOW IS NOT IMPEDED BY OTHER CONVECTION...CONTINUING TO
SUPPORT INSTABILITY ADVECTION AND LOW LEVEL MOISTURE CONVERGENCE.

WITH THE SHORTWAVE ENERGY REMAINING UPSTREAM...AND BEING ON THE
NORTH SIDE OF THE JET AXIS...CONTINUED PVA AS WELL AS UPPER LEVEL
LEFT EXIT DYNAMICS WILL SUPPORT CONTINUED UPSTREAM DEVELOPMENT AND
A SLIGHT INCREASE OF MEAN CELL MOTIONS.  THIS WILL ALLOW FOR
CURRENT CONVECTION TO SHIFT EASTWARD SLOWLY...AS SUGGESTED BY THE
MOST RECENT HRRR.  THIS MAY REDUCE SOME PROLONGED VERY HIGH TOTALS
BUT RATES IN EXCESS OF 2"/HR WILL BE LIKELY TO CONTINUE.  UPSTREAM
REDEVELOPMENT THOUGH WILL BE LIKELY GIVEN THE DYNAMIC SUPPORT AND
STEEPENING LAPSE RATES WITH A NARROW RIBBON OF LOW LEVEL
MOISTURE/HEATING NEARER THE FRONT RANGE THAT WAS UNAFFECTED BY THE
FIRST ROUND.  THIS WILL LIKELY TRAIN/REPEAT OVER AREAS CURRENTLY
AFFECTED...AND EXPECT INCREASED COVERAGE WITH THE EJECTION OF THE
SHORTWAVE. 


GALLINA

ATTN...WFO...BOU...CYS...GLD...LBF...PUB...

ATTN...RFC...ABRFC...MBRFC...

LAT...LON   42060365 42000246 41010170 40040210 39640254 
            39480279 39110344 38830553 39080552 39600541 
            40360530 41140513 41740476