Alert archive / Arizona / Red Flag Warnings in 2021
Red Flag Warning 10, NWS Las Vegas, NV
NWS Las Vegas, NV issued this red flag warning at May 20, 2021, 3:52 AM MST for Mohave County, Arizona; San Bernardino County, California; Clark County, Nevada. It took effect at May 21, 2021, 11:00 AM MST. 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
- May 20, 2021, 3:52 AM MST (10:52 UTC)
- In effect from
- May 21, 2021, 11:00 AM MST
- Expired
- May 21, 2021, 8:00 PM MST
- In force
- 9 hr
- Issued by
- NWS Las Vegas, NV
Counties Mohave County, AZ, San Bernardino County, CA, Clark County, NV
The radar
The Las Vegas radar (KESX), 15 km from the middle of the area, began a volume at 10:55 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
Las Vegas, NV (KVEF), launched 00:00Z, 10.9 hours before the alert went out and 101 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 4475 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -8 m²/s²
- 0-3 km storm-relative helicity
- 12 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
561 WWUS85 KVEF 201052 CCA RFWVEF URGENT - FIRE WEATHER MESSAGE...CORRECTED National Weather Service Las Vegas NV 352 AM PDT Thu May 20 2021 AZZ101-CAZ228-229-NVZ461-463>466-202200- /O.CAN.KVEF.FW.A.0006.210521T1200Z-210522T0600Z/ /O.EXT.KVEF.FW.W.0009.000000T0000Z-210521T0600Z/ Lake Mead NRA/Colorado River-AZ side- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley-Lincoln County/Ely Dispatch- Sheep Range-Spring Mountains- Clark and SW Lincoln County Deserts/Las Vegas Dispatch- Lake Mead NRA/Colorado River-NV side- 352 AM PDT Thu May 20 2021 /352 AM MST Thu May 20 2021/ ...RED FLAG WARNING NOW IN EFFECT UNTIL 11 PM PDT /11 PM MST/ THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR SOUTHERN NEVADA...THE LAKE MEAD NATIONAL RECREATION AREA...AND THE MOJAVE DESERT OF SOUTHEAST CALIFORNIA... ...FIRE WEATHER WATCH FRIDAY IS CANCELLED FOR THESE AREAS... * AFFECTED AREA...In Arizona...Fire weather zone 101. In California...Fire weather zone 228 and 229. In Nevada... Fire weather zones 461, 463, 464, 465, and 466. * TIMING...A Red Flag Warning is in effect until 11 PM PDT/MST this evening. * WIND...South to southwest winds 25 to 35 mph with gusts 40 to 50 mph. The strongest winds are expected across western San Bernardino County where gusts 45 to 55 mph are possible. * HUMIDITY...Minimum relative humidity values will be in the single digits. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ AZZ102-202200- /O.UPG.KVEF.FW.A.0006.210521T1200Z-210522T0600Z/ /O.NEW.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ /O.EXT.KVEF.FW.W.0009.000000T0000Z-210521T0600Z/ Northwest Deserts/Northwest Plateau- 352 AM MST Thu May 20 2021 ...RED FLAG WARNING NOW IN EFFECT UNTIL 11 PM MST THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... ...RED FLAG WARNING IN EFFECT FROM 11 AM TO 8 PM MST FRIDAY FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... The National Weather Service in Las Vegas has issued a Red Flag Warning, which is in effect from 11 AM to 8 PM MST Friday. The Fire Weather Watch is no longer in effect. * AFFECTED AREA...In Arizona...zone 102. * TIMING...A Red Flag Warning is in effect until 11 PM MST this evening then again from 11 AM until 8 PM MST Friday. * WIND...South to southwest winds 25 to 35 mph with gusts 40 to 50 mph today. Southwest winds gusting 35 to 40 mph will persist Friday. * HUMIDITY...Minimum relative humidity values will be in the single digits today with marginal overnight recovery then will remain below 15 percent Friday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ NVZ462-202200- /O.EXT.KVEF.FW.W.0009.000000T0000Z-210521T0600Z/ Nye County Deserts/Las Vegas Dispatch- 352 AM PDT Thu May 20 2021 ...RED FLAG WARNING NOW IN EFFECT UNTIL 11 PM PDT THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR THE NYE COUNTY DESERTS... * AFFECTED AREA...In Nevada...Fire weather zone 462. * TIMING...until 11 PM PDT this evening. * WIND...South to southwest winds 25 to 35 mph with gusts 