263
FXUS64 KEWX 190003
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
703 PM CDT MON MAY 18 2026
..NEW AVIATION
KEY MESSAGES
- LOW CHANCE FOR A FEW SHOWERS AND STORMS TODAY MAINLY ALONG THE
RIO GRANDE
- LINE OF STRONG TO SEVERE STORMS WITH LOCALLY HEAVY RAIN POSSIBLE
TUESDAY EVENING/NIGHT.
- ACTIVE WEATHER PATTERN FROM MID-WEEK THROUGH THE UPCOMING
MEMORIAL HOLIDAY WEEKEND. HEAVY RAIN AT TIMES COULD LEAD TO
LOCALIZED FLOODING.
SHORT TERM
(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 133 PM CDT MON MAY 18 2026
THE CAP SHOULD CONTINUE TO HOLD THIS AFTERNOON, BUT SUFFICIENT
WARMING COULD SPARK ISOLATED STORMS ALONG THE RIO GRANDE IN THE
EVENING WHICH MAY PUSH EAST IF THEY DO DEVELOP. WHILE ONLY THE 12Z
HRW ARW AND FV3 CAMS DEPICTED DEEP CONVECTION DEVELOPING IN THIS
MANNER OUT OF THE HREF SUITE, THE MOIST AND BUOYANT ENVIRONMENT DOES
INCREASE THE BACKGROUND POTENTIAL RELATIVE TO TYPICAL EXPECTATIONS,
SO STORM CHANCES THIS EVENING ARE BUT WERE ADJUSTED HIGHER THAN THE
NBM MAINLY OVER THE RIO GRANDE PLAINS AND SOUTHERN EDWARDS PLATEAU.
THE LOW-LEVEL JET THAT DELIVERED SEVERAL DAYS OF ABNORMALLY BREEZY
AND HUMID CONDITIONS WILL CONTINUE FOR ANOTHER NIGHT (ALBEIT WITH
SLIGHTLY REDUCED STRENGTH), IMPARTING SOUTHERLY GUSTS IN THE 20-30
MPH TONIGHT. THE UPPER-AIR DISTURBANCE OVER THE CENTRAL PLAINS THAT
ENABLED THE LLJ IS ACTIVELY MOVING FARTHER AWAY, SO WE EXPECT THAT
WINDS WILL START TO GRADUALLY SUBSIDE TOMORROW.
HUMID AIR WILL LIKELY PERSIST THROUGH THE WEEK, BUT LOWS TUESDAY
MORNING SHOULD CAP OFF A STREAK OF MORNINGS WITH NEAR-RECORD TO
RECORD-SETTING MILD TEMPERATURES. A WEAK COLD FRONT WILL SLOWLY
CRAWL SOUTH TOWARDS OUR LOCAL AREA THROUGHOUT THE DAY. THIS FRONT
ARRIVES WITHOUT THE SUPPORT OF NORTHERLY WINDS ALOFT, SO THIS WON'T
BE A FRONT KNOWN FOR ITS NORTHERLY POST-FRONTAL WINDS OR BRISK
ARRIVAL. INSTEAD, THE INTERACTION OF THE FRONT WITH THE HUMID
AIRMASS STOCKPILED OVER OUR AREA SHOULD PRODUCE SCATTERED TO
WIDESPREAD SHOWER AND STORM ACTIVITY, WITH THAT ACTION ENCROACHING
UPON THE HILL COUNTRY BY THE EVENING HOURS. ADDITIONALLY,
SOUTHWESTERLY DIVERGENT FLOW ALOFT SHOULD PRODUCE ISOLATED TO
SCATTERED THUNDERSTORMS ALONG THE DRY LINE ATOP THE HIGHER TERRAIN
OVER MEXICO, WHICH MAY MOVE EAST TOWARDS THE RIO GRANDE AND JOIN UP
WITH THE FRONT. A STEADY CAP SHOULD BE ABLE TO GENERALLY MUTE STORM
DEVELOPMENT OVER SOUTH-CENTRAL TEXAS FOR MOST OF MORNING AND
AFTERNOON TUESDAY. DESPITE THE CLOUDS AND MOIST AIR, HIGHS IN THE
90S WITH THE AMPLE HUMIDITY SHOULD AGAIN BOOST HEAT INDICES ABOVE
100F FOR PORTIONS OF THE RIO GRANDE PLAINS AND COASTAL PLAINS, WITH
VALUES IN THE MID TO UPPER 90S ELSEWHERE. HOWEVER, AS THE FRONT AND
DRY LINE GET ACTIVE AND MOVE CLOSER, RAIN CHANCES GO UP QUICKLY
AFTER SUNSET AND TEMPERATURES SHOULD BEGIN TO FALL OFF MORE THAN
THEY HAVE ON PREVIOUS DAYS.
