Alert archive / Idaho / Red Flag Warnings in 2021

Red Flag Warning 23, NWS Pocatello, ID

August 4, 20214 counties in Idaho

NWS Pocatello, ID issued this red flag warning at Aug 4, 2021, 1:55 PM MDT for 4 counties in Idaho. It took effect at Aug 5, 2021, 12:00 PM MDT. It was in force for 10 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
Aug 4, 2021, 1:55 PM MDT (19:55 UTC)
In effect from
Aug 5, 2021, 12:00 PM MDT
Expired
Aug 5, 2021, 10:00 PM MDT
In force
10 hr
Issued by
NWS Pocatello, ID

Counties Custer County, ID, Idaho County, ID, Lemhi County, ID, Valley County, ID

The radar

The Boise radar (KCBX), 198 km from the middle of the area, began a volume at 19:55 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

Boise Airport, ID (KBOI), launched 12:00Z, 7.9 hours before the alert went out and 189 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 2021-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 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
28 J/kg
Mixed-layer CIN
-486 J/kg
Mixed-layer LCL
2886 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
45 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.

389 
WWUS85 KPIH 041955
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
155 PM MDT Wed Aug 4 2021


IDZ475-051100-
/O.NEW.KPIH.FW.W.0023.210805T1800Z-210806T0400Z/
East Salmon River Mountains/Salmon NF-
155 PM MDT Wed Aug 4 2021

...RED FLAG WARNING IN EFFECT FROM NOON TO 10 PM MDT THURSDAY FOR
SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONE 475...

The National Weather Service in Pocatello has issued a Red Flag
Warning for scattered thunderstorms, which is in effect from noon
to 10 PM MDT Thursday.

* AFFECTED AREA...Fire Weather Zone 475 East Salmon River 
  Mountains/Salmon NF.

* IMPACTS...Scattered thunderstorms may produce new fire starts.
  Also, gusty and erratic winds will likely cause existing fires
  to spread. Initial thunderstorms in the afternoon will start 
  more dry but by the evening will transition into more wet 
  thunderstorms. Moderate to heavy rain is possible Thursday 
  evening into Friday morning. Localized flooding will be 
  possible.

* OUTFLOW WINDS...Wind gusts of 40 to 50 mph are possible near 
  thunderstorms.

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:

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


&&

$$
3 follow-up statements
630 
WWUS85 KPIH 050853
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
253 AM MDT Thu Aug 5 2021

IDZ475-060400-
/O.CON.KPIH.FW.W.0023.210805T1800Z-210806T0400Z/
East Salmon River Mountains/Salmon NF-
253 AM MDT Thu Aug 5 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 10 PM
MDT THIS EVENING FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER 
ZONE 475...

* AFFECTED AREA...Fire Weather Zone 475 East Salmon River 
  Mountains/Salmon NF.

* IMPACTS...Scattered thunderstorms may produce new fire starts. 
  Also, gusty and erratic winds will likely cause existing fires 
  to spread. Initial thunderstorms in the afternoon will start 
  more dry but by the evening will transition into more wet 
  thunderstorms. Moderate to heavy rain is possible Thursday 
  evening into Friday morning. Localized flooding will be 
  possible.

* OUTFLOW WINDS...Wind gusts of 40 to 50 mph are possible near 
  thunderstorms.

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:

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

&&

$$
127 
WWUS85 KPIH 051858
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
1258 PM MDT Thu Aug 5 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 PM MDT THIS
EVENING FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONE 475...

IDZ475-060400-
/O.CON.KPIH.FW.W.0023.000000T0000Z-210806T0400Z/
East Salmon River Mountains/Salmon NF-
1258 PM MDT Thu Aug 5 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 PM MDT THIS
EVENING FOR SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONE 475...

* AFFECTED AREA...Fire Weather Zone 475 East Salmon River 
  Mountains/Salmon NF.

* IMPACTS...Scattered thunderstorms may produce new fire starts.
  Also, gusty and erratic winds will likely cause existing fires
  to spread. Initial thunderstorms in the afternoon will start
  more dry but by the evening will transition into more wet
  thunderstorms. Moderate to heavy rain is possible later Thursday
  evening into Friday morning. Localized flooding will be 
  possible.

* OUTFLOW WINDS...Wind gusts of 40 to 50 mph are possible near 
  thunderstorms.

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:

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

&&

$$
667 
WWUS85 KPIH 060400
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
1000 PM MDT Thu Aug 5 2021


IDZ475-060500-
/O.EXP.KPIH.FW.W.0023.000000T0000Z-210806T0400Z/
East Salmon River Mountains/Salmon NF-
1000 PM MDT Thu Aug 5 2021

...RED FLAG WARNING WILL EXPIRE AT 10 PM MDT THIS EVENING FOR
SCATTERED THUNDERSTORMS FOR FIRE WEATHER ZONE 475...

Thunderstorms are moving to more isolated in coverage for the 
remainder of the night and into tomorrow. Also, relative 
humidities are expected to rise significantly. Additional showers 
and thunderstorms that will move in with the cold front late 
tonight into tomorrow morning will be more wet in nature. Some 
moderate to heavy showers will need to be monitored for flooding 
potential. Also, daytime temperatures on Friday with the cold 
front will be 10 to 15 degrees cooler than Thursday.


$$

The office that day

Everything else NWS Pocatello, ID issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 3, 6:18 PM MDTAreal Flood AdvisoryPIHBlaine, Butte, Custer117 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.