40-50 mph this afternoon then becoming northwest this evening. * HUMIDITY...Relative humidity values will mostly be in the single digits this afternoon. Good recovery is expected late tonight and Friday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ CAZ227-NVZ460-202200- /O.COR.KVEF.FW.W.0009.210520T1800Z-210521T0600Z/ Death Valley National Park- Esmeralda and Nye County Deserts/CNC Dispatch- 352 AM PDT Thu May 20 2021 ...RED FLAG WARNING NOW IN EFFECT FROM 11 AM THIS MORNING TO 11 PM PDT THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR DEATH VALLEY NATIONAL PARK AND ESMERALDA AND NYE COUNTY DESERTS... * AFFECTED AREA...In California...Fire weather zone 227. In Nevada...Fire Weather Zone 460. * TIMING...11 AM PDT this morning until 11 PM PDT this evening. * WIND...Southwest to west winds winds 25 to 35 mph with gusts 40 to 50 mph becoming northwest late this afternoon and evening. * HUMIDITY...Minimum relative humidity values will be in the single digits. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ weather.gov/lasvegas
6 follow-up statements
976 WWUS85 KVEF 202150 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 250 PM PDT Thu May 20 2021 AZZ102-210700- /O.CON.KVEF.FW.W.0009.000000T0000Z-210521T0600Z/ /O.CON.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ Northwest Deserts/Northwest Plateau- 250 PM MST Thu May 20 2021 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM MST THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 8 PM MST FRIDAY FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... The National Weather Service in Las Vegas has issued a Red Flag Warning, which is in effect from 11 AM to 8 PM MST Friday. The Fire Weather Watch is no longer in effect. * AFFECTED AREA...In Arizona...zone 102. * TIMING...A Red Flag Warning is in effect until 11 PM MST this evening then again from 11 AM until 8 PM MST Friday. * WIND...South to southwest winds 25 to 35 mph with gusts 40 to 50 mph today. Southwest winds gusting 35 to 40 mph will persist Friday. * HUMIDITY...Minimum relative humidity values will be in the single digits today with marginal overnight recovery then will remain below 15 percent Friday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ AZZ101-CAZ227>229-NVZ460>466-210600- /O.CON.KVEF.FW.W.0009.000000T0000Z-210521T0600Z/ Lake Mead NRA/Colorado River-AZ side-Death Valley National Park- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley- Esmeralda and Nye County Deserts/CNC Dispatch- Lincoln County/Ely Dispatch-Nye County Deserts/Las Vegas Dispatch- Sheep Range-Spring Mountains- Clark and SW Lincoln County Deserts/Las Vegas Dispatch- Lake Mead NRA/Colorado River-NV side- 250 PM PDT Thu May 20 2021 /250 PM MST Thu May 20 2021/ ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT /11 PM MST/ THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR THE NYE COUNTY DESERTS... * AFFECTED AREA...In Nevada...Fire weather zone 462. * TIMING...until 11 PM PDT this evening. * WIND...South to southwest winds 25 to 35 mph with gusts 40-50 mph this afternoon then becoming northwest this evening. * HUMIDITY...Relative humidity values will mostly be in the single digits this afternoon. Good recovery is expected late tonight and Friday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$
071 WWUS85 KVEF 210541 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 1041 PM PDT Thu May 20 2021 .The Red Flag Warning has been extended until 2 AM Friday morning. Gusty winds 35 to 50 mph late this evening will gradually decrease overnight to between 15 and 25 mph for most of the region. AZZ102-210900- /O.EXT.KVEF.FW.W.0009.000000T0000Z-210521T0900Z/ /O.CON.