National Weather Service Raw Text Product

993 
FXUS64 KEWX 180444 AAA
AFDEWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1144 PM CDT WED SEP 17 2014

.AVIATION...KEWX RADAR HAS LIT UP WITHIN THE PAST HOUR...WITH A
LARGE AREA OF SHOWERS AND THUNDERSTORMS MOVING TOWARDS THE SOUTH-
SOUTHWEST INTO THE NORTHEAST QUADRANT OF SOUTH-CENTRAL TEXAS. AS
THIS CONVECTION IS IN CLOSEST PROXIMITY TO AUS...THE TAF FOR THIS
SITE WAS REWORKED HEAVILY TO ACCOUNT FOR THE EXPECTED TIMING OF
THE ARRIVAL OF THE SHOWERS/THUNDERSTORMS. ELSEWHERE...FOR SAT AND
SSF...ALTHOUGH THE PREVIOUSLY-MENTIONED CONVECTION IS NOT EXPECTED
TO REACH THESE TWO AERODROMES...OUTFLOW BOUNDARIES MAY INITIATE
NEW CONVECTION DURING THE NEAR-SUNRISE HOURS OF THURSDAY MORNING...
AND THEREFORE THE TEMPO PERIODS FOR CONVECTION BETWEEN 10 AND 14
UTC WERE RETAINED FROM THE PREVIOUS TAFS. ONLY THE AERODROME IN
DRT IS LIKELY TO REMAIN ALL QUIET ON THE WESTERN FRONT THROUGH THE
NEXT 24 HOURS. OVERALL...AT ALL OF THE AERODROMES...VFR/MVFR IS
FORECAST TO PREVAIL. AMENDMENTS TO THE FORTHCOMING ISSUANCE OF
TAFS ARE POSSIBLE THROUGH THE OVERNIGHT HOURS AS THE CURRENT AREA
OF CONVECTION EVOLVES AND NEW SHOWERS AND THUNDERSTORMS DEVELOP.
&&

.PREV DISCUSSION... /ISSUED 907 PM CDT WED SEP 17 2014/ 

UPDATE...
A QUICK UPDATE ISSUED TO REFLECT LOWER EVENING POPS OVER WESTERN
AND CENTRAL COUNTIES TO STRESS THE LATE NIGHT TIMING OF THE
EXPECTED HEAVY PRECIPITATION OVER CENTRAL TX. ONE OR TWO OF THE
FINER RES MODELS SUGGESTED A POTENTIAL FOR SWWD PROPATING CELLS IN
THE OVERNIGHT HOURS TO EXPAND THE HEAVY RAIN THREAT DEEPER INTO
THE HILL COUNTRY. A MORE CONSERVATIVE APPROACH IS FAVORED OUTSIDE
THE WATCH AREA AS IS NOTED FROM THE MINIMAL INFLOW FROM THE LLJ AS
NOTED IN THE LATEST SPENES PRODUCT FROM NESDIS. AS OUTFLOW
BOUNDARIES INTERSECT OVER CENTRAL TX...THE FLASH FLOOD POTENTIAL
WILL ONLY INCREASE IN THE EARLY MORNING HOURS FOR THE COUNTIES IN
THE FLASH FLOOD WATCH.

PREV DISCUSSION... /ISSUED 633 PM CDT WED SEP 17 2014/ 

AVIATION...REASONING OF PREVIOUS SET OF TAFS APPEARED FINE AND NO
CHANGES WERE MADE EXCEPT FOR INITIAL CONDITIONS. CEILINGS CONTINUE
TO BE EXPECTED TO DROP TO MVFR AT THE AERODROMES DURING THE OVERNIGHT
HOURS...WITH VFR LIKELY TO RESUME DURING THE POST-SUNRISE HOURS OF
THURSDAY. CONVECTION WILL LIKELY AFFECT 3 OUT OF 4 TAF SITES. 

