Alert archive / Idaho / Frost Advisories in 2021

Frost Advisory 2, NWS Spokane, WA

September 1, 20216 counties in Idaho; 5 counties in Washington

NWS Spokane, WA issued this frost advisory at Sep 1, 2021, 2:06 PM PDT for 6 counties in Idaho; 5 counties in Washington. It took effect at Sep 2, 2021, 4:00 AM PDT. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Sep 1, 2021, 2:06 PM PDT (21:06 UTC)
In effect from
Sep 2, 2021, 4:00 AM PDT
Expired
Sep 2, 2021, 9:00 AM PDT
In force
5 hr
Issued by
NWS Spokane, WA

Counties Benewah County, ID, Bonner County, ID, Boundary County, ID, Kootenai County, ID, Latah County, ID, Shoshone County, ID, Ferry County, WA, Okanogan County, WA, Pend Oreille County, WA, Spokane County, WA, Stevens County, WA

The radar

The Spokane radar (KOTX), 43 km from the middle of the area, began a volume at 21:10 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, 9.1 hours before the alert went out and 71 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 2021-09-01Temperature 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 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
1398 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

591 
WWUS76 KOTX 012106
NPWOTX

URGENT - WEATHER MESSAGE
National Weather Service Spokane WA
206 PM PDT Wed Sep 1 2021

IDZ001-003-004-WAZ037-038-020915-
/O.NEW.KOTX.FR.Y.0002.210902T1100Z-210902T1600Z/
Northern Panhandle-Idaho Palouse-Central Panhandle Mountains-
Northeast Mountains-Okanogan Highlands-
Including the cities of Chewelah, Wallace, Osburn, Rathdrum,
Republic, Eastport, St Maries, Moscow, Bonners Ferry, Kellogg,
Mullan, Kettle Falls, Sandpoint, Wauconda, Newport, Priest River,
Potlatch, Plummer, Genesee, Deer Park, Pinehurst, Colville, and
Inchelium
206 PM PDT Wed Sep 1 2021

...FROST ADVISORY IN EFFECT FROM 4 AM TO 9 AM PDT THURSDAY...

* WHAT...Temperatures as low as 37 will result in frost formation.

* WHERE...Chewelah, Republic, St Maries, Moscow, Kellogg, Mullan, 
  Kettle Falls, Sandpoint, Wauconda, Newport, Priest River, 
  Potlatch, Deer Park, Pinehurst, Colville.

* WHEN...From 4 AM to 9 AM PDT Thursday.

* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive 
  outdoor plants may be killed if left uncovered.

* ADDITIONAL DETAILS...Coolest temperatures will likely be just 
  before sunrise Thursday morning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

RP
2 follow-up statements
216 
WWUS76 KOTX 020238
NPWOTX

URGENT - WEATHER MESSAGE
National Weather Service Spokane WA
738 PM PDT Wed Sep 1 2021

IDZ001-003-004-WAZ037-038-021600-
/O.CON.KOTX.FR.Y.0002.210902T1100Z-210902T1600Z/
Northern Panhandle-Idaho Palouse-Central Panhandle Mountains-
Northeast Mountains-Okanogan Highlands-
Including the cities of Chewelah, Wallace, Osburn, Rathdrum,
Republic, Eastport, St Maries, Moscow, Bonners Ferry, Kellogg,
Mullan, Kettle Falls, Sandpoint, Wauconda, Newport, Priest River,
Potlatch, Plummer, Genesee, Deer Park, Pinehurst, Colville, and
Inchelium
738 PM PDT Wed Sep 1 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 4 AM TO 9 AM PDT THURSDAY...

* WHAT...Low temperatures in the 30s will result in frost formation.

* WHERE...Chewelah, Wallace, Osburn, Rathdrum, Republic, Eastport, 
  St Maries, Moscow, Bonners Ferry, Kellogg, Mullan, Kettle Falls, 
  Sandpoint, Wauconda, Newport, Priest River, Potlatch, Plummer, 
  Genesee, Deer Park, Pinehurst, Colville, and Inchelium.

* WHEN...From 4 AM to 9 AM PDT Thursday.

* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive 
  outdoor plants may be killed if left uncovered.

* ADDITIONAL DETAILS...Coolest temperatures will likely be just 
  after sunrise Thursday morning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

TW
008 
WWUS76 KOTX 021610
NPWOTX

URGENT - WEATHER MESSAGE
National Weather Service Spokane WA
910 AM PDT Thu Sep 2 2021

IDZ001-003-004-WAZ037-038-021715-
/O.EXP.KOTX.FR.Y.0002.000000T0000Z-210902T1600Z/
Northern Panhandle-Idaho Palouse-Central Panhandle Mountains-
Northeast Mountains-Okanogan Highlands-
Including the cities of Chewelah, Wallace, Osburn, Rathdrum,
Republic, Eastport, St Maries, Moscow, Bonners Ferry, Kellogg,
Mullan, Kettle Falls, Sandpoint, Wauconda, Newport, Priest River,
Potlatch, Plummer, Genesee, Deer Park, Pinehurst, Colville, and
Inchelium
910 AM PDT Thu Sep 2 2021

...FROST ADVISORY HAS EXPIRED...

The threat has ended.

$$

JCLEV

Nearby

Frost Advisories in Idaho, 2021Frost Advisories in Washington, 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.