MESO: Nws Weather Prediction Center College Park Md

AWUS01 KWNH 150433
FFGMPD
NMZ000-COZ000-AZZ000-150832-

MESOSCALE PRECIPITATION DISCUSSION 0253
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1233 AM EDT SUN SEP 15 2013

AREAS AFFECTED...FAR SE AZ...FAR SW CO...SW AND CNTRL NM

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

VALID 150432Z - 150832Z

SUMMARY...UPPER SUPPORT REMAINS EFFICIENT ENOUGH TO SUSTAIN
CLUSTERS OF THUNDERSTORMS OVERNIGHT. SLOW MOVEMENT MAY RESULT IN
1-2 INCH RAINFALL IN SPOTS AND LOCAL FLASH FLOODING.

DISCUSSION...THUNDERSTORMS HAD SURVIVED ALREADY A FEW HOURS INTO
THE NIGHT. RAOBS INDICATED THE SURFACE WOULD DECOUPLE RATHER
EASILY...BUT GIVEN THE PERSISTENCE OF CONVECTION IN SW NM AND SW
CO...AND NEW DEVELOPMENT NEAR ABQ AND ALSO OFF THE HIGHER
ELEVATIONS OF SE AZ AT 04Z...IT APPEARS THAT MID LEVEL
MOISTURE...MODERATELY STEEP LAPSE RATES...AND SUBTLE UPPER FORCING
COULD SUSTAIN THUNDERSTORMS ANOTHER FEW HOURS.

WEAK WARM ADVECTION WAS OBSERVED IN THE 700-600 MB
LAYER...COINCIDENT WITH SOME OF THE MORE UNSTABLE PARCELS IN THE
OBSERVED AND FORECAST SOUNDINGS...RAP AND NAM. THE SREF MEAN
PREDICTS MAINTENANCE OF MUCAPE AT LEAST 500-750 J/KG THROUGH 09Z
ACROSS THIS REGION...AS THE LOWER/MID LEVEL WARM ADVECTION AND
WEAKLY DIFFLUENT UPPER LEVEL FLOW IS SUSTAINED AHEAD OF A 45-50 KT
JET STREAK AT 250 MB.

SUSPECT DUAL POL ESTIMATES ARE UNDERESTIMATING IN THE CONVECTIVE
LINE APPROACHING SOCCORRO NM...GIVEN THE DISTANCE FROM RADAR...AND
PLACEMENT OF ALL THE BASE ELEVATION ECHOES AT RANGE BEYOND THE
MELTING LAYER. LEGACY ESTIMATES SUGGEST RATES CLOSER TO 1.5-2 INCH
PER HOUR IN ISOLATED SPOTS. WOULD NOT EXPECT ANYTHING MUCH HEAVIER
THAN THIS WITH PW VALUES HAVING FALLEN BELOW 1 INCH OVER THIS
REGION...BUT WITH FLASH FLOOD GUIDANCE VALUES VERY
LOW...ESPECIALLY IN NM...FLASH FLOODING IS CERTAINLY A
POSSIBILITY. ACTIVITY MAY PERSIST EVEN BEYOND 09Z...ESPECIALLY
TOWARD SOUTHWEST CO WHERE UPPER LIFT BECOMES CONCENTRATED.
INTENSITY IS LIKELY TO DECREASE DIURNALLY...BUT SOME AREAS COULD
SEE MULTIPLE ROUNDS OF MODERATE RAIN ADDING UP OVER TIME.

BURKE

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

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

ATTN...RFC...ABRFC...CBRFC...CNRFC...WGRFC...

LAT...LON 37590695 36730590 35730544 33890581 32740723 32320906
32520994 33221044 33640960 34380859 35350788 36550873
37210888 37590857 37590695

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