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

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000
FXUS64 KEWX 310414
AFDEWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1114 PM CDT WED JUL 30 2014

.AVIATION... /ISSUED FOR 06Z TAF UPDATE/
LOW MVFR CIGS WILL DEVELOP BENEATH INTERMITTENT HIGH CLOUDS BY
AROUND 09Z AND COULD THUS BE ERRATIC IN COVERAGE ALONG I-35. SOME
CIGS COULD FLIRT WITH IFR CRITERIA FROM 09Z THROUGH 15Z...BUT WILL
RUN WITH LOW END MVFR DUE TO THE BREEZY BOUNDARY LAYER CONDITIONS
POSSIBLY MIXING IN SOME DRIER AIR FROM ALOFT.

A COLD FRONT SHOULD ENTER THE SOUTHERN EDWARDS PLATEAU/NRN HILL
COUNTRY BEFORE DAYBREAK THURSDAY...BUT IS EXPECTED TO STALL
BY MIDDAY WHILE MIXING IS ROBUST. THE FROPA TIME LINE HAS BEEN
ACCELERATED FOR THE TAF SITES AS SUGGESTED BY THE EVENING PROGRESS
AND THE LATEST RUNS OF THE HIGHER RES MODELS. WITH MOST MODEL DATA
SHOWING CONVECTION IN THE MID-AFTERNOON HOURS AROUND THE
ESCARPMENT...WILL CONTINUE TO RUN PROB30 PERIODS ALONG I-35 AND
KEEP DRT BENIGN. OTHERWISE...ISOLATED CONVECTION WILL BE POSSIBLE
MAINLY FROM 18Z THROUGH THE ENDS OF THE TAF PERIODS OVER ALL
TERMINALS. SOME SOUTHERLY WINDS AHEAD OF THE FRONT COULD EXCEED 12
KNOTS WITH GUSTS TO 20 KNOTS...BUT MOST OF THE NON-CONVECTIVE
WINDS SHOULD REMAIN AROUND OR BELOW 10 KNOTS. IN THE FINAL 12 TO
18 HOURS OF THE TAF PERIODS...SOME PATCHES OF MVFR OR POSSIBLY IFR
CIGS COULD REDEVELOP ALONG I-35 WITH THE BEST CHANCE OCCURRING
AFTER MIDNIGHT.

&&

.PREV DISCUSSION... /ISSUED 814 PM CDT WED JUL 30 2014/

UPDATE...
THE MAIN UPDATE ISSUE IS THE PROSPECT FOR CONVECTION...NOW OVER
NORTHWEST TEXAS AND THE TRANS-PECOS...PROPAGATING SOUTHEAST INTO OUR
AREA LATE TONIGHT. VARIOUS MESOSCALE MODELS DISSIPATE THE
CONVECTION ABOUT 50 MILES NORTHWEST OF OUR AREA...ALTHOUGH THE ONE
WITH THE BEST HANDLE VS. CURRENT OBSERVATIONS IS THE COLORADO
STATE WRF...AND IT BRINGS SHOWERS INTO THE NORTHERN 50-75 MILES OF
OUR AREA. WE DECIDED TO STICK WITH THE CURRENT FORECAST OF LOW
POPS ALONG THE NORTHERN COUNTIES FOR SHOWERS BETWEEN 06Z AND 12Z.
THERE IS A SMALL CHANCE OF A FEW LIGHTNING STRIKES...BUT THE LINE
OF SHOWERS WOULD NOT ARRIVE UNTIL THE DIURNAL MINIMUM OF HEATING...
AND AFTER THE PEAK OF LOW LEVEL JET FOR SUPPORT...THUS NO MENTION
OF THUNDER AT THIS TIME. THE FORECAST IS ON TRACK...BUT WE WILL
SEND AN UPDATE TO RE-TREND THE HOURLY FORECAST ELEMENTS THROUGH
12Z THURSDAY.

PREV DISCUSSION... /ISSUED 318 PM CDT WED JUL 30 2014/

SHORT TERM (TONIGHT THROUGH THURSDAY NIGHT)...
ALTHOUGH TEMPERATURES ARE STILL IN THE MIDDLE TO UPPER
90S...DEWPOINTS HAVE MIXED OUT MUCH MORE TODAY. THIS HAS KEPT THE
HEAT INDICES IN CHECK WITH MOST LOCATIONS BELOW 100 EXCEPT FOR THE
COASTAL PLAINS WHERE DEWPOINTS REMAIN IN THE MIDDLE TO UPPER 60S.
THE MAIN STORY OVER THE PAST SEVERAL DAYS HAS BEEN THE LATE
JULY/EARLY AUGUST COLD FRONT EXPECTED TOMORROW. AS OF 2 PM...THE
FRONT WAS STILL LOCATED IN THE TEXAS PANHANDLE BUT IT CONTINUES TO
MOVE SOUTH AT THIS HOUR. SHORT-TERM MODEL GUIDANCE IS FIRING OFF
STORMS IN WEST TEXAS LATE THIS AFTERNOON AND EVENING AND THE ONLY
EFFECT THESE MAY HAVE IN OUR CWA IS LIGHT RAIN AS THE STORMS
WEAKEN AND DIE AS THEY NEAR THE AREA. WILL MENTION RAIN SHOWERS
WITH 10 POPS AFTER 06Z TO ACCOUNT FOR THIS.

