Alert archive / California / Excessive Heat Warnings in 2021

Excessive Heat Warning 1, NWS Phoenix, AZ

June 2, 2021Imperial County, Riverside County, San Bernardino County, California

NWS Phoenix, AZ issued this excessive heat warning at Jun 2, 2021, 2:15 AM PDT for Imperial County, Riverside County, San Bernardino County, California. It took effect at Jun 2, 2021, 11:00 AM PDT. It was in force for 58 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
Jun 2, 2021, 2:15 AM PDT (09:15 UTC)
In effect from
Jun 2, 2021, 11:00 AM PDT
Expired
Jun 4, 2021, 9:00 PM PDT
In force
58 hr
Issued by
NWS Phoenix, AZ

Counties Imperial County, CA, Riverside County, CA, San Bernardino County, CA

The radar

The San Diego radar (KNKX), 154 km from the middle of the area, began a volume at 09:20 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

San Diego, CA (KNKX), launched 00:00Z, 9.3 hours before the alert went out and 174 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, San Diego, CA at 00:00Z on 2021-06-02Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 00:00Z on 2021-06-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
1501 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
47 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

747 
WWUS75 KPSR 020915
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
215 AM MST Wed Jun 2 2021

CAZ562-566-022300-
/O.NEW.KPSR.EH.W.0001.210602T1800Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
215 AM PDT Wed Jun 2 2021

...EXCESSIVE HEAT WARNING IN EFFECT FROM 11 AM THIS MORNING TO
9 PM PDT FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 109 
  to 112 expected.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...From 11 AM this morning to 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-022300-
/O.NEW.KPSR.EH.W.0001.210602T1800Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
215 AM PDT Wed Jun 2 2021

...EXCESSIVE HEAT WARNING IN EFFECT FROM 11 AM THIS MORNING TO
9 PM PDT FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 103 
  to 113 expected.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...From 11 AM this morning to 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$
5 follow-up statements
249 
WWUS75 KPSR 022005
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
105 PM MST Wed Jun 2 2021

CAZ562-566-031200-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
105 PM PDT Wed Jun 2 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 107 to
  112.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-031200-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
105 PM PDT Wed Jun 2 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 103 
  to 113.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$
128 
WWUS75 KPSR 031107
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
407 AM MST Thu Jun 3 2021

CAZ562-566-032300-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
407 AM PDT Thu Jun 3 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 107 
  to 112.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-032300-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
407 AM PDT Thu Jun 3 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 106 
  to 113.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$
665 
WWUS75 KPSR 032206
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
306 PM MST Thu Jun 3 2021

CAZ562-566-041130-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
306 PM PDT Thu Jun 3 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 105 
  to 112.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-041130-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
306 PM PDT Thu Jun 3 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT
FRIDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 105 to
  112.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...Until 9 PM PDT Friday.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$
981 
WWUS75 KPSR 041006
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
306 AM MST Fri Jun 4 2021

CAZ562-566-042300-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
306 AM PDT Fri Jun 4 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS
EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 108 
  to 112.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...Until 9 PM PDT this evening.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-042300-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
306 AM PDT Fri Jun 4 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS
EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 106 
  to 113.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...Until 9 PM PDT this evening.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$
599 
WWUS75 KPSR 042042
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
142 PM MST Fri Jun 4 2021

CAZ562-566-050400-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Imperial County Southwest-Imperial County West-
Including the cities of Coolidge Springs, Salton City, Winona, 
Coyote Wells, Ocotillo, and Plaster City
142 PM PDT Fri Jun 4 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS
EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 107 
  to 112.

* WHERE...Southwest corner of Imperial County and Western 
  Imperial County.

* WHEN...Until 9 PM PDT this evening.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

CAZ561-570-050400-
/O.CON.KPSR.EH.W.0001.000000T0000Z-210605T0400Z/
Joshua Tree NP East-Chuckwalla Valley-
Including the city of Midland
142 PM PDT Fri Jun 4 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS
EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 106 to
  112.

* WHERE...Eastern portion of Joshua Tree National Park and 
  Chuckwalla Valley.

* WHEN...Until 9 PM PDT this evening.

* IMPACTS...High Heat Risk. Overexposure can cause heat cramps 
  and heat exhaustion to develop and, without intervention, can 
  lead to heat stroke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a period of very hot
temperatures, even by local standards, will occur. Actions should
be taken to lessen the impact of the extreme heat.

Stay indoors and seek air-conditioned buildings. Drink water,
more than usual, and avoid dehydrating alcoholic, sugary, or
caffeinated drinks. Dress for the heat - lightweight and light-
colored clothing. Eat small meals and eat more often. Monitor
those with a higher vulnerability to heat, including small
children. Check in on family, friends, and neighbors, especially
the elderly. If engaging in outdoor activity, take longer and
more frequent breaks and avoid the hottest parts of the day.
Never leave kids or pets unattended in cars.

Public cooling shelters are available in some areas. Consult
county officials for more details, which may include guidance for
proper social distancing measures.

Recognize the signs and symptoms of heat-related illness. Early
signs include thirst and muscle cramps. Heat exhaustion may
include: cool, moist, pale skin; headache; dizziness; weakness or
exhaustion; nausea. The most serious illness is heat stroke,
which may include: vomiting; confusion; throbbing headache;
decreased alertness or loss of consciousness; high body
temperature (above 105F); hot, dry skin; rapid, weak pulse;
rapid, shallow breathing; seizures.

Heat stroke can be DEADLY. Treat as an emergency and call 9 1 1.

Continue to monitor NWS forecasts, broadcast outlets, and local
government for updates.

&&

$$

What forecasters said that day

The local office's own words before this excessive heat warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Phoenix, AZ wrote its last area forecast discussion before this excessive heat warning went out at Jun 1, 10:41 PM PDT, 3 hours 34 minutes earlier.

