Excessive Heat Warning 3, NWS Phoenix, AZ

160 
WWUS75 KPSR 262052
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
152 PM MST Sat Jun 26 2021

AZZ530-532-CAZ560>570-270900-
/O.CON.KPSR.EH.W.0003.210627T1700Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
152 PM MST Sat Jun 26 2021 /152 PM PDT Sat Jun 26 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM 10 AM MST /10 AM
PDT/ SUNDAY TO 8 PM MST /8 PM PDT/ MONDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 106 
  to 118 expected.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...From 10 AM MST /10 AM PDT/ Sunday to 8 PM MST /8 PM 
  PDT/ Monday.

* 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.

&&

$$

315 
WWUS75 KPSR 270914
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
214 AM MST Sun Jun 27 2021

AZZ530-532-CAZ560>570-272115-
/O.CON.KPSR.EH.W.0003.210627T1700Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
214 AM MST Sun Jun 27 2021 /214 AM PDT Sun Jun 27 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM 10 AM MST /10 AM
PDT/ THIS MORNING TO 8 PM MST /8 PM PDT/ MONDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 106 
  to 118 expected.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...From 10 AM MST /10 AM PDT/ Sunday to 8 PM MST /8 PM 
  PDT/ Monday.

* 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.

&&

$$

534 
WWUS75 KPSR 272038
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
138 PM MST Sun Jun 27 2021

AZZ530-532-CAZ560>570-280845-
/O.CON.KPSR.EH.W.0003.000000T0000Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
138 PM MST Sun Jun 27 2021 /138 PM PDT Sun Jun 27 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM MST /8 PM
PDT/ MONDAY...

* WHAT...Dangerously hot conditions. Afternoon temperatures 108 
  to 119.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...Until 8 PM MST /8 PM PDT/ Monday.

* 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.

&&

$$

974 
WWUS75 KPSR 281028
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
328 AM MST Mon Jun 28 2021

AZZ530-532-CAZ560>570-282230-
/O.CON.KPSR.EH.W.0003.000000T0000Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
328 AM MST Mon Jun 28 2021 /328 AM PDT Mon Jun 28 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM MST /8 PM
PDT/ THIS EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 105 
  to 115.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...Until 8 PM MST /8 PM PDT/ Monday.

* 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.

&&

$$

943 
WWUS75 KPSR 281413
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
713 AM MST Mon Jun 28 2021

AZZ530-532-CAZ560>570-290300-
/O.CON.KPSR.EH.W.0003.000000T0000Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
713 AM MST Mon Jun 28 2021 /713 AM PDT Mon Jun 28 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM MST /8 PM
PDT/ THIS EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 105 
  to 115.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...Until 8 PM MST /8 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.

&&

$$

445 
WWUS75 KPSR 281658
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
958 AM MST Mon Jun 28 2021

AZZ530-532-CAZ560>570-290300-
/O.CON.KPSR.EH.W.0003.000000T0000Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
958 AM MST Mon Jun 28 2021 /958 AM PDT Mon Jun 28 2021/

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM MST /8 PM
PDT/ THIS EVENING...

* WHAT...Dangerously hot conditions. Afternoon temperatures 107 
  to 116.

* WHERE...Portions of southwest Arizona and southeast and 
  southern California.

* WHEN...Until 8 PM MST /8 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.

&&

$$

AZZ550-551-553-554-290400-
/O.NEW.KPSR.DU.Y.0007.210629T0000Z-210629T0400Z/
South Mountain/Ahwatukee-Southeast Valley/Queen Creek-
Northwest Pinal County-West Pinal County-
Including the cities of Sun Lakes, Queen Creek, Casa Grande, 
Florence, and Coolidge
958 AM MST Mon Jun 28 2021

...BLOWING DUST ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO
9 PM MST THIS EVENING...

* WHAT...Visibility between one quarter mile and one mile in 
  blowing dust expected.

* WHERE...South Mountain/Ahwatukee, Southeast Valley/Queen 
  Creek, Northwest Pinal County and West Pinal County.

* WHEN...From 5 PM this afternoon to 9 PM MST this evening.

* IMPACTS...Hazardous driving conditions due to reduced 
  visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be ready for a sudden drop in visibility. If you encounter
blowing dust or blowing sand on the roadway or see it
approaching, pull off the road as far as possible and put your
vehicle in park. Turn the lights all the way off and keep your
foot off the brake pedal.

Remember, pull aside, stay alive.

