Graphic for MPD #0520

MESOSCALE PRECIPITATION DISCUSSION 0520...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
905 PM EDT THU JUL 20 2017

CORRECTED FOR WORDING OF MID LEVEL TROUGH AXIS

AREAS AFFECTED...FAR SOUTHWEST TX...WESTERN NM...AZ

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 210100Z - 210600Z

SUMMARY...AN EXTENSIVE AREA OF SHOWERS AND THUNDERSTORMS CONTINUES
ACROSS AREAS OF WESTERN NM AND AZ. LOCALLY INTENSE RAINFALL WILL
CONTINUE THROUGH LATE EVENING WITH ADDITIONAL FLASH FLOODING
CONCERNS.

DISCUSSION...LATE-DAY EXPERIMENTAL GOES-16 MICRON/IR SATELLITE
IMAGERY SHOW A WIDESPREAD AREA OF COLD-TOPPED PULSE CONVECTION
OVER WESTERN NM AND A LARGE AREA OF AZ THAT CONTINUES TO GENERATE
LOCALLY INTENSE RAINFALL RATES OF UP TO 2 INCHES/HR. THE OVERALL
CLOUD PATTERN IS REPRESENTATIVE OF A CLASSIC MONSOON SET-UP AND
THE LATEST CIRA-LPW PRODUCT AGAIN SHOWS A DEEP COLUMN OF MOISTURE
SUPPORTING PWAT ANOMALIES OF 2 TO 2.5 STANDARD DEVIATIONS ABOVE
NORMAL FROM SOUTHWEST NM ACROSS SOUTHERN AND WESTERN AZ POINTS
NORTH UP ACROSS MUCH OF UT AND INTO WESTERN CO AROUND THE WESTERN
PERIPHERY OF A MID LEVEL SUBTROPICAL RIDGE.

THE MOISTURE IN CONJUNCTION WITH DIURNAL HEATING AND OROGRAPHICS
WILL CONTINUE TO FOSTER NUMEROUS SHOWERS/THUNDERSTORMS THROUGH THE
EVENING...AND THERE IS ADDED SUPPORT BY PRESENCE OF A WEAK MID
LEVEL TROUGH/SHEAR AXIS THAT IS ORIENTED NNW/SSE FROM NORTHERN TO
SOUTHEAST AZ.

GIVEN THE AFOREMENTIONED RAINFALL RATES...FLASH FLOODING WILL
AGAIN BE A CONCERN OVER AREA DRY WASHES/ARROYOS AND ALSO THE MORE
FAVORED HIGHER TERRAIN AROUND AND ADJACENT TO THE MOGOLLON RIM.
THE LATEST HRRR GUIDANCE SUGGESTS AS MUCH AS AN ADDITIONAL 2 TO 3
INCHES OF RAIN LOCALLY THROUGH 06Z...AND ACTUALLY THERE IS SOME
SUPPORT FOR ADDITIONAL CONVECTION PERHAPS BEYOND THIS PERIOD OVER
PARTS OF EASTERN AND SOUTHERN AZ...AND ALSO SOUTHWEST NM WHERE
SOME LINGERING INSTABILITY AND WEAK MID LEVEL FORCING IS SUPPORTED
BY THE HIRES GUIDANCE. MORE BROADLY ON THE LARGE SCALE
THOUGH...THERE WILL TEND TO BE A WEAKENING TREND OF THE CONVECTION
BY LATE EVENING.

ORRISON

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

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

LAT...LON   37031178 36920992 36420874 35260762 33300634
            31970534 31270545 31280598 31720665 31700786
            31280842 31291006 31371103 31991213 32761289
            33461346 34231395 35581408 36631340


Last Updated: 917 PM EDT THU JUL 20 2017