MESOSCALE PRECIPITATION DISCUSSION 0562
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
437 PM EDT TUE OCT 06 2015
 
AREAS AFFECTED...AZ/FAR WESTERN NM... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 062036Z - 070136Z
 
SUMMARY...AN UPPER LOW SPINNING OVER FAR WEST-CENTRAL AZ HAS
HELPED FIRE A BROAD AREA OF SLOW-MOVING CONVECTION. TO THE
EAST...MULTIPLE 
THUNDERSTORMS CONTINUE TO LIFT NORTH-NORTHEAST WHILE BEING
ENTRENCHED IN GENERAL UNIDIRECTIONAL FLOW. BOTH REGIONS CAN EXPECT
A THREAT FOR FLASH FLOOD THREAT INTO THE EVENING HOURS.

DISCUSSION...WATER VAPOR IMAGERY SHOWED A NEARLY STATIONARY UPPER
LOW ACROSS FAR WEST-CENTRAL AZ. STEEP MID-LEVEL LAPSE RATES
ACCOMPANYING THIS FEATURE HAS SPAWNED NUMEROUS THUNDERSTORMS IN
ITS VICINITY. THE MOST ACTIVE CONVECTION JUST MOVED THROUGH THE
WESTERN SIDE OF THE PHOENIX AZ METRO AREA. RECENT OBSERVATIONS
FROM NWS CHAT SHOWED 0.68 INCHES OF RAIN IN ONLY 20 MINUTES.
CORFIDI VECTORS ARE QUITE SMALL IN THE VICINITY OF THIS UPPER LOW
WHICH SUPPORTS AN INHERENT FLASH FLOOD RISK.

FARTHER EAST...MULTIPLE THUNDERSTORM CLUSTERS HAVE FIRED AMIDST AN
UNCAPPED AND HIGHLY BUOYANT ATMOSPHERE. THE 20Z RAP OBJECTIVE
ANALYSIS SHOWED 500 TO 1000 J/KG OF MIXED-LAYER CAPES ACROSS THE
REGION. THE BETTER MOISTURE TRANSPORT AND HIGHER PWAT AIR
CONCENTRATES ON THE WESTERN SIDE OF THE STATE. HOWEVER...THE 0.50
TO 0.75 INCH PWATS ACROSS EASTERN AZ SHOULD BE ENOUGH TO SUPPORT
HEAVY DOWNPOURS CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING.
ADDITIONALLY...THE 12Z SOUNDING FROM TUCSON SHOWED NEARLY
UNIDIRECTIONAL FLOW IN PLACE WITH RECENT RAP FORECAST SOUNDINGS
SUPPORTING A SIMILAR VERTICAL WIND PROFILE THIS AFTERNOON/EVENING.
THERE ARE STILL PLENTY OF REGIONS OF NEARLY CLOUD-FREE SKIES
ACROSS THE SOUTHERN SIDE OF THE STATE WHICH COULD PROMOTE THE
DEVELOPMENT OF ADDITIONAL CONVECTION THIS AFTERNOON. FORECAST CELL
MOTIONS WOULD CARRY THESE FUTURE CELLS NORTHWARD INTO AREAS
CURRENTLY CONVECTING. RECENT HRRR RUNS DO SHOW THIS SCENARIO WHICH
COULD LEAD TO POTENTIAL FLASH FLOODING WHERE REPEAT CONVECTION
OCCURS.


RUBIN-OSTER

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

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

LAT...LON   36590966 36400886 34210882 32580934 31850983 
            31831115 32341207 32691313 33561365 34711387 
            35451327 35881111