Alert archive / California / Frost Advisories in 2018

Frost Advisory 41, NWS Eureka, CA

December 25, 2018Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Dec 25, 2018, 2:52 AM PST for Humboldt County, Mendocino County, California. It took effect at Dec 26, 2018, 1:00 AM PST. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Dec 25, 2018, 2:52 AM PST (10:52 UTC)
In effect from
Dec 26, 2018, 1:00 AM PST
Expired
Dec 26, 2018, 9:00 AM PST
In force
8 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 10:50 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, 10.9 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 00:00Z on 2018-12-25Temperature 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 00:00Z on 2018-12-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
599 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

220 
WWUS76 KEKA 251052
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
252 AM PST Tue Dec 25 2018

CAZ103-260000-
/O.NEW.KEKA.FR.Y.0041.181226T0900Z-181226T1700Z/
Northern Humboldt Coast-
252 AM PST Tue Dec 25 2018

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM PST WEDNESDAY...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect from 1 AM to 9 AM PST Wednesday. 

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Arcata, Eureka, Fortuna and Blue Lake.

* 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
639 
WWUS76 KEKA 252222
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
222 PM PST Tue Dec 25 2018


CAZ109-112-261130-
/O.EXA.KEKA.FR.Y.0041.181226T0900Z-181226T1700Z/
Mendocino Coast-Southwestern Mendocino Interior-
222 PM PST Tue Dec 25 2018

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM PST WEDNESDAY...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect from 1 AM to 9 AM PST Wednesday. 

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Fort Bragg...Point Arena...Boonville...
  Comptche.

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

$$

CAZ103-261130-
/O.CON.KEKA.FR.Y.0041.181226T0900Z-181226T1700Z/
Northern Humboldt Coast-
222 PM PST Tue Dec 25 2018

...FROST ADVISORY REMAINS IN EFFECT FROM 1 AM TO 9 AM PST
WEDNESDAY...

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Arcata...Eureka...Fortuna.

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

$$
170 
WWUS76 KEKA 261123
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
323 AM PST Wed Dec 26 2018

CAZ103-109-112-261700-
/O.CON.KEKA.FR.Y.0041.000000T0000Z-181226T1700Z/
Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
323 AM PST Wed Dec 26 2018

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING...

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Fort Bragg...Point Arena...Boonville...
  Comptche...Arcata...Eureka...Fortuna.

* 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
Dec 25, 3:54 AM PSTSmall Craft AdvisoryEKA17 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.