028
FXUS65 KTWC 051738
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
1038 AM MST Sat Jul 5 2025

.SYNOPSIS...Expect isolated to scattered storm coverage focused
on locales south and southwest of Tucson. Temperatures will warm
back up to above normal levels this weekend with the potential for
extreme heat to return to Southeast Arizona by the middle of next
week.

&&

.DISCUSSION...The following day in the wake of the all of those
exciting pops, crackles and thick smoke from spent fireworks can
sometimes be disorienting. Trying to make sense of your surroundings.
Trying to make sense of what changed. Today is one of those days.

Case in point, the latest satellite imagery indicated a long
plume of mid-level clouds with a few embedded very weak showers
extending in a SW/NE orientation from the shearing mid-to-upper
remnants of Flossie in the Eastern Pacific into SE Pinal and
Graham counties. Second, we have seen a surge of deeper lower
level moisture filter into the lower deserts of SW Arizona from
the Gulf of Mexico. You can see this moisture increase on the
latest GOES TPW imagery, which indicates PWAT values of 1.50+
inches across Pima, southwest Pinal and western portions of Santa
Cruz county this morning. Higher values between 1.50-1.75 inches
are observed near the aforementioned mid-level plume from Flossie.
This is a nice reinforcement of surface moisture across the
region, as dewpoints this morning range from the mid 60s from
Tucson west, and lower to mid 50s to the east.

The upper pattern this morning is defined by a high pressure at
500 mb high extending across Sonora Mexico into New Mexico with
two high centers over central Sonora and southwest NM. Southeast
Arizona resides in a weak col between these two centers which may
aid convection across our neck of the woods today, but won`t
assist convective initiation. Taking stock of the local environment,
we may have to do things the old-fashoned way for storms today,
relying on the moisture that is available. I would expect to see
isolated to scattered thunderstorms develop early this afternoon
along and near the 850-700 mb Theta-E ridge which has aligned
itself along a line extending from southwest Cochise into Santa
Cruz and over into the central portions of the Tohono O`odham
Nation. The deeper moisture will provide the source for localized
heavy rainfall again today. The HREF isn`t as excited for heavy
rain as it was yesterday, but there is still a 10-30% chance
rainfall will exceed 1 inch withing a 40 km distance of a point
in the aforementioned favored location. The best threat for strong
winds will be across the northern extent of this area...closer to
the drier air (mainly the northern Tohono O`odham Nation and
southwest portions of Pinal county) where the SPC Mesoscale
Analysis indicated DCAPES around 1200-1500 J/kg.

Sunday, there isn`t too much change in the upper high across the
region. The surface moisture that surged into lower deserts will
have another day to mix eastward shifting the Theta-E ridge east.
A slight tilting in the orientation of the upper high from SW-NE
to WSW-ENE may provide enough deformation aloft to focus thunderstorm
coverage back to the east, with isolated to scattered thunderstorms
mainly across Cochise county/SE of Tucson Sunday.

We begin to see some movement in the upper high at both 500 mb and
300 mb toward the NNW and over central Arizona by Wednesday. This
will allow for temperatures to rise the first half of the week,
with the possibility of extreme heat returning by Wednesday. In
fact, the 05/15Z NBM probabilities of reaching 110+ degrees at
KTUS is 25% Tuesday, 62% Wednesday and back down to 25% Thursday.
This will likely be the big story this week with increasing
confidence in this to occur.

The upper high will begin to break down late next week with it
shifting west then back toward northern Arizona by next weekend.
This motion will open up Southeast Arizona to a more favorable
diffluent flow aloft and an uptick int thunderstorm coverage and
activity.

&&

.AVIATION...Valid through 06/18Z. SCT 7-12k ft AGL SCT-BKN 10-14k
ft AGL thru 05/21Z...then SCT-BKN 7-12k ft AGL aft 21Z. Isold-SCT
-SHRA/-TSRA mainly S/SW of KTUS thru 04/04Z with CIGS BKN 5-8k ft
AGL and gusty outflow winds up to 40 kts. Surface winds generally
WLY 8-13 kts, becoming SLY less than 10 kts overnight. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms this afternoon into this evening mainly south and
southwest of Tucson. A decrease in thunderstorm activity is
expected Sunday into next week as the area transitions into a low
grade monsoon pattern. An eventual uptick in monsoon activity is
possible the middle of next week but will be dependent on how
quick the high pressure aloft shifts north. Temperatures heating
up this weekend into next week with the potential for very hot
temperatures to return the middle of next 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...None.

&&

$$

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