MESOSCALE PRECIPITATION DISCUSSION 0708
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
720 PM EDT SUN AUG 20 2017

AREAS AFFECTED...PORTIONS OF WEST TX / ERN NM

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

VALID 202320Z - 210520Z

SUMMARY...AN INCREASING COVERAGE OF CONVECTION IS EXPECTED THROUGH
06Z ACROSS FAR WEST TX INTO SERN NM ALONG WITH TRAINING CELLS.
RAINFALL RATES OF 1-2 IN/HR WITH 6 HOUR RAINFALL TOTALS OF 2-4
INCHES WHICH MAY CAUSE FLASH FLOODING IN A FEW LOCATIONS.

DISCUSSION...REGIONAL RADAR IMAGERY OVER THE PAST 1-2 HOURS HAS
SHOWN AN UPTICK IN CONVECTION ALONG THE SWRN TX PANHANDLE INTO ERN
NM AND PORTIONS OF FAR WEST TX. PRECIPITABLE WATER VALUES ARE
ALREADY NEAR 1.2 TO 1.6 INCHES OR TWO STANDARDIZED ANOMALIES ABOVE
THE AVERAGE AND MLCAPE IS ESTIMATED TO BE SUFFICIENT...500-1500
J/KG...TO SUPPORT STRONG ENOUGH UPDRAFTS RESULTING IN HEAVY
RAINFALL. KFDX REFLECTIVITY AT 23Z SHOWED NUMEROUS RAIN CORES WITH
CELL AND OUTFLOW MERGERS RESULTING IN RADAR ESTIMATED RAINFALL
RATES OVER 1 IN/HR IN ERN CHAVES AND NRN LEA COUNTIES.

AS AN UPPER LEVEL SHORTWAVE...NOTED ALONG THE AZ/NM BORDER VIA
WATER VAPOR IMAGERY...ADVANCES EAST OVER THE NEXT 3-6 HOURS...700
MB FLOW OVER ERN NM INTO FAR WEST TX IS FORECAST TO INCREASE TO
25-35 KT WHICH EXCEEDS LFC-EL MEAN WIND SPEEDS OF 10-20 KT WHICH
SHOULD ALLOW FOR BACK BUILDING AND TRAINING OF HEAVY RAIN CORES.
IN ADDITION...AS AN UPPER LEVEL RIDGE PRESENTLY OVER EAST TX
EXPANDS SWWD INTO NERN MX BY 06Z...UPPER LEVEL DIFFLUENCE SHOULD
INCREASE AHEAD OF THE ADVANCING SHORTWAVE MOST NOTABLY IN THE
VICINITY OF THE GUADALUPE AND DAVIS MOUNTAINS...WEST OF ONGOING
ACTIVITY.

INCREASING MOISTURE FLUX SHOULD ALLOW CONVECTION TO TRACK NORTH
FROM MEXICO INTO WEST TX AND PORTIONS OF SERN NM PAST SUNSET. A
FLASH FLOOD THREAT WILL BE PRESENT WHERE TRAINING
DEVELOPS...ESPECIALLY IN AREAS OF LOWER FLASH FLOOD GUIDANCE...1-2
IN/HR ACROSS FAR WEST TX AND INTO POCKETS OF NM.

OTTO

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

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

LAT...LON   35260405 35050327 34270283 31930306 29980387
            29750502 30550624 32080662 34270587 35180534