188
AWUS01 KWNH 130116
FFGMPD
AZZ000-NVZ000-CAZ000-130700-
MESOSCALE PRECIPITATION DISCUSSION 1029
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
915 PM EDT WED AUG 12 2026
AREAS AFFECTED...SOUTHEAST CALIFORNIA...SOUTHERN ARIZONA...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 130115Z - 130700Z
SUMMARY...COLLIDING OUTFLOW BOUNDARIES SEEKING OUT REMAINING
CONDITIONALLY UNSTABLE BUT MOIST ENVIRONMENT IN THE LOW VALLEYS.
SMALL CLUSTERS MAY EVOLVE AND PROGRESS EASTWARD FOR RANDOM
REPEATING OF AREAS AFFECTED EARLIER THIS EVENING. RATES OF
1-1.5"/HR AND SPOTS OF ADDITIONAL 2" THROUGH EARLY OVERNIGHT
PERIOD MAY RESULT IN LOCALIZED INCIDENTS OF FLASH FLOODING.
DISCUSSION...GOES-E WV SUITE CONTINUES TO DEPICT ENHANCING
SOUTHWESTERLY SUB-TROPICAL FLOW IN ADVANCE OF DEEPER LAYER CLOSED
LOW OFF WEST-CENTRAL CA COAST. INCREASING FLUX OFF THE WARM GULF
OF CALIFORNIA COMBINED WITH OUTFLOW BOUNDARIES FROM INITIAL
CONVECTION NEAR THE SALTON SEA MERGING WITH SOUTHWARD PROPAGATING
OUTFLOW OFF THE WESTERN MOGOLLON RIM INTO THE DESERTS ARE
PROVIDING INCREASINGLY BROADER AREAS OF CONVERGENCE FROM SE SAN
BERNARDINO TO LA PAZ AND NOW STARTING ACROSS MARICOPA COUNTY.
FADING VISIBLE IMAGERY SHOWS SCATTERED TOWERING CU STARTING TO
DEVELOP INTO BROADER UPDRAFTS AND DEEPER CONVECTION ACROSS THOSE
AREAS.
CIRA LPW NOTES, .75-.8" SFC-850MB LPW AND BROAD .5 TO .7"
850-700MB COVER MUCH OF THE LOWER COLORADO INTO SOUTHERN ARIZONA
SUPPORTING SHIFTING LOW LEVEL PROFILES TO SUPPORT INCREASED CAPE
ACROSS THE VALLEY FLOOR FOR THESE BOUNDARIES TO OVERTURN. RAP
ANALYSIS SHOWS AN AXIS OF WEAKENING OR ZERO CINH FROM E RIVERSIDE
TO S MARICOPA WITH 1500-2000 J/KG OF MLCAPE TO WORK WITH.
SLIGHTLY LOWER MOISTURE/THETA-E AIR AT THE SURFACE FURTHER EAST
INTO NW PIMA COUNTY STILL REMAINS CONDITIONALLY UNSTABLE WITH
VALUES IN THE 1000 J/KG RANGE. AS SUCH, THE SCATTERED CONVECTION
WILL CONTINUE TO INTENSIFY AND EXPAND IN COVERAGE WITH RATES OF
1-1.5" OCCASIONALLY REACHING 1.75" IN THE STRONGEST CORES NEAR THE
COLORADO RIVER AND POINTS EAST. DEEP LAYER FLOW SHOWS SOME
VEERING IN THE NEXT FEW HOURS AS CLUSTERS/MERGERS WILL FORM OR
PROPAGATE ALONG OUTFLOW BOUNDARIES EASTWARD INTO THAT REMAINING
UNSTABLE AIR ACROSS SOUTH-CENTRAL AZ, PERHAPS WITH A BITH
SOUTHWEST TO NORTHEASTWARD TREND TOWARD THE LOWER MOGOLLON RIM
SLOPES GIVING AN OPPORTUNITY AFTER 05-06Z TO INTERSECT AREAS
ALREADY AFFECTED EARLIER THIS EVENING. AS SUCH, WIDELY SCATTERED
AREAS OF 1.5-2" TOTALS IN 1-2 HOURS ARE POSSIBLE WHICH MAY RESULT
IN LOCALIZED INCIDENTS OF FLASH FLOODING THROUGH THE EARLY
OVERNIGHT PERIOD.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...FGZ...PSR...TWC...VEF...
ATTN...RFC...RSA...STR...NWC...
LAT...LON 35491499 35171397 34431299 34201139 34201036
33530989 32850990 32131040 31761139 31831242
32181350 32441404 32861440 33531482 33931553
34881582
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