Flash Flood Guidance
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000
AWUS01 KWNH 250923
FFGMPD
TXZ000-NMZ000-251402-

MESOSCALE PRECIPITATION DISCUSSION 0396
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
523 AM EDT SUN JUN 25 2017

AREAS AFFECTED...EAST-CENTRAL TX/NM BORDER

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

VALID 250922Z - 251402Z

SUMMARY...THUNDERSTORMS WITH HOURLY RAIN RATES TO 2.5" ARE MOVING
FASTER TO THE SOUTH THAN ORIGINALLY EXPECTED.  LOCAL AMOUNTS TO 4"
ARE POSSIBLE.

DISCUSSION...CONVECTION WITH COOLING CLOUD TOPS HAS BEEN NOTED
NEAR THE TX/NM BORDER AS OF LATE.  WATER VAPOR IMAGERY REVEALS A
SHORTWAVE MOVING INTO NORTHEAST NM WHICH WHEN COMBINED WITH AN
OUTFLOW JET FROM A DYING CONVECTIVE CLUSTER OVER NORTHERN MEXICO
ARE AIDING DIVERGENCE ALOFT.  A SURFACE BOUNDARY HAS BEEN EVIDENT
IN THE THERMAL FIELD AND RADAR IMAGERY TO THE SOUTHWEST OF
FDX/CANNON AIR FORCE BASE NM OVERNIGHT.  INFLOW AT 850 HPA IS
SOUTHEASTERLY WITH AT 25-30 KTS PER VAD WIND PROFILES, MORE THAN
DOUBLE THE MEAN 850-400 HPA WIND.  EFFECTIVE BULK SHEAR IS 30-40
KTS.  GPS VALUES OF PRECIPITABLE WATER LIE BETWEEN 1.2-1.4".

AN INCREASINGLY SATURATED VERTICAL PROFILE  HAS BEEN MAKING
EFFECTIVE USE OF THE MUCAPE VALUES, WHICH ARE IN THE 500-1000 J/KG
RANGE.  SHOWER AND THUNDERSTORM COVERAGE HAS INCREASED FASTER THAN
EXPECTED AND IS MOVING ON A MORE SOUTHERLY TRAJECTORY.  A BUILDING
CONVECTIVE COLD POOL COULD EVENTUALLY INCREASE CONVERGENCE ALONG
THE SURFACE BOUNDARY AND SHIFT IT FAIRLY FAR DOWN THE TX/NM
BORDER.  CELL TRAINING AND BACKBUILDING ARE BEING OBSERVED, WITH
THE BULK SHEAR HELPING TO ORGANIZE BANDS AND POSSIBLY A
MESOCYCLONE OR TWO.  CELL MOTION TO THE SOUTH-SOUTHEAST AT 20 KTS
WILL INCREASE THE LOW-LEVEL INFLOW IN A STORM RELATIVE SENSE.
HOURLY RAIN RATES UP TO 2.5" HAVE BEEN NOTED ON RADAR ESTIMATES.
THE 00Z SPC WRF, 00Z WRF NSSL, AND RECENT HRRR RUNS HAVE BEEN
CAPTURING THIS MORE SOUTHWARD MOVEMENT.  LOCAL MAXIMA OF 4" APPEAR
POSSIBLE HERE.

ROTH

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

ATTN...WFO...ABQ...LUB...MAF...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   35110354 33810232 32740206 32450311 32530384
            33700399


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