Alert archive / California / Freeze Warnings in 2013

Freeze Warning 21, NWS Medford, OR

May 30, 2013Modoc County, Siskiyou County, California; Klamath County, Oregon

NWS Medford, OR issued this freeze warning at May 30, 2013, 7:41 PM PDT for Modoc County, Siskiyou County, California; Klamath County, Oregon. It took effect at May 31, 2013, 2:00 AM PDT. It was in force for 7 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 30, 2013, 7:41 PM PDT (02:41 UTC)
In effect from
May 31, 2013, 2:00 AM PDT
Expired
May 31, 2013, 9:00 AM PDT
In force
7 hr
Issued by
NWS Medford, OR

Counties Modoc County, CA, Siskiyou County, CA, Klamath County, OR

The radar

The Medford radar (KMAX), 90 km from the middle of the area, began a volume at 02:41 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, 2.7 hours before the alert went out and 106 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 2013-05-31Temperature 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 2013-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2277 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

145 
WWUS76 KMFR 310241
NPWMFR

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE MEDFORD OR
741 PM PDT THU MAY 30 2013

...AREAS OF FREEZING TEMPERATURES EXPECTED TONIGHT...

.LIGHT WINDS, CLEAR SKIES, AND A DRYING AIRMASS WILL RESULT IN
AREAS OF FREEZING TEMPERATURES ON FRIDAY MORNING.

CAZ084-ORZ029-311600-
/O.NEW.KMFR.FZ.W.0021.130531T0900Z-130531T1600Z/
NORTHEAST SISKIYOU AND NORTHWEST MODOC COUNTIES-KLAMATH BASIN-
INCLUDING THE CITY OF...DORRIS
741 PM PDT THU MAY 30 2013

...FREEZE WARNING IN EFFECT FROM 2 AM TO 9 AM PDT FRIDAY...

THE NATIONAL WEATHER SERVICE IN MEDFORD HAS ISSUED A FREEZE
WARNING...WHICH IS IN EFFECT FROM 2 AM TO 9 AM PDT FRIDAY. 

* TEMPERATURES...24 TO 32 DEGREES.

* TIMING...BELOW FREEZING TEMPERATURES WILL BE POSSIBLE BETWEEN 2
  AM AND 9 AM PDT FRIDAY MORNING.

* LOCATIONS INCLUDE: DORRIS...CHILOQUIN...BONANZA...OUTLYING
  PORTIONS OF THE TULE LAKE BASIN...AND OUTLYING PORTIONS OF KLAMATH
  FALLS.

* IMPACTS...LOW TEMPERATURES ON FRIDAY MORNING WILL BE GENERALLY
  WITHIN 2 DEGREES OF THOSE OBSERVED ON THURSDAY MORNING.
  HOWEVER...A STRONGER INVERSION AND DRIER AIR UNDER CLEAR SKIES
  MEANS THAT THE POSSIBILITY EXISTS FOR TEMPERATURES SLIGHTLY
  COLDER IN SOME LOW LYING SHELTERED AREAS. THE COLDEST
  TEMPERATURES ARE LIKELY TO BE IN THE CHILOQUIN AREA...WITH
  MILDER BUT STILL FREEZING VALUES EXPECTED NEAR KLAMATH FALLS AND
  PORTIONS OF THE TULE LAKE BASIN.

* FOR A DETAILED VIEW OF THE HAZARD AREA...VISIT 
  HTTP://WWW.WRH.NOAA.GOV/WRH/WHV/?WFO=MFR 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FREEZE WARNING MEANS SUB-FREEZING TEMPERATURES ARE IMMINENT OR
HIGHLY LIKELY. THESE CONDITIONS WILL KILL CROPS AND OTHER
SENSITIVE VEGETATION.

&&

$$

BTL

The office that day

Everything else NWS Medford, OR issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 31, 2:22 AM PDTSmall Craft Advisory for WindsMFR12 hr
May 31, 2:22 AM PDTSmall Craft Advisory for Hazardous SeasMFR12 hr
May 31, 2:26 PM PDTGale WatchMFR9 hr

Nearby

Freeze Warnings in California, 2013Freeze Warnings in Oregon, 2013Every freeze warning in 2013

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.