MESOSCALE PRECIPITATION DISCUSSION 0133
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
546 AM EDT TUE MAY 26 2015
 
AREAS AFFECTED...SOUTHEAST TX & SOUTHWEST LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260945Z - 261400Z
 
SUMMARY...THUNDERSTORMS ARE REGENERATING BETWEEN SAN ANTONIO AND
BEAUMONT TX.  DESPITE HOW MUCH RAIN HAS ALREADY FALLEN, ADDITIONAL
FLASH FLOODING REMAINS POSSIBLE.

DISCUSSION...THE RAP GUIDANCE, AMONGST OTHER MESOSCALE MODELS, HAS
BEEN MISHANDLING THE LOW-LEVEL INFLOW WHICH THE VAD WIND PROFILES
HAVE BEEN INDICATING EARLY THIS MORNING.  LOW-LEVEL INFLOW IS
OVERRUNNING A STATIONARY OUTFLOW BOUNDARY NESTLED INTO
SOUTH-CENTRAL TX, WITH CONVECTION FOCUSING UP TO 100 MILES TO ITS
NORTH.  INFLOW AT 850 HPA REMAINS 25-40 KTS INTO THE REGION, NEAR
THE MAGNITUDE OF THE 850-400 HPA WIND, WHICH IS IMPORTING CAPE
VALUES OF UP TO 5000 J/KG FROM SOUTH OF THE OUTFLOW BOUNDARY AS
SEEN ON RECENT SPC MESOANALYSES.  PRECIPITABLE WATER VALUES REMAIN
1.8-1.9" PER GPS DATA.  RAINFALL TOTALS OVER SOUTHWEST HARRIS
COUNTY TX ARE UP TO 10.80", OVER HALF OF WHICH HAS OCCURRED IN THE
PAST SIX HOURS.

ONLY THE 00Z ARW AND 06Z NAM CONEST SHOW A SIGNAL FOR LOCAL
AMOUNTS OF 2-4" BEING POSSIBLE INTO THE MORNING HOURS.  AS POOR AS
THE RAP 850 HPA FORECAST WIND PATTERNS HAVE BEEN, THEY INDICATE
INFLOW RETURNING TO THE REGION BETWEEN 10-14Z, WHICH SHOULD
MAINTAIN SOME LEVEL OF CONVECTIVE ORGANIZATION.  ORGANIZED
CONVECTION SHOULD MOVE EAST AT 15-20 KTS PER FORWARD PROPAGATING
CORFIDI VECTORS.  CONSIDERING THE AVAILABLE MOISTURE, HOURLY
RAINFALL RATES UP TO 2" REMAIN POSSIBLE.  CONSIDERABLE FORECAST
UNCERTAINTY KEPT THE CATEGORY OF THIS MPD AS POSSIBLE.

ROTH

ATTN...WFO...CRP...EWX...HGX...LCH...

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

LAT...LON   30809565 30699345 30259240 29519229 29539262 
            29719333 29589417 29179481 28729551 28469645 
            29539725 30349712