MESOSCALE PRECIPITATION DISCUSSION 0283
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
858 PM EDT SUN MAY 28 2017

AREAS AFFECTED...CENTRAL TX...EASTERN TX...WESTERN LA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 290057Z - 290507Z

OVERVIEW...STRONG THUNDERSTORMS CONTINUING FROM JUST EAST OF BIG
BEND TX ALONG A LINE ACROSS EASTERN TX INTO WESTERN LA WILL LIKELY
RESULT IN ADDITIONAL FLASH FLOODING DURING THE NEXT SEVERAL HOURS.

DISCUSSION...STRONG THUNDERSTORMS CONTINUE ALONG A FRONTAL
BOUNDARY THAT EXTENDS EAST-NORTHEAST FROM NEAR CRYSTAL SPRINGS TX
ACROSS EASTERN TX INTO WESTERN LA. THESE STORMS ARE PRODUCING
LOCAL HOURLY RAIN RATES OF 1-2.5"...AND RADARS ACROSS THE REGION
SHOW LOCAL RAINFALL TOTALS UP TO 4".

SURFACE DEW POINTS ARE STILL MAINLY 70 DEGREES F AND HIGHER ACROSS
THE REGION...WITH PRECIPITABLE WATER AROUND 1.6-2.2" LOW LEVEL
SOUTHERLY FLOW OF 15-20 KT WILL CONTINUE TO FEED MOISTURE INTO THE
REGION. SPC MESOANALYSES SHOW THAT THE ENVIRONMENT IS STILL VERY
UNSTABLE WITH MUCAPE IN THE RANGE OF 3000-5000 J/KG.

HIRES MODELS ARE IN FAIRLY GOOD AGREEMENT THAT ADDITIONAL LOCAL
RAINFALL AMOUNTS UP TO 3" ARE LIKELY DURING THE NEXT SEVERAL
HOURS. THEY ALSO AGREE FAIRLY WELL THAT CONVECTION WILL BEGIN TO
EASE 04Z-05Z. THE LINE OF CONVECTION SHOULD CONTINUE TO SHIFT
SLOWLY SOUTH AND EAST DURING THE PERIOD.

THE 3 HOUR FLASH FLOOD GUIDANCE ACROSS THE THREAT AREA IS
GENERALLY 3-5"...BUT AS MENTIONED ABOVE LOCAL TOTALS OF 4" HAVE
ALREADY OCCURRED. SO ADDITIONAL FLASH FLOODING IS LIKELY FOR THE
NEXT SEVERAL HOURS THIS EVENING.

MCDONNAL

ATTN...WFO...EWX...FWD...HGX...LCH...SHV...SJT...

ATTN...RFC...LMRFC...WGRFC...

LAT...LON   32769291 32379212 31679216 30889267 30339378
            29999494 28909866 28829914 28829990 29210053
            30180070 31099912 31549777 31629758 32099596
            32619416