Alert archive / Arizona / Red Flag Warnings in 2021

Red Flag Warning 2, NWS Phoenix, AZ

April 20, 20215 counties in Arizona

NWS Phoenix, AZ issued this red flag warning at Apr 20, 2021, 1:21 PM MST for 5 counties in Arizona. It took effect at Apr 21, 2021, 11:00 AM MST. It was in force for 9 hr. 1 report 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
Apr 20, 2021, 1:21 PM MST (20:21 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 Phoenix, AZ

Counties Gila County, AZ, La Paz County, AZ, Maricopa County, AZ, Pinal County, AZ, Yuma County, AZ

The radar

The Phoenix radar (KIWA), 78 km from the middle of the area, began a volume at 20:22 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
Apr 21, 11:20 AM MSTNON-TSTM WND GST 409 Se Queen Creek, AZVISIBILITY 1 MILE IN BLOWING DUST.

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

The nearest sounding before it

Tuscon, AZ (KTUS), launched 12:00Z, 8.4 hours before the alert went out and 197 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, Tuscon, AZ at 12:00Z on 2021-04-20Temperature 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, Tuscon, AZ at 12:00Z on 2021-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 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
3454 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

686 
WWUS85 KPSR 202021
RFWPSR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Phoenix AZ
121 PM MST Tue Apr 20 2021

AZZ133-211200-
/O.UPG.KPSR.FW.A.0002.210421T1800Z-210422T0100Z/
/O.NEW.KPSR.FW.W.0002.210421T1800Z-210422T0300Z/
Southern Gila County/Tonto National Forest Foothills-
121 PM MST Tue Apr 20 2021

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 8 PM MST WEDNESDAY
FOR STRONG WINDS, LOW RELATIVE HUMIDITY AND HIGH FIRE DANGER
FOR SOUTHERN GILA COUNTY...

The National Weather Service in Phoenix has issued a Red Flag
Warning for strong winds, low relative humidity and high fire
danger, which is in effect from 11 AM to 8 PM MST Wednesday. The 
Fire Weather Watch is no longer in effect.

* AFFECTED AREA...Southern Gila County/Tonto National Forest 
  Foothills.

* TIMING...Wednesday morning through Wednesday afternoon.

* WINDS...Southwest 15 to 25 mph with gusts of 30 to 40 mph.
  Isolated stronger gusts up to 45 mph cannot be ruled out.

* RELATIVE HUMIDITY...As low as 5 percent.

* IMPACTS...Fuels are dry and fire danger is high. These 
  conditions combined with low relative humidity and strong 
  winds may lead to widespread hazardous fire weather conditions.

* IMPACTS...Fuels are dry and fire danger is anticipated to be
  high. These conditions combined with low relative humidity and 
  strong winds will lead to widespread hazardous fire weather 
  conditions.
  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please advise the appropriate officials and fire crews in the
field of this red flag warning.

&&

$$

AZZ132-211200-
/O.NEW.KPSR.FW.W.0002.210421T1800Z-210422T0300Z/
Central Deserts-
121 PM MST Tue Apr 20 2021

...RED FLAG WARNING IN EFFECT FROM 11 AM TO 8 PM MST WEDNESDAY
FOR STRONG WINDS, LOW RELATIVE HUMIDITY AND HIGH FIRE DANGER FOR 
MARICOPA COUNTY AND NORTHERN PINAL COUNTY...

The National Weather Service in Phoenix has issued a Red Flag
Warning for strong winds, low relative humidity and high fire
danger, which is in effect from 11 AM to 8 PM MST Wednesday.

* AFFECTED AREA...Central Deserts to include all of Maricopa
  County and northern Pinal County.

* TIMING...

* WINDS...Southwest 15 to 25 mph with gusts up to 40 mph.

* RELATIVE HUMIDITY...As low as 7 percent.

* IMPACTS...Fuels are dry and fire danger is high. These 
  conditions combined with low relative humidity and strong winds 
  will lead to widespread hazardous fire weather conditions. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please advise the appropriate officials and fire crews in the
field of this red flag warning.

&&

$$

National Weather Service Phoenix is on the internet at

weather.gov/phoenix
3 follow-up statements
273 
WWUS85 KPSR 210846
RFWPSR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Phoenix AZ
146 AM MST Wed Apr 21 2021

AZZ132-133-212315-
/O.CON.KPSR.FW.W.0002.210421T1800Z-210422T0300Z/
Central Deserts-
Southern Gila County/Tonto National Forest Foothills-
146 AM MST Wed Apr 21 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO
8 PM MST THIS EVENING FOR STRONG WINDS, LOW RELATIVE HUMIDITY AND
HIGH FIRE DANGER FOR MARICOPA COUNTY, NORTHERN PINAL COUNTY, AND 
SOUTHERN GILA COUNTY...

* AFFECTED AREA...Central Deserts including all of Maricopa County
  and northern Pinal County and Southern Gila County/Tonto 
  National Forest Foothills.

* TIMING...Late this morning through early evening.

* WINDS...Southwest 15 to 25 mph with gusts up to 40 mph.

* RELATIVE HUMIDITY...As low as 6 percent.

* IMPACTS...Fuels are dry and fire danger is high. These 
  conditions combined with low relative humidity and strong 
  winds may lead to widespread hazardous fire weather conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please advise the appropriate officials and fire crews in the
field of this red flag warning.

&&

$$

National Weather Service Phoenix is on the internet at

weather.gov/phoenix
146 
WWUS85 KPSR 212034
RFWPSR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Phoenix AZ
134 PM MST Wed Apr 21 2021

AZZ132-133-220300-
/O.CON.KPSR.FW.W.0002.000000T0000Z-210422T0300Z/
Central Deserts-
Southern Gila County/Tonto National Forest Foothills-
134 PM MST Wed Apr 21 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM MST THIS EVENING
FOR STRONG WINDS, LOW RELATIVE HUMIDITY AND HIGH FIRE DANGER IN
SOUTHERN GILA COUNTY, MARICOPA COUNTY, AND PINAL COUNTY...

* AFFECTED AREA...Central Deserts and Southern Gila County/Tonto 
  National Forest Foothills.

* TIMING...Until 8 pm tonight.

* WINDS...Southwest 15 to 25 mph with gusts up to 45 mph.

* RELATIVE HUMIDITY...As low as 5 percent.

* IMPACTS...Fuels are dry and fire danger is high. These 
  conditions combined with low relative humidity and strong 
  winds may lead to widespread hazardous fire weather conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please advise the appropriate officials and fire crews in the
field of this red flag warning.

&&

$$

National Weather Service Phoenix is on the internet at

weather.gov/phoenix
822 
WWUS85 KPSR 220308
RFWPSR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Phoenix AZ
808 PM MST Wed Apr 21 2021

AZZ132-133-220415-
/O.EXP.KPSR.FW.W.0002.000000T0000Z-210422T0300Z/
Central Deserts-
Southern Gila County/Tonto National Forest Foothills-
808 PM MST Wed Apr 21 2021

...RED FLAG WARNING HAS EXPIRED FOR STRONG WINDS, LOW RELATIVE
HUMIDITY AND VERY HIGH TO EXTREME FIRE DANGER FOR SOUTH-CENTRAL
ARIZONA...

Winds have weakened below Red Flag thresholds and will continue to
do so. In addition, humidities have begun to increase and are
expected to improve as the night progresses.


$$

National Weather Service Phoenix is on the internet at

weather.gov/phoenix

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.