281
FXUS65 KTWC 061658
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
958 AM MST Sun Jul 6 2025

.SYNOPSIS...Expect scattered storm coverage today focused on
locales generally south and southeast of Tucson. The main hazard
from the storms today will be their capability to produce strong
gusty outflow winds, but locally heavy rain. Otherwise, temperatures
will be above normal this week with the potential for extreme
heat to return to Southeast Arizona by the middle of the week.

&&

.DISCUSSION...It is a seemingly pleasant and quiet start to Sunday
morning across Southeast Arizona as the latest satellite imagery
indicated generally sunny skies across the forecast area. The
upper pattern is defined by an upper high extending across Sonora
Mexico into southern New Mexico. The 500 mb high center shifts
ever-so-sligtly into western Sonora this afternoon, resulting in a
very weak diffluent flow across Santa Cruz and Cochise counties
this afternoon. This very subtle shift this time of year are the
factors that help define and assist convective initiation. The
deeper moisture that was in place yesterday has shifted west, with
the latest GOES TPW imagery indicating 1.25-1.40 inches across
western Pima county, around an inch near the Tucson Metro Area,
and lower values of 0.90-1.00 inch across Cochise/Graham and
Greenlee counties. Given the lower atmosphere moisture, the
06/12Z HREF members are suggesting the majority of the storms
today will be across Santa Cruz into Cochise county with a 10-30%
chance for 3-hr ensemble probability matched mean values (40-km
neighborhood probability) exceeding an inch confined to Santa
Cruz/SW half of Cochise counties. The drier air does bring back
the potential for evaporating downdrafts resulting in strong
outflow winds with around a 50 percent chance that outflows will
exceed 30kts this afternoon across the same area.

As mentioned in the previous forecast discussion...the main theme
this week will be an expanding strong ridge of high pressure aloft
over the state resulting in very hot, near record high temperatures
mid-week and a low grade monsoon pattern. The high centers continue
to drift north the next few days, resulting in stacked mid and
high level highs Wednesday. not much variation in 06/14Z NBM
ensemble members Wednesday with only a 2 degree variation (110-112
degrees) between the 25th-75th percentile at KTUS. The overall
probability of exceeding 110 degrees at KTUS is 8% Tuesday, 75%
Wednesday and back down to a 17% Thursday. Solid confidence in the
Extreme Heat Watch in effect for Pima, SE Pinal and Graham
counties Wednesday.

We will see the upper high shift the second half of the week into
the weekend resulting in a general uptick in thunderstorm coverage,
especially across the eastern half of our forecast area. The 500
mb high center is now progged to shift into southern California by
Saturday and sit there for a while. This location will allow for
a more diffluent upper flow across the eastern zones driving
storms that develop in the Whites and along the AZ/NM border SSW
into northern Sonora. Its not a favored location for the more
active rim-shot pattern for storms to drive SW into Tucson, but I
suspect that large day-to-day thunderstorm complexes will develop
in Sonora, reinforcing the surface moisture back into Southeast
Arizona with their outflows and eventually having a hand in
nudging the upper high centers back toward northern Arizona.

Until then, expect a low-grade Monsoon pattern to persist with
afternoon high-temperatures moving into the very hot/record high
temperature range Wednesday.

&&

.AVIATION...Valid through 07/18Z. SKC to FEW 10-12k ft AGL thru
06/19Z then SCT-BKN 7-12k ft AGL with ISOLD-SCT -SHRA/-TSRA mainly
S/SE of KTUS thru 07/04Z with CIGS BKN 5-8k ft AGL and gusty
outflow winds up to 45 kts. Surface winds generally WLY 8-13 kts,
becoming SLY less than 10 kts overnight. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Although Southeast Arizona will be experiencing a
low-grade monsoon pattern the first half of the week, isolated to
low-end scattered thunderstorm coverage is expected to the south
and southeast of Tucson for the next several days. The main threat
for storms will be the potential for strong gusty and erratic
outflow winds. Otherwise, an eventual uptick in monsoon activity
is possible the second half of the week into next weekend as the
upper high shifts to a more favorable location aloft. Temperatures
will be above normal this week with hottest temperatures mid-week.
Winds generally light and under 15 mph with the exception of
gusty and erratic winds up to 35-45 mph near any thunderstorms.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...

Extreme Heat Watch from Wednesday morning through Wednesday
evening for AZZ501-502-504>506-509.

&&

$$

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