Alert archive / California / Frost Advisories in 2018

Frost Advisory 40, NWS Eureka, CA

December 21, 2018Del Norte County, Humboldt County, Mendocino County, California

NWS Eureka, CA issued this frost advisory at Dec 21, 2018, 7:44 PM PST for Del Norte County, Humboldt County, Mendocino County, California. It took effect at Dec 21, 2018, 10:00 PM PST. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Dec 21, 2018, 7:44 PM PST (03:44 UTC)
In effect from
Dec 21, 2018, 10:00 PM PST
Expired
Dec 22, 2018, 8:00 AM PST
In force
10 hr
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA, Mendocino County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 47 km from the middle of the area, began a volume at 03:44 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, 3.7 hours before the alert went out and 210 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 2018-12-22Temperature 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 2018-12-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 square meters per square second.1939587897Sfc1 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
1135 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

261 
WWUS76 KEKA 220344
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
744 PM PST Fri Dec 21 2018

CAZ101-103-109-112-221600-
/O.NEW.KEKA.FR.Y.0040.181222T0600Z-181222T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
744 PM PST Fri Dec 21 2018

...FROST ADVISORY IN EFFECT UNTIL 8 AM SATURDAY...

* LOW TEMPERATURES...Mid 30s.

* LOCATIONS INCLUDE...Crescent City, Arcata, Eureka, Fortuna, Fort
  Bragg, Boonville, and Comptche.

* 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.

$$
1 follow-up statement
240 
WWUS76 KEKA 221157
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
357 AM PST Sat Dec 22 2018

CAZ101-103-109-112-221600-
/O.CON.KEKA.FR.Y.0040.000000T0000Z-181222T1600Z/
Coastal Del Norte-Northern Humboldt Coast-Mendocino Coast-
Southwestern Mendocino Interior-
357 AM PST Sat Dec 22 2018

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

* LOW TEMPERATURES...mid 30s.

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

* 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 22, 4:03 AM PSTCoastal Flood AdvisoryEKADel Norte, Humboldt33 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.