MESOSCALE PRECIPITATION DISCUSSION 0517
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 PM EDT THU JUL 20 2017

AREAS AFFECTED...AZ...WESTERN NM

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

VALID 201905Z - 210105Z

SUMMARY...A GRADUAL INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY
IS EXPECTED THROUGH THE AFTERNOON HOURS. SOME FLASH FLOODING WILL
BE POSSIBLE.

DISCUSSION...A RELATIVELY BROAD AND WEAK LOW TO MID LEVEL
LOW/TROUGH CAN BE SEEN IN EXPERIMENTAL GOES-16 7.3 MICRON/LLWV
IMAGERY MOVING SLOWLY NORTHWEST ACROSS WESTERN NM AND EASTERN AZ.
MEANWHILE...A VERY WELL-DEFINED MCV IS NOTED OVER CENTRAL AREAS OF
THE MOGOLLON RIM. THE ENVIRONMENT OVERALL IS NOT QUITE AS MOIST AS
IN RECENT DAYS...HOWEVER PWATS ARE STILL RUNNING UP BETWEEN 1.5
AND 1.8 INCHES...WITH THE MOISTURE A BIT MORE CONCENTRATED AND
THROUGH A DEEPER COLUMN OVER SOUTHERN AND WESTERN AZ. RELATIVELY
MODEST INSTABILITY IS IN PLACE CURRENTLY WITH 500 TO 1000 J/KG OF
MLCAPE...BUT ADDITIONAL STRONG DIURNAL HEATING WILL INCREASE THESE
VALUES THROUGH THE AFTERNOON...AND THIS COUPLED WITH THE BROAD
CYCLONIC FLOW AND SMALL SCALE VORT CENTER ENERGY WILL ALLOW
CONVECTION TO GRADUALLY INTENSIFY AND EXPAND IN COVERAGE. ALREADY
CONVECTIVE INITIATION IS UNDERWAY OVER AREAS OF WESTERN NM AND IS
A VERY SCATTERED MANNER OVER THE MOGOLLON RIM AND ADJACENT AREAS
OF CENTRAL/EASTERN AZ.

A CONSENSUS OF THE HIRES GUIDANCE INCLUDING THE 12Z ARW/NMMB AND
NSSL-WRF...ALONG WITH THE LATEST HRRR RUN...SUPPORT THE HEAVIEST
RAINFALL POTENTIAL GENERALLY IN NW/SE FASHION FROM THE MOGOLLON
RIM NEAR THE CURRENT MCV AND STRETCHING DOWN INTO SOUTHEAST AZ
THROUGH THE 00Z TIME-FRAME.

RAINFALL RATES OF 1.5 TO 2 INCHES/HR WILL BE EXPECTED WITH THE
CURRENT DEGREE OF MOISTURE IN THE VERTICAL COLUMN...WITH STORM
TOTAL POTENTIAL PERHAPS AS HIGH AS 3 INCHES. GIVEN THE SENSITIVITY
OF THE LAND-MASS AREAS SUCH AS DRY WASHES AND ARROYOS...INCLUDING
BURN SCARS...AND ESPECIALLY STEEP TERRAIN...THERE WILL REMAIN A
RISK OF FLASH FLOODING.

ORRISON

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

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

LAT...LON   37051184 36920963 36230846 34840774 33310757
            31680801 31170976 31521196 32831293 33361335
            34191396 35581408 36621353