Red Flag Warning 35, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
454 AM CDT THU JUN 15 2006

.DISCUSSION...
THE WEATHER PATTERN WILL CHANGE FROM HOT AND DRY TO A MOIST AND
TROPICAL ONE STARTING THIS WEEKEND. AN UPPER TROUGH DIGGING OVER
THE GREAT BASIN WILL APPROACH TX WHILE PULLING A SMALL UPPER
DISTURBANCE OFF THE WESTERN GULF INTO A DEVELOPING BROAD CONVEYOR
BELT OF MOISTURE OVER TX FRIDAY INTO SATURDAY.

ON THE BACKSIDE OF THE GULF DISTURBANCE IS TROPICAL MOISTURE
PUSHING NORTHWARD FROM THE BAY OF CAMPECHE. AS THIS SYSTEM MOVES
INTO DEEP SOUTH TX TODAY, AN INCREASE OF DIURNAL CONVECTION WILL
BEGIN TO PUSH INTO EASTERN PARTS OF SOUTH CENTRAL TEXAS LATE
TODAY. A FLATTENING RIDGE AXIS STILL REMAINS ORIENTED SW-NE OVER
TX, SO THE PUSH OF MOISTURE WILL FOCUS MAINLY OVER THE SOUTHEAST
COUNTIES THROUGH THIS EVENING. BY FRIDAY, THE GFS SHOWS MUCH MORE
MOISTURE SPEADING OVER THE EASTERN COUNTIES WITH SCATTERED
CONVECTION REACHING INTO CENTRAL COUNTIES INCLUDING THE EASTERN
HILL COUNTRY. MODEL FORECAST WINDS SHOW STRONG ONSHORE FLOW
TONIGHT THROUGH FRIDAY EVENING, SO THE CHANCE FOR SOME OF THIS
ACTIVITY TO HOLD TOGETHER AND REACH WESTERN COUNTIES IS GOOD.
HOWEVER, EXPECT IT TO WEAKEN WHILE MOVING NNW, SO WILL CALL FOR
SILENT TENS OVER WESTERN COUNTIES FRIDAY AFTN/EVE.

BY LATE SATURDAY THE PATTERN COULD EVOLVE TO REPLACE DROUGHT WITH
DELUGE. THE GFS IS BULLISH ON HIGH QPF AMOUNTS, GIVING THE
EASTWARD MOVING UPPER LOW AN EXTENDED STAY OVER CENTRAL TX AS A
CUT-OFF LOW HANGING AROUND THROUGH THE EXTENDED FORECAST. THIS IS
A COMMON JUNE/JULY FLASH FLOOD PATTERN FOR TX. THE PRESENCE OF THE
GULF UPPER DISTURBANCE COULD CREATE SOME FORECAST CHALLENGES, BUT
OVERALL, THE GFS HAS BEEN FAIRLY CONISTENT WITH THIS PATTERN. ONLY
IN THE PAST DAY OR SO HAS THE GFS AND NAM MODELS BEEFED UP THE
PRECIPITABLE WATER VALUES, WITH BOTH SHOWING OCCASIONAL VALUES
OVER 2 INCHES IN THE VICINITY OF THE LOOSELY DEFINED UPPER LOW.

HAVE ADDED MENTION OF LOCALLY HEAVY RAINFALL FOR SATURDAY NIGHT
THROUGH MONDAY FOR MAINLY THE NE HALF, BUT KEPT POPS MAINLY IN THE
30-50 PERCENT RANGE FOR NOW. A STRONGLY WORDED HWO WILL BE ISSUED
FOR THE POSSIBLE THREAT OF FLOODING. BY THE MIDDLE PART OF NEXT
WEEK, WILL BACK OFF POPS A BIT. THE ECMWF WHICH IS LESS BULLISH ON
THE WEEKEND RAINS AND INDICATES A MORE STABLE PATTERN THAN DOES
THE GFS AND THE DGEX.

.FIRE WEATHER...
A BRIEF 3-5 HOUR PERIOD OF RED FLAG CONDITIONS IS EXPECTED OVER
THE WESTERN COUNTIES WHERE GULF MOISTURE IS EXPECTED TO MIX WITH THE
DRIER AIR ALOFT THIS AFTERNOON INTO EARLY THIS EVENING. THIS
MOISTURE SHOULD EVENTUALLY DEEPEN TO RAISE RH VALUES ABOVE THE
THE 25 PERCENT THRESHOLD. THIS WESTERN AREA CONTINUES TO SEE HIGH
FIRE DANGER CLASSIFICATIONS ON MOST DAYS AND EXTREME DROUGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              98  74  90  75 / 10 10 40 20
AUSTIN BERGSTROM INTL AIRPORT  97  74  89  74 / -  10 40 20
DEL RIO INTL AIRPORT          101  78  96  76 / -  -  10 10
SAN ANTONIO INTL AIRPORT       96  76  91  74 / -  10 30 10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM THURSDAY TO 9 PM THURSDAY FOR THE
FOLLOWING COUNTIES: EDWARDS... KINNEY...MAVERICK... AND VAL
VERDE.

&&

18/10