Alert archive / California / Freeze Warnings in 2017

Freeze Warning 5, NWS Eureka, CA

May 17, 2017Trinity County, California

NWS Eureka, CA issued this freeze warning at May 17, 2017, 4:19 AM PDT for Trinity County, California. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 17, 2017, 4:19 AM PDT (11:19 UTC)
Expired
May 17, 2017, 8:00 AM PDT
In force
4 hr
Issued by
NWS Eureka, CA

County Trinity County, CA

The radar

The Eureka (Bunker Hill) radar (KBHX), 101 km from the middle of the area, began a volume at 11:19 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, 11.3 hours before the alert went out and 193 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 2017-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 80 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 00:00Z on 2017-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939587897117Sfc1 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
80 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
1542 m above ground
0-6 km bulk shear
85 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

706 
WWUS76 KEKA 171119
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
419 AM PDT Wed May 17 2017

CAZ107-108-171500-
/O.UPG.KEKA.FR.Y.0013.000000T0000Z-170517T1500Z/
/O.NEW.KEKA.FZ.W.0005.170517T1119Z-170517T1500Z/
Northern Trinity-Southern Trinity-
419 AM PDT Wed May 17 2017

...FREEZE WARNING IN EFFECT UNTIL 8 AM PDT THIS MORNING...

The National Weather Service in Eureka has issued a Freeze
Warning...which is in effect until 8 AM PDT this morning. The
Frost Advisory is no longer in effect. 

* LOW TEMPERATURES...upper 20S to lower 30S.

* LOCATIONS INCLUDE...Weaverville...Burnt Ranch...Trinity
  Center...Hayfork...Ruth.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Freeze Warning means sub-freezing temperatures are imminent or
highly likely. These conditions will kill crops and other
sensitive vegetation.

&&

$$
1 follow-up statement
147 
WWUS76 KEKA 171433
NPWEKA

URGENT - WEATHER MESSAGE
National Weather Service Eureka CA
733 AM PDT Wed May 17 2017

CAZ107-108-171545-
/O.EXP.KEKA.FZ.W.0005.000000T0000Z-170517T1500Z/
Northern Trinity-Southern Trinity-
733 AM PDT Wed May 17 2017

...FREEZE WARNING WILL EXPIRE AT 8 AM PDT THIS MORNING...

THIS WILL BE THE FINAL STATEMENT ISSUED FOR THIS EVENT.

$$

Nearby

Freeze Warnings in California, 2017Every freeze warning in 2017

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.