Flash Flood Guidance
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000
AWUS01 KWNH 170622
FFGMPD
TXZ000-NMZ000-AZZ000-171221-

MESOSCALE PRECIPITATION DISCUSSION 0377
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 AM EDT WED SEP 17 2014

AREAS AFFECTED...SOUTHERN AZ/SOUTHWESTERN NM/FAR WEST TX...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 170621Z - 171221Z

SUMMARY...MODERATE TO HEAVY RAINFALL WILL GRADUALLY EXPAND IN
COVERAGE AS TROPICAL MOISTURE FROM T.S. ODILE BEGINS TO MOVE INTO
SOUTHERN AZ/ SOUTHWESTERN NM. HIGH-RESOLUTION MODELS SHOW A CLEAR
SIGNAL OF HEAVY PRECIPITATION THROUGH 12Z WHICH INCREASES THE
CONFIDENCE OF FLASH FLOODING TAKING PLACE.

DISCUSSION...AS OF 06Z...A BROAD AREA OF LIGHT TO MODERATE RAIN
WAS MOVING FROM NORTHWESTERN MX INTO SOUTHEASTERN AZ/SOUTHWESTERN
NM. SOME EMBEDDED HEAVIER SHOWERS SHOULD CROSS INTO THESE REGIONS
OF THE SOUTHWESTERN U.S. DURING THE NEXT HOUR OR SO. THE 00Z
SOUNDING OUT OF TUCSON AZ WAS QUITE MOIST WITH PWATS AROUND 1.77
INCHES WHICH IS JUST ABOVE THE 99TH PERCENTILE FOR MID-SEPTEMBER.
THE 05Z RAP SHOWED MOISTURE CONTINUING TO INCREASE AHEAD OF
TROPICAL STORM ODILE WITH PWATS APPROACHING 2 INCHES.

WHILE THE HIGH-RESOLUTION MODELS DO NOT COMPLETELY AGREE WITH ONE
ANOTHER...THERE IS STILL A STRONG SIGNAL OF HEAVY RAINFALL THROUGH
12Z ACROSS THE MPD AREA. THE 04Z HRRR AND 00Z ARW/NMM-B/NAM CONEST
ALL FOCUS MUCH OF THE PRECIPITATION OVER SOUTHWESTERN NM WITH 2 TO
4 INCHES PAINTED OVER THIS REGION THROUGH 12Z. THERE APPEARS TO BE
A SEPARATE MAXIMA BEING FORECASTED ACROSS SOUTHERN TO SOUTHEASTERN
AZ. 1 HOUR FFG VALUES ARE RATHER LOW SO EXPECT HIGH RAINFALL RATES
TO TRUMP THE GUIDANCE. AS USUAL...REGIONS OF COMPLEX TERRAIN CAN
EXPECT THE BEST THREAT FOR FLASH FLOODING GIVEN THE RAPID RUNOFF
ISSUES. CONFIDENCE IS HIGH IN THE EVENT UNFOLDING GIVEN THE AMOUNT
OF TROPICAL MOISTURE RISING NORTHWARD INTO AN AREA OF TERRAIN.
HOWEVER...IT REMAINS DIFFICULT TO PINPOINT EXACTLY WHERE THE
HEAVIEST RAINFALL WILL OCCUR.


RUBIN-OSTER

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ABQ...EPZ...FGZ...PSR...TWC...

ATTN...RFC...CBRFC...WGRFC...

LAT...LON   34260581 32830495 31840633 30760778 31061046
            31361282 32601321 33311189 33500998 34220729



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