Alert archive / Arizona / Red Flag Warnings in 2021

Red Flag Warning 5, NWS Las Vegas, NV

April 20, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this red flag warning at Apr 20, 2021, 6:56 PM MST for Mohave County, Arizona. It took effect at Apr 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
Apr 20, 2021, 6:56 PM MST (01:56 UTC)
In effect from
Apr 21, 2021, 11:00 AM MST
Expired
Apr 21, 2021, 8:00 PM MST
In force
9 hr
Issued by
NWS Las Vegas, NV

County Mohave County, AZ

The radar

The Las Vegas radar (KESX), 102 km from the middle of the area, began a volume at 01:59 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, 1.9 hours before the alert went out and 177 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, Las Vegas, NV at 00:00Z on 2021-04-21Temperature 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, Las Vegas, NV at 00:00Z on 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 142 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
4363 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
142 m²/s²
0-3 km storm-relative helicity
264 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

201 
WWUS85 KVEF 210156
RFWVEF

URGENT - FIRE WEATHER MESSAGE
National Weather Service Las Vegas NV
656 PM PDT Tue Apr 20 2021

An area of low pressure will enter our region Wednesday, bringing
strong southwesterly winds to the eastern Mojave Desert and
Arizona Strip, encompassing the majority of Mohave County.
Relative humidity values will be critical through the afternoon,
resulting in enhanced fire danger through the day.

AZZ102-211800-
/O.NEW.KVEF.FW.W.0005.210421T1800Z-210422T0300Z/
Northwest Deserts/Northwest Plateau-
656 PM MST Tue Apr 20 2021

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 8 PM MST WEDNESDAY
FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONE 102 IN
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 Wednesday. 

* AFFECTED AREA...In Arizona...Fire weather zone 102.

* TIMING...From 11am to 8pm MST Wednesday.

* WIND...Southwest wind 15 to 25 mph with gusts 30 to 35 mph.

* HUMIDITY..8 to 15 percent.

* IMPACTS...Any fires that develop will likely spread rapidly. 
  Outdoor burning is not recommended. Heed all fire restrictions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$


weather.gov/lasvegas
2 follow-up statements
663 
WWUS85 KVEF 211809
RFWVEF

URGENT - FIRE WEATHER MESSAGE
National Weather Service Las Vegas NV
1109 AM PDT Wed Apr 21 2021

AZZ102-220300-
/O.CON.KVEF.FW.W.0005.000000T0000Z-210422T0300Z/
Northwest Deserts/Northwest Plateau-
1109 AM MST Wed Apr 21 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MST THIS EVENING
FOR STRONG WINDS AND LOW HUMIDITY FOR FIRE WEATHER ZONE 102 IN
ARIZONA...

* AFFECTED AREA...In Arizona...Fire weather zone 102.

* TIMING...Until 8 PM MST this evening.

* WIND...Southwest 20 to 25 mph with gusts 35 to 40 mph.

* HUMIDITY..8 to 15 percent.

* IMPACTS...A combination of strong winds...low relative 
  humidity...and warm temperatures can contribute to extreme fire 
  behavior. Any fires that develop will likely spread rapidly. 
 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Outdoor burning is not recommended. Heed all fire restrictions.

&&

$$


weather.gov/lasvegas
198 
WWUS85 KVEF 220309
RFWVEF

URGENT - FIRE WEATHER MESSAGE
National Weather Service Las Vegas NV
809 PM PDT Wed Apr 21 2021

AZZ102-220415-
/O.EXP.KVEF.FW.W.0005.000000T0000Z-210422T0300Z/
Northwest Deserts/Northwest Plateau-
809 PM MST Wed Apr 21 2021

...RED FLAG WARNING HAS EXPIRED FOR STRONG WINDS AND LOW HUMIDITY
FOR FIRE WEATHER ZONE 102 IN ARIZONA...

The warning was allowed to expire as winds have decreased and 
humidity levels are on the rise.

$$


weather.gov/lasvegas

Nearby

Red Flag Warnings in Arizona, 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.