Alert archive / California / Flash Flood Warnings in 2018

Flash Flood Warning 1, NWS Eureka, CA

October 3, 2018Mendocino County, California

NWS Eureka, CA issued this flash flood warning at Oct 3, 2018, 1:01 PM PDT for Mendocino County, California. 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
Oct 3, 2018, 1:01 PM PDT (20:01 UTC)
Expired
Oct 3, 2018, 4:00 PM PDT
In force
3 hr
Issued by
NWS Eureka, CA
Area
Storm-based polygon
Flood severity
None

County Mendocino County, CA

The radar

The Beale AFB radar (KBBX), 125 km from the middle of the area, began a volume at 20:03 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
Oct 3, 1:10 PM PDTFLASH FLOOD8 Ene Talmage, CAEMERGENCY MANAGER RELAYED A REPORT OF A CREEK BEGINNING TO FLOOD A BARN NEAR THE MENDOCINO-LAKE COUNTY BORDER. THE WATER WAS BLACK FROM ASH IN THE MENDOCINO COMPLEX AND HIGHER THAN THE RESIDENT HAD EVER SEEN BEFORE.

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

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 8.0 hours before the alert went out and 185 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, Oakland, CA at 12:00Z on 2018-10-03Temperature 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, Oakland, CA at 12:00Z on 2018-10-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 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
1131 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

174 
WGUS56 KEKA 032001
FFWEKA
CAC045-032300-
/O.NEW.KEKA.FF.W.0001.181003T2001Z-181003T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Eureka CA
101 PM PDT WED OCT 3 2018

The National Weather Service in Eureka California has issued a

* Flash Flood Warning for...
  East central Mendocino County in northwestern California...

* Until 400 PM PDT.
  
* At 1259 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 expected to begin shortly.

* Flash flooding will remain over mainly rural areas of east central
  Mendocino County.
  Excessive rainfall over the Mendocino Complex burn scar will 
  result in rock and mudslides and possible debris flows in areas of 
  steep terrain near highway 20 east of Ukiah.
  This is a dangerous situation. If you observe movement of soils,
  debris, or large amounts of water you should move to higher ground
  immediately.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3923 12301 3922 12302 3918 12305 3917 12307
      3920 12312 3925 12315 3928 12310 3932 12308
      3933 12303 3932 12303 3932 12302 3928 12302
      3928 12300 3924 12299

$$

KR
2 follow-up statements
688 
WGUS76 KEKA 032112
FFSEKA

Flash Flood Statement
National Weather Service Eureka CA
212 PM PDT WED OCT 3 2018

CAC045-032300-
/O.CON.KEKA.FF.W.0001.000000T0000Z-181003T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mendocino CA-
212 PM PDT WED OCT 3 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM PDT FOR
EAST CENTRAL MENDOCINO COUNTY...

At 209 PM PDT, the public reported flash flooding of a creek near 
the Mendocino and Lake County boarder. Up to one inch of rain has 
already fallen in this area. 

Excessive rainfall over the Mendocino Complex fire burn scar will 
result in debris flows. Debris flows can consist of rock, mud, 
vegetation and other loose materials.

Flash flooding will remain over mainly rural areas of east central
Mendocino County.

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.

&&

LAT...LON 3923 12301 3922 12302 3918 12305 3917 12307
      3920 12312 3925 12315 3928 12310 3932 12308
      3933 12303 3932 12303 3932 12302 3928 12302
      3928 12300 3924 12299

$$

KR
083 
WGUS76 KEKA 032258
FFSEKA

Flash Flood Statement
National Weather Service Eureka CA
358 PM PDT WED OCT 3 2018

CAC045-032308-
/O.EXP.KEKA.FF.W.0001.000000T0000Z-181003T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mendocino CA-
358 PM PDT WED OCT 3 2018

...THE FLASH FLOOD WARNING FOR EAST CENTRAL MENDOCINO COUNTY WILL
EXPIRE AT 400 PM PDT...

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

LAT...LON 3923 12301 3922 12302 3918 12305 3917 12307
      3920 12312 3925 12315 3928 12310 3932 12308
      3933 12303 3932 12303 3932 12302 3928 12302
      3928 12300 3924 12299

$$

MKK

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 3, 9:54 AM PDTFlash Flood WatchEKAMendocino9 hr
Oct 3, 3:01 PM PDTSmall Craft AdvisoryEKA36 hr

Nearby

Flash Flood Warnings in California, 2018Every flash flood warning in 2018

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.