Alert archive / California / Flash Flood Warnings in 2023

Flash Flood Warning 1, NWS Eureka, CA

August 19, 2023Trinity County, California

NWS Eureka, CA issued this flash flood warning at Aug 19, 2023, 1:15 PM PDT for Trinity County, California. It was in force for 3 hr. 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, 1:15 PM PDT (20:15 UTC)
Expired
Aug 19, 2023, 3:45 PM PDT
In force
3 hr
Issued by
NWS Eureka, CA
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 103 km from the middle of the area, began a volume at 20:20 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, 8.3 hours before the alert went out and 225 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, Medford/Jackson, OR at 12:00Z on 2023-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Medford/Jackson, OR at 12:00Z on 2023-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 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
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.

468 
WGUS56 KEKA 192015
FFWEKA
CAC105-192145-
/O.NEW.KEKA.FF.W.0001.230819T2015Z-230819T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Eureka has issued a

* Flash Flood Warning for...
  Southern Trinity County in northwestern California...

* Until 245 PM PDT.

* At 115 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. The expected rainfall rate is 0.5 to 1 inch in 1 
  hour. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  mainly rural areas of Southern Trinity County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4030 12307 4032 12314 4034 12313 4036 12316
      4038 12315 4039 12315 4039 12314 4038 12313
      4040 12311 4040 12308 4039 12306 4037 12303
      4036 12304 4035 12304 4035 12306 4033 12307
      4031 12306 4031 12307

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...0.5-1 INCH IN 1 HOUR

$$

SEC
2 follow-up statements
264 
WGUS56 KEKA 192142
FFWEKA
CAC105-192245-
/O.EXT.KEKA.FF.W.0001.000000T0000Z-230819T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Eureka has extended the

* Flash Flood Warning for...
  Southern Trinity County in northwestern California...

* Until 345 PM PDT.

* At 242 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 to 2.5 inches of 
  rainfall have fallen. Additional rainfall amounts of 0.5 to 1 inch 
  are possible in the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  mainly rural areas of Southern Trinity County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4030 12307 4032 12314 4034 12313 4036 12316
      4038 12315 4039 12315 4039 12314 4038 12313
      4040 12311 4040 12308 4039 12306 4037 12303
      4036 12304 4035 12304 4035 12306 4033 12307
      4031 12306 4031 12307

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1.5-2.5 INCHES IN 2 HOURS

$$

SEC
980 
WGUS76 KEKA 192245
FFSEKA

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

CAC105-192255-
/O.EXP.KEKA.FF.W.0001.000000T0000Z-230819T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Trinity CA-
345 PM PDT Sat Aug 19 2023

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHERN TRINITY COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 4030 12307 4032 12314 4034 12313 4036 12316
      4038 12315 4039 12315 4039 12314 4038 12313
      4040 12311 4040 12308 4039 12306 4037 12303
      4036 12304 4035 12304 4035 12306 4033 12307
      4031 12306 4031 12307

$$

MKK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 5:26 PM PDTSpecial Weather StatementEKATrinity34 min
Aug 18, 5:32 PM PDTSpecial Weather StatementEKATrinity28 min
Aug 18, 6:26 PM PDTSpecial Weather StatementEKATrinity34 min
Aug 19, 3:35 AM PDTRed Flag WarningEKA16 hr
Aug 19, 9:02 AM PDTSmall Craft AdvisoryEKA39 hr
Aug 19, 12:36 PM PDTSpecial Weather StatementEKATrinity39 min
Aug 19, 2:30 PM PDTSpecial Weather StatementEKA45 min
Aug 19, 2:32 PM PDTSpecial Weather StatementEKAMendocino43 min
Aug 19, 2:41 PM PDTSpecial Weather StatementEKATrinity34 min
Aug 19, 2:45 PM PDTSpecial Weather StatementEKAHumboldt45 min
Aug 19, 2:54 PM PDTSpecial Weather StatementEKAHumboldt36 min
Aug 19, 3:10 PM PDTSevere Thunderstorm WarningEKAHumboldt, Mendocino, Trinity20 min
Aug 19, 3:17 PM PDTSpecial Weather StatementEKATrinity43 min
Aug 19, 3:50 PM PDTFlash Flood WarningEKATrinity85 min

Nearby

Flash Flood Warnings in California, 2023Every 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.