&&

$$

299 
WWUS75 KPSR 290301
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
801 PM MST Mon Jun 28 2021

AZZ530-532-CAZ560>570-290415-
/O.EXP.KPSR.EH.W.0003.000000T0000Z-210629T0300Z/
Parker Valley-Yuma-Joshua Tree NP West-Joshua Tree NP East-
Imperial County Southwest-Salton Sea-Chuckwalla Mountains-
Imperial County Southeast-Imperial County West-Imperial Valley-
Chiriaco Summit-Palo Verde Valley-Chuckwalla Valley-
Including the cities of Parker, Ehrenberg, Yuma, 
Fortuna Foothills, Cottonwood Visitor, Lost Horse-Keys Village, 
Desert Shores, Imperial Hot Mineral Springs, Winterhaven, 
Coolidge Springs, Salton City, Winona, Coyote Wells, Ocotillo, 
Plaster City, El Centro, Calexico, Alamorio, Brawley, 
Chiriaco Summit, Martinez Lake, Blythe, Palo Verde, Ripley, 
and Midland
801 PM MST Mon Jun 28 2021 /801 PM PDT Mon Jun 28 2021/

...EXCESSIVE HEAT WARNING WILL EXPIRE AT 8 PM MST /8 PM PDT/ THIS
EVENING...

Afternoon temperatures will settle closer to seasonal normal
temperatures beginning Tuesday. Everyone is still encouraged to 
maintain their heat precautions such as hydrating adequately and 
moving outdoor activity to the early morning hours. 

$$

AZZ550-551-553-554-290415-
/O.CON.KPSR.DU.Y.0007.000000T0000Z-210629T0400Z/
South Mountain/Ahwatukee-Southeast Valley/Queen Creek-
Northwest Pinal County-West Pinal County-
Including the cities of Sun Lakes, Queen Creek, Casa Grande, 
Florence, and Coolidge
801 PM MST Mon Jun 28 2021

...BLOWING DUST ADVISORY REMAINS IN EFFECT UNTIL 9 PM MST THIS
EVENING...

* WHAT...Visibility between one quarter mile and one mile in 
  blowing dust.

* WHERE...Northwest Pinal County, Southeast Valley/Queen Creek, 
  South Mountain/Ahwatukee and West Pinal County.

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

* IMPACTS...Hazardous driving conditions due to reduced 
  visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be ready for a sudden drop in visibility. If you encounter
blowing dust or blowing sand on the roadway or see it
approaching, pull off the road as far as possible and put your
vehicle in park. Turn the lights all the way off and keep your
foot off the brake pedal.

Remember, pull aside, stay alive.

&&

$$

Area Forecast Discussion
National Weather Service Phoenix AZ
1000 PM MST Fri Jun 25 2021

.UPDATE...
Updated 06Z aviation discussion.

.SYNOPSIS...
Increasing high pressure aloft and drier conditions will bring a
warming trend through the weekend and high temperatures back to
around 110 degrees across the lower deserts over the weekend.
Unsettled weather conditions are expected starting next Monday as
increased moisture is likely to bring even better shower and
thunderstorm chances.

&&

.DISCUSSION...
Visible satellite shows a large field of cumulus clouds
stretching across the northeastern two-thirds of Arizona, but so
far, most have struggled to grow vertically under increasingly
dry westerly-southwesterly flow aloft. Conditions favorable for
thunderstorms this afternoon are focused across the northern
portion of the state close to the Utah border but a passing upper
level trough may support some storm development farther south
closer to Interstate 40 this evening. For us, we will just have
the clouds as temperatures top out between 105-109 degrees.

The latest HREF guidance keeps most convection out of our forecast
area again tomorrow but the focus of activity is anticipated to
shift closer to the Mogollon Rim-White Mountains as the
aforementioned upper level trough moves farther east. The highest
PoPs for our area are over the higher terrain of northeastern and
southern Gila County at less than 10% as southwesterly flow will
make it difficult for storms to move off the Rim and towards the
lower desert. The drying airmass will be more suitable for long-
traveling outflow winds, a common threat from distant storms, but
those too may have to combat southwesterly flow from the surface
through the midlevels. Still, the latest HREF indicates a 10-30%
chance for 35 mph thunderstorm related winds (outflows) reaching
those aforementioned portions of Maricopa and Gila Counties. The
probability for such winds in the Phoenix metro are less than 10%
and probably much closer to zero at this time.

