Flash Flood Guidance
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000
AWUS01 KWNH 012256
FFGMPD
LAZ000-TXZ000-020254-

MESOSCALE PRECIPITATION DISCUSSION 0167
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
655 PM EDT SUN MAY 01 2016

AREAS AFFECTED...WESTERN LA AND SOUTHEAST TX

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

VALID 012254Z - 020254Z

SUMMARY...THUNDERSTORMS WITH HEAVY RAIN ARE OCCURRING OVER
SATURATED SOILS.  FLASH FLOODING REMAINS POSSIBLE.

DISCUSSION...THERE ARE TWO FOCI FOR CONVECTIVE DEVELOPMENT: A
STATIONARY FRONT IN THE PINEY WOODS AND BIG THICKET OF EAST TX
DOWN TOWARDS HOUSTON (NEAR THE APPARENT CAP EDGE) AND A STATIONARY
FRONT-LIKE FEATURE IN THE GULF OF MEXICO WITH CIN ALONG IT.
SOUTHEAST FLOW AT 20 KTS IS OVERRIDING THE STATIONARY FRONT IN THE
GULF AND CONTINUING TO CAUSE FRAGMENTS OF CONVECTION ACROSS
SOUTHWESTERN LA AND NEAR HIGH ISLAND TX.  THE STATIONARY FRONT IN
EASTERN TX HAS BEEN LIGHTING UP WITH NEW ACTIVITY DURING THE PAST
COUPLE HOURS, AND RAIN RATES THERE ARE INCREASING.  MLCAPES ALONG
THE EAST TX BOUNDARY ARE 2000 J/KG WHILE MUCAPES OF 1000+ J/KG LIE
OFFSHORE THE LA COAST.  PRECIPITABLE WATER VALUES ARE 1.50-1.75".

THE 18Z NAM CONEST AND RECENT RUNS OF THE HRRR AND EXPERIMENTAL
HRRR HAVE AN IDEA REGARDING ACTIVITY IN EASTERN TX, THOUGH NONE OF
THE GUIDANCE IS A FAN OF ACTIVITY CONTINUING IN SOUTHWEST LA.
EVEN SO, BELIEVE CONVECTION REMAINS POSSIBLE INTO THE OVERNIGHT
HOURS, UNTIL LOW-LEVEL INFLOW DECREASES FURTHER AROUND 03Z PER
RECENT RAP RUNS.  CONVECTION ALONG THE BOUNDARY IN EASTERN TX WILL
HAVE PROBLEMS FORWARD PROPAGATING TO THE EAST DUE TO SOUTHEAST 850
HPA INFLOW -- IT COULD REMAIN QUASI-STATIONARY.  HOURLY RAIN RATES
UP TO 2", WITH LOCAL AMOUNTS OF 3-5", ARE POSSIBLE IN THIS REGION,
THOUGH MORE LIKELY NEAR THE CENTRAL TX/LA BORDER.  IN AN AREA
SATURATED BY RECENT RAINS, FLASH FLOODING REMAINS POSSIBLE.

ROTH

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

ATTN...WFO...HGX...LCH...SHV...

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

LAT...LON   32529318 30609216 29109179 29399401 29839573
            31079486



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