Alert archive / California / Frost Advisories in 2018

Frost Advisory 9, NWS Eureka, CA

April 12, 2018Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Apr 12, 2018, 3:21 PM PDT for Humboldt County, Mendocino County, California. It took effect at Apr 13, 2018, 1:00 AM PDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 12, 2018, 3:21 PM PDT (22:21 UTC)
In effect from
Apr 13, 2018, 1:00 AM PDT
Expired
Apr 13, 2018, 8:00 AM PDT
In force
7 hr
Issued by
NWS Eureka, CA

Counties Humboldt County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 71 km from the middle of the area, began a volume at 22:24 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, 10.4 hours before the alert went out and 266 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 2018-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 2018-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.19395878Sfc1 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
2 J/kg
Mixed-layer CIN
-13 J/kg
Mixed-layer LCL
840 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

156 
WWUS76 KEKA 122221
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
321 PM PDT Thu Apr 12 2018

CAZ106-110-111-113-131130-
/O.NEW.KEKA.FR.Y.0009.180413T0800Z-180413T1500Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southeastern Mendocino Interior-
321 PM PDT Thu Apr 12 2018

...FROST ADVISORY IN EFFECT FROM 1 AM TO 8 AM PDT FRIDAY...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect from 1 AM to 8 AM PDT Friday. 

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Garberville...Bridgeville...Leggett...
  Laytonville...Willits...Covelo...Hopland....

* FOR A DETAILED VIEW OF THE HAZARD AREA...visit 
  http://www.wrh.noaa.gov/map

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Frost Advisory means that frost is possible. Sensitive outdoor
plants may be killed if left uncovered.

&&

$$
2 follow-up statements
075 
WWUS76 KEKA 130504
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1004 PM PDT Thu Apr 12 2018

CAZ112-131500-
/O.EXA.KEKA.FR.Y.0009.180413T0800Z-180413T1500Z/
Southwestern Mendocino Interior-
1004 PM PDT Thu Apr 12 2018

...FROST ADVISORY IN EFFECT UNTIL 8 AM PDT FRIDAY...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect until 8 AM PDT Friday. 

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Boonville...Comptche...

* FOR A DETAILED VIEW OF THE HAZARD AREA...visit 
  http://www.wrh.noaa.gov/map

$$

CAZ106-110-111-113-131500-
/O.CON.KEKA.FR.Y.0009.180413T0800Z-180413T1500Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southeastern Mendocino Interior-
1004 PM PDT Thu Apr 12 2018

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM PDT FRIDAY...

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Garberville...Bridgeville...Leggett...
  Laytonville...Willits...Covelo...Hopland....

* FOR A DETAILED VIEW OF THE HAZARD AREA...visit 
  http://www.wrh.noaa.gov/map

$$
961 
WWUS76 KEKA 130957
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
257 AM PDT Fri Apr 13 2018

CAZ106-110>113-131500-
/O.CON.KEKA.FR.Y.0009.000000T0000Z-180413T1500Z/
Southern Humboldt Interior-Northwestern Mendocino Interior-
Northeastern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-
257 AM PDT Fri Apr 13 2018

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM PDT THIS MORNING...

* LOW TEMPERATURES...mid 30s.

* LOCATIONS
  INCLUDE...Boonville...Comptche...Leggett...Laytonville...Willits...
  and Covelo.

* FOR A DETAILED VIEW OF THE HAZARD AREA...visit 
  http://www.wrh.noaa.gov/map

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 11, 6:11 PM PDTWinter Weather AdvisoryEKADel Norte, Humboldt18 hr

Nearby

Frost Advisories in California, 2018Every frost advisory 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.