938
AWUS01 KWNH 082158
FFGMPD
AZZ000-UTZ000-NVZ000-090345-
MESOSCALE PRECIPITATION DISCUSSION 0978
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
557 PM EDT SAT AUG 08 2026
AREAS AFFECTED...CENTRAL TO NORTHWEST AZ...SOUTHERN NV...SOUTHWEST
UT
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 082157Z - 090345Z
SUMMARY...AN ISOLATED THREAT FOR FLASH FLOODING WILL EXIST FROM
SCATTERED AREAS OF MONSOONAL SHOWERS AND THUNDERSTORMS THROUGH
EARLY THIS EVENING.
DISCUSSION...THE LATEST GOES-W SATELLITE IMAGERY, LIGHTNINGCAST,
AND GREMLIN PRODUCTS SHOW SCATTERED AREAS OF LOCALLY HEAVY SHOWERS
AND THUNDERSTORMS IMPACTING PORTIONS OF SOUTHEAST NV THROUGH
SOUTHWEST UT AND NORTHWEST/CENTRAL AZ. NEW AREAS OF CONVECTION ARE
EXPECTED TO INITIATE AND LOCALLY EXPAND IN COVERAGE THIS AFTERNOON
THROUGH EARLY THIS EVENING AS THE FULL DIURNAL HEATING CYCLE PLAYS
OUT.
MUCH OF THE ACTIVITY WILL CONTINUE TO BE TERRAIN-FOCUSED, BUT THE
ACTIVITY WILL INCREASINGLY MOVE OFF AREAS OF HIGHER TERRAIN OVER
THE NEXT FEW HOURS AND PROPAGATE DOWNWIND INTO AREAS OF STRONGER
BOUNDARY LAYER INSTABILITY AND ALSO WITH POTENTIAL FOR INTERACTING
WITH MULTIPLE OUTFLOW BOUNDARIES.
SBCAPE VALUES HAVE REACHED LOCALLY AS HIGH AS 1000 J/KG WITH THE
CONTINUATION OF STRONG BOUNDARY LAYER HEATING, AND WITH AREAS OF
TERRAIN STILL ENHANCING SOME DIFFERENTIAL HEATING BOUNDARIES,
CONVECTION WILL STILL BE CAPABLE OF FOCUSING ALONG THESE MESOSCALE
FEATURES THROUGHOUT THE AFTERNOON.
PWS ARE AS HIGH AS 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL ACROSS
AREAS OF SOUTHERN NV DOWN INTO WESTERN AZ. THESE ELEVATED PWS ARE
DUE TO THE DEEPER LAYER TRANSPORT OF MONSOONAL MOISTURE AROUND THE
WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE OVER THE SOUTHWEST.
THE MODEL GUIDANCE IS OVERALL PRETTY MODEST WITH ITS QPF OVER THE
NEXT SEVERAL HOURS, BUT WITH AREAS OF DEEPER AND SUSTAINABLE CLOUD
TOP COOLING SEEN, THERE WILL BE CONCERNS FOR LOCALLY HEAVY
RAINFALL. SLOW CELL-MOTIONS AND THE DEGREE OF MOISTURE THAT IS IN
PLACE MAY FOSTER SOME RAINFALL RATES OF UP TO 1.5 INCHES/HOUR, BUT
THIS WOULD BE HIGHLY ISOLATED IN NATURE. THE INSTABILITY UPTICK
ACROSS AREAS OF CENTRAL AND WESTERN AZ TO THE WEST OF THE MOGOLLON
RIM MAY FACILITATE THE DEVELOPMENT OR SUSTENANCE OF WESTWARD
MOVING CONVECTION OFF THE TERRAIN OF THE MOGOLLON RIM. SOME SPOTTY
RAINFALL AMOUNTS MAY REACH UP TO 2 INCHES GOING THROUGH EARLY THIS
EVENING, AND THIS MAY RESULT IN AN ISOLATED OCCURRENCE OF SOME
FLASH FLOODING. THE LOCAL BURN SCAR AND SLOT CANYON AREAS WILL BE
MOST SUSCEPTIBLE TO POTENTIAL IMPACTS ALONG WITH THE NORMALLY DRY
WASHES.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...FGZ...LKN...PSR...SLC...TWC...VEF...
ATTN...RFC...RSA...STR...NWC...
LAT...LON 40071466 39501390 38931273 39061190 38611130
37531144 36891148 36111145 35331121 34731077
34420995 33840972 33261013 33091109 33231233
33831331 34561379 35401404 36311432 36891480
37331621 37681691 38331739 39491723 39991621
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