Severe Thunderstorm Warning 147, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
116 PM MST Sun Aug 9 2026

.SYNOPSIS...Expect daily chances of showers and thunderstorms
much of this week. While there will be day to day variability,
Monday and Wednesday look to be the most active days. Storm coverage
will Friday through next weekend. High temperatures this afternoon
will run 5 to 8 degrees above normal, lowering to near normal Monday
and Tuesday with additional lowering to around 3 to 6 degrees below
normal Wednesday and Thursday before temperatures warm again.

&&

.DISCUSSION...Visible satellite imagery shows cumulus cloud
development this afternoon across the higher terrain of southeast
Arizona. The area is under easterly flow aloft with mid/upper level
high near the Four Corners. Still plenty of moisture for much of
southeast Arizona with PWAT around 1 to 1.5 inches, highest values
west. Cochise County PWAT is a bit lower in the 0.7 to 0.9 inch
range and that area will struggle most with convection this
afternoon into evening. CAMs are showing two primary areas of storms
developing this afternoon, the first being south to southwest of
Tucson close to the Int'l border and another area moving off the
White Mountains with storm movement today towards the west. Given
the ample surface heating, elevated DCAPE values will support gusty
winds in excess of 50 mph with the strongest storms. In fact, the
HREF has an area of 10% 40-km neighborhood probability of 50 kts
from Tucson westward with a smaller area of 30 percent over central
and western Pima County. These strong winds will also result in
areas of blowing dust due to strong outflows. In addition to the
gusty winds, a few storms may cluster west of Tucson resulting in
isolated flash flooding potential into the evening hours.

Monday is shaping up to be a bit more active than today as easterly
flow aloft continues with PWAT values ticking up slightly compared
to today and modest mid/upper level support for storms. This will
result in another round of showers and thunderstorms for most of
southeast Arizona, with the highest chances from Tucson westward.
WPC has highlighted the area in a SLGT risk of excessive rainfall
and that looks good. HREF has a widespread area of greater than 50%
40-km neighborhood probability of 3-hr QPF of 1 inch or greater.
While there is still some uncertainty on storm mode for Monday, and
whether storms stay more discrete or become more clustered resulting
in heavier rain potential especially into the evening, felt it was
prudent to highlight the potential for heavy rain by hoisting a
Flash Flood Watch from Tucson area westward from 2 PM to 10 PM. In
addition to the flash flood threat, severe winds will also be a
threat with considerable DCAPE and even around 20-30 kts of 0-6km
bulk shear brining the potential for small hail as well. Given the
wind potential, added in areas of blowing dust north and west of
Tucson into the forecast.

The active pattern will persist Tuesday and Wednesday with Wednesday
still looking like a more active day as a disturbance in northern
Sonora may help aid storm development then. Thereafter, as southwest
flow moves in starting Thursday, that will shift storm chances from
about the Tucson area eastward Thursday, then generally near the NM
border Friday through next weekend with most of SE Arizona remaining
dry those days.

Temperatures will lower to near normal levels Monday and Tuesday,
then to about 3 to 6 degrees below normal Wednesday and Thursday,
with warming thereafter to above normal values for next weekend.

&&

.AVIATION...Valid thru 11/00Z.
ISOLD-WDLY SCTD -SHRA/-TSRA with clouds 8-12k ft AGL, mainly west of
a KSAD-KOLS line into this evening and then again Monday afternoon
for much of SE Arizona. Gusty erratic winds of 35-45 kts possible
with any thunderstorm. Outside of storms SFC winds WLY/NWLY at 8-12
kts with occasional afternoon gusts to 20 kts this afternoon and
evening. SFC winds light and terrain driven after 10/06Z thru 10/18Z
with WLY/NWLY winds resuming thereafter. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Expect daily afternoon and evening showers and
thunderstorms through Thursday with less coverage Friday into n ext
weekend. Minimum relative humidity will be 20-40 percent Monday
through Thursday lowering to around 15-30 percent thereafter.
Temperatures will be near normal through Tuesday, dropping to below
normal Wednesday and Thursday, then warming again next weekend.
Outside of thunderstorms, winds terrain driven to around 10 mph with
occasional afternoon gusts to 20 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Monday afternoon through Monday evening for
AZZ501>506-514-515.

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