Alert archive / California / Frost Advisories in 2018

Frost Advisory 13, NWS Eureka, CA

April 30, 2018Del Norte County, Humboldt County, Trinity County, California

NWS Eureka, CA issued this frost advisory at Apr 30, 2018, 2:50 AM PDT for Del Norte County, Humboldt County, Trinity County, California. It took effect at May 1, 2018, 3:00 AM PDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 30, 2018, 2:50 AM PDT (09:50 UTC)
In effect from
May 1, 2018, 3:00 AM PDT
Expired
May 1, 2018, 9:00 AM PDT
In force
6 hr
Issued by
NWS Eureka, CA

Counties Del Norte County, CA, Humboldt County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 80 km from the middle of the area, began a volume at 09:50 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, 9.8 hours before the alert went out and 165 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 2018-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 14 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 00:00Z on 2018-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -27 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
14 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
859 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
-27 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.

573 
WWUS76 KEKA 300950
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
250 AM PDT Mon Apr 30 2018


CAZ102-105-107-108-302300-
/O.NEW.KEKA.FR.Y.0013.180501T1000Z-180501T1600Z/
Del Norte Interior-Northern Humboldt Interior-Northern Trinity-
Southern Trinity-
250 AM PDT Mon Apr 30 2018

...FROST ADVISORY IN EFFECT FROM 3 AM TO 9 AM PDT TUESDAY...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect from 3 AM to 9 AM PDT Tuesday. 

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Orleans...Willow Creek...
  Weaverville...Burnt Ranch...Trinity Center...Hayfork and Hyampom.

* 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
663 
WWUS76 KEKA 302028
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
128 PM PDT Mon Apr 30 2018

CAZ102-105-107-108-011130-
/O.CON.KEKA.FR.Y.0013.180501T1000Z-180501T1600Z/
Del Norte Interior-Northern Humboldt Interior-Northern Trinity-
Southern Trinity-
128 PM PDT Mon Apr 30 2018

...FROST ADVISORY REMAINS IN EFFECT FROM 3 AM TO 9 AM PDT
TUESDAY...

* LOW TEMPERATURES...mid 30s.

* LOCATIONS INCLUDE...Hayfork...Ruth...Gasquet...Orleans... Willow
  Creek ...Weaverville...Burnt Ranch...Trinity Center

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

$$
054 
WWUS76 KEKA 010958
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
258 AM PDT Tue May 1 2018


CAZ106-011600-
/O.EXA.KEKA.FR.Y.0013.180501T1000Z-180501T1600Z/
Southern Humboldt Interior-
258 AM PDT Tue May 1 2018

...FROST ADVISORY IN EFFECT UNTIL 9 AM PDT THIS MORNING...

The National Weather Service in Eureka has issued a Frost
Advisory...which is in effect until 9 AM PDT this morning. 

* LOW TEMPERATURES...Mid 30s.

* LOCATIONS INCLUDE...Garberville...Bridgeville.

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

$$

CAZ102-105-107-108-011600-
/O.CON.KEKA.FR.Y.0013.180501T1000Z-180501T1600Z/
Del Norte Interior-Northern Humboldt Interior-Northern Trinity-
Southern Trinity-
258 AM PDT Tue May 1 2018

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

* LOW TEMPERATURES...Mid 30s.

* LOCATIONS INCLUDE...Hayfork...Ruth...Gasquet...Orleans... Willow
  Creek...Weaverville...Burnt Ranch...Trinity Center.

* 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 30, 3:07 AM PDTGale WarningEKA48 hr
Apr 30, 2:02 PM PDTSmall Craft AdvisoryEKA7 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.