Area forecast discussion, Jun 1, 10:41 PM PDT, 3 hours 34 minutes before
Area Forecast Discussion
National Weather Service Phoenix AZ
1041 PM MST Tue Jun 1 2021

.UPDATE...
Updated Aviation discussion.

&&

.SYNOPSIS...
Temperatures will warm through the middle of the week with afternoon
highs in the 102 to 107 degree range along with moderate heat risk
for many places through the rest of the workweek. A persistent weak
upper level low and a slight uptick in moisture will result in a
chance of isolated showers and thunderstorms over the higher Arizona
terrain most afternoons. Showers and storms are most favored to
remain north and east of Phoenix but an isolated shower or
thunderstorm may survive into the lower desert areas near Phoenix.
A cooling trend is possible late in the weekend and early next week
as low pressure increases from the west.

&&

.DISCUSSION...
The upper level RAP mesoscale analysis indicates N to E flow
aloft on the north side of a closed cut-off low circulation over
offshore Baja. A small vort max in NW MX is rotating out in front
of the low. The skies are mostly clear across our region with
northerly flow across the western States in advance of the strong
ridge of high pressure building inland. There’s also some weak
elevated CAPE south of Gila County. METSAT showed mostly clear
skies across the region with convective CU and isolated mostly
light showers/sprinkles and an isolated storm cell on radar
returns forming across N and E and SE AZ. Mid-level WV shows some
slightly elevated moisture across the lower deserts and some
light patchy moisture with the cut-off low near Baja.

Local ACARs soundings evolution showed W flow below 700 mb and NE
flow above that with some elevated moisture near H5 and an above
average PW near 0.65" which is near to slightly increased from
yesterday. Yesterday’s high in Phoenix was 101 degrees. The
month of May ended with 11 days of 100 degree plus days which is
very near the normal of 100+ degree days for May in Phx. Today
the warm-up continues with a highs of 102 to 104 in and around
Phoenix and 103 to 106 out west.

The models agree on the Baja cut-off low remaining mostly stationary
through Thu as the ridge maintains strength over the West while only
shifting slightly east also through Thu. As a result there is good
confidence of the elevated heat persisting into Saturday. This will
result in up to moderate heat risk and highs of 103-106 degrees in
Phoenix and the lower deserts, and up to 104-109 out west. Highs are
then expected stay close or just under this range on Sat.

The lingering low pressure system will also make for low-end
shower/storm chances each afternoon and evening through the late
work week. The HREF family and the NMM6Km are still in good
agreement on very isolated, weak high-terrain/Mogollon Rim
showers/storms every afternoon and evening through Fri. These
storms would be high-based storms with dry lightning and gusty
outflow winds with little to no rainfall. The HRW FV3 may once
again be a slightly more bullish outlier favoring slightly better
coverage of storms E and near Phx.

Although the low will be in position to rotate small vort
disturbances across the area for a few days, it is still fairly
weak and unable to attract more pronounced mid level (and BL)
moisture, with the GEFs plume now showing PW spiking near 0.77"
late this week. In addition there are still no IVT moisture plumes
currently depicted in ensembles with this system.

For Sat the Clusters analysis favors the ridge axis to the north
flattening and shifting E with weak zonal troughing near the PAC
NW. There is also flattened lingering high pressure and weak flow
over the Desert SW along with dry conditions being favored.
Tuesday Clusters depict differing positions of a W coast to W US
trough with clusters 3 and 4 showing a slight potential for light
QPF for central and S-Cent AZ likely associated with isolated
showers and storms. There is slightly better confidence however
for lower temperature from Sun and early next week associated with
increasing low pressure from the W.

&&

.AVIATION...Updated at 0541Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

The forecast area lies between a weak upper low is centered near
the Baja Spur and a high amplitude ridge of high pressure with an
axis near the West Coast. There will be varying amounts of cirrus
streaming from northeast to southwest. Anticipate isolated
afternoon thunderstorms once again over the Mogollon Rim, White
Mountains and southeast AZ Wednesday afternoon. Storms are not
expected over the Valley floor. While there is some potential for
outflow from distant storms to reach the metro area, most likely
there will be no associated wind shifts at the TAF sites. Otherwise,
anticipate typical warm season surface winds with
westerly directions continuing to weaken tonight and transition to
downvalley/easterly directions (after 09Z for PHX).
Upvalley/westerly directions resume midday/early afternoon
Wednesday with gusts of 15-20kts common.

Southeast California/Southwest Arizona including KIPL and KBLH:

The forecast area lies between a weak upper low is centered near
the Baja Spur and a high amplitude ridge of high pressure with an
axis near the West Coast. The end result though will be varying
amounts of thin cirrus and familiar warm season surface wind
patterns with some afternoon gustiness (20-25kts). For KIPL,
directions will favor south- southeast and at KBLH, south-
southwest.

&&

.FIRE WEATHER...
Friday through Tuesday:
Isolated thunderstorms, mainly over the AZ higher terrain, could
drift into portions of Maricopa and Gila Counties, including the
Tonto NF Thursday-Friday. The main threats with any storms, even
distant ones, will be lightning and gusty outflow winds of 25-40
mph. Otherwise, the subtle moisture increase will not do much to
improve RH with afternoon values dropping into the 7-15% range and
overnight recoveries mostly in the 20-35% range. Outside of
outflows, winds will generally be light to occasionally moderate
and follow typical diurnal/terrain influences with afternoon
breeziness.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

DISCUSSION...Sawtelle
AVIATION...AJ
FIRE WEATHER...Sawtelle/AD

Nearby

Excessive Heat Warnings in California, 2021Every excessive heat 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.