921
FXUS65 KTWC 030913
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
213 AM MST Sun Aug 3 2025

.SYNOPSIS...Very hot weather will continue this week with high
temperatures near monthly August records for some locales Wednesday
and Thursday. Dry conditions prevail through Monday, then a very low
grade monsoon pattern returns starting Tuesday with slight chances
of precipitation, mostly focused closer to the Int`l border.

&&

.DISCUSSION...The main weather story for this week is going to be
the extreme heat as an anomalously strong mid-upper level high sets
up across the region. In the near term, monsoonal moisture is being
shunted to our south through Monday as drier air continues to work
its way in from the north and west today. As the mid-upper level
high continues to strengthen it will nudge closer to the AZ/NM
border Tuesday and then into western NM Wednesday and Thursday. With
the high itself becoming so strong and expansive (500mb heights
peaking above 600dm Wed-Thu and 4 standard deviations above normal),
any monsoon moisture that does seep in will be limited to areas
right along the Int`l border Tuesday, then mainly from Tucson south
and west mid to late week. Even as such, we`re talking a low grade
pattern with only slight (10-20%) chances through Thursday. Longer
range ensemble guidance gradually weaken the high Friday into next
weekend allowing a bit more moisture with a modest uptick in storm
chances Friday and Saturday.

Temperatures are expected to peak Wednesday and Thursday at 8 to 14
degrees above normal. We`ve gone ahead and upgraded the previously
active Extreme Heat Watch Wednesday through Friday to an Extreme
Heat Warning and also included Zone 509 in Cochise County into the
warning Tuesday. Highs Wednesday and Thursday will be at or near
August monthly records across southeast Arizona. See climate section
below for additional information.


&&

.AVIATION...Valid through 04/12Z.
Mainly SKC for the forecast period with FEW clouds 10-12 kft from
03/18z to 04/03Z at KDUG.  Aviation discussion not updated for TAF
amendments. Sfc winds mainly light this morning at 8 kts or less,
becoming WLY/NWLY 03/18Z to 04/02Z at 8-12 kts with gusts up to
around 20 kts. Aft 04/02Z sfc winds mainly 8 kts or less again thru
end of valid period.

&&

.FIRE WEATHER...Dry and hot weather will prevail through Monday.
Temperatures continue to rise and peak at 8 to 14 degrees above
normal Wednesday and Thursday. A very low grade monsoon pattern
returns starting Tuesday initially along the International Border
and then gradually expands to the rest of southeast Arizona.
However, that will only result in slight (10-20%) chances through
Friday for most locales before a possible uptick in storms next
weekend. Min RH values around 8 to 15 percent through Thursday then
15 to 25 percent starting Friday.

&&


.CLIMATE...All-time August record highs including date and
forecast highs for Wednesday and Thursday.
                                             WED FCST   THU FCST
Ajo                 118 on August 28, 2023     116         115
Organ Pipe Cactus   116 on August  5, 1995     116         113
Picacho Peak        114 on August 28, 1998     112         112
Tucson Intl airport 112 on August  1, 1993     112         112
Safford (town)      110 on August 16, 2024     110         110
Willcox             108 on August  1, 2020     106         105
Nogales (town)      107 on August  5, 2023     105         104
Douglas airport     106 on August  5, 2023     105         104
Sierra Vista        105 on August  6, 2023     103         102

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM MST Friday for AZZ501>507-509.

Extreme Heat Warning from 10 AM Tuesday to 8 PM MST Friday for
AZZ508.


&&

$$


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