Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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000
FXUS64 KEWX 051129
AFDEWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
629 AM CDT TUE MAY 5 2015

.AVIATION DISCUSSION...FOR 12Z TAF PACKAGE...
WILL BE DEALING WITH MVFR/IFR CIGS AGAIN THIS MORNING FOR ALL THE
I35 CORRIDOR TERMINALS. INCLUDED TEMPO GROUP FOR SPORADIC IFR
CONDITIONS THROUGH THE FIRST COUPLE HOURS OF THE TAF PERIOD. SLOW
BUT GRADUAL IMPROVEMENT IS EXPECTED THROUGH THE MORNING TO CIGS
JUST OVER 3 KFT. ISOLATED SHRA AND TS MAY OCCUR TODAY BUT
CONFIDENCE IS LOW SO LEFT OUT OF THE TAF FOR THE 35 TERMINALS.
INCLUDED VCTS AT KDRT AS POTENTIAL IS A BIT HIGHER OUT ON THE RIO
GRANDE.

TB3

&&

.PREV DISCUSSION... /ISSUED 341 AM CDT TUE MAY 5 2015/

SHORT TERM (TODAY THROUGH WEDNESDAY)...
OVERNIGHT CONVECTION HAS SHIFTED WELL NORTH OF VAL VERDE COUNTY AS
LIFT MOVES AWAY FROM OUR AREA. 00Z UPPER AIR ANALYSIS SHOWS A WEAK
TROUGH CURRENTLY NEAR ARIZONA WITH SHORTWAVE RIDGING TO THE EAST
OF THE AREA. THE WEATHER PATTERN OVER THE NEXT WEEK WILL REMAIN
SOMEWHAT ACTIVE WITH CHANCES OF RAIN EACH DAY. HOWEVER...THERE
WILL BE TWO MAIN SYSTEMS THAT WILL MOST LIKELY BRING THE BEST
CHANCES OF RAIN TO THE REGION AND THE FIRST IS ASSOCIATED WITH THE
LOW CURRENTLY TO OUT WEST. THE MAIN FORCING ASSOCIATED WITH THIS
SYSTEM WILL CONTINUE TO BE JUST TO OUR NORTH AS IT TRACKS THROUGH
THE TEXAS PANHANDLE THEN NORTHEAST INTO THE CENTRAL PLAINS LATER
TONIGHT. HOWEVER...THE BASE OF THE UPPER LOW WILL BE NEAR OUR
NORTHERN COUNTIES TONIGHT AND THE THIS TIME FRAME WILL BE OUR
HIGHEST POPS IN THE SHORT-TERM AT 50 PERCENT ACROSS THE NORTHERN
COUNTIES. FOR TODAY...WEAK LIFT IN THE LOWER LEVELS OF THE
ATMOSPHERE ASSOCIATED WITH PERSISTENT SOUTHERLY LOW-LEVEL FLOW
AROUND 30-35 KNOTS SHOULD ALLOW FOR ISOLATED TO SCATTERED
CONVECTION TO DEVELOP. IT IS TOUGH TO REALLY ANTICIPATE WHERE THIS
ACTIVITY WILL ACTUALLY OCCUR...BUT SCATTERED COVERAGE CAN BE
EXPECTED AS SHOWERS AND THUNDERSTORMS WILL BE HIT OR MISS. CAPE
AND SHEAR VALUES WILL BE MARGINAL BUT ONE OR TWO STRONG STORMS ARE
POSSIBLE. WITH ABUNDANT CLOUD COVER...HIGHS TODAY WILL BE IN THE
UPPER 70S TO LOWER 80S ACROSS MUCH OF THE AREA.

