MESOSCALE PRECIPITATION DISCUSSION 0371
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
407 PM EDT MON JUL 20 2015
 
AREAS AFFECTED...CENTRAL TO EASTERN NM/TX PANHANDLE... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 202006Z - 210036Z
 
SUMMARY...VISIBLE SATELLITE IMAGERY SHOWED NUMEROUS CONVECTIVE
TOWERS ERUPTING OVER THE ELEVATED HEATING SOURCE OF THE SOUTHERN
ROCKIES. SLOW CELL MOTIONS OVER THE COMPLEX TERRAIN MAY LEAD TO
PERIODS OF FLASH FLOODING THIS AFTERNOON/EVENING. FARTHER
EAST...AN ADDITIONAL THREAT FOR HEAVY RAINFALL EXISTS ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE EXTENDING INTO THE TX
PANHANDLE. 

DISCUSSION...THE 19Z SURFACE ANALYSIS OVER THE SOUTHERN ROCKIES
AND ADJACENT PLAINS SHOWED A PAIR OF BOUNDARIES IN PLACE. SURFACE
CONVERGENCE ALONG THE HIGHER TERRAIN OF NM IN CONJUNCTION WITH
SUFFICIENT DIURNAL HEATING HAS SUPPORTED THE DEVELOPMENT OF
NUMEROUS AREAS OF THUNDERSTORMS. THE 19Z RAP OBJECTIVE ANALYSIS
INDICATED VERY STEEP LAPSE RATES IN THE LOWER/MIDDLE TROPOSPHERE
ACROSS CENTRAL NM WITH 9 TO 9.5 C/KM RATES ANCHORING THE 0 TO 3 KM
LAYER. FARTHER TO THE EAST...SOME CU HAVE DEVELOPED ALONG THE
EAST-WEST TEMPERATURE GRADIENT WITH ROBUST SURFACE-BASED CAPE
VALUES IN THE 5000 TO 6000 J/KG RANGE. THESE SEEM SOMEWHAT BIASED
BY QUESTIONABLE SURFACE DEW POINTS IN THE REGION.
REGARDLESS...TREMENDOUS BUOYANCY IN THE ATMOSPHERE WILL SUPPORT
ADDITIONAL CONVECTION SPREADING EASTWARD INTO THE TX PANHANDLE
DURING THE NEXT FEW HOURS.

LOW-LEVEL WIND FIELDS SHOW A SUBTLE UPSLOPE COMPONENT IN THE FLOW
WHICH SHOULD HELP MAINTAIN SOME OF THE ACTIVITY ALONG THE EASTERN
FLANK OF THE SOUTHERN ROCKIES. SLOW CELL MOTIONS OVER THIS REGION
WILL SUPPORT AN INHERENT FLASH FLOOD RISK...PARTICULARLY IN AREAS
OF LOWER FFG VALUES. THE RISK DOWNSTREAM IS A BIT MORE UNCERTAIN
PENDING ANY SORT OF CELL TRAINING/BACKBUILDING ALONG THE BOUNDARY.

CONVECTION-ALLOWING MODELS ARE CONSISTENT WITH HEAVIER RAINFALL
OVER THE NM TERRAIN WITH PLACEMENT UNCERTAINTY TOWARD THE TX
PANHANDLE. THE PAST FEW CYCLES OF THE OPERATIONAL HRRR HAVE
STRUGGLED WITH CONVECTIVE INITATION. TENDED TO LEAN A BIT MORE ON
THE EXPERIMENTAL RUNS. PLEASE VIEW THE LATEST SPE FROM NESDIS/SAB
FOR ADDITIONAL INFORMATION.


RUBIN-OSTER

ATTN...WFO...ABQ...AMA...EPZ...LUB...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   36800569 36650469 36150425 35470364 35440255 
            35670190 35540127 34970108 34620169 34440295 
            34150423 33700464 32580499 32380573 32930633 
            33910641 34810627 35540625 36420631