Alert archive / Oregon / Frost Advisories in 2021

Frost Advisory 8, NWS Medford, OR

April 11, 2021Coos County, Curry County, Douglas County, Oregon

NWS Medford, OR issued this frost advisory at Apr 11, 2021, 1:15 PM PDT for Coos County, Curry County, Douglas County, Oregon. It took effect at Apr 12, 2021, 2:00 AM PDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 11, 2021, 1:15 PM PDT (20:15 UTC)
In effect from
Apr 12, 2021, 2:00 AM PDT
Expired
Apr 12, 2021, 9:00 AM PDT
In force
7 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 20:14 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, 8.3 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 2021-04-11Temperature 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 2021-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.193958Sfc1 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
822 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

134 
WWUS76 KMFR 112015
NPWMFR

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
115 PM PDT Sun Apr 11 2021

ORZ021-121200-
/O.NEW.KMFR.FR.Y.0008.210412T0900Z-210412T1600Z/
South Central Oregon Coast-
Including the cities of Coos Bay, North Bend, Reedsport, 
and Coquille
115 PM PDT Sun Apr 11 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM PDT MONDAY...

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

* WHERE...South Central Oregon Coast, including the cities of
  Reedsport, Coos Bay, North Bend, Myrtle Point and Powers.

* WHEN...From 2 AM to 9 AM PDT Monday.

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

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Visit us at https://www.weather.gov/Medford
2 follow-up statements
602 
WWUS76 KMFR 121000
NPWMFR

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
300 AM PDT Mon Apr 12 2021

ORZ021-121600-
/O.CON.KMFR.FR.Y.0008.000000T0000Z-210412T1600Z/
South Central Oregon Coast-
Including the cities of Coos Bay, North Bend, Reedsport, 
and Coquille
300 AM PDT Mon Apr 12 2021

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

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

* WHERE...South Central Oregon Coast, including the cities of 
  Reedsport, Coos Bay, North Bend, Myrtle Point and Powers.

* WHEN...Until 9 AM PDT Monday.

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

* View the hazard area in detail at 
  https://www.wrh.noaa.gov/map/?wfo=mfr

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Visit us at https://www.weather.gov/Medford
674 
WWUS76 KMFR 121543
NPWMFR

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
843 AM PDT Mon Apr 12 2021

ORZ021-121645-
/O.EXP.KMFR.FR.Y.0008.000000T0000Z-210412T1600Z/
South Central Oregon Coast-
Including the cities of Coos Bay, North Bend, Reedsport, 
and Coquille
843 AM PDT Mon Apr 12 2021

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

Temperatures will continue to rise above critical thresholds this
morning.

$$

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

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.