Alert archive / California / Areal Flood Advisories in 2012

Areal Flood Advisory 21, NWS Eureka, CA

December 22, 2012Humboldt County, Mendocino County, Trinity County, California

NWS Eureka, CA issued this areal flood advisory at Dec 22, 2012, 1:38 AM PST for Humboldt County, Mendocino County, Trinity County, California. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Dec 22, 2012, 1:38 AM PST (09:38 UTC)
Expired
Dec 22, 2012, 7:30 AM PST
In force
6 hr
Issued by
NWS Eureka, CA
Area
Storm-based polygon

Counties Humboldt County, CA, Mendocino County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 124 km from the middle of the area, began a volume at 09:38 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

Oakland, CA (KOAK), launched 00:00Z, 9.6 hours before the alert went out and 237 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 00:00Z on 2012-12-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 19 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 00:00Z on 2012-12-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 215 square meters per square second.1939587897117Sfc1 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
19 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
788 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
215 m²/s²
0-3 km storm-relative helicity
280 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

291 
WGUS86 KEKA 220938
FLSEKA

FLOOD ADVISORY
NATIONAL WEATHER SERVICE EUREKA CA
138 AM PST SAT DEC 22 2012

CAC023-045-105-221530-
/O.NEW.KEKA.FA.Y.0021.121222T0938Z-121222T1530Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HUMBOLDT CA-MENDOCINO CA-TRINITY CA-
138 AM PST SAT DEC 22 2012

THE NATIONAL WEATHER SERVICE IN EUREKA HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR HEAVY RAIN IN...
  SOUTHEASTERN HUMBOLDT COUNTY IN NORTHWEST CALIFORNIA...
  NORTHERN MENDOCINO COUNTY IN NORTHWEST CALIFORNIA...
  THIS INCLUDES THE CITIES OF...WILLITS...LAYTONVILLE...FORT BRAGG...
  COVELO...
  SOUTHWESTERN TRINITY COUNTY IN NORTHWEST CALIFORNIA...

* UNTIL 730 AM PST

* AT 136 AM PST DOPPLER RADAR INDICATED HEAVY RAINFALL ACROSS THE 
REGION WITH UP TO AN INCH OF RAIN IN THE LAST FOUR HOURS. ADDITIONAL 
RAINFALL BETWEEN A HALF AND ONE INCH IS EXPECTED THROUGH EARLY 
MORNING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER ON COUNTRY ROADS AND 
FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS. MOTORISTS SHOULD BE 
ON THE LOOK OUT FOR HIGH WATER ON AREA ROADS. WATER CAN BE VERY 
DIFFICULT TO SEE AT NIGHT.

&&

LAT...LON 3911 12372 3941 12364 3935 12304 3942 12307
      3950 12305 3952 12289 3956 12288 3970 12288
      3976 12293 3984 12295 3992 12291 3998 12292
      3998 12306 4014 12331 4049 12363 4002 12374
      4000 12403 3971 12376 3934 12384 3919 12379

$$

RPA

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 21, 7:40 PM PSTAreal Flood AdvisoryEKAHumboldt12 hr
Dec 21, 10:47 PM PSTSpecial Weather StatementEKAMendocino13 min
Dec 21, 11:53 PM PSTSpecial Weather StatementEKAMendocino22 min
Dec 22, 12:16 AM PSTSpecial Weather StatementEKALake44 min
Dec 22, 12:45 AM PSTAreal Flood AdvisoryEKAMendocino7 hr
Dec 22, 12:50 AM PSTSpecial Marine WarningEKA55 min
Dec 22, 1:32 AM PSTSpecial Weather StatementEKADel Norte43 min
Dec 22, 1:56 AM PSTSpecial Marine WarningEKA49 min
Dec 22, 2:08 AM PSTSpecial Weather StatementEKA37 min
Dec 22, 2:44 AM PSTSpecial Weather StatementEKAMendocino46 min
Dec 22, 2:47 AM PSTSpecial Marine WarningEKA47 min
Dec 22, 3:03 AM PSTGale WatchEKA12 hr
Dec 22, 3:09 AM PSTSpecial Weather StatementEKAMendocino21 min
Dec 22, 6:48 AM PSTSpecial Weather StatementEKADel Norte27 min
Dec 22, 10:01 AM PSTRiver Flood WatchEKAMendocino24 hr
Dec 22, 11:33 AM PSTSpecial Weather StatementEKAHumboldt42 min
Dec 22, 11:43 AM PSTSpecial Weather StatementEKAMendocino47 min
Dec 22, 11:50 AM PSTSpecial Marine WarningEKA25 min
Dec 22, 12:59 PM PSTSpecial Marine WarningEKA31 min
Dec 22, 1:02 PM PSTSpecial Weather StatementEKA43 min
Dec 22, 1:47 PM PSTSpecial Weather StatementEKADel Norte43 min
Dec 22, 2:26 PM PSTSpecial Weather StatementEKA19 min
Dec 22, 2:34 PM PSTGale WarningEKA23 hr
Dec 22, 2:52 PM PSTWind AdvisoryEKA20 hr
Dec 22, 3:06 PM PSTWinter Weather AdvisoryEKA24 hr
Dec 22, 3:10 PM PSTSpecial Weather StatementEKADel Norte50 min

Nearby

Areal Flood Advisories in California, 2012Every areal flood advisory in 2012

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.