THE FRONT IS EXPECTED TO MAKE IT INTO THE NORTHERN PORTIONS OF THE
CWA AROUND 18Z TOMORROW. IT WILL ARRIVE DURING PEAK HEATING AND WE
SHOULD SEE SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP ALONG THE
BOUNDARY ACROSS THE HILL COUNTRY. ALL ACTIVITY WILL MOVE TO THE
SOUTHEAST DURING THE EVENING HOURS THURSDAY AS THE FRONT SLOWLY
MOVES SOUTH. UNFORTUNATELY THE MAIN TROUGH AXIS WILL BE LOCATED
NEAR THE ARKLATEX REGION AND WE WILL NOT BE IN A FAVORABLE REGION
FOR LARGE SCALE ASCENT. THE MAIN LIFTING MECHANISM WILL BE THE
SURFACE FOCUS ASSOCIATED WITH THE FROPA. 850 MB FLOW AHEAD OF THE
FRONT WILL ALSO BE WEAK...WHICH WILL NOT HELP MUCH WITH THE
PRODUCTION OF RAINFALL. HIGH-RES GUIDANCE IS FORECASTING A BROKEN
LINE OF SHOWERS AND STORMS WITH THE FROPA WITH SOME LINGERING
LIGHT RAIN BEHIND THE BOUNDARY ASSOCIATED WITH THE WEAK LIFT AT
850 MB. THIS SEEMS PLAUSIBLE AND WILL CARRY 30/40 POPS FOR MUCH OF
THE AREA THURSDAY AND THURSDAY NIGHT ASSOCIATED WITH THE FROPA.
ALTHOUGH LARGE SCALE LIFT IS LACKING...MOISTURE WILL CERTAINLY
NOT BE. PW VALUES AHEAD OF THE BOUNDARY ARE EXPECTED TO INCREASE
TO NEAR 2.3 INCHES ACROSS THE COASTAL PLAINS AND NEARLY 2 INCHES
ELSEWHERE. THE ABUNDANT MOISTURE COULD ALLOW FOR ISOLATED POCKETS
OF HEAVY RAINFALL AND WILL KEEP THE MENTION OF LOCALLY HEAVY RAIN
IN THE HWO.

LONG TERM (FRIDAY THROUGH WEDNESDAY)...
FOR FRIDAY...NORTH FLOW IS EXPECTED TO BE PREVAILING ACROSS MUCH
OF THE CWA FROM THE SURFACE INTO THE MID-LEVELS OF THE ATMOSPHERE.
THIS WILL LEAD TO DRYING ALOFT AND WITH THE WEAK SUBSIDENCE...THE
COVERAGE OF ACTIVITY SHOULD BE LESS FOR MUCH OF THE AREA. WILL
LINGER POPS IN THE RIO GRANDE AND COASTAL PLAINS IN CLOSER
PROXIMITY TO THE FRONT. THE POPS ARE MAINLY FOR THE MORNING
HOURS...AS WE SHOULD SEE LESS ACTIVITY DURING THE AFTERNOON GIVEN
THE DRYING ATMOSPHERE. BY FRIDAY NIGHT...PW VALUES WILL BE BELOW 2
INCHES FOR ALL BUT EXTREME SOUTHWESTERN ZONES AND WILL KEEP THE
BEST POPS IN THIS AREA. BY SATURDAY NIGHT...ALL POPS HAVE BEEN
REMOVED FROM THE FORECAST. TEMPERATURES FRIDAY AND SATURDAY WILL
BE QUITE NICE FOR THIS TIME OF YEAR. EXPECT NEAR 90 FOR THE HILL
COUNTRY AND LOWER TO MIDDLE 90S ELSEWHERE.

EAST/SOUTHEAST WINDS RETURN AT THE SURFACE SUNDAY THEN CONTINUE
THROUGH THE PERIOD. ISOLATED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE IN THE COASTAL PLAINS ASSOCIATED WITH THE AFTERNOON
SEABREEZE. EXPECTING A BIT MORE THAN ISOLATED ACTIVITY MONDAY AND
TUESDAY ACROSS THE COASTAL PLAINS AS A WEAK TROUGH SITS NEARLY
STATIONARY OVER THE WESTERN GULF OF MEXICO. THIS SHOULD INCREASE
THE COVERAGE OF ACTIVITY SLIGHTLY. THIS WEAK TROUGH/SHEAR AXIS
WILL CONTINUE TO BE IN PLACE THROUGH EARLY NEXT WEEK. THIS SHOULD
HELP KEEP HIGHS FROM WARMING BACK INTO THE UPPER 90S TO NEAR 100
FOR MUCH OF THE REGION FOR THE REMAINDER OF THE FORECAST PERIOD.

HAMPSHIRE

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              74  94  74  95  73 /  10  30  20  10  10
AUSTIN BERGSTROM INTL AIRPORT  72  94  72  93  70 /  10  30  30  10  10
NEW BRAUNFELS MUNI AIRPORT     73  96  73  93  71 /  -   20  40  10  20
BURNET MUNI AIRPORT            72  91  72  91  71 /  10  30  20  10  10
DEL RIO INTL AIRPORT           78  99  79  95  77 /  10  20  40  20  30
GEORGETOWN MUNI AIRPORT        73  92  72  92  71 /  10  30  20  10  10
HONDO MUNI AIRPORT             72  97  74  94  73 /  -   20  40  20  20
SAN MARCOS MUNI AIRPORT        73  95  73  92  71 /  -   30  40  10  10
LA GRANGE - FAYETTE REGIONAL   75  94  76  91  73 /  -   20  40  20  10
SAN ANTONIO INTL AIRPORT       76  96  76  93  74 /  -   20  40  10  20
STINSON MUNI AIRPORT           74  97  75  94  74 /  -   20  40  10  20

&&

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

$$

MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...26
PUBLIC SERVICE/DATA COLLECTION...00




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