THE PRIMARY PERIOD OF STORMINESS TUESDAY IS LIKELY FROM TUESDAY
EVENING INTO THE OVERNIGHT HOURS. THE SPC HAS HIGHLIGHTED A LEVEL 2
OF 5 (SLIGHT) RISK OF SEVERE WEATHER WITH THE GREATEST RISK
GENERALLY ALONG AND WEST OF THE I-35 CORRIDOR. WHILE THE SIMULATED
RADAR OUTPUTS FROM THE HI-RES MODELS DISAGREE IN THE GENERAL
ARRANGEMENT OF STORMS TUESDAY EVENING, THE OVERALL ENVIRONMENT WITH
WEAK MID-LEVEL FLOW ALONG THE FRONT SUPPORTS A LINE OF THUNDERSTORMS
ALONG THE FRONT PUSHING SOUTH OVER THE AREA. THERE'S A SOMEWHAT
EMERGENT MODEL CONSENSUS THAT THIS LINE COULD REACH THE HILL COUNTRY
/ EDWARDS PLATEAU NEAR OR JUST BEFORE SUNSET AND THEN PROGRESS SOUTH
THROUGH THE REST OF OUR AREA BEFORE WINDING DOWN IN THE PRE-DAWN
HOURS WEDNESDAY, NOT TOO UNLIKE OUR LINE OF STORMS LAST WEEK. THE
PRIMARY SEVERE THREAT WOULD LIKELY BE ISOLATED STRONG TO DAMAGING
WIND AS STORMS RIPPLE ALONG THE FRONT. THERE COULD BE SOME ISOLATED
LARGE HAIL POTENTIAL MAINLY OVER THE EDWARDS PLATEAU, BUT THE RATHER
MODEST EFFECTIVE BULK SHEAR (GENERALLY UNDER 30 KT) AND HIGH
FREEZING LEVEL WILL GENERALLY LIMIT THAT RISK TO ONLY THE STRONGEST
UPDRAFTS. THE HEAVY RAIN POTENTIAL WILL ALSO NEED TO BE MONITORED AS
WELL AS THE FRONT BRUSHES UP AGAINST THE MOIST, ACCUMULATED GULF
AIR. THE WPC HAS UP TO A LEVEL 2 OF 4 (SLIGHT) RISK FOR ISOLATED
HEAVY RAIN CAPABLE OF FLASH FLOODING ACROSS A SUBSTANTIAL PORTION OF
OUR WARNING AREA, AND THE GENERALLY WEAK FLOW ALOFT AND THICK WARM
CLOUD DEPTH COULD SUPPORT MORE EFFICIENT DOWNPOURS. STORMS THAT
MANAGE TO DEVELOP AHEAD OF THE FRONT WOULD FIND THEMSELVES BRIEFLY
IN A SLOW-MOVING ENVIRONMENT AND ADD TO THIS RAIN. THIS SIGNAL IS
SLIGHTLY HIGHER IN THE SOUTHERN HILL COUNTRY RAIN TOTALS WILL
GENERALLY DEPEND ON HOW QUICKLY THE RAIN-COOLED AIR PUSHING THE LINE
OF STORMS KICKS INTO GEAR, BUT THE OVERALL PROSPECTS FOR WIDESPREAD
AMOUNTS ABOVE 1 INCH LOOKS LIKELY. A FEW LOCALIZED POCKETS OF 3-5"
OF RAIN IS ALSO HINTED AT BY THE CAMS, AND THIS WOULD BE
COMMENSURATE WITH THE MOIST ENVIRONMENT. WHILE THE SEVERE RISK IS
MORE ESTABLISHED FOR NORTHERN PORTIONS OF THE CWA, THE GEOGRAPHIC
PLACEMENT OF THE HEAVIEST RAINS IS A LITTLE MORE UNCERTAIN.
LONG TERM
(WEDNESDAY THROUGH NEXT MONDAY)
ISSUED AT 133 PM CDT MON MAY 18 2026
TUESDAY'S FRONT WILL LIKELY BE PUSHED ALONG BY THE RAIN-COOLED
AIR FROM TUESDAY NIGHT'S STORMS, AND WEDNESDAY MORNING SHOULD
START OUT MORE SEASONABLY WITH TEMPERATURES IN THE 60S TO LOW 70S.