FOR WEDNESDAY...THE MAIN FORCING FOR ASCENT WILL BE WELL TO OUR
NORTHEAST AS THE UPPER LOW MOVES INTO THE NORTHERN PLAINS.
HOWEVER...MODELS ARE CONTINUING TO SHOW WEAK UPGLIDE WITH THE
PERSISTENT LOW-LEVEL WINDS. LOW-LEVEL SPEEDS SHOULD BE A BIT LESS
ON WEDNESDAY AND THEREFORE...THE COVERAGE OF MAINLY DIURNALLY
DRIVEN CONVECTION SHOULD BE A BIT LESS. WILL GO WITH 20 POPS
ACROSS MUCH OF THE FORECAST AREA FOR WEDNESDAY. CAPE VALUES WILL
BE SLIGHTLY HIGHER BUT SHEAR VALUES WILL DECREASE...AND A STRONG
STORM OR TWO WILL ONCE AGAIN BE POSSIBLE. MODELS ARE CONSISTENTLY
SHOWING LOW-LEVEL WARMING WITH 850 TEMPS ABOUT A DEGREE WARMER
THAN TODAY. HIGH TEMPERATURES SHOULD RESPOND WITH HIGHS REACHING
THE LOWER TO UPPER 80S.

LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
RAIN CHANCES WILL CONTINUE TO BE AROUND 20 TO 30 PERCENT ON
THURSDAY AND FRIDAY ACROSS THE AREA AND WILL BE MAINLY IN THE
AFTERNOON AND EVENING HOURS WITH PEAK HEATING. LARGE SCALE
FORCING FOR ASCENT WILL IS NOT EXPECTED AS WEAK RIDGING IS
ACTUALLY EXPECTED ACROSS THE EASTERN COUNTIES. THIS WILL KEEP THE
SLIGHTLY HIGHER POPS MAINLY FOR THE CENTRAL COUNTIES.

WE SHOULD SEE SLIGHTLY HIGHER POPS...MAINLY SATURDAY EVENING
THROUGH SUNDAY AS THE NEXT SYSTEM NEARS TEXAS. THE MAIN AREA OF
FORCING FOR ASCENT WILL BE NORTHWEST OF THE AREA AS THIS UPPER LOW
TAKES A SIMILAR TRACK TO THE PREVIOUS. HOWEVER...MODELS ARE IN
FAIRLY GOOD AGREEMENT THAT A WEAK DISTURBANCE WILL MOVE INTO THE
AREA FROM THE SOUTHWEST TO ALLOW FOR A SLIGHTLY HIGHER COVERAGE OF
SHOWERS AND STORMS. ANY STORMS THAT DO DEVELOP COULD BE STRONG TO
SEVERE. THE HIGHER COVERAGE OF SEVERE STORMS SHOULD BE NORTH OF
THE AREA WHERE THE DRYLINE IS EXPECTED TO COINCIDE WITH THE BEST
UPPER SUPPORT. MODELS THEN DIVERGE WITH THE REST OF THE LONG-
TERM FORECAST WITH THE HANDLING OF A COLD FRONT ON THE BACKSIDE OF
THE UPPER LOW. THE GFS KEEPS THE FRONT WELL NORTH OF THE
CWA...WHILE THE ECMWF BRINGS IT THROUGH THE AREA WITH A MUCH MORE
WIDESPREAD COVERAGE OF SHOWERS AND STORMS MONDAY. WILL KEEP POPS
IN THE 30 PERCENT RANGE FOR NOW AS IT IS NEARLY A WEEK AWAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              81  69  83  70  83 /  40  40  20  20  30
AUSTIN BERGSTROM INTL AIRPORT  81  69  83  70  84 /  40  40  20  20  30
NEW BRAUNFELS MUNI AIRPORT     81  69  84  70  84 /  30  30  20  20  30
BURNET MUNI AIRPORT            78  67  81  68  82 /  40  50  30  20  30
DEL RIO INTL AIRPORT           81  70  84  70  88 /  30  30  20  20  20
GEORGETOWN MUNI AIRPORT        80  68  82  69  83 /  40  50  30  20  30
HONDO MUNI AIRPORT             79  69  84  70  85 /  30  30  20  20  30
SAN MARCOS MUNI AIRPORT        81  69  83  70  84 /  40  30  20  20  30
LA GRANGE - FAYETTE REGIONAL   82  70  82  71  85 /  30  30  30  20  20
SAN ANTONIO INTL AIRPORT       80  69  84  70  83 /  30  30  20  20  30
STINSON MUNI AIRPORT           81  70  85  71  85 /  30  30  20  20  30

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...29



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