Flash Flood Guidance
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724
AWUS01 KWNH 232025
FFGMPD
TXZ000-NMZ000-AZZ000-240130-

MESOSCALE PRECIPITATION DISCUSSION 0716
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
424 PM EDT WED AUG 23 2017

AREAS AFFECTED...EASTERN AZ...WESTERN NM...FAR WEST TX

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

VALID 232030Z - 240130Z

SUMMARY...SLOW MOVING CONVECTION DEVELOPING IN A HIGH MOISTURE
ENVIRONMENT COULD RESULT IN A FLASH FLOOD THREAT THROUGH LATE
AFTERNOON.

DISCUSSION...REGIONAL RADARS ACROSS EASTERN AZ AND WESTERN NM HAVE
SHOWN AN UPTICK IN CONVECTIVE COVERAGE EARLY THIS AFTERNOON. THE
CONVECTION IS FORMING IN AN AREA OF 500-1000 J/KG MLCAPE (AS THE
CIN CONTINUES TO ERODE). THE MOST RECENT RAP ANALYSIS SHOWED
1.25/1.50 INCH PRECIPITABLE WATER AIR OVER EASTERN NM/WESTERN
NM...WITH HIGHER AMOUNTS OVER SOUTHEAST AZ (CLOSER TO THE MODIFIED
MONSOONAL FLOW).

THE KEMX RADAR SHOWED HOURLY RAINFALL RATES NEAR 2.00 INCHES OVER
SOUTHWEST COCHISE COUNTY IN SOUTHEAST AZ. HOWEVER...THIS COULD BE
HAIL CONTAMINATED...AS MODEL SOUNDINGS SHOWED SOME DRY AIR IN THE
MID LEVELS...AND THE KEMX HCA PRODUCT INDICATED THE PRESENCE OF
HAIL.

THE CONVECTION IS FORMING NEAR THE AXIS OF THE MID LEVEL RIDGE
OVER EASTERN AZ/WESTERN NM...AND BECAUSE OF THIS...THE CONVECTION
FORMING OVER THE HIGHER TERRAIN HAS BEEN MOVING SLOWLY. AS AN MCV
OVER NORTHERN MEXICO TRACKS NORTH INTO SOUTHEAST AZ...THE FORCING
COULD ALLOW THE CONVECTION TO BECOME MORE WIDESPREAD. AHEAD OF THE
MCV...A LOW LEVEL 15 TO 20 KNOT SOUTHEAST INFLOW SHOULD CONTINUE
TO SUPPLY DEEP MOISTURE TO THE DEVELOPING CONVECTION.

THE MOST RECENT HRRR SHOWED LOCAL 1.50 TO 2.50 INCH RAINFALL
AMOUNTS OVER PORTIONS OF SOUTHEAST AZ INTO FAR WESTERN TX AND
SOUTH CENTRAL NM THROUGH 0130Z. THE COVERAGE SHOULD BE SUFFICIENT
TO INCREASE THE FLASH FLOOD THREAT...EVEN AS CELL MOTIONS
INCREASE.

HAYES

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

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

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

LAT...LON   35280851 35270726 33370538 32480512 31490535
            30670726 31090972 31191105 31541153 32131147
            32751096 34670944



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