Flash Flood Warning 174, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
739 AM CDT SUN MAY 27 2007

.UPDATE...
BASED ON THE PAST BEHAVIOR OF THE LATE MORNING MCV IMPACTS ON
CONVECTION, HAVE SHORTENED THE VALID TIME OF THE FFA TO 10 AM. THE
DAY SHIFT WILL HAVE A COUPLE HOURS TO MONITOR TRENDS TO EVALUATE
ANY POTENTIAL FOR FUTURE HEAVY RAINS, BUT THE CURRENT COMPLEX
LOOKS ON TRACK TO SWEEP AWAY CONVERGENCE INTO EAST TX FOR SEVERAL
HOURS WHILE ANOTHER WEAK CLUSTER OF STORMS NEAR THE RIO GRANDE
STAND A POOR CHANCE OF HOLDING TOGETHER AS THEY BECOME INFLUENCED
BY THE STABILIZING CONDITIONS TO THE EAST.

PRECIPITABLE WATER VALUES NEVER SEEMED TO RECOVER AFTER THE FIRST
LARGE MCS MOVED THROUGH THE AREA THU NITE/FRI MORN. RAINFALL
TRENDS ONLY BRIEFLY SHOWED EFFICIENT RAINFALL PRODUCTION WITH
TRAINING OF CELLS PRODUCING THE SPOTTY OVERNIGHT FLOODING. THE 500
MB TROUGH AXIS IS EXPECTED TO SLIP EAST OF THE ESCARPMENT TODAY,
SHIFTING MOST OF THE LIFT NORTH AND EAST OF SOUTH CENTRAL TEXAS.
DESPITE CONTINUED HEALTHY RAIN CHANCES, MODEL QPF TRENDS ARE
DECREASING, SUGGESTING NO MORE LARGE AND SLOW MOVING MCS ACTIVITY
AFTER THIS MORNING. EXPECT CONVECTION FOR THE NEXT COUPLE DAYS TO
BE LESS ORGANIZED AND UNABLE TO TAP INTO DEEP SURFACE MOISTURE
POOLS.

&&

.PREV DISCUSSION... /ISSUED 645 AM CDT SUN MAY 27 2007/

AVIATION...
AREAS OF IFR/MVFR CIGS WILL LIFT TO VFR THIS AFTERNOON, THEN FALL
BACK TO MVFR THIS EVENING AND THEN IFR OVERNIGHT. PATCHES OF RA
WITH SCT SHRA AND ISOLD TSRA WILL PERSIST THIS MORNING, THEN ISOLD
TO SCT SHRA AND TSRA ARE POSSIBLE THIS AFTERNOON THRU TONIGHT.
LOCAL IFR/MVFR VSBYS CAN BE EXPECTED IN PRECIP. SELY WINDS AROUND
10 KTS OR LESS WILL PREVAIL.

PREV DISCUSSION... /ISSUED 440 AM CDT SUN MAY 27 2007/

DISCUSSION...
ESCARPMENT RAIN EVENT IS FINALLY UNFOLDING EARLY THIS MORNING,
WITH REDUCED RAIN POTENTIAL STEMMING FROM A SERIES OF MCS TRACKS
ACROSS THE COASTAL BEND OVER THE PAST 36 HOURS. THE FEW AREAS THAT
SAW 8-10 INCHES OF RAIN THU NITE/FRI MORN COULD SEE ANOTHER 2-4
INCHES OF RAIN, BUT MOST AREAS WILL SEE A 5 DAY TOTAL OF 3-5
INCHES BY THE TIME THE UPPER TROUGH AXIS SHIFTS EAST MONDAY.
WHILE THIS MIGHT BE WELCOME NEWS TO THOSE PLANNING HOLIDAY
ACTIVITIES NEAR THE WATER, TEMPERATURES WILL CONTINUE TO TOP OUT
IN THE 80-85 DEGREE RANGE THE NEXT COUPLE DAYS.

ASSUMING THE TROUGH DOESNT RETROGRADE DUE TO WEAK MESOSCALE
IMPULSES, AND THE RAINS DO NOT CREATE SIGNIFICANT RIVER RISES THIS
MORNING, THE FFA MAY NOT NEED AN EXTENSION PAST TODAY. WILL LET THE
WESTERN COUNTIES EXPIRE AT 7 AM AND PLAN A FFA UPDATE TO CONTINUE
THE EASTERN COUNTIES THROUGH 7 PM. THE CHANCE FOR HEAVY DOWNPOURS
WILL CONTINUE THROUGH MEMORIAL DAY, BUT THE PATTERN DOESNT
SUPPORT CELL TRAINING, AND PWAT VALUES SHOULD CONTINUE TO RETREAT
BACK TO NORMAL LATER TODAY.

