Alert archive / California / Frost Advisories in 2021
Frost Advisory 60, NWS Eureka, CA
NWS Eureka, CA issued this frost advisory at Dec 17, 2021, 8:35 PM PST for Humboldt County, Mendocino County, California. It took effect at Dec 18, 2021, 12:00 AM PST. It was in force for 9 hr.
The area
The counties it named.
The facts
- Issued
- Dec 17, 2021, 8:35 PM PST (04:35 UTC)
- In effect from
- Dec 18, 2021, 12:00 AM PST
- Expired
- Dec 18, 2021, 9:00 AM PST
- In force
- 9 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 04:39 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, 4.6 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 975 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
425 WWUS76 KEKA 180435 NPWEKA URGENT - WEATHER MESSAGE National Weather Service Eureka CA 835 PM PST Fri Dec 17 2021 CAZ103-109-181245- /O.NEW.KEKA.FR.Y.0060.211218T0800Z-211218T1700Z/ Northern Humboldt Coast-Mendocino Coast- 835 PM PST Fri Dec 17 2021 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM PST SATURDAY... * WHAT...Temperatures as low as 33 will result in frost formation. * WHERE...Northern Humboldt Coast and Mendocino Coast Counties. * WHEN...From midnight tonight to 9 AM PST Saturday. * IMPACTS...Frost could kill sensitive outdoor vegetation if left uncovered. * ADDITIONAL DETAILS...Areas that remain clear tonight will see frost form. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. Frost Advisories and Freeze Warnings are issued during the local growing season as defined by climatology and local agriculture experts. Once the growing season has ended these statements will no longer be issued until the spring. && $$
2 follow-up statements
946 WWUS76 KEKA 181230 NPWEKA URGENT - WEATHER MESSAGE National Weather Service Eureka CA 430 AM PST Sat Dec 18 2021 CAZ103-109-181700- /O.CON.KEKA.FR.Y.0060.000000T0000Z-211218T1700Z/ Northern Humboldt Coast-Mendocino Coast- 430 AM PST Sat Dec 18 2021 ...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PST THIS MORNING... * WHAT...Temperatures as low as 33 will result in frost formation. * WHERE...Mendocino Coast and Northern Humboldt Coast Counties. * WHEN...Until 9 AM PST this morning. * IMPACTS...Frost could kill sensitive outdoor vegetation if left uncovered. * ADDITIONAL DETAILS...Temperatures have dropped to 36 around Humboldt Bay and may cool a couple more degrees by sunrise. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold. Frost Advisories and Freeze Warnings are issued during the local growing season as defined by climatology and local agriculture experts. Once the growing season has ended these statements will no longer be issued until the spring. && $$
503 WWUS76 KEKA 181702 NPWEKA URGENT - WEATHER MESSAGE National Weather Service Eureka CA 902 AM PST Sat Dec 18 2021 CAZ103-109-181815- /O.EXP.KEKA.FR.Y.0060.000000T0000Z-211218T1700Z/ Northern Humboldt Coast-Mendocino Coast- 902 AM PST Sat Dec 18 2021 ...FROST ADVISORY HAS EXPIRED... Temperatures are rising into the 40s and will continue to moderate with daytime heating. Frost is not expected tonight. $$
The office that day
Everything else NWS Eureka, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 18, 2:06 AM PST | Gale Warning | EKA | 67 hr | |
| Dec 18, 2:06 AM PST | Small Craft Advisory | EKA | 4 days |
Nearby
Frost Advisories in California, 2021Every frost advisory in 2021
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.