FXUS65 KPSR 261725

AFDPSR



Area Forecast Discussion

National Weather Service Phoenix AZ

1025 AM MST Thu Jun 26 2025



.UPDATE...Updated 18Z Aviation Discussion



&&



.KEY MESSAGES...



- Temperatures will gradually heat up into the weekend reaching 

  to above normal levels with widespread Moderate HeatRisk across 

  all areas by Sunday



- Extreme Heat Watch is in effect for the Phoenix metro Sunday

  through Tuesday with areas of Major HeatRisk and high

  temperatures topping 110 degrees



- Dry conditions will prevail through at least the weekend, but a

  gradual increase in moisture next week is likely to lead to

  increasing chances for showers and thunderstorms by the middle

  to latter part of the week

  

&&



.DISCUSSION...

A dry air mass remains in place across all of southern California

and Arizona as the stationary trough over the region continues to

erode. This feature should still be recognizable through the rest

of today, but as it continues to fill we will begin the process of

warming up. After the below normal highs yesterday of around or

just over 100 degrees, we are expecting highs back into the normal

range today and even a few degrees above normal on Friday. By

Friday night into Saturday, the sub-tropical ridge will quickly 

become the dominant weather feature over our region with H5

heights rising to near 590dm. With the dry air mass remaining over

the region, the high pressure ridge will push daytime highs to

around 110 degrees by Saturday resulting in widespread Moderate

HeatRisk across the area. 



Once the ridge fully settles back over our region this weekend,

guidance shows it strengthening a bit further Sunday into Monday 

with H5 heights likely peaking between 591-593dm on Monday. This

should easily push daytime highs to over 110 degrees for Sunday

and Monday and likely even into Tuesday if the ridge stays in

place. NBM temperature guidance shows highs peaking on Monday 

between 111-115 degrees across the lower deserts with areas of 

Major HeatRisk focused over the Phoenix Metro. An Extreme Heat 

Watch remains in effect for the Phoenix area for Sunday-Tuesday. 

This time around, the heat episode is likely to be accompanied by 

higher moisture levels as we will begin to see surface dew points 

creep upward into the 40s for Sunday and Monday to as high as the 

lower 50s for Tuesday. The marginally higher humidities are likely

to keep overnight lows quite warm starting Sunday night with KPHX

potentially seeing it's first 90 degree low of the season. 



This next heat episode is likely to meet its end by next

Wednesday, not fully due to the ridge getting displaced out of 

the region or weakening, but also because of our first good dose 

of monsoon moisture advecting into the region from the southeast. 

Guidance has been consistent in showing modest sub-tropical 

moisture advecting first into southeast Arizona Monday and Tuesday

and then likely into south-central Arizona by next Wednesday and 

Thursday. This moisture advection is likely to be partially aided 

by an increase in southerly flow in between a weak Pacific trough 

that develops just off the California coast Sunday into Monday and

the ridge to our northeast. This should help to gradually 

increase moisture over our region into the middle part of next 

week with high terrain convection possible as early as Tuesday and

maybe into the south-central lower deserts as early as Wednesday.

By late next week, we may even be able to see some deeper 

tropical moisture seep into portions of our area, but this will be

dependent upon what happens with a potential Tropical Cyclone 

south of Baja during the middle part of next week. If we do end up

seeing some tropical moisture at some point late next week, right

now it looks to fall on around next Friday. There are still a lot

of what-ifs, but we can at least point toward the 6-10 day CPC 

outlook which shows a 70-80% chance of above normal precipitation

late next week. We will hopefully have a better idea on our 

rainfall potential over the next few days. 



&&



.AVIATION...Updated at 1725Z.



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

No aviation weather concerns are expected during the TAF period.

Another similar pattern today as winds will continue to follow

typical diurnal shifts. Seasonal afternoon sporadic gusts in the 

mid to upper teens will develop during the afternoon hours. Only 

clouds present over the region will be a FEW mid-level clouds to 

the far east of the terminals. 



Southeast California/Southwest Arizona including KIPL and KBLH: 

No aviation concerns are expected during the TAF period. Winds

will continue to follow diurnal trends, with some occasional

breeziness at KBLH in the afternoon. While not directly impacting

sfc visibilities, lofted smoke/haze may occasionally affect

slantwise visibilities during the late afternoon/evening hours at

KIPL. 



&&



.FIRE WEATHER...

High pressure will gradually strengthen across the region through

the weekend leading to a strong warming trend and continued dry

conditions. Temperatures will warm to above normal starting Friday

before peaking early next week. Expect little change in humidity

trends as MinRH values continue to range between 5-15% each day

and overnight recoveries stay between 20-35%. Winds will follow 

familiar diurnal trends with typical afternoon breeziness, gusting

mainly between 15-20 mph. Eventually, the weather pattern should 

become more favorable for increasing moisture and at least some 

scattered high terrain showers and thunderstorms by around next 

Tuesday. This may initially result a day or two of dry lightning 

concerns before moisture and rainfall chances increases later next

week.



&&



.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...Extreme Heat Watch from Sunday morning through Tuesday evening 

     for AZZ537-540-542>544-546-548-550-551.



CA...None.

&&



$$



DISCUSSION...Kuhlman

AVIATION...Ryan/RW

FIRE WEATHER...Young/Kuhlman

