MESOSCALE PRECIPITATION DISCUSSION 0267
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
753 PM EDT TUE AUG 12 2014
 
AREAS AFFECTED...EXTREME SWRN NM INTO AZ...SRN NV AND SERN CA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 122352Z - 130552Z
 
SUMMARY...RAIN RATES UP TO 1.25 IN/HR WILL REMAIN POSSIBLE BEFORE
CAPE IS EXHAUSTED ACROSS EXTREME SWRN NM INTO CNTRL/SRN AZ AND SRN
NV. INCREASING SELY FLOW AT 700 MB MAY ALLOW FOR REPEATING CELL
MOTIONS AND LOCALIZED STORM TOTALS OF 2-4 INCHES BY 06Z.

DISCUSSION...VISIBLE SATELLITE IMAGERY SHOWED A SLOW MOVING...WELL
DEFINED CIRCULATION OVER SWRN AZ WHICH HAD BEEN ASSOCIATED WITH
ENHANCED CLOUD COVER THROUGH MUCH OF THE DAY WHICH HAS KEPT THE
REGION CAPPED. SOME RECENT BREAKS IN CLOUD COVER HAVE ALLOWING
SURFACE TEMPERATURES TO RISE INTO THE UPPER 80S BUT THE BEST
INSTABILITY AND COVERAGE OF SHOWERS REMAINS TO THE NORTH OF THE
LOW WHERE BETTER DAYTIME HEATING TOOK PLACE DURING THE AFTERNOON.
SURFACE BASED GPS PRECIPITABLE WATER MEASUREMENTS SHOW VALUES OF
1.9 TO 2.1 INCHES ACROSS SWRN AZ WITH FLOW AROUND THE LOW HELPING
TO FEED IN MOISTURE FROM SONORA.

FLOW AT 700 MB IS EXPECTED TO INCREASE ANOTHER 10 KTS OVER THE
NEXT FEW HOURS OVER AZ WHICH WILL PARALLEL AND EXCEED SLOW STORM
MOVEMENT FROM SE TO NW...POSSIBLY ALLOWING FOR REPEAT CELL
MOTIONS. GIVEN REMAINING ML CAPE OF 500 TO 1500 J/KG...RAINFALL
RATES WILL CONTINUE TO RANGE FROM ABOUT 0.5 TO 1.25 IN/HR WITH
REPEATING CELL MOVEMENT POSSIBLY ALLOWING FOR ADDITIONAL 2-4 INCH
STORM TOTALS ON A LOCALIZED BASIS. SOME OF THE HI-RES MODEL
GUIDANCE SUGGESTS THE POTENTIAL FOR CONVECTION TO FIRE AFTER 00Z
NEAR THE UPPER LOW CENTER BUT IT APPEARS THE SWRN CORNER OF
ARIZONA WILL REMAIN FREE OF CONVECTION WITH ONLY A VERY SMALL
CHANCE FOR FLASH FLOODING IF STORMS DO HAPPEN TO FIRE.

OTTO

ATTN...WFO...ABQ...EPZ...TWC...FGZ...PSR...VEF...

ATTN...RFC...CBRFC...CNRFC...WGRFC...

LAT...LON   34761567 36271607 36891550 36671383 35461153 34130971
            32440800 31210757 30970919 31181121 31471256 32121378
            34181473 34761567