Alert archive / California / Freeze Watches in 2021

Freeze Watch 5, NWS Eureka, CA

May 19, 2021Humboldt County, Trinity County, California

NWS Eureka, CA issued this freeze watch at May 19, 2021, 4:00 AM PDT for Humboldt County, Trinity County, California. It took effect at May 20, 2021, 1:00 AM PDT. It was in force for .

The area

The counties it named.

The facts

Issued
May 19, 2021, 4:00 AM PDT (11:00 UTC)
In effect from
May 20, 2021, 1:00 AM PDT
Expired
May 19, 2021, 2:35 PM PDT
In force
Issued by
NWS Eureka, CA

Counties Humboldt County, CA, Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 69 km from the middle of the area, began a volume at 11:05 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, 11.0 hours before the alert went out and 197 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 2021-05-19Temperature 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 2021-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -61 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
2412 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-61 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

803 
WWUS76 KEKA 191100
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
400 AM PDT Wed May 19 2021

CAZ111-114-191200-
/O.CAN.KEKA.FR.Y.0035.000000T0000Z-210519T1600Z/
Northeastern Mendocino Interior-Northern Lake-
400 AM PDT Wed May 19 2021

...FROST ADVISORY IS CANCELLED...

$$

CAZ106-108-191600-
/O.NEW.KEKA.FZ.A.0005.210520T0800Z-210520T1600Z/
/O.CON.KEKA.FR.Y.0035.000000T0000Z-210519T1600Z/
Southern Humboldt Interior-Southern Trinity-
400 AM PDT Wed May 19 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM PDT THIS MORNING...
...FREEZE WATCH IN EFFECT FROM LATE TONIGHT THROUGH THURSDAY
MORNING...

* WHAT...For the Frost Advisory, temperatures in the low to mid
  30s will result in frost formation. For the Freeze Watch, sub-
  freezing temperatures in the low 30s and upper 20s possible.

* WHERE...Southern Humboldt Interior and Southern Trinity 
  Counties.

* WHEN...For the Frost Advisory, until 9 AM PDT this morning. 
  For the Freeze Watch, from late tonight through Thursday 
  morning.

* IMPACTS...Frost and freeze conditions could kill crops and 
  other sensitive vegetation.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

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.

&&

$$

CAZ102-105-107-110-191600-
/O.CON.KEKA.FR.Y.0035.000000T0000Z-210519T1600Z/
Del Norte Interior-Northern Humboldt Interior-Northern Trinity-
Northwestern Mendocino Interior-
400 AM PDT Wed May 19 2021

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

* WHAT...Temperatures in the low to mid 30s will result in frost 
  formation.

* WHERE...Sheltered valleys in the Northwestern Mendocino 
  Interior, Del Norte Interior, Northern Humboldt Interior and 
  Northern Trinity Counties.

* WHEN...Until 9 AM PDT this morning.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

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
137 
WWUS76 KEKA 191915
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
1215 PM PDT Wed May 19 2021

CAZ110-112>115-200315-
/O.NEW.KEKA.WI.Y.0010.210520T0100Z-210521T0000Z/
Northwestern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
1215 PM PDT Wed May 19 2021

...WIND ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 5 PM PDT
THURSDAY ABOVE 2000 FEET...

* WHAT...Northwest winds 15 to 25 mph with gusts up to 45 mph
  expected along elevated communities above 2000 feet in elevation.

* WHERE...Northwestern Mendocino Interior, Southwestern 
  Mendocino Interior, Southeastern Mendocino Interior, Northern 
  Lake and Southern Lake Counties.

* WHEN...From 6 PM this evening to 5 PM PDT Thursday.

* IMPACTS...Gusty winds could blow around unsecured objects. 
  Tree limbs could be blown down and a few power outages may 
  result.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

&&

$$

CAZ106-108-200315-
/O.CON.KEKA.FZ.A.0005.210520T0800Z-210520T1600Z/
Southern Humboldt Interior-Southern Trinity-
1215 PM PDT Wed May 19 2021

...FREEZE WATCH REMAINS IN EFFECT FROM LATE TONIGHT THROUGH
THURSDAY MORNING...

* WHAT...Sub-freezing temperatures as low as 28 possible.

* WHERE...Southern Trinity and Southern Humboldt Interior 
  Counties.

* WHEN...From late tonight through Thursday morning.

* IMPACTS...Frost and freeze conditions could kill crops and 
  other sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. Provide
adequate shelter for outdoor pets or consider bringing them
indoors.

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.

&&

$$
294 
WWUS76 KEKA 192135
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
235 PM PDT Wed May 19 2021

CAZ106-108-200545-
/O.UPG.KEKA.FZ.A.0005.210520T0800Z-210520T1600Z/
/O.NEW.KEKA.FR.Y.0036.210520T0800Z-210520T1600Z/
Southern Humboldt Interior-Southern Trinity-
235 PM PDT Wed May 19 2021

...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM PDT THURSDAY...

* WHAT...Temperatures as low as 30 will result in frost 
  formation.

* WHERE...Southern Humboldt Interior and Southern Trinity 
  Counties.

* WHEN...From 1 AM to 9 AM PDT Thursday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.


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.

&&

$$

CAZ110-112>115-200545-
/O.CON.KEKA.WI.Y.0010.210520T0100Z-210521T0000Z/
Northwestern Mendocino Interior-Southwestern Mendocino Interior-
Southeastern Mendocino Interior-Northern Lake-Southern Lake-
235 PM PDT Wed May 19 2021

...WIND ADVISORY REMAINS IN EFFECT FROM 6 PM THIS EVENING TO 5 PM
PDT THURSDAY ABOVE 2000 FEET...

* WHAT...Northwest winds 10 to 20 mph with gusts up to 50 mph 
  expected above 2,000 feet.

* WHERE...Southwestern Mendocino Interior, Southeastern 
  Mendocino Interior, Northwestern Mendocino Interior, Northern 
  Lake and Southern Lake Counties.

* WHEN...From 6 PM this evening to 5 PM PDT Thursday.

* IMPACTS...Gusty winds could blow around unsecured objects. 
  Tree limbs could be blown down and a few power outages may 
  result.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 18, 5:23 PM PDTGale WarningEKA27 hr
May 19, 12:15 PM PDTWind AdvisoryEKALake, Mendocino15 hr
May 19, 2:35 PM PDTFrost AdvisoryEKADel Norte, Humboldt, Lake, Mendocino, Trinity18 hr

Nearby

Freeze Watches in California, 2021Every freeze watch 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.