THE MEDIUM-RANGE MODEL GUIDANCE SHOWS SEVERAL PROTUBERANCES OF
VORTICITY ALOFT MOVING OVER OUR AREA WEDNESDAY. HOWEVER, THE
ATMOSPHERE WILL PROBABLY TAKE SOME TIME TO RECUPERATE FROM THE
PRECEDING NIGHT'S STORMS, AND EVEN WITH THE MOIST AIRMASS
REMAINING IN PLACE IT WOULD NOT BE A SURPRISE TO SPEND MOST OF THE
DAY WEDNESDAY RAIN-FREE. STILL, THE CONTINUED PRESENCE OF
MOISTURE AND A CONDUCIVE SOUTHWESTERLY FLOW PERSISTING ALOFT
THANKS TO BROAD TROUGHING OVER THE WESTERN US MEANS THAT THERE
WILL BE MORE OPPORTUNITIES FOR RAIN AND STORMS THROUGHOUT THE
WEEK. HEAVY RAIN POTENTIAL WILL CONTINUE WITH PRECIPITABLE WATER
VALUES REPEATEDLY NEAR OR OVER THE 90TH PERCENTILE FOR THIS TIME
OF YEAR. KEY ELEMENTS TO WATCH WILL BE ANY RESIDUAL BOUNDARIES
LEFT OVER BY PREVIOUS ROUNDS OF STORMS, WHICH CAN BE FOCI FOR NEW
STORM DEVELOPMENT, AND BUNDLES OF VORTICITY ALOFT MOVING OVER THE
AREA TO ENHANCE CERTAIN WINDOWS OF OPPORTUNITY FOR RAIN. THE
PRECISE TIMING AND PLACEMENT OF STORMS WILL BE BASED ON THESE
FACTORS, WHICH WILL BE SENSITIVE TO THE EVOLUTION OF EACH
SUCCESSIVE PERIOD OF STORMS.
BASED ON THEIR DEPICTIONS OF MID-LEVEL 700MB VORTICITY, A FEW OF THE
MEDIUM-RANGE MODELS, INCLUDING THE GFS, ECMWF, AND THEIR ENSEMBLE
SUITE AND AI COUNTERPARTS SUGGEST A FAVORABLE PERIOD FOR RAIN
THURSDAY. THE WPC HAS UP TO A LEVEL 2 OF 4 (SLIGHT) RISK FOR HEAVY
RAIN DURING THAT WINDOW. ANOTHER CONDUCIVE PERIOD MAY TAKE SHAPE
THIS WEEKEND. THIS TIMING SHOULD BE CONSIDERED WITH BROAD
BRUSHSTROKES, AS IT'S STILL TOO EARLY TO DECIPHER WHICH AREAS MAY
SEE HEAVIER RAINS AND WHEN. HOWEVER, TAKEN ALTOGETHER, THERE COULD
BE A GRADUALLY INCREASING POTENTIAL FOR FLASH AND RIVERINE FLOODING
AS EACH ROUND OF RAIN SATURATES GROUNDS FURTHER. THE BOTTOM LINE IS
THAT AN ACTIVE AND WET PATTERN LOOKS LIKELY FOR THE ENTIRETY OF
SOUTH CENTRAL TEXAS THROUGH THE WEEK. CONTINUE TO CHECK BACK AS
DETAILS GET CLEARER OVER THE COMING DAYS.
AVIATION
(00Z TAFS)
ISSUED AT 637 PM CDT MON MAY 18 2026
VFR CIGS, GUSTY SOUTHEASTERLY WINDS, AND SCATTERED CLOUDS
CONTINUE THROUGH THIS EVENING BEFORE WINDS RELAX A BIT AND MVFR
CIGS RETURN FOR ALL I-35 TAF SITES BY AROUND 04Z. COULD EVEN SEE
IFR CIGS BY EARLY MORNING HOWEVER CONFIDENCE REMAINS LOW ON THIS
OCCURRING. A LINE OF CONVECTION COMING FROM THE NORTH IS SHOWN BY
NUMEROUS MODELS IMPACTING KAUS AND KSAT TOWARDS THE END OF THE
FORECAST PERIOD, HOWEVER TIMING REMAINS UNCERTAIN. ADDED IN
PROB30S FOR THIS TIME THOUGH FUTURE PACKAGES WILL NEED TO REFINE
THE TIMING. ADDITIONALLY, PROB30S WILL LIKELY BE NEEDED FOR KSSF
AND EVENTUALLY KDRT IN FUTURE FORECASTS. FOR KDRT EXPECT VFR CIGS
UNTIL EARLY MORNING BEFORE MVFR CIGS OCCUR WITH VFR CIGS
RETURNING BY THE AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
AUSTIN CAMP MABRY 77 90 71 85 / 10 30 80 60
AUSTIN BERGSTROM INTL AIRPORT 79 90 71 85 / 10 30 70 60
NEW BRAUNFELS MUNI AIRPORT 77 90 70 85 / 10 20 70 60
BURNET MUNI AIRPORT 75 86 67 82 / 10 40 80 60
DEL RIO INTL AIRPORT 76 93 71 88 / 20 20 50 40
GEORGETOWN MUNI AIRPORT 77 88 69 83 / 10 40 80 60
HONDO MUNI AIRPORT 78 90 70 84 / 10 20 70 60
SAN MARCOS MUNI AIRPORT 78 91 71 85 / 10 20 70 60
LA GRANGE - FAYETTE REGIONAL 78 90 72 85 / 10 20 70 60
SAN ANTONIO INTL AIRPORT 78 91 71 85 / 10 20 70 60
STINSON MUNI AIRPORT 79 92 71 86 / 10 10 70 60
EWX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...TRAN
LONG TERM....TRAN
AVIATION...CJM
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