Alert archive / Texas / Flash Flood Warnings in 2002

Flash Flood Warning 184, NWS Austin/San Antonio, TX

July 17, 2002Comal County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Jul 17, 2002, 1:25 PM CDT for Comal County, Texas. It was in force for 110 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 17, 2002, 1:25 PM CDT (18:25 UTC)
Expired
Jul 17, 2002, 3:15 PM CDT
In force
110 min
Issued by
NWS Austin/San Antonio, TX
Area
Counties, with a storm outline in the text

County Comal County, TX

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 6.4 hours before the alert went out and 241 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Corpus Christi, TX at 12:00Z on 2002-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2554 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Corpus Christi, TX at 12:00Z on 2002-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -46 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2554 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
559 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-46 m²/s²
0-3 km storm-relative helicity
-7 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS54 KEWX 171825
FFWSAT
TXC091-172015-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
125 PM CDT WED JUL 17 2002

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR THE FOLLOWING COUNTIES...
  COMAL

* UNTIL 315 PM CDT

* AT 125 PM...WEATHER SERVICE DOPPLER RADAR INDICATED A BAND OF 
  THUNDERSTORMS...WITH VERY HEAVY RAIN...MOVING NORTHWEST AT 20 
  MPH ACROSS COMAL COUNTY. THESE STORMS WILL LIKELY PRODUCE BETWEEN
  1 AND 2 INCHES OF RAIN ACROSS PARTS OF COMAL COUNTY. THESE 
  HEAVY RAINFALL AMOUNTS WILL PRODUCE FLASH FLOODING.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL 
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. MANY STREAMS ARE 
ALREADY NEAR CAPACITY AND WILL QUICKLY RISE OUT OF BANKS WITH THE 
ADDED RAINFALL.  

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS 
IMMINENT. MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT 
ATTEMPT TO CROSS BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS 
THE ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL 
ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

LAT...LON 2957 9827 2972 9814 2995 9825 2985 9848

What forecasters said that day

The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Jul 17, 9:30 AM CDT, 3 hours 55 minutes earlier.

Area forecast discussion, Jul 17, 9:30 AM CDT, 3 hours 55 minutes before
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
930 AM CDT WED JUL 17 2002

CURRENT WEATHER ANALYSIS...
A SURFACE RIDGE OVER THE NORTHERN GULF CONTINUES TO DOMINATE
SOUTH TEXAS WEATHER WITH EAST TO SOUTHEAST WINDS PREVAILING.
UPPER LEVEL TROUGH OVER THE REGION WILL CONTINUE TO BE A FOCUS
FOR THE ONGOING CONVECTIVE WEATHER.

OUTLOOK...
LOOK FOR UPPER LEVEL TROUGH TO SLIDE NORTH TO NORTHWEST OVER THE
NEXT 24 TO 48 HOURS. SURFACE RIDGE TO REMAIN A DOMINATE FOCUS
WITH CONTINUES GULF INFLOW INTO THE SOUTH CENTRAL TEXAS AND HILL
COUNTRY FORECAST WARNING AREA.

MODEL GUIDANCE PRECIPITABLE WATER GIVES THE REGION 1.5 TO 2.8
INCHES OVER THE NEXT 24 HOURS. IR/WV SATELLITE LOOP HAS YET ANOTHER
SHORTWAVE COMING ONSHORE AROUND MIDDAY TODAY.

CONSIDERING ALL OF THE ABOVE...WILL CONTINUE PRECIPITATION AND
CLOUDINESS TRENDS. WILL UPDATE THE 4AM ZONE FORECAST...
ADJUSTING FOR ONGOING WEATHER. WILL RE-ISSUE FORECAST SHORTLY.

PREVIOUS DISCUSSION....
FINALLY A QUIET NIGHT ACROSS SCNTRL TX AND AN IMPENDING CHANGE IN
THE FORECAST THE MAIN FORECAST ISSUES ARE THE NEED FOR AN FFA TODAY
AND POPS THROUGH DAY 7. THE 00Z NCEP MODELS ARE IN FAIR AGREEMENT.
PREFER THE AVN AS BETTER VERIFYING WITH CURRENT ACTIVITY AND MORE
REALISTIC THAN TOO WET ETA AND TOO DRY NGM. SIMILARLY...PREFER MAV
TEMPS/POPS. WILL BLEND EXTENDED GUIDANCE AND LEAN TOWARD 00Z
CANADIAN/12Z 7/16 NOGAPS...BUT WILL CHECK 00Z NOGAPS AND MRF BEFORE
FINAL DECISIONS.

THE 00Z FWD/LCH/DRT/BRO RAOBS STILL SHOW HIGH PW...BUT LESS THAN
TWO STANDARD DEVIATIONS ABOVE NORMAL...WHICH SEEMS TO BE A CRITICAL
LEVEL FOR HEAVY RAIN. CRP IS STILL NEAR 2 STD ABOVE NORMAL.
FYI...THE OLD UPPER AIR DATA FROM SAT INDICATES A CRITICAL PW OF
2.00 FOR HEAVY RAIN OVER CNTRL SECTIONS OF THE CWA. WERE LEANING
TOWARD NO FFA...BUT WILL DECIDE AT POST TIME.

OTHERWISE...ALL MODELS DEPICT THE SHEAR AXIS SLIDING WEST...WITH THE
SFC HIGH...THEN UPPER LEVEL RIDGE...BUILDING OVER TX BY LATE WEEK.
CANT GET TOO EXCITED FOR DRYING THROUGH...AS SEA BREEZE SHOULD HAVE
IDEAL CONDITIONS FOR THE WEEKEND...FOLLOWED BY TROPICAL WAVES IN THE
INCREASINGLY ACTIVE ATLANTIC MONSOON TROUGH. SO WILL RETAIN POPS IN
THE EXTENDED PERIOD...BUT LOWER TO SLIGHT CHANCE AND TREND TOWARD
POSSIBLY DRIER IN LATER PACKAGES.

PRELIMINARY NUMBERS
AUS 88/74/92/74/94 52211
DRT 89/74/91/75/95 43321
SAT 88/75/92/76/94 53211

.EWX...NONE.

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 16, 7:01 PM CDTFlash Flood WarningEWXCaldwell, Comal, Hays3 hr
Jul 17, 12:09 PM CDTFlash Flood WarningEWXCaldwell, Guadalupe, Hays, Travis3 hr
Jul 17, 12:45 PM CDTFlash Flood WarningEWXWilliamson2 hr
Jul 17, 2:22 PM CDTFlash Flood WarningEWXBexar, Blanco, Kendall3 hr
Jul 17, 3:11 PM CDTFlash Flood WarningEWXBandera, Medina109 min
Jul 17, 5:04 PM CDTFlash Flood WarningEWXBexar, Kendall3 hr
Jul 17, 5:24 PM CDTFlash Flood WarningEWXComal3 hr

Nearby

Flash Flood Warnings in Texas, 2002Every flash flood warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.