Alert archive / California / Red Flag Warnings in 2021

Red Flag Warning 12, NWS Reno, NV

July 17, 20219 counties in California; 5 counties in Nevada

NWS Reno, NV issued this red flag warning at Jul 17, 2021, 11:54 AM PDT for 9 counties in California; 5 counties in Nevada. It took effect at Jul 18, 2021, 11:00 AM PDT. It was in force for 16 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
Jul 17, 2021, 11:54 AM PDT (18:54 UTC)
In effect from
Jul 18, 2021, 11:00 AM PDT
Expired
Jul 19, 2021, 3:05 AM PDT
In force
16 hr
Issued by
NWS Reno, NV

Counties El Dorado County, CA, Lassen County, CA, Madera County, CA, Modoc County, CA, Mono County, CA, Nevada County, CA, Placer County, CA, Plumas County, CA, Sierra County, CA, Douglas County, NV, Lyon County, NV, Mineral County, NV, Storey County, NV, Washoe County, NV

The radar

The Reno radar (KRGX), 64 km from the middle of the area, began a volume at 18:51 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

Reno, NV (KREV), launched 12:00Z, 6.9 hours before the alert went out and 155 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, Reno, NV at 12:00Z on 2021-07-17Temperature 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, Reno, NV at 12:00Z on 2021-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 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
3899 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

442 
WWUS85 KREV 171854
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
1154 AM PDT Sat Jul 17 2021

CAZ274-NVZ421-182300-
/O.UPG.KREV.FW.A.0011.210718T2100Z-210719T1500Z/
/O.NEW.KREV.FW.W.0012.210718T1800Z-210719T1800Z/
Southern Mono County-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
1154 AM PDT Sat Jul 17 2021

...RED FLAG WARNING IN EFFECT FROM 11 AM SUNDAY TO 11 AM PDT
MONDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR SOUTHERN SIERRA 
FRONT AND SOUTHERN MONO COUNTY...

The National Weather Service in Reno has issued a Red Flag
Warning for abundant lightning on dry fuels, which is in effect 
from 11 AM Sunday to 11 AM PDT Monday. The Fire Weather Watch is 
no longer in effect.

* CHANGES...upgrade to Red Flag Warning.

* Affected Area...Fire Zone 274 Southern Mono County, Fire Zone 
  421 Southern Sierra Front including Alpine, Northern Mono, 
  Southern Lyon and and Western Mineral Counties.

* Thunderstorms...Scattered mixed wet and dry thunderstorms late
  Sunday afternoon, then nocturnal storms Sunday night into Monday
  morning. Storms will become much wetter by Monday afternoon.

* Outflow Winds...Gusts up to 40 mph possible.

* Impacts...Recent hot and dry conditions have created very
  receptive vegetation for new lightning fires. New fire starts
  may combine with outflow winds to cause a fire to rapidly grow 
  in size and intensity before first responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ270>272-278-NVZ420-458-182300-
/O.UPG.KREV.FW.A.0011.210719T0700Z-210720T0700Z/
/O.NEW.KREV.FW.W.0012.210719T0700Z-210720T0300Z/
Surprise Valley California-
Western Lassen, Eastern Plumas, and Eastern Sierra Counties-
Greater Lake Tahoe and Truckee Area-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
Northern Washoe County-
1154 AM PDT Sat Jul 17 2021

...RED FLAG WARNING IN EFFECT FROM MIDNIGHT SUNDAY NIGHT TO 8 PM
PDT MONDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR NORTHERN 
SIERRA FRONT...TAHOE BASIN...AND NORTHEAST CALIFORNIA...

The National Weather Service in Reno has issued a Red Flag
Warning for abundant lightning on dry fuels, which is in effect 
from midnight Sunday night to 8 PM PDT Monday. The Fire Weather 
Watch is no longer in effect.

* CHANGES...upgrade to Red Flag Warning.

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 271 Western Lassen, Eastern Plumas, and Eastern Sierra 
  Counties, Fire Zone 272 Greater Lake Tahoe and Truckee Area, 
  Fire Zone 278 Eastern Lassen County, Fire Zone 420 Northern 
  Sierra Front including Carson City, Douglas, Storey, Southern 
  Washoe, Western Lyon, and Far Southern Lassen Counties and 
  Fire Zone 458 Northern Washoe County.

* Thunderstorms...Isolated to scattered mixed wet and dry 
  thunderstorms late Sunday night through Monday.

* Outflow Winds...Gusts up to 40 mph possible.

* Impacts...Recent hot and dry conditions have created very
  receptive vegetation to new lightning fires. New fire starts may
  combine with outflow winds to cause a fire to rapidly grow in 
  size and intensity before first responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

Hoon

http://weather.gov/reno
3 follow-up statements
461 
WWUS85 KREV 182039
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
139 PM PDT Sun Jul 18 2021

CAZ274-NVZ421-190600-
/O.EXT.KREV.FW.W.0012.000000T0000Z-210719T0600Z/
Southern Mono County-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
139 PM PDT Sun Jul 18 2021

...RED FLAG WARNING NOW IN EFFECT UNTIL 11 PM PDT THIS EVENING
FOR ABUNDANT LIGHTNING ON DRY FUELS FOR SOUTHERN SIERRA FRONT AND
SOUTHERN MONO COUNTY...

* CHANGES...Changed the end time from 11 am Monday to 11 pm
  Sunday.

* Affected Area...Fire Zone 274 Southern Mono County, Fire Zone 
  421 Southern Sierra Front including Alpine, Northern Mono, 
  Southern Lyon and and Western Mineral Counties.

