Alert archive / California / Flash Flood Warnings in 2023

Flash Flood Warning 2, NWS Eureka, CA

August 19, 2023Trinity County, California

NWS Eureka, CA issued this flash flood warning at Aug 19, 2023, 3:50 PM PDT for Trinity County, California. It was in force for 85 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: Aug 19, 2023, 3:50 PM PDT (22:50 UTC)
Expired: Aug 19, 2023, 5:15 PM PDT
In force: 85 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Flood severity: None

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 81 km from the middle of the area, began a volume at 22:49 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.

The nearest sounding before it

Medford/Jackson, OR (KMFR), launched 12:00Z, 10.8 hours before the alert went out and 255 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1937 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 60 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

485 
WGUS56 KEKA 192250
FFWEKA
CAC105-200015-
/O.NEW.KEKA.FF.W.0002.230819T2250Z-230820T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Eureka CA
350 PM PDT Sat Aug 19 2023

The National Weather Service in Eureka has issued a

* Flash Flood Warning for...
  The August Complex burn scar in...
  Southwestern Trinity County in northwestern California...

* Until 515 PM PDT.

* At 350 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the August Complex Burn Scar. Between 1 and 1.5 
  inches of rain have fallen. Flash flooding is ongoing or expected 
  to begin shortly.

Excessive rainfall over the burn scar will result in the potential 
for debris flow. The debris flow can consist of rock, mud, 
vegetation and other loose materials.

  HAZARD...Flash flooding caused by thunderstorms in and around
           the August Complex Burn Scar.

  SOURCE...Radar.

  IMPACT...Flooding of areas in and around the August Complex
           Burn Scar.

* Some locations that will experience flash flooding include...
  Zenia.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause 
extensive and severe flash flooding of creeks...streams...and 
ditches in the August Complex Burn Scar. Severe debris flows can 
also be anticipated across roads. Roads and driveways may be washed 
away in places. If you encounter flood waters...climb to safety.

&&

LAT...LON 4024 12354 3998 12354 3999 12342 4011 12335
      4021 12341

FLASH FLOOD...RADAR INDICATED

$$

MKK

1 follow-up statement

232 
WGUS76 KEKA 200015
FFSEKA

Flash Flood Statement
National Weather Service Eureka CA
515 PM PDT Sat Aug 19 2023

CAC105-200025-
/O.EXP.KEKA.FF.W.0002.000000T0000Z-230820T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Trinity CA-
515 PM PDT Sat Aug 19 2023

...FLASH FLOOD WARNING FOR THE AUGUST COMPLEX BURN SCAR HAS EXPIRED 
FOR SOUTHWESTERN TRINITY COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4024 12354 3998 12354 3999 12342 4011 12335
      4021 12341

$$

EYS

The office that day

Everything else NWS Eureka, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 5:26 PM PDT	Special Weather Statement	EKA	Trinity	34 min
Aug 18, 5:32 PM PDT	Special Weather Statement	EKA	Trinity	28 min
Aug 18, 6:26 PM PDT	Special Weather Statement	EKA	Trinity	34 min
Aug 19, 3:35 AM PDT	Red Flag Warning	EKA		16 hr
Aug 19, 9:02 AM PDT	Small Craft Advisory	EKA		39 hr
Aug 19, 12:36 PM PDT	Special Weather Statement	EKA	Trinity	39 min
Aug 19, 1:15 PM PDT	Flash Flood Warning Considerable damage threat	EKA	Trinity	3 hr
Aug 19, 2:30 PM PDT	Special Weather Statement	EKA		45 min
Aug 19, 2:32 PM PDT	Special Weather Statement	EKA	Mendocino	43 min
Aug 19, 2:41 PM PDT	Special Weather Statement	EKA	Trinity	34 min
Aug 19, 2:45 PM PDT	Special Weather Statement	EKA	Humboldt	45 min
Aug 19, 2:54 PM PDT	Special Weather Statement	EKA	Humboldt	36 min
Aug 19, 3:10 PM PDT	Severe Thunderstorm Warning	EKA	Humboldt, Mendocino, Trinity	20 min
Aug 19, 3:17 PM PDT	Special Weather Statement	EKA	Trinity	43 min

Nearby

Flash Flood Warnings in California, 2023 Every flash flood warning in 2023

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; radar from the NEXRAD Level II archive.