224
FXUS65 KTWC 011615
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
915 AM MST Fri Aug 1 2025

.SYNOPSIS...A drying trend with continued above normal
temperatures through this weekend. Still enough moisture for
isolated thunderstorms from Sells eastward today, then south and
east of Tucson Saturday with dry air overtaking all of southeast
Arizona Sunday. Thereafter, below normal monsoonal activity is
expected next week. Extreme heat will continue through the weekend
and perhaps continuing through much of next week as temperatures
remain well above normal.

&&

.UPDATE...Abundant sunshine this morning with high temperatures
slightly warmer than yesterday. Extreme Heat Warning goes into
effect at 10 am and lasts through Sunday. Moisture on the limited
side with PWATs in the 0.90" to 1.10" range with isolated spots
up to 1.30" per GOES. Isolated to widely scattered thunderstorms
this afternoon/evening with brief heavy rain and gusts up to 40
mph from the strongest storms. Forecast for today looks in great
shape.

&&

.KEY MESSAGES...
-A low grade monsoon pattern into the weekend with just isolated
showers and thunderstorms mainly from Sells eastward today and then
south and east of Tucson Saturday with dry conditions areawide
Sunday. Below normal monsoonal thunderstorm activity is expected
next week.

-Extreme heat is expected through the weekend with high temperatures
6 to 10 degrees above normal. Above normal temperatures continue
next week with increasing likelihood of continued extreme heat,
especially around next Wednesday and Thursday.

&&

.DISCUSSION...After a somewhat more active day yesterday and last
night, we`re transitioning right back into a low grade monsoon
pattern today. The mid/upper level high will be settling back in
over southern Arizona which is not a favorable position for storms
due to subsidence aloft. However, there is still quite a bit of
lower level moisture recycling underneath which will be enough for
isolated showers and thunderstorms this afternoon into this evening.
These storms won`t be particularly strong or well organized but can
result in brief heavy rain and gusty winds. The activity will mainly
be from Sells eastward with more of a focus on the higher terrain
and a few storms over the valleys. As drier air continues to move in
from the west on Saturday that will shunt isolated thunderstorms to
locales mainly south and east of Tucson. With the high still over
the area Sunday and lower to mid level flow becoming west to
northwest, even drier air will overspread the region with any
thunderstorms south of the Int`l border. An Extreme Heat Warning is
in effect today through the weekend for much of the area with highs
6 to 10 degrees above normal. HeatRisk values are marginal today but
will continue the heat headline as is for continuity.

Next week is shaping up to be another hot week. Ensembles are in
good agreement in briefly nudging a strengthening high aloft to our
east early next week. This could open the door for a bit of a
moisture push by Monday and Tuesday for low grade/slight chances of
thunderstorm activity through midweek. The 500mb high will then
nudge west to near the AZ/NM border and continue to strengthen,
peaking Thursday with heights near 6000 meters. This is quite
anomalous at 3 to 4 standard deviations above normal. It`s becoming
increasingly likely later shifts will need to hoist more heat
headlines especially mid to late next week. The main uncertainty for
the time period between the heat this weekend and the heat mid to
late next week is the potential for a bit of moisture early next
week that could keep temperatures slightly lower than currently
forecast. The current forecast high is 110 degrees in Tucson next
Thursday. The all time high for August in Tucson is 112 degrees
(1993) and locally used heights/thickness regressions indicate this
could be in jeopardy next Thursday so we`ll be keeping a close eye
on the trends with the mid/upper high placement and strength.

&&

.AVIATION...Valid through 02/12Z.
SKC-FEW clouds 10-15k ft AGL thru 01/18Z, then SCT clouds 8-12k
ft AGL with isold -SHRA/-TSRA thru 02/03Z. Skies then clearing
thereafter thru the end of the valid period. Winds generally below
12 kts away from thunderstorm activity, with occasional afternoon
gusts to 20 kts. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Isolated thunderstorms this afternoon into this
evening, then drying this weekend with slight chances of showers
and thunderstorms mainly south and east of Tucson Saturday with
dry conditions areawide Sunday. Overall winds are expected to
remain under 15 mph with occasional afternoon gustiness, however
strong erratic winds are possible with any thunderstorm. Hot
temperatures will continue into next week with a low grade monsoon
pattern early next week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM MST Sunday for AZZ501>507-509-515.

&&

$$

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