Alert archive / Washington / Freeze Warnings in 2021

Freeze Warning 2, NWS Spokane, WA

September 15, 20215 counties in Washington

NWS Spokane, WA issued this freeze warning at Sep 15, 2021, 2:31 PM PDT for 5 counties in Washington. It took effect at Sep 15, 2021, 11:00 PM PDT. It was in force for 9 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
Sep 15, 2021, 2:31 PM PDT (21:31 UTC)
In effect from
Sep 15, 2021, 11:00 PM PDT
Expired
Sep 16, 2021, 8:00 AM PDT
In force
9 hr
Issued by
NWS Spokane, WA

Counties Ferry County, WA, Okanogan County, WA, Pend Oreille County, WA, Spokane County, WA, Stevens County, WA

The radar

The Spokane radar (KOTX), 81 km from the middle of the area, began a volume at 21:31 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

Spokane, WA (KOTX), launched 12:00Z, 9.5 hours before the alert went out and 148 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, Spokane, WA at 12:00Z on 2021-09-15Temperature 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, Spokane, WA at 12:00Z on 2021-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 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
1359 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

793 
WWUS76 KOTX 152131
NPWOTX

URGENT - WEATHER MESSAGE
National Weather Service Spokane WA
231 PM PDT Wed Sep 15 2021

WAZ037-038-161500-
/O.UPG.KOTX.FZ.A.0001.210916T0600Z-210916T1500Z/
/O.NEW.KOTX.FZ.W.0002.210916T0600Z-210916T1500Z/
Northeast Mountains-Okanogan Highlands-
Including the cities of Colville, Deer Park, Chewelah, Newport, 
Kettle Falls, Republic, Inchelium, and Wauconda
231 PM PDT Wed Sep 15 2021

...FREEZE WARNING IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT
THURSDAY...

* WHAT...Sub-freezing temperatures as low as 30 expected.

* WHERE...Colville, Deer Park, Chewelah, Newport, Kettle Falls, 
  Republic, Inchelium, and Wauconda.

* WHEN...From 11 PM this evening to 8 AM PDT Thursday.

* IMPACTS...Frost and freeze conditions may kill crops and other 
  sensitive vegetation, and possibly damage unprotected outdoor 
  plumbing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold. To prevent
freezing and possible bursting of outdoor water pipes they should
be wrapped, drained, or allowed to drip slowly. Those that have
in-ground sprinkler systems should drain them and cover above-
ground pipes to protect them from freezing.

&&

$$

IDZ001-161500-
/O.UPG.KOTX.FZ.A.0001.210916T0600Z-210916T1500Z/
/O.NEW.KOTX.FR.Y.0003.210916T0600Z-210916T1500Z/
Northern Panhandle-
Including the cities of Sandpoint, Rathdrum, Bonners Ferry, 
Priest River, and Eastport
231 PM PDT Wed Sep 15 2021

...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT
THURSDAY...

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

* WHERE...Sandpoint, Rathdrum, Bonners Ferry, Priest River, and 
  Eastport.

* WHEN...From 11 PM this evening to 8 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.

&&

$$

IDZ003-WAZ033-035-036-047-049-161500-
/O.NEW.KOTX.FR.Y.0003.210916T0600Z-210916T1500Z/
Idaho Palouse-Washington Palouse-Upper Columbia Basin-
Spokane Area-Central Chelan County-Western Okanogan County-
Including the cities of Moscow, Plummer, Potlatch, Genesee, 
Pullman, Colfax, Rosalia, La Crosse, Oakesdale, Tekoa, Uniontown,
Ritzville, Grand Coulee, Odessa, Wilbur, Coulee City, Spokane, 
Cheney, Davenport, Rockford, Leavenworth, Plain, Lake Wenatchee, 
Mazama, Winthrop, Twisp, Methow, and Conconully
231 PM PDT Wed Sep 15 2021

...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT
THURSDAY...

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

* WHERE...Moscow, Pullman, Colfax, Ritzville, Grand Coulee,
  Odessa, Coulee City, Spokane, Cheney, Davenport, Rockford,
  Leavenworth, Mazama, Winthrop, Twisp, Methow, and Conconully.

* WHEN...From 11 PM this evening to 8 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.

&&

$$
1 follow-up statement
730 
WWUS76 KOTX 161517
NPWOTX

URGENT - WEATHER MESSAGE
National Weather Service Spokane WA
817 AM PDT Thu Sep 16 2021

WAZ037-038-161630-
/O.EXP.KOTX.FZ.W.0002.000000T0000Z-210916T1500Z/
Northeast Mountains-Okanogan Highlands-
Including the cities of Colville, Deer Park, Chewelah, Newport, 
Kettle Falls, Republic, Inchelium, and Wauconda
817 AM PDT Thu Sep 16 2021

...FREEZE WARNING HAS EXPIRED...

The threat of freezing temperatures has ended for the day.

$$

IDZ001-003-WAZ033-035-036-047-049-161630-
/O.EXP.KOTX.FR.Y.0003.000000T0000Z-210916T1500Z/
Northern Panhandle-Idaho Palouse-Washington Palouse-
Upper Columbia Basin-Spokane Area-Central Chelan County-
Western Okanogan County-
Including the cities of Sandpoint, Rathdrum, Bonners Ferry, 
Priest River, Eastport, Moscow, Plummer, Potlatch, Genesee, 
Pullman, Colfax, Rosalia, La Crosse, Oakesdale, Tekoa, Uniontown,
Ritzville, Grand Coulee, Odessa, Wilbur, Coulee City, Spokane, 
Cheney, Davenport, Rockford, Leavenworth, Plain, Lake Wenatchee, 
Mazama, Winthrop, Twisp, Methow, and Conconully
817 AM PDT Thu Sep 16 2021

...FROST ADVISORY HAS EXPIRED...

The threat of frost has ended for the day.


$$

The office that day

Everything else NWS Spokane, WA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 15, 2:31 PM PDTFrost AdvisoryOTXAdams, Chelan, Douglas, Grant, Lincoln, Okanogan and 2 more17 hr

Nearby

Freeze Warnings in Washington, 2021Every freeze warning 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.