PREV DISCUSSION... /ISSUED 331 PM CDT WED SEP 17 2014/ 

SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
MORNING RAOB DATA CONTINUES TO SHOW ABUNDANT MOISTURE IN PLACE 
ACROSS SOUTH CENTRAL TEXAS WITH PRECIPITABLE WATER VALUES OF 2.0" AT 
KDRT...WHICH IS ALMOST +2 SD ABOVE NORMAL. THE LATEST WATER VAPOR 
LOOP ALSO SHOWS NORTHWEST FLOW ALOFT ACROSS THE REGION WITH PLENTY 
OF MID AND UPPER LEVEL MOISTURE FROM THE REMNANTS OF ODILE. LATE 
AFTERNOON RADAR IMAGERY SHOWS SCATTERED CONVECTION ONGOING ACROSS A 
GOOD PORTION OF SOUTH CENTRAL TEXAS. WE EXPECT THIS CONVECTION TO 
CONTINUE INTO THE MID-EVENING HOURS...THEN GRADUALLY WEAKEN FOR
MOST LOCATIONS. HOWEVER...GIVEN NORTHWEST FLOW ALOFT AND THE
LATEST HI-RES MODEL GUIDANCE...CAN/T RULE OUT ADDITIONAL
CONVECTION THROUGH THE OVERNIGHT HOURS ACROSS PORTIONS OF THE HILL
COUNTRY AND ADJACENT NORTHERN I-35 CORRIDOR
(LLANO...BURNET...WILLIAMSON COUNTIES). NORTHWEST FLOW ALOFT
PERSISTS ON THURSDAY AND THE LATEST GUIDANCE CONTINUES TO SHOW
GOOD POTENTIAL FOR ADDITIONAL RAINFALL FOR AREAS GENERALLY ALONG
AND NORTH OF HIGHWAY 71. BASED ON RECENT RAINFALL AMOUNTS ACROSS
THE MENTIONED REGION AND THE POTENTIAL FOR ADDITIONAL RAINFALL
TONIGHT AND ESPECIALLY THURSDAY...WE HAVE ISSUED A FLASH FLOOD
WATCH. THE FLASH FLOOD WATCH WILL RUN FROM TONIGHT THROUGH
THURSDAY AFTERNOON FOR AREAS ALONG AND NORTH OF HIGHWAY 71.
AVERAGE RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE EXPECTED WITH
LOCALLY HIGHER TOTALS OF 3 TO 5 INCHES POSSIBLE. 

LONG TERM (FRIDAY THROUGH WEDNESDAY)...
OVERALL...WE HAVE MADE LITTLE CHANGES TO THE FORECAST FOR THE 
REMAINDER OF THIS WEEK INTO EARLY NEXT WEEK. THE SUBTROPICAL RIDGE 
AXIS TRIES TO BUILD INTO THE REGION ON FRIDAY. HOWEVER...THE MEDIUM 
RANGE MODELS SUGGEST MOISTURE LEVEL WILL NOT DROP SIGNIFICANTLY ON 
FRIDAY AND WE/LL MAINTAIN A 30-50% CHANCE FOR RAINFALL. MOISTURE 
LEVELS TO DROP A LITTLE THIS WEEKEND...SO A DECREASE TO 20-30% RAIN 
CHANCES LOOKS REASONABLE. THE MODELS CONTINUE TO STRUGGLE WITH THE 
STRENGTH OF A COLD FRONT MOVING INTO NORTH TEXAS ON MONDAY. RECENT 
MODEL TRENDS FROM THE ECMWF HAVE SHOWN A WEAKER FRONT ON THE 12Z
RUN VS. A STRONGER FRONT ON THE 00Z RUN. TODAY/S DATA FOLLOWS A
SIMILAR TREND AND TO PRESERVE SOME CONSISTENCY...WE/LL NOT DEVIATE
MUCH FROM THE INHERITED FORECAST. WE/LL SHOW A NORTHEAST TO EAST
WIND SHIFT WITH THE BOUNDARY ON MONDAY...BUT ANY COLD AIR
ADVECTION SHOULD BE RATHER WEAK. SOUTHEAST WINDS RETURN ON TUESDAY
AND WEDNESDAY. A 20% CHANCE FOR SHOWERS AND THUNDERSTORMS WILL
REMAIN IN THE FORECAST ON TUESDAY FOR AREAS GENERALLY SOUTH OF
HIGHWAY 90 AS MOISTURE LEVELS WILL BE HIGHER ACROSS OUR SOUTHERN
AREAS.
&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              74  87  71  91  72 /  70  80  30  40  20 
AUSTIN BERGSTROM INTL AIRPORT  71  87  70  90  72 /  70  80  30  40  20 
NEW BRAUNFELS MUNI AIRPORT     73  89  72  90  72 /  50  50  30  40  20 
BURNET MUNI AIRPORT            72  85  70  89  72 /  70  80  30  40  20 
DEL RIO INTL AIRPORT           74  91  76  90  74 /  20  20  20  30  20 
GEORGETOWN MUNI AIRPORT        74  84  71  90  72 /  80  80  30  40  20 
HONDO MUNI AIRPORT             73  91  73  92  72 /  40  30  30  40  20 
SAN MARCOS MUNI AIRPORT        73  88  71  90  73 /  60  60  30  40  20 
LA GRANGE - FAYETTE REGIONAL   74  87  73  91  72 /  80  80  30  50  20 
SAN ANTONIO INTL AIRPORT       76  90  75  91  75 /  50  40  30  40  20 
STINSON MUNI AIRPORT           75  91  75  92  74 /  50  40  30  40  20 
&&

.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR THE FOLLOWING 
COUNTIES: BASTROP...BURNET...FAYETTE...LEE...LLANO...TRAVIS...
WILLIAMSON.
&&

$$

MESOSCALE/AVIATION...TOMASELLI