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ Northwest Deserts/Northwest Plateau- 1041 PM MST Thu May 20 2021 ...RED FLAG WARNING NOW IN EFFECT UNTIL 2 AM MST FRIDAY FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA......RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 8 PM MST FRIDAY FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... * AFFECTED AREA...In Arizona...zone 102. * TIMING...A Red Flag Warning has been extended until 2 AM MST Friday morning. A Red Flag Warning remains in effect again from 11 AM until 8 PM MST Friday. * WIND...South to southwest winds 25 to 35 mph with gusts 40 to 50 mph. Southwest winds gusting 35 to 40 mph will persist Friday. * HUMIDITY...Relative humidity will have poor or marginal overnight recovery then will remain below 15 percent Friday. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ AZZ101-CAZ227>229-NVZ460>466-210900- /O.EXT.KVEF.FW.W.0009.000000T0000Z-210521T0900Z/ Lake Mead NRA/Colorado River-AZ side-Death Valley National Park- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley- Esmeralda and Nye County Deserts/CNC Dispatch- Lincoln County/Ely Dispatch-Nye County Deserts/Las Vegas Dispatch- Sheep Range-Spring Mountains- Clark and SW Lincoln County Deserts/Las Vegas Dispatch- Lake Mead NRA/Colorado River-NV side- 1041 PM PDT Thu May 20 2021 /1041 PM MST Thu May 20 2021/ ...RED FLAG WARNING NOW IN EFFECT UNTIL 2 AM PDT /2 AM MST/ FRIDAY FOR STRONG WINDS AND LOW HUMIDITY FOR THE NYE COUNTY DESERTS... * AFFECTED AREA...In Nevada...Fire weather zone 462. * TIMING...Extended until 2 AM Friday morning. * WIND...South to southwest winds 25 to 35 mph with gusts 40-50 mph this afternoon then becoming northwest this evening. * HUMIDITY...Good RH recovery is expected over south central Nevada late tonight and Friday. Recovery will be poor or marginal over the deserts of San Bernardino and Clark counties. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ weather.gov/lasvegas
731 WWUS85 KVEF 210902 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 202 AM PDT Fri May 21 2021 AZZ102-211800- /O.EXP.KVEF.FW.W.0009.000000T0000Z-210521T0900Z/ /O.CON.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ Northwest Deserts/Northwest Plateau- 202 AM MST Fri May 21 2021 ...RED FLAG WARNING WILL EXPIRE AT 2 AM MST EARLY THIS MORNING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM TO 8 PM MST TODAY FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... * TIMING...Wind speeds will increase again late this morning through the afternoon and a Red Flag Warning will go into effect again from 11 AM this morning until 8 PM MST this evening. * WIND...Southwest winds gusting 35 to 40 mph. * HUMIDITY...Relative humidity will be below 15 percent late this morning through early this evening. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ AZZ101-CAZ227>229-NVZ460>466-211015- /O.EXP.KVEF.FW.W.0009.000000T0000Z-210521T0900Z/ Lake Mead NRA/Colorado River-AZ side-Death Valley National Park- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley- Esmeralda and Nye County Deserts/CNC Dispatch- Lincoln County/Ely Dispatch-Nye County Deserts/Las Vegas Dispatch- Sheep Range-Spring Mountains- Clark and SW Lincoln County Deserts/Las Vegas Dispatch- Lake Mead NRA/Colorado River-NV side- 202 AM PDT Fri May 21 2021 /202 AM MST Fri May 21 2021/ ...RED FLAG WARNING WILL EXPIRE AT 2 AM PDT /2 AM MST/ EARLY THIS MORNING FOR STRONG WINDS AND LOW HUMIDITY FOR THE NYE COUNTY DESERTS... Wind speeds will continue decrease overnight though west to southwest winds gusting 30 to 35 mph will persist for many sites with poor or marginal RH recovery over the desert areas. $$ weather.gov/lasvegas
657 WWUS85 KVEF 211106 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 406 AM PDT Fri May 21 2021 .A belt of west to southwest winds gusting 35 to 45 mph will combine with low relative humidity to create another round of critical fire weather conditions over the San Bernardino County deserts up across the Lake Mead National Recreation area and northwest Arizona late this afternoon into this evening. AZZ101-CAZ228-229-NVZ466-212200- /O.EXA.