401
AWUS01 KWNH 171853
FFGMPD
AZZ000-UTZ000-NVZ000-172350-
MESOSCALE PRECIPITATION DISCUSSION 0755
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 PM EDT FRI JUL 17 2026
AREAS AFFECTED...NORTHERN ARIZONA
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 171851Z - 172350Z
SUMMARY...WIDELY SCATTERED TERRAIN BASED THUNDERSTORMS OVER
SOUTHERN UTAH AND NORTHERN ARIZONA WILL MOVE SLOWLY THROUGH THIS
AFTERNOON. HOURLY RAINFALL TO 2.0" ARE LIKELY WITH WIDELY
SCATTERED FLASH FLOODING EXPECTED.
DISCUSSION...AS OF 1830Z... TERRAIN-BASED THUNDERSTORMS HAVE
DEVELOPED OVER SOUTHERN UTAH AND NORTHERN/CENTRAL ARIZONA WHERE
SUNSHINE HAS BEEN PRESENT. PERSISTENT CLOUDS OVER LAS VEGAS AND
LAKE MEAD HAS LIMITED DEVELOPMENT THERE. ELEVATED MOISTURE IS
SHIFTING NORTH UP THE COLORADO RIVER VALLEY WITH 2.3" PW ALONG THE
CA/AZ BORDER AND 1.5" EXTENDING OVER SOUTHERN NV AND 1.2" INTO THE
SLOT CANYON REGION OF SOUTHERN UT AND AROUND THE GRAND CANYON,
WHICH ABOUT 3 SIGMA ABOVE NORMAL. ACTIVITY SHOULD EXPAND FARTHER
EAST AS THE NOTED CLOUD COVER FURTHER ERODES.
LIGHT CYCLONIC FLOW IS NOTED IN THE MID LEVELS FROM A WEAK LOW
OVER NORTHERN AZ GENERALLY BRINGING NORTHEASTERLY FLOW AND
SOUTHWESTWARD STORM MOTION OVER THE DISCUSSION AREA. AMPLE
INSTABILITY IS PRESENT OVER THE AREAS THAT HAVE HAD SUNSHINE WITH
SBCAPE AROUND 1500 J/KG WHICH SHOULD RISE TO AROUND 3000 J/KG
LATER THIS AFTERNOON. RAIN RATES SHOULD PEAK AROUND 2"/HR AS
OUTFLOW PROMOTES STORM CLUSTERS. THIS WILL CONTINUE TO BE
MONITORED AS DESTABILIZATION EXPANDS.
JACKSON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...FGZ...GJT...PSR...SLC...VEF...
ATTN...RFC...STR...NWC...
LAT...LON 38501226 38501108 36591079 34631052 34021287
34391394 34561422 35141461 35901430 36531414
37181400 37311390 37931318
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