* Thunderstorms...Isolated to scattered mixed wet and dry 
  thunderstorms this afternoon into the evening. After an 
  overnight break, storms will become much wetter by Monday 
  afternoon.

* Outflow Winds...Gusts up to 40 mph possible.

* Impacts...Recent hot and dry conditions have created very 
  receptive vegetation for new lightning fires. New fire starts 
  may combine with outflow winds to cause a fire to rapidly grow 
  in size and intensity before first responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ270>272-278-NVZ420-458-191800-
/O.EXT.KREV.FW.W.0012.210719T0300Z-210719T1800Z/
Surprise Valley California-
Western Lassen, Eastern Plumas, and Eastern Sierra Counties-
Greater Lake Tahoe and Truckee Area-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
Northern Washoe County-
139 PM PDT Sun Jul 18 2021

...RED FLAG WARNING NOW IN EFFECT FROM 8 PM THIS EVENING TO 11 AM
PDT MONDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR NORTHERN
SIERRA FRONT...TAHOE BASIN...AND NORTHEAST CALIFORNIA...

* CHANGES...Earlier start time by a few hours and also an earlier
  end time Monday morning instead of Monday evening.  

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 271 Western Lassen, Eastern Plumas, and Eastern Sierra 
  Counties, Fire Zone 272 Greater Lake Tahoe and Truckee Area, 
  Fire Zone 278 Eastern Lassen County, Fire Zone 420 Northern 
  Sierra Front including Carson City, Douglas, Storey, Southern 
  Washoe, Western Lyon, and Far Southern Lassen Counties and 
  Fire Zone 458 Northern Washoe County.

* Thunderstorms...Isolated mixed wet and dry thunderstorms tonight
  through Monday morning. Additional storms are expected Monday
  afternoon but they will be much wetter.

* Outflow Winds...Gusts up to 40 mph possible.

* Impacts...Recent hot and dry conditions have created very 
  receptive vegetation to new lightning fires. New fire starts 
  may combine with outflow winds to cause a fire to rapidly grow 
  in size and intensity before first responders can contain them.

* Additional Info...Storms are anticipated this evening for the
  Tahoe Basin and northern Sierra Front, moving north into
  northeast California overnight.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

http://weather.gov/reno
673 
WWUS85 KREV 190529
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
1029 PM PDT Sun Jul 18 2021

CAZ274-NVZ421-190630-
/O.CAN.KREV.FW.W.0012.000000T0000Z-210719T0600Z/
Southern Mono County-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
1029 PM PDT Sun Jul 18 2021

...RED FLAG WARNING IS CANCELLED FOR ABUNDANT LIGHTNING ON DRY
FUELS FOR SOUTHERN SIERRA FRONT AND SOUTHERN MONO COUNTY...

The National Weather Service in Reno has cancelled the Red Flag
Warning.

Thunderstorms will remain isolated and the abundant lightning
threat has ended. Storms Monday will be wetter and capable of
heavy rainfall.

$$

CAZ270>272-278-NVZ420-458-191800-
/O.CON.KREV.FW.W.0012.000000T0000Z-210719T1800Z/
Surprise Valley California-
Western Lassen, Eastern Plumas, and Eastern Sierra Counties-
Greater Lake Tahoe and Truckee Area-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
Northern Washoe County-
1029 PM PDT Sun Jul 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT MONDAY FOR
ABUNDANT LIGHTNING ON DRY FUELS FOR NORTHERN SIERRA FRONT...TAHOE
BASIN...AND NORTHEAST CALIFORNIA...

* CHANGES...None.

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 271 Western Lassen, Eastern Plumas, and Eastern Sierra 
  Counties, Fire Zone 272 Greater Lake Tahoe and Truckee Area, 
  Fire Zone 278 Eastern Lassen County, Fire Zone 420 Northern 
  Sierra Front including Carson City, Douglas, Storey, Southern 
  Washoe, Western Lyon, and Far Southern Lassen Counties and 
  Fire Zone 458 Northern Washoe County.

* Thunderstorms...Isolated mixed wet and dry thunderstorms tonight
  through Monday morning. Additional storms are expected Monday
  afternoon but they will be much wetter.

* Outflow Winds...Gusts up to 40 mph possible.

* Impacts...Recent hot and dry conditions have created very 
  receptive vegetation to new lightning fires. New fire starts 
  may combine with outflow winds to cause a fire to rapidly grow 
  in size and intensity before first responders can contain them.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

http://weather.gov/reno
884 
WWUS85 KREV 191005
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
305 AM PDT Mon Jul 19 2021

CAZ270>272-278-NVZ420-458-191115-
/O.CAN.KREV.FW.W.0012.000000T0000Z-210719T1800Z/
Surprise Valley California-
Western Lassen, Eastern Plumas, and Eastern Sierra Counties-
Greater Lake Tahoe and Truckee Area-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
Northern Washoe County-
305 AM PDT Mon Jul 19 2021

...RED FLAG WARNING IS CANCELLED FOR ABUNDANT LIGHTNING ON DRY
FUELS FOR NORTHERN SIERRA FRONT...TAHOE BASIN...AND NORTHEAST
CALIFORNIA...

The National Weather Service in Reno has cancelled the Red Flag
Warning.

The threat for nocturnal/early morning storms has diminished and
the Red Flag warnings have been cancelled as a result. 

Additional thunderstorms are expected later this afternoon;
however, storms will become wetter and RH will increase as the 
main push of monsoon moistures arrives. 

$$

http://weather.gov/reno

Nearby

Red Flag Warnings in California, 2021Red Flag Warnings in Nevada, 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.