Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 16, NWS Houston/Galveston, TX

May 24, 2021Harris County, Montgomery County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at May 24, 2021, 12:42 PM CDT for Harris County, Montgomery County, Texas. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 24, 2021, 12:42 PM CDT (17:42 UTC)
Expired
May 24, 2021, 3:45 PM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

Counties Harris County, TX, Montgomery County, TX

The radar

The Houston radar (KHGX), 37 km from the middle of the area, began a volume at 17:44 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
May 24, 1:07 PM CDTFLASH FLOOD4 Ese West University P, TXLOCAL MEDIA SHOWS VIDEO FROM HOUSTON TRAFFIC CAMS SHOWING WATER COVERING SH-288 AT HOLCOMBE BLVD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.7 hours before the alert went out and 204 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, Lake Charles Mun, LA at 12:00Z on 2021-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 505 joules per kilogram.LCLLFCEL10008507005003002001001 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, Lake Charles Mun, LA at 12:00Z on 2021-05-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.193958Sfc1 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
505 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
687 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

The text

As transmitted.

145 
WGUS54 KHGX 241742
FFWHGX
TXC201-339-242045-
/O.NEW.KHGX.FF.W.0016.210524T1742Z-210524T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
1242 PM CDT Mon May 24 2021

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  Harris County in southeastern Texas...
  Southeastern Montgomery County in southeastern Texas...

* Until 345 PM CDT.

* At 1242 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 4 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly. A band of storms continues to bring heavy rainfall to the 
  area and these storms will be tracking across areas that have 
  already been hit by earlier rainfall. Rainfall rates of nearly 
  3"/hour will be likely with these storms. Street flooding will 
  likely we worsening across the area.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Northwestern Pasadena, northern Pearland, Deer Park, South 
  Houston, Bellaire, Humble, West University Place, Galena Park, 
  Jacinto City, Greater Fifth Ward, Second Ward, Near Northside 
  Houston, Cloverleaf, Greater Eastwood, Downtown Houston, Greater 
  Third Ward, southeastern Northside / Northline, Fourth Ward, 
  Midtown Houston and Greater Heights.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

&&

LAT...LON 2958 9542 2964 9544 2973 9545 2980 9542
      2986 9535 3002 9533 3010 9533 3010 9528
      3004 9520 2996 9513 2987 9510 2971 9511
      2971 9516 2972 9523 2959 9518 2957 9522
      2957 9525 2959 9526 2960 9528 2960 9533

FLASH FLOOD...RADAR INDICATED

$$

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 23, 10:07 PM CDTRip Current StatementHGXBrazoria, Galveston, Matagorda65 hr
May 24, 9:28 AM CDTRiver Flood WarningHGXLavaca31 hr
May 24, 10:19 AM CDTAreal Flood AdvisoryHGXBrazoria, Fort Bend, Harris, Montgomery, Waller116 min
May 24, 11:14 AM CDTAreal Flood AdvisoryHGXHarris, Montgomery3 hr
May 24, 11:40 AM CDTSpecial Marine WarningHGX50 min
May 24, 11:42 AM CDTAreal Flood AdvisoryHGXBrazoria, Fort Bend, Galveston, Harris2 hr
May 24, 1:54 PM CDTSpecial Weather StatementHGXBrazoria51 min
May 24, 2:50 PM CDTAreal Flood AdvisoryHGXBrazoria115 min
May 24, 3:44 PM CDTAreal Flood WarningHGXBrazoria, Harris2 hr
May 24, 5:47 PM CDTFlash Flood WarningHGXAustin, Colorado, Washington4 hr
May 24, 6:18 PM CDTSpecial Weather StatementHGXAustin42 min

Nearby

Flash Flood Warnings in Texas, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.