FXUS65 KPSR 262311

AFDPSR



Area Forecast Discussion

National Weather Service Phoenix AZ

410 PM MST Thu Jun 26 2025



.UPDATE...

Updated Aviation



&&



.KEY MESSAGES...



- Temperatures will gradually heat up into the weekend reaching 

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...

Early afternoon satellite depicts a very dry airmass overhead with 

the favored area of convection well removed to the east across 

central to eastern New Mexico. General troughing across the region 

continues the dry southwesterly flow, but as this feature dissipates 

over the coming days, the strong area of high pressure that brought 

oppressive heat to the eastern part of the country the last few days 

will meander back westward going into this weekend. This will lead 

to seasonable temperatures to warm to above normal levels by the end 

of this weekend, with widespread Moderate HeatRisk. Temperatures 

will be hot enough to reasonably have Extreme Heat products out for 

at least the Phoenix metro Sunday-Tuesday as highs warm into the 110-

115 range and lows warm into the mid to upper 80s (probs of KPHX 

hitting a low of 90 is around 40-60%). Thus, an Extreme Heat Watch 

is in effect, with additional areas of south-central Arizona 

included on Monday when Major HeatRisk is the most expansive across 

the lower deserts.



The weather pattern evolution becomes much more muddled starting 

early next week as a weak trough begins to amplify across the West 

Coast. This feature will influence the movement of the subtropical 

high overhead the region early next week to retreat near the Four 

Corners. This retreat should present the first indication of low 

level southeasterly flow with the first significant moisture returns 

of the season, a typical feature of the monsoon. However, large 

discrepancies are apparent amongst the ensembles on how early and 

how quick this moisture will develop across Arizona. The GEFS 

remains much quicker than the ECMWF as the latest means depict the 

high center north of the Four Corners (GEFS), which would cause the 

moisture levels to increase faster than the high center positioned 

further south (ECMWF). Thus, GEFS members show an earlier increase 

to above normal PWAT's as early as Monday evening, with the 

increasing PWAT signal for the ECMWF delayed more into the Tuesday-

Wednesday timeframe. 



Thus, the timing of moisture increases, dictated by the strength of 

this troughing and subtropical high positioning, will determine how 

soon the region could conceivably see convection potential increase. 

The current thinking is convection potential will first increase 

across higher terrain areas of south-central Arizona as early as 

Tuesday, with gradual increasing chances into the lower deserts 

going into mid to late week. Prior to higher potential of 

showers/storms into the lower deserts, this transition from dry to 

more moist conditions may be preceded by a couple of days of gusty 

winds and blowing dust impacts due to outflows stemming from 

periphery convective activity in southeastern Arizona and higher 

terrain areas during the late afternoon and evening hours. We also 

cannot rule out a day or two of a dry lightning threat ahead of more 

robust convection.



&&



.PREVIOUS DISCUSSION...

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 2310Z.



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

No significant weather issues will exist through Friday afternoon 

with a few midlevel cloud decks, primarily during the afternoon over 

mountains east of the terminals. Behavior of wind speeds and 

directions will be very similar to the past 24 hours including only 

modest gusts during the late afternoon/early evening. 





Southeast California/Southwest Arizona including KIPL and KBLH: 

No weather concerns will exist through Friday afternoon under clear 

skies. Wind trends will be very similar to the past 24 hours with 

directions varying between SE and SW with only limited 

afternoon/evening gustiness. 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.



     Extreme Heat Watch from Monday morning through Monday evening 

     for AZZ534-538-539-552>555-559.



CA...None.



&&



$$



DISCUSSION...Young

PREVIOUS DISCUSSION...Kuhlman

AVIATION...18

FIRE WEATHER...Young/Kuhlman

