Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Eureka, CA

July 30, 2021Del Norte County, California

NWS Eureka, CA issued this flash flood warning at Jul 30, 2021, 5:02 PM PDT for Del Norte County, California. It was in force for 118 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 30, 2021, 5:02 PM PDT (00:02 UTC)
Expired: Jul 30, 2021, 7:00 PM PDT
In force: 118 min
Issued by: NWS Eureka, CA
Area: Storm-based polygon
Flood severity: None

County Del Norte County, CA

The radar

The Medford radar (KMAX), 73 km from the middle of the area, began a volume at 00:06 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 00:00Z, 0.0 hours before the alert went out and 80 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: 56 J/kg
Mixed-layer CIN: -307 J/kg
Mixed-layer LCL: 3581 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

965 
WGUS56 KEKA 310002
FFWEKA
CAC015-310300-
/O.NEW.KEKA.FF.W.0001.210731T0002Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Eureka CA
502 PM PDT Fri Jul 30 2021

The National Weather Service in Eureka California has issued a

* Flash Flood Warning for...
  Northeastern Del Norte County in northwestern California...

* Until 800 PM PDT.

* At 501 PM PDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has 
  already fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

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

Excessive rainfall over the burn scar will result in debris flow 
moving through the Slater Fire Burn Scar. The debris flow can 
consist of rock, mud, vegetation and other loose materials.

Additional rainfall amounts of an inch are possible in the warned 
area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4200 12352 4199 12354 4196 12353 4193 12355
      4191 12355 4190 12356 4190 12359 4189 12361
      4191 12364 4195 12363 4196 12365 4200 12365

FLASH FLOOD...RADAR INDICATED

$$

JAW

1 follow-up statement

509 
WGUS76 KEKA 310200
FFSEKA

Flash Flood Statement
National Weather Service Eureka CA
700 PM PDT Fri Jul 30 2021

CAC015-310210-
/O.CAN.KEKA.FF.W.0001.000000T0000Z-210731T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Del Norte CA-
700 PM PDT Fri Jul 30 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN DEL NORTE 
COUNTY...

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

LAT...LON 4200 12352 4199 12354 4196 12353 4193 12355
      4191 12355 4190 12356 4190 12359 4189 12361
      4191 12364 4195 12363 4196 12365 4200 12365

$$

JAW

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 2:45 AM PDT	Small Craft Advisory	EKA		30 hr

Nearby

Flash Flood Warnings in California, 2021 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.