MESOSCALE PRECIPITATION DISCUSSION 0526
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 PM EDT FRI JUL 21 2017

AREAS AFFECTED...SOUTHWEST TX...NM...AZ...FAR SOUTHERN UT...FAR
SOUTHWEST CO

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

VALID 211850Z - 220050Z

SUMMARY...MONSOONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP AND
EXPAND ACROSS THE SOUTHWEST THIS AFTERNOON AND CONTINUE INTO THE
EVENING. INTENSE RAINFALL RATES UP TO 2 INCHES/HR WILL AGAIN FAVOR
CONCERNS FOR FLASH FLOODING.

DISCUSSION...EXPERIMENTAL GOES-16 MICRON/IR SATELLITE IMAGERY
SHOWS SCATTERED AREAS OF THUNDERSTORMS DEVELOPING OVER AREAS OF
SOUTHWEST TX...CENTRAL/SOUTHERN NM AND WESTWARD INTO AZ ADJACENT
AREAS OF SOUTHERN UT AND FAR SOUTHWEST CO. THE CONVECTIVE
INITIATION WILL CONTINUE TO ENSUE THROUGH THE AFTERNOON AND EXPAND
IN COVERAGE AS PLENTY OF MONSOONAL MOISTURE REMAINS IN PLACE. THE
15Z CIRA-LPW DATA ALONG WITH MORNING 12Z RAOB DATA CONFIRMS THE
PERSISTENCE OF A RATHER DEEP COLUMN OF MOISTURE THAT REMAINS
RATHER CONCENTRATED UP IN THE 500/300 MB LAYER. THIS WILL AGAIN
FAVOR EFFICIENT RAINFALL PROCESSES THAT WILL LEAD TO ENHANCED
RAINFALL RATES. PWATS ARE RUNNING 1.5 TO 2.5 STANDARD DEVIATIONS
ABOVE NORMAL WITH THE HIGHEST ANOMALIES NOTED OVER SOUTHEAST AZ
AND SOUTHWEST NM.

THE CONVECTIVE MODE THIS AFTERNOON AND EVENING WILL AGAIN BE OF
THE PULSE TO MULTI-CELLULAR NATURE GIVEN RATHER WEAK SHEAR/WIND
FIELDS ALOFT...BUT THE RAINFALL RATES ARE LIKELY TO BE UPWARDS OF
2 INCHES/HR WITHIN THE STRONGER INSTABILITY DRIVEN CORES GIVEN THE
LEVEL OF MOISTURE IN PLACE.

THE LATEST EXPERIMENTAL GOES-16 0.64 MICRON/VIS SATELLITE IMAGERY
IS SHOWING MULTIPLE MCVS RESULTING FROM PRIOR CONVECTION OVER THE
LAST 24 HOURS...WITH ONE NOTE JUST EAST OFF THE AZ/NM BORDER
NORTHWEST OF SILVER CITY...AND ANOTHER ONE OVER NORTHEAST AZ
NORTHEAST OF THE MOGOLLON RIM. THESE CONVECTIVE VORTS ARE EMBEDDED
WITHIN A BROAD LOW/MID LEVEL TROUGH AXIS OVER THE REGION AND THE
BROADER CYCLONIC FLOW COUPLED WITH THE SMALL SCALE VORT
ENERGY/FORCING SHOULD FACILITATE BROADER CONVECTIVE COVERAGE WITH
SOME LOCALLY FOCUSED AREAS OF STRONGER CONVECTIVE CORES AS
STRONGER DIURNAL HEATING COMMENCES.

GIVEN THE AFOREMENTIONED RAINFALL RATES...FLASH FLOODING WILL
AGAIN BE A CONCERN OVER AREA DRY WASHES/ARROYOS AND ALSO THE MORE
FAVORED HIGHER TERRAIN INCLUDING THE MOGOLLON RIM. THE LATEST
HIRES MODEL CONSENSUS FROM THE ARW/NMMB AND NSSL-WRF...ALONG WITH
RECENT HRRR GUIDANCE SUPPORTS AS MUCH AS 2 TO 3 INCHES OF RAIN
LOCALLY THROUGH 00Z...WITH SOME ISOLATED HEAVIER AMOUNTS NOT OUT
OF THE QUESTION.

ORRISON

ATTN...WFO...ABQ...EPZ...FGZ...GJT...MAF...PSR...PUB...SLC...
TWC...VEF...

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

LAT...LON   38081242 37831183 37691121 37670995 37570862
            37390778 37460709 36500680 35840627 35280577
            33740487 32680436 31820369 30900366 30640475
            31050611 31530676 31650753 31370812 31250879
            31291056 31501143 33151247 34651388 36171416
            37621359