For this weekend, ensembles show a narrow high amplitude ridge
rapidly strengthening across the West Coast and peaking into
Western Canada. Expansion of the ridge into our region will be
slowed by our lingering trough as it slowly moves through the
southern Rockies and eventually into the Plains. Increasing
thickness by Sunday/Monday as H5 heights rise by 2-4 dm will
translate to a warming trend with Sunday forecast to be the
hottest day. The heat will be felt the most across southeastern CA
and western AZ along the Colorado River where highs Sunday are
forecast to reach 113-116 degrees. NBM probability data shows
KNYL has a 79% chance of reaching 110 degrees, 18% chance of
reaching 115 degrees, and no chance for temps above 118 degrees.
The same probability data shows KIPL with an 87% chance for temps
of 110 degrees, 41% chance to reach 115 degrees, and no chance for
reaching 119 degrees. Yes, the afternoons will be hot but the
probability for extreme heat is less clear, with limited patchy
areas of High/Very High Heat Risk Sun-Mon, as overnight lows warm
slowly and potential moisture increases reduce daytime heating.
Given the uncertainty, an Excessive Heat Watch has been issued
Sunday and Monday for portions of southeastern California for now.

Temperatures will warm farther east into the 107-112 degree range
across the lower deserts of south-central AZ Sunday, and perhaps
again Monday, but with even more uncertainty in the temp forecast,
as the anticipated synoptic pattern and ensemble guidance trends
remain favorable for increasing moisture beginning Sunday. By
Monday, the ECMWF Ens and GEFS mean PWs both exceed 1.00" and then
peak near 1.50" late next week. Daytime heating and increasing
moisture could produce a more unstable atmosphere capable of
afternoon convection on multiple days next week. Storm chances
will first improve over the higher terrain north and east of
Phoenix, such as the San Francisco Peaks, Mogollon Rim, and White
Mountains, then spread into the higher terrain of Gila County by
Sunday afternoon. If trends hold, storm chances are then forecast
to spread westward through the Phoenix area and into western AZ
Monday, and possibly past the Colorado River and into southeastern
CA Tuesday. The NBM and GEFS probabilities for measurable
rainfall (0.01") seem to depict the increasing storm chances well
spatially and temporally, with our biggest (and first for many)
convective day so far this young monsoon to occur sometime between
Monday and Wednesday.

As mentioned, evolving conditions will keep forecast specifics
less clear but we can anticipate the typical threats with any
thunderstorms that do develop, such as lightning strikes, strong
gusty winds, and potentially blowing dust. While guidance is
bearish on rainfall totals, locally heavy rain cannot be ruled
out, with growing concern for flash flooding on any areas burned
by wildfires, even at lower amounts of rain.

&&

.AVIATION...Updated at 0500Z.

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

Minimal aviation impacts are expected through Saturday night at the
Phoenix terminals. Light westerly winds will persist through late
tonight. Light easterly or variable flow will return towards morning
on Saturday with an early westerly switch by 17Z. Shower and
thunderstorms should remain well to the north of the Phoenix
terminals through the TAF period, but there is a very slight 10-15%
chance of outflows pushing into the Phoenix terminals tomorrow.
Otherwise, typical 15-20 knot afternoon gusts with mostly clear
skies aside from a few clouds with bases down to 10 kft are expected
tomorrow.

Southeast California/Southwest Arizona including KIPL and KBLH:

Minimal aviation impacts are expected through Saturday aside. Winds
to remain west-southwesterly at KIPL and south to southwesterly at
KBLH through the TAF period, but with an extended period of
light/variable winds likely at both TAF sites late tonight thru
early Saturday afternoon. SKies to remain mainly CLR thru the TAF
period.

&&

.FIRE WEATHER...
Monday through Friday:
Temperatures will be the hottest Monday, near 100-110 degrees,
before temps cool to more typical values. Moisture levels are
anticipated to increase which will improve min RH values and
overnight recoveries. Min RH of 20-35% and recoveries to 35-60%
will be common. Winds will generally be light, with typical
afternoon breezes, while directions favor diurnal/terrain
influences. Chances for thunderstorms will exist almost
everywhere,and could occur almost daily. Storms will have a good
chance for producing wetting rains but could also produce hazards
such as lightning strikes, strong wind gusts, and outflow winds.

&&

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

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Excessive Heat Watch from Sunday morning through Monday evening
     for CAZ560>563-566>568-570.

&&

DISCUSSION...AD
AVIATION...Hopper/Percha
FIRE WEATHER...AD