Alert archive / Idaho / Red Flag Warnings in 2021

Red Flag Warning 24, NWS Pocatello, ID

August 20, 202110 counties in Idaho

NWS Pocatello, ID issued this red flag warning at Aug 20, 2021, 9:50 AM MDT for 10 counties in Idaho. It took effect at Aug 21, 2021, 12:00 PM MDT. It was in force for 11 hr. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 20, 2021, 9:50 AM MDT (15:50 UTC)
In effect from
Aug 21, 2021, 12:00 PM MDT
Expired
Aug 21, 2021, 11:00 PM MDT
In force
11 hr
Issued by
NWS Pocatello, ID

Counties Blaine County, ID, Boise County, ID, Butte County, ID, Cassia County, ID, Custer County, ID, Jerome County, ID, Lincoln County, ID, Minidoka County, ID, Power County, ID, Twin Falls County, ID

The radar

The Pocatello radar (KSFX), 109 km from the middle of the area, began a volume at 15:49 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.

What was reported inside it

TimeReportWhereRemark
Aug 21, 3:44 PM MDTTSTM WND GST 446 S Sun Valley, IDMESONET STATION OHOI1 6 S SUN VALLEY OHIO GULCH.
Aug 21, 5:15 PM MDTTSTM WND GST 458 Nnw Dickey, IDOUTFLOW WINDS MEASURED AT WILLOW SUMMIT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 3.8 hours before the alert went out and 182 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, Boise Airport, ID at 12:00Z on 2021-08-20Temperature 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, Boise Airport, ID at 12:00Z on 2021-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.19395878Sfc1 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
1908 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
42 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.

311 
WWUS85 KPIH 201550
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
950 AM MDT Fri Aug 20 2021

...RED FLAG WARNING IN EFFECT FROM NOON SATURDAY TO MIDNIGHT MDT
SATURDAY NIGHT FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONES
422, 425 AND 427...

IDZ422-425-427-211200-
/O.NEW.KPIH.FW.W.0024.210821T1800Z-210822T0600Z/
Sawtooth Range/Northern Sawtooth NF-
Middle Snake River Valley/Twin Falls BLM north of the Snake River-
Goose Creek and Raft River Valley/Southern Sawtooth NF/Twin Falls
BLM south of the Snake River-
950 AM MDT Fri Aug 20 2021

...RED FLAG WARNING IN EFFECT FROM NOON SATURDAY TO MIDNIGHT MDT
SATURDAY NIGHT FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONES
422, 425 AND 427...

The National Weather Service in Pocatello has issued a Red Flag
Warning for scattered thunderstorms, which is in effect from noon
Saturday to midnight MDT Saturday night.

* AFFECTED AREA...Fire Weather Zone 422 Sawtooth Range/Northern 
  Sawtooth NF, Fire Weather Zone 425 Middle Snake River 
  Valley/Twin Falls BLM north of the Snake River and Fire 
  Weather Zone 427 Goose Creek and Raft River Valley/Southern 
  Sawtooth NF/Twin Falls BLM south of the Snake River.

* IMPACTS...Scattered thunderstorms with gusty outflow winds may
  produce new starts or help spread existing fires. Most storms 
  WILL NOT produce wetting rains. 

* OUTFLOW WINDS...Gusts over 35 mph.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A red flag warning means that critical fire weather conditions
are either occurring now, or will shortly based on these criteria
for Southeastern Idaho:

- Relative humidity at or below 15 percent and wind gusts of at
least 25 mph in the mountains, or 30 mph in the Snake Plain.

- Thunderstorm coverage of 25 percent, without specific rainfall
criteria.

- Other high impact events deemed critical by the National
Weather Service and area fire management agencies.

&&

$$
3 follow-up statements
133 
WWUS85 KPIH 210743
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
143 AM MDT Sat Aug 21 2021

IDZ422-425-427-212045-
/O.EXT.KPIH.FW.W.0024.210821T1800Z-210822T0500Z/
Sawtooth Range/Northern Sawtooth NF-
Middle Snake River Valley/Twin Falls BLM north of the Snake River-
Goose Creek and Raft River Valley/Southern Sawtooth NF/Twin Falls
BLM south of the Snake River-
143 AM MDT Sat Aug 21 2021

...RED FLAG WARNING NOW IN EFFECT FROM NOON TODAY TO 11 PM MDT
THIS EVENING FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONES
422, 425 AND 427...

* AFFECTED AREA...Fire Weather Zone 422 Sawtooth Range/Northern 
  Sawtooth NF, Fire Weather Zone 425 Middle Snake River 
  Valley/Twin Falls BLM north of the Snake River and Fire 
  Weather Zone 427 Goose Creek and Raft River Valley/Southern 
  Sawtooth NF/Twin Falls BLM south of the Snake River.

* IMPACTS...Scattered thunderstorms with gusty outflow winds may
  produce new fire starts or help spread existing fires. Most 
  storms WILL NOT produce wetting rains.

* OUTFLOW WINDS...Gusts up to 40 mph possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A red flag warning means that critical fire weather conditions
are expected based on these criteria for Southeastern Idaho:

- Thunderstorm coverage of 25 percent, without specific rainfall
criteria.

&&

$$
257 
WWUS85 KPIH 211954
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
154 PM MDT Sat Aug 21 2021

IDZ422-425-427-220400-
/O.CON.KPIH.FW.W.0024.000000T0000Z-210822T0500Z/
Sawtooth Range/Northern Sawtooth NF-
Middle Snake River Valley/Twin Falls BLM north of the Snake River-
Goose Creek and Raft River Valley/Southern Sawtooth NF/Twin Falls
BLM south of the Snake River-
154 PM MDT Sat Aug 21 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM MDT THIS
EVENING FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONES 422,
425 AND 427...

* AFFECTED AREA...Fire Weather Zone 422 Sawtooth Range/Northern 
  Sawtooth NF, Fire Weather Zone 425 Middle Snake River 
  Valley/Twin Falls BLM north of the Snake River and Fire 
  Weather Zone 427 Goose Creek and Raft River Valley/Southern 
  Sawtooth NF/Twin Falls BLM south of the Snake River.

* IMPACTS...Scattered thunderstorms with gusty outflow winds may 
  produce new fire starts or help spread existing fires. Most 
  storms WILL NOT produce wetting rains.

* OUTFLOW WINDS...Gusts up to 50 mph possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A red flag warning means that critical fire weather conditions
are expected based on these criteria for Southeastern Idaho:

- Thunderstorm coverage of 25 percent, without specific rainfall
criteria.

&&

Messick

$$
130 
WWUS85 KPIH 220438
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
1038 PM MDT Sat Aug 21 2021

IDZ422-425-427-220545-
/O.EXP.KPIH.FW.W.0024.000000T0000Z-210822T0500Z/
Sawtooth Range/Northern Sawtooth NF-
Middle Snake River Valley/Twin Falls BLM north of the Snake River-
Goose Creek and Raft River Valley/Southern Sawtooth NF/Twin Falls
BLM south of the Snake River-
1038 PM MDT Sat Aug 21 2021

...RED FLAG WARNING WILL EXPIRE AT 11 PM MDT THIS EVENING FOR  
FIRE WEATHER ZONES 422, 425 AND 427...

A few isolated thunderstorms remain in place across these areas
but activity will diminish over the next hour or so. 

$$

Nearby

Red Flag Warnings in Idaho, 2021Every red flag 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.