MESOSCALE PRECIPITATION DISCUSSION 0505
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1224 PM EDT TUE JUL 18 2017

AREAS AFFECTED...PORTIONS OF EASTERN AZ

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

VALID 181623Z - 182223Z

SUMMARY...CIN IS ERODING WITHIN AN ANOMALOUSLY MOIST ENVIRONMENT
ACROSS AZ.  HOURLY RAIN RATES UP TO 2" WITH LOCAL AMOUNTS TO 3"
ARE EXPECTED.

DISCUSSION...EXPERIMENTAL GOES-16 IMAGERY SHOWS CUMULI ENHANCING
ACROSS PORTIONS OF SOUTHEAST AND EAST-CENTRAL AZ IN THE VICINITY
OF CYCLONIC FLOW NEAR AN INVERTED TROUGH AT 700 HPA, WHICH ALSO
SHOWS UP WITHIN SURFACE OBSERVATIONS.  WINDS AT THAT LEVEL ARE
10-15 KTS, DOUBLE THE MEAN 850-400 HPA WIND.  DIVERGENCE ALOFT IS
BEING AIDED BY AN UPPER TROUGH APPARENT ON WATER VAPOR IMAGERY
ACROSS SOUTH-CENTRAL NM, WHICH HAS AN EMBEDDED MCV EAST OF RESERVE
NM.  PRECIPITABLE WATER VALUES OF 1-1.7" EXIST HERE, MORE THAN 2.5
SIGMAS ABOVE THE MEAN FOR MID JULY.  ML CAPE VALUES ARE 500-1500
J/KG AND RISING WITH AN AREA OF MOSTLY CLEAR SKIES.

THE 06Z SSEO NEIGHBORHOOD PROBABILITIES INDICATE THAT CONVECTION
SHOULD GET GOING BETWEEN NOW AND 19Z AND EXPAND IN COVERAGE WITH
TIME.  AN ADDITIONAL 1000+ J/KG OF ML CAPE IS EXPECTED TO BUILD
INTO THIS AFTERNOON.  DEEP EASTERLY FLOW SHOULD LEAD TO SOME
WESTWARD MOTION CLOSE TO 15 KTS INTO LOWER VALLEYS, BUT
INSTABILITY LURKING NEARBY TO THE EAST COULD LEAD TO SHORT
TRAINING BANDS AND/OR BACKBUILDING AT TIMES.  THE MESOSCALE
GUIDANCE INDICATES THAT LOCAL AMOUNTS TO 3" ARE POSSIBLE HERE,
SIMILAR TO YESTERDAY.  THE AVAILABLE MOISTURE AND INSTABILITY
COULD LEAD TO HOURLY RAIN RATES UP TO 2".

ROTH

ATTN...WFO...FGZ...PSR...TWC...

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

LAT...LON   34711116 33701021 31480985 31281038 31291124
            31751218 33261219 34621192