Flash Flood and Hail in Texas, May 12, 2003

Name: Flash Flood and Hail in Texas, May 12, 2003
Start: 2003-05-12T10:30
End: 2003-05-12T13:30
Location: Texas

May 12, 2003 · NWS EWX · 2 events in 1 county or zone

1 hail, 1 flash flood, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $10,000
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Austin/San Antonio, TX wrote its last area forecast discussion before the first event at May 12, 9:35 AM CST, 55 minutes earlier.

Area forecast discussion, May 12, 9:35 AM CST, 55 minutes before

SOUTH CENTRAL TEXAS FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1035 AM CDT MON MAY 12 2003

UPDATED FORECAST AT AROUND 9 AM THIS MORNING TO REFINE PECIPITATION
CHANCES TO REFLECT THE WARM ADVECTION PATTERN. MOST OF THE
SIGNIFICANT RAIN IS OCCURRING OVER NORTHEAST PORTIONS OF SOUTH
CENTRAL TX WHERE ISENTROPIC LIFTING IS MAXIMIZED BY THE DEEPER PART
OF THE FRONT INTERFACED WITH STRONGER SOUTHERLY WINDS ABOVE THE
BOUNDARY LAYER.

THE CURRENT POPS STILL LOOK ON TRACK, BUT WILL UPDATE AGAIN BY 11 AM
TO TWEAK TEMPS AND WINDS WITH MAIN ADJUSTMENTS OCCURRING OVER THE
SOUTHEAST COUNTIES. IF SURFACE BASED CONVECTION FAILS TO DEVELOP
OVER THE SHALLOW PART OF THE FRONT HERE THIS AFTERNOON, WILL LIKELY
REMOVE POPS FOR THIS EVENING AND BEYOND FOR THESE SOUTHERN COUNTIES
IN THE AFTERNOON PACKAGE. CURRENT POPS ARE ADMITTEDLY ON THE
CONSERVATIVE SIDE AS THE LIKELIHOOD OF RAIN BEING OBSERVED IS
SIGNIFICANTLY LESS THAN THE LIKELIHOOD OF MEASURABLE AMOUNTS.

.EWX...NONE

18/8

.EARLY MORNING DISCUSSION........................................
CURRENT WX...CDFNT HAS STALLED OVER COASTAL PLAINS THIS MORNING...
WITH WIDESPREAD LOW CLOUDINESS AREAWIDE. PRECIP IN FORM OF TSTMS IS
CONFINED TO LOWER RIO GRANDE AREA. STRONG H8 RIDGE OVERLIES NRN
TX...WHICH WOULD GENERALLY SUGGEST A SLOWER RETURN NWD OF THE WARM
AIR...BUT 305K PLOT INDICATES LIFTING HAS ALREADY BEGUN.

TODAY AND TONITE...EXPECT AIRMASS TO SATURATE SLOWLY THRU THE
MORNING... WITH SHOWERS SPREADING NWD THRU THE AFTN AND ACROSS MOST
SECTIONS. FCST PACKAGE WILL TREND CLOSEST TO ETA AS THE AVN APPEARS
TO BE ON SOME SERIOUS STERIODS WITH ITS 40 PVA NEAR THE END OF THE
PERIOD.

TUE...ETA SHOWS MARKED DRYING ABOVE H8 LEVEL BY TUE AFTN WITH WARM
AIR...SLY LO LVL WINDS...AND SMOKE...BACK IN PLACE AGAIN.

EXTENDED...ONCE THE MOISTURE RETURNS...A RATHER DULL SAMENESS WILL
TAKE OVER FOR AT LEAST 48 HRS.  BACK TO VERY WARM AND HUMID DAYS
WITH MILD TO WARM NIGHTS AT LEAST THRU THU.  THERE IS ONLY A SLIM
POSSIBILITY OF RAIN ON FRIDAY AS AN UPPER SYSTEM SLIPS ACROSS SERN
TX.  BUT MODELS PLACE SC TX IN A DRIER SLOT WITH LIMITED
MOISTURE...SO WILL CONTINUE AT THIS TIME WITH DRY EXTENDED FCST.

Hazardous weather outlook, May 11, 4:10 PM CST, 18 hours 20 minutes before

TXZ171>173-183>194-202>209-217>225-228-121100-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
510 PM CDT SUN MAY 11 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY

SHOWERS AND THUNDERSTORMS ARE EXPECTED TO REDEVELOP LATE TONIGHT AS
THE COLD FRONT WHICH MOVED THROUGH TODAY...MOVES BACK NORTH AS A
WARM FRONT. HOWEVER...NO SEVERE STORMS ARE EXPECTED.

.DAYS TWO THROUGH SEVEN...

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE MONDAY AND TAPER
OFF FROM SOUTHWEST TO NORTHEAST AS A WARM FRONT MOVES NORTH OF THE
REGION. HOT AND HUMID WEATHER IS EXPECTED BY THE END OF THE
WEEK...AND HEAT INDICES MAY APPROACH 100 TO 105 BY FRIDAY AT
LOCATIONS SOUTH OF INTERSTATE 10.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 hail, 1 flash flood. Local standard time, as filed.

Hail, Williamson

When: May 12, 10:30 AM CST to 10:50 AM CST
Where: Williamson County, 3 mi SW of Round Rock
Measured: 0.75 in hail
Reported by: GENERAL PUBLIC
Coordinates: 30.467, -97.717

Flash Flood, Williamson

When: May 12, 12:15 PM CST to 1:30 PM CST
Where: Williamson County, Cedar Park
Property damage: $10,000
Reported by: LAW ENFORCEMENT
Coordinates: 30.648, -97.601 (the zone’s center; the record gives no point)

Widespread light showers and thunderstorms formed over Williamson County in the late morning. Between 11 am CST and noon CST, very heavy rain fell across extreme southern Williamson County between Cedar Park and Round Rock. Both locations reported between 4 and 5 inches of rain in the one hour period. The Williamson County Sheriff's Department reported flash flooding across numerous roads and low water crossings in the two cities as well as along Brushy Creek which runs between the cities.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Texas in 2003 Every state in 2003 This day in weather history Warnings in Texas, May 2003

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5353637, 5353638.