Alert archive / Oregon / Frost Advisories in 2021

Frost Advisory 1, NWS Medford, OR

February 23, 2021Coos County, Curry County, Douglas County, Oregon

NWS Medford, OR issued this frost advisory at Feb 23, 2021, 2:37 PM PST for Coos County, Curry County, Douglas County, Oregon. It took effect at Feb 24, 2021, 4:00 AM PST. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Feb 23, 2021, 2:37 PM PST (22:37 UTC)
In effect from
Feb 24, 2021, 4:00 AM PST
Expired
Feb 24, 2021, 9:00 AM PST
In force
5 hr
Issued by
NWS Medford, OR

Counties Coos County, OR, Curry County, OR, Douglas County, OR

The radar

The Medford radar (KMAX), 135 km from the middle of the area, began a volume at 22:43 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 12:00Z, 10.6 hours before the alert went out and 108 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 12:00Z on 2021-02-23Temperature 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 12:00Z on 2021-02-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
801 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

848 
WWUS76 KMFR 232237
NPWMFR

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
237 PM PST Tue Feb 23 2021

ORZ021-022-241700-
/O.NEW.KMFR.FR.Y.0001.210224T1200Z-210224T1700Z/
South Central Oregon Coast-Curry County Coast-
Including the cities of Coos Bay, North Bend, Reedsport, 
and Bandon
237 PM PST Tue Feb 23 2021

...FROST ADVISORY IN EFFECT FROM 4 AM TO 9 AM PST WEDNESDAY...

* WHAT...Temperatures as low as 29 degrees will result in frost 
  formation.

* WHERE...South Central Oregon Coast and Curry County Coast to
  include Coos Bay, North Bend, Reedsport, Bandon, and sheltered
  areas near the Curry County coast.

* WHEN...From 4 AM to 9 AM PST Wednesday.

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

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/mfr/HAZARD

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Visit us at https://www.weather.gov/Medford
1 follow-up statement
797 
WWUS76 KMFR 241651
NPWMFR

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
851 AM PST Wed Feb 24 2021

ORZ021-022-241800-
/O.EXP.KMFR.FR.Y.0001.000000T0000Z-210224T1700Z/
South Central Oregon Coast-Curry County Coast-
Including the cities of Coos Bay, North Bend, Reedsport, 
and Bandon
851 AM PST Wed Feb 24 2021

...FROST ADVISORY WILL EXPIRE AT 9 AM PST THIS MORNING...

Temperatures are warming above freezing.

$$

Visit us at https://www.weather.gov/Medford

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 23, 2:04 PM PSTHazardous Seas WatchMFR24 hr

Nearby

Frost Advisories in Oregon, 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.