919
AWUS01 KWNH 101812
FFGMPD
COZ000-NMZ000-AZZ000-UTZ000-NVZ000-CAZ000-110010-
MESOSCALE PRECIPITATION DISCUSSION 1472
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
210 PM EDT SAT OCT 10 2026
AREAS AFFECTED...SOUTHWEST U.S.
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 101810Z - 110010Z
SUMMARY...SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP TODAY
ACROSS THE SOUTHWEST U.S. LOCALLY HEAVY RAINFALL RATES OF UP TO 1
TO 2 INCHES/HOUR WILL BE POSSIBLE, AND THIS MAY RESULT IN SOME
AREAS OF FLASH FLOODING. THIS WILL INCLUDE POTENTIAL IMPACTS TO
THE NORMALLY DRY WASHES, BURN SCARS AND SLOT CANYONS.
DISCUSSION...GOES-W GEOCOLOR SATELLITE IMAGERY OVER THE LAST
COUPLE OF HOURS ALONG WITH MRMS DATA HAS BEEN SHOWING SOME
DEVELOPMENT AND LOCALIZED EXPANSION OF SHOWER AND THUNDERSTORM
ACTIVITY ACROSS AREAS OF SOUTHWEST UT, AND SEPARATELY DOWN ACROSS
SOUTHWEST AZ AND ADJACENT AREAS OF THE NORTHERN BAJA PENINSULA.
MUCH OF THE CURRENT ACTIVITY ACROSS SOUTHWEST UT IS MORE CONNECTED
TO INCREASING DEEP LAYER MOISTURE TRANSPORT, OROGRAPHICS AND SOME
MODEST UPPER-JET FORCING OVER THE REGION. WHEREAS DOWN ACROSS
SOUTHWEST AZ AND THE ADJACENT BAJA PENINSULA, IT IS MORE CONNECTED
TO INCREASING SOUTHERLY LOW-LEVEL MOISTURE AND INSTABILITY
TRANSPORT OFF OF THE GULF OF CA IN RESPONSE TO THE APPROACH OF
T.S. RACHEL. THIS IS CONFIRMED BY THE LATEST EXPERIMENTAL
CIRA-LAYERED VAPOR TRANSPORT PRODUCT.
A NOSE OF SBCAPE VALUES REACHING 1000+ J/KG HAS REACHED UP ACROSS
SOUTHWEST AZ AND FAR SOUTHEAST CA, AND OVER THE NEXT SEVERAL
HOURS, A MORE REGIONAL INCREASE IN BOUNDARY LAYER INSTABILITY IS
EXPECTED VIA FILTERED SOLAR INSOLATION. THE INCREASE IN
INSTABILITY ALONG WITH A BROADER INCREASE IN MOISTURE THROUGH THE
COLUMN WILL ENCOURAGE THE FURTHER DEVELOPMENT AND EXPANSION OF
MAINLY SCATTERED SHOWERS AND THUNDERSTORMS OVER THE NEXT SEVERAL
HOURS. THIS WILL BE FURTHER AIDED BY AREAS OF OROGRAPHIC ASCENT.
PW ANOMALIES CONTINUE TO INCREASE IN ASSOCIATION WITH T.S.
RACHEL'S MID AND HIGH LEVEL MOISTURE AND THE INCREASING LOW-LEVEL
GULF OF CA CONTRIBUTION, AND BY LATER TODAY THESE ANOMALIES FOR
MANY AREAS WILL BE EXCEEDING THE 95TH PERCENTILE OF CLIMATOLOGY.
RAINFALL RATES MAY REACH AS HIGH AS 1 TO 2 INCHES/HOUR WITH SOME
OF THE MORE ORGANIZED CONVECTIVE CORES TODAY, AND THE LATEST HIRES
CAM GUIDANCE AND GENERAL THERMODYNAMIC TRENDS SUGGEST AT LEAST AN
ISOLATED THREAT FOR SOME 2 TO 3 INCH RAINFALL TOTALS. AREAS OF
SOUTHEAST CA AND SOUTHERN AZ WILL BE AT GREATEST RISK FOR THESE
TOTALS GIVEN GREATER MOISTURE AND INSTABILITY CONCENTRATIONS.
THIS MAY RESULT IN SOME AREAS OF FLASH FLOODING, WITH THE NORMALLY
DRY WASHES, BURN SCAR AREAS, AND SLOT CANYONS AT GREATEST RISK FOR
IMPACTS.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ABQ...FGZ...GJT...LOX...PSR...SGX...SLC...TWC...
VEF...
ATTN...RFC...RSA...STR...NWC...
LAT...LON 38921035 38820865 38030823 37060848 36130915
35320989 34181036 33161025 32160962 31290988
31221182 31591286 31951388 32201512 32221659
32541746 33221818 33771912 34421901 34681790
35101654 36051519 37311423 38081329 38611191
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