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ Lake Mead NRA/Colorado River-AZ side- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley-Lake Mead NRA/Colorado River-NV side- 406 AM PDT Fri May 21 2021 /406 AM MST Fri May 21 2021/ ...RED FLAG WARNING IN EFFECT FROM 11 AM THIS MORNING TO 8 PM THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR THE MOJAVE DESERT OF SAN BERNARDINO COUNTY AND THE COLORADO RIVER VALLEY INCLUDING THE LAKE MEAD NATIONAL RECREATION AREA... The National Weather Service in Las Vegas has issued a Red Flag Warning, which is in effect from 11 AM PDT /11 AM MST/ this morning to 8 PM PDT /8 PM MST/ this evening. * TIMING...Wind speeds will increase again late this morning through the afternoon and a Red Flag Warning will go into effect again from 11 AM this morning until 8 PM MST this evening. * WIND...Southwest winds gusting 35 to 45 mph. * HUMIDITY...Minimum relative humidity values of 8 to 13 percent can be expected late this morning through early this evening. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ AZZ102-212200- /O.CON.KVEF.FW.W.0010.210521T1800Z-210522T0300Z/ Northwest Deserts/Northwest Plateau- 406 AM MST Fri May 21 2021 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO 8 PM MST THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA... * TIMING...Wind speeds will increase again late this morning through the afternoon and a Red Flag Warning will go into effect again from 11 AM this morning until 8 PM MST this evening. * WIND...Southwest winds gusting 35 to 40 mph. * HUMIDITY...Relative humidity will be below 15 percent late this morning through early this evening. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ weather.gov/lasvegas
444 WWUS85 KVEF 211851 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 1151 AM PDT Fri May 21 2021 .A belt of west to southwest winds gusting 35 to 45 mph will combine with low relative humidity to create another round of critical fire weather conditions over the San Bernardino County deserts up across the Lake Mead National Recreation area and northwest Arizona today. AZZ101-102-CAZ228-229-NVZ466-220300- /O.CON.KVEF.FW.W.0010.000000T0000Z-210522T0300Z/ Lake Mead NRA/Colorado River-AZ side- Northwest Deserts/Northwest Plateau- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley-Lake Mead NRA/Colorado River-NV side- 1151 AM PDT Fri May 21 2021 /1151 AM MST Fri May 21 2021/ ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM PDT /8 PM MST/ THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA, THE MOJAVE DESERT OF SAN BERNARDINO COUNTY AND THE COLORADO RIVER VALLEY INCLUDING THE LAKE MEAD NATIONAL RECREATION AREA... * TIMING...Wind speeds will remain elevated through this afternoon. * WIND...Southwest winds gusting 35 to 45 mph. * HUMIDITY...Minimum relative humidity values of 8 to 13 percent can be expected through early this evening. PRECAUTIONARY/PREPAREDNESS ACTIONS... A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. Make outdoor plans accordingly, use extra caution with any ignition sources and heed all fire restrictions. && $$ weather.gov/lasvegas
245 WWUS85 KVEF 220251 RFWVEF URGENT - FIRE WEATHER MESSAGE National Weather Service Las Vegas NV 751 PM PDT Fri May 21 2021 AZZ101-102-CAZ228-229-NVZ466-220400- /O.EXP.KVEF.FW.W.0010.000000T0000Z-210522T0300Z/ Lake Mead NRA/Colorado River-AZ side- Northwest Deserts/Northwest Plateau- Mojave Desert Including Morongo Valley/Yucca Valley- Lower Colorado River Valley-Lake Mead NRA/Colorado River-NV side- 751 PM PDT Fri May 21 2021 /751 PM MST Fri May 21 2021/ ...RED FLAG WARNING WILL EXPIRE AT 8 PM PDT /8 PM MST/ THIS EVENING FOR STRONG WINDS AND LOW HUMIDITY FOR NORTHWEST ARIZONA, THE MOJAVE DESERT OF SAN BERNARDINO COUNTY AND THE COLORADO RIVER VALLEY INCLUDING THE LAKE MEAD NATIONAL RECREATION AREA... Winds will continue to decrease this evening as RH values increase above critical thresholds. Therefore, the Red Flag Warning will be allowed to expire on time. $$ weather.gov/lasvegas
The office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 11:04 AM MST | High Wind Warning | VEF | San Bernardino | 15 hr |
Nearby
Red Flag Warnings in Arizona, 2021Red 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.