MODEL TRENDS SHOW AN INCREASING TREND TOWARD FAIR WEATHER TUE AND
WED, BUT A DEEPENING TREND IN A NORTHERN PLAINS TROUGH SIGNALS A
COOL FRONT AND A ROUND OF THUNDERSTORMS THURSDAY AND A FEW
LINGERING CELLS POSSIBLE IN UNSTABLE FLOW ALOFT FRIDAY. WILL KEEP
POPS LOW FOR NOW AS TIMING COULD BE OFF BY UP TO 12 HRS. THE WAKE
OF THIS TROUGH WILL BE A HIGH AMPLITUDE RIDGE PROMISING A MORE
SEASONAL WARMING TREND FOR THE WEEKEND THE GFS DOES SHOW A WEAK
CUT-OFF LOW CAPABLE OF UNDERCUTTING THE RIDGE NEXT SUNDAY, BUT MOST
MODELS SHOW THIS DISTURBANCE TO BE WEAK.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              80  67  82  68  85 /  70  40  50  20  20
AUSTIN BERGSTROM INTL AIRPORT  80  67  81  65  85 /  70  40  50  20  20
DEL RIO INTL AIRPORT           83  70  86  71  90 /  30  30  20  20  10
SAN ANTONIO INTL AIRPORT       79  69  81  69  85 /  60  40  40  20  20

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR THE FOLLOWING
ZONES: ATASCOSA...BASTROP...BEXAR...BLANCO...BURNET...CALDWELL...
COMAL...DE WITT...FAYETTE...GILLESPIE...GONZALES...GUADALUPE...
HAYS...KARNES...KENDALL...LAVACA...LEE...LLANO...TRAVIS...
WILLIAMSON...WILSON.

&&

18/04

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
741 AM CDT SUN MAY 27 2007

TXZ171>173-188>194-205>209-220>225-281015-
LLANO-BURNET-WILLIAMSON-GILLESPIE-KENDALL-BLANCO-HAYS-TRAVIS-
BASTROP-LEE-BEXAR-COMAL-GUADALUPE-CALDWELL-FAYETTE-ATASCOSA-
WILSON-KARNES-GONZALES-DE WITT-LAVACA-
741 AM CDT SUN MAY 27 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT

A FLASH FLOOD WATCH IS IN EFFECT THIS MORNING. SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS...SOME WITH LOCALLY HEAVY RAINS...CAN BE
EXPECTED. DUE TO SATURATED SOILS FROM RECENT RAINS...RUN OFF WILL BE
RAPID LEADING TO FLASH FLOODING. GUSTY WINDS AND SMALL HAIL ARE ALSO
POSSIBLE IN STORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE ARE CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY THROUGH
FRIDAY. LOCALLY HEAVY DOWNPOURS...GUSTY WINDS AND SMALL HAIL ARE
POSSIBLE IN STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

TXZ183>187-202>204-217>219-228-281015-
VAL VERDE-EDWARDS-REAL-KERR-BANDERA-KINNEY-UVALDE-MEDINA-MAVERICK-
ZAVALA-FRIO-DIMMIT-
741 AM CDT SUN MAY 27 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED. LOCALLY HEAVY
RAINS...GUSTY WINDS AND SMALL HAIL ARE POSSIBLE IN STORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE ARE SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS ON MONDAY
AND THURSDAY THROUGH FRIDAY. BRIEF HEAVY DOWNPOURS...GUSTY WINDS
AND SMALL HAIL ARE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
620 AM CDT SUN MAY 27 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0416 AM     FLASH FLOOD      SAN ANTONIO             29.46N 98.51W
05/27/2007                   BEXAR              TX   DEPT OF HIGHWAYS

            NUMEROUS ROAD CLOSURES

0559 AM     FLASH FLOOD      LAKEHILLS               29.60N 98.94W
05/27/2007                   BANDERA            TX   LAW ENFORCEMENT

            PARK RD 73 CLOSED IN TWO PLACES

0556 AM     FLASH FLOOD      13 N HONDO              29.54N 99.16W
05/27/2007                   MEDINA             TX   LAW ENFORCEMENT

            HIGHWAY 173 CLOSED AT VERDE CREEK. ALSO FM ROAD 471 NEAR
            LACOSTE CLOSED.

&&

MO