374
AWUS01 KWNH 041811
FFGMPD
TXZ000-NMZ000-AZZ000-050010-
MESOSCALE PRECIPITATION DISCUSSION 1199
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
210 PM EDT FRI SEP 04 2026
AREAS AFFECTED...SOUTHEAST AZ...WESTERN AND CENTRAL NM
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 041810Z - 050010Z
SUMMARY...MONSOONAL SHOWERS AND THUNDERSTORMS WITH SOME HIGH-LEVEL
MOISTURE TAP FROM HURRICANE MARIE IN THE EASTERN PACIFIC WILL
IMPACT SOUTHEAST AZ THROUGH THE WESTERN HALF OF NM THIS AFTERNOON.
SCATTERED AREAS OF FLASH FLOODING ARE LIKELY WITH IMPACTS MOST
LIKELY FOCUSED ON BURN SCARS AND ARROYOS.
DISCUSSION...THE LATE MORNING GOES-W GEOCOLOR SATELLITE IMAGERY
ALONG WITH LIGHTNINGCAST DATA SHOWS CONVECTIVE INITIATION TAKING
PLACE ACROSS AREAS OF THE SOUTHWEST WITH AN EMPHASIS ON SOUTHEAST
AZ THROUGH MUCH OF WESTERN AND CENTRAL NM. THE LARGER SCALE VIEW
OF THE SOUTHWEST SHOWS A RATHER WELL-DEFINED MID TO UPPER-LEVEL
CHANNEL OF MOISTURE STREAMING NORTHEASTWARD UP ACROSS THE REGION,
WITH ORIGINS OF SOME OF THIS MOISTURE EXTENDING WELL SOUTHWEST
DOWN TO HURRICANE MARIE SOUTHWEST OF THE BAJA PENINSULA.
OSPO-ALPW AND EXPERIMENTAL CIRA-LVT DATA SHOWS MOISTURE UP IN THE
500/300 MB LAYER THAT WILL FACILITATE A NOTABLY EFFICIENT VERTICAL
COLUMN FOR ENHANCED RAINFALL RATES THIS AFTERNOON AS THE DIURNAL
HEATING CYCLE/BOUNDARY LAYER DESTABILIZATION PROCESS CONTINUES AND
CONVECTION DEVELOPS AND EXPANDS IN COVERAGE.
SBCAPE VALUES HAVE ALREADY RISEN TO AS MUCH AS 1000 TO 2000 J/KG
AND THE AFOREMENTIONED MOISTURE TRANSPORT IS DRIVING PWS AS HIGH
AS 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SOME MODEST EFFECTIVE
BULK SHEAR OF 20 TO 30 KTS IS IN PLACE WITH THE STRONGER MID TO
UPPER-LEVEL SOUTHWEST FLOW ALOFT, AND THIS SHEAR COUPLED WITH THE
THERMODYNAMIC ENVIRONMENT MAY FAVOR SOME LOCALLY ORGANIZED
CONVECTIVE CELLS, WITH A MIX OF PULSE AND MULTI-CELL CONVECTION
BEING THE PRIMARY CONVECTIVE MODE.
THE RAINFALL RATES ARE LIKELY TO BE QUITE HIGH GIVEN THE
ENVIRONMENT AND THE ADDITION OF OROGRAPHIC ASCENT/TERRAIN-FOCUSED
CONVECTION WILL HELP SUPPORT SOME RAINFALL RATES AS HIGH AS 1 INCH
IN 20 TO 30 MINUTES, AND SOME HOURLY TOTALS UP TO 2 INCHES. THE
HIRES MULTI-MODEL CAM GUIDANCE SUGGESTS SOME SPOTTY TOTALS BY
LATER THIS AFTERNOON OF 2 TO 4 INCHES AND THIS MAY BE DRIVEN NOT
ONLY BY TERRAIN, BUT ALSO A COUPLE OF CELL-MERGERS.
GIVEN THE SETUP WITH RAINFALL RATES AND TOTALS, SCATTERED AREAS OF
FLASH FLOODING ARE LIKELY. THE GREATEST IMPACTS ARE EXPECTED TO BE
FOR THE NORMALLY DRY WASHES/ARROYOS AND BURN SCAR LOCATIONS,
INCLUDING DOWNSTREAM AREAS EVEN AWAY FROM WHERE THE HEAVIEST
RAINFALL OCCURS.
ORRISON
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...
ATTN...RFC...FWR...STR...TUA...NWC...
LAT...LON 36360644 36130545 35280495 33830504 33060525
32600549 31740661 31250860 31201036 31401137
32071189 33111187 34091124 35131011 36030843
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