Flash Flood Warning 2, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
225 AM CDT TUE JUN 15 1999

NOT MUCH HAS CHANGED SYNOPTICALLY OVER THE PAST 24 HOURS AS DEEP
SOUTH TEXAS CONTINUES TO BE INFLUENCED BY A WEAK UPPER TROUGH.  THE
AXIS OF THIS POSITIVELY TILTED TROUGH RUNS FROM TEXAS TO THE GREAT
LAKES.  THIS FEATURE HAS EFFECTIVELY UNCAPPED THE ATMOSPHERE AS
EVIDENCED BY THIS EVENINGS BRO SOUNDING.  THE UPPER TROUGH IS
PROGGED TO MAINTAIN ITS POSITION OVER THE EASTERN TWO-THIRDS OF THE
COUNTRY UNTIL WEDNESDAY WHEN IT BEGINS TO RETREAT.  DEEP MOISTURE
AND HIGH PRECIPITABLE WATER VALUES SPELL THE LIKELIHOOD OF MORE
DIURNAL CONVECTION LATER TODAY.  A NORTH-SOUTH THETA-E RIDGE AXIS
ALSO IS PROGGED TO BE ORIENTED MORE OR LESS OVER THE AREA.  BOTH FAN
AND FWC REFLECT THESE SCENARIOS WITH RELATIVELY HIGH DAYTIME POPS
FOR TODAY.  WILL KEEP 40 PERCENT POPS IN ALL ZONES FOR TODAY.  WITH
WEAK MID-LEVEL WINDS AND A HIGH PRECIPITABLE WATER VALUE...THINK
THAT PRECIP WILL TEND TO BE HEAVY IN SPOTS AND CELLS WILL MOVE
RATHER SLOWLY.  WILL MENTION LOCALLY HEAVY RAIN POSSIBLE.  A VERY
WEAK PRESSURE GRADIENT OVER AREA WILL CONTINUE THE WEAK ONSHORE
SURFACE FLOW.  GUIDANCE TEMPS ARE A FEW DEGREES COOLER THAN WHAT
THEY HAVE BEEN RUNNING.  THIS SEEMS REASONABLE ASSUMING THE EXPECTED
CONVECTION FIRES DURING THE AFTERNOON WHICH WILL TEND TO HOLD THE
TEMPS DOWN SOMEWHAT.

EXTENDED...THE UPPER TROUGH RETREATS AND AN UPPER RIDGE BEGINS TO
BUILD INTO AREA BY LATE TOMORROW.  AVN TIME SECTION DEPICTS A RETURN
TO A MORE NORTHERLY FLOW ALOFT WHICH WILL DRY OUT THE UPPER AND MID-
LAYERS.  THE RIDGE WILL ALSO WARM THE MID-LEVELS WHICH SHOULD AGAIN
CAP THE ATMOSPHERE.  THIS WILL TEND TO SUPPRESS THE DIURNAL
CONVECTION.  WILL LEAVE OUT POPS FROM THE EXTENDED.  MRF SHOWS THIS
UPPER RIDGE WILL HOLD OVER THE SOUTH CENTRAL PART OF THE COUNTRY
THROUGH THE WEEKEND.

CWF...WEAK PRESSURE GRADIENT OFFSHORE WILL RESULT IN A RELATIVELY
WEAK EAST TO NORTHEAST FLOW THROUGH THE FORECAST PERIOD.

BRO BB 090/073 091/074 092 40/10/30/10
MFE BB 093/072 094/074 097 40/10/30/10
RGC BB 098/074 099/074 100 40/10/30/10
SPI BB 087/077 087/077 088 40/10/30/10

LCM...56

.BRO...NONE.

GMZ130-150-155-170-175-TXZ248>255-151545-

DEEP SOUTH TEXAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
458 AM CDT TUE JUN 15 1999

HEAVY RAINFALL CONTINUED OVERNIGHT IN THE WESTERN VALLEY OF DEEP
SOUTH TEXAS. FROM TWO TO FOUR INCHES OF RAIN FELL IN PORTIONS OF
ZAPATA COUNTY...WHERE HEAVY RAINS WERE ALSO EXPERIENCED MONDAY
AFTERNOON. OTHER AREAS OF THE VALLEY RECEIVED AN ADDITIONAL ONE HALF
TO ONE INCH OF RAINFALL OVERNIGHT.

A WEAK UPPER TROUGH REAMINS IN THE AREA WITH UPPER LEVEL
DISTURBANCES PASSING THOUGH THE AREA TODAY. A MOIST AND
UNSTABLE ATMOSPHERE REMAINS IN PLACE OVER THE VALLEY. METEOROLOGISTS
AT THE NATIONAL WEATHER SERVICE IN BROWNSVILLE ARE FORECASTING
SCATTERED TO NUMEROUS THUNDERSTORMS...WITH HEAVY RAINFALL
POSSIBLE...TO CONTINUE THROUGH THIS AFTERNOON. THIS ADDED RAINFALL
COULD CREATE HAZARDOUS CONDITIONS...WITH FLOODING OF LOW-LYING
AREAS AND DANGEROUS PONDING ON ROADWAYS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS OBSERVED...
ACT QUICKLY. MOVE UP TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING. IT IS VERY DIFFICULT
AT NIGHT TO TELL HOW MUCH WATER IS ON ROADS. MOTORISTS SHOULD NOT
DRIVE THROUGH WATER OF UNKNOWN DEPTH.

SATY TUNED TO NOAA WEATHER RADIO OR OTHER RELIABLE WEATHER NEWS
SOURCES FOR THE LATEST WEATHER INFORMATION.

PHILO