921
FXUS65 KTWC 102108
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
Issued by National Weather Service Phoenix AZ
208 PM MST Mon Aug 10 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
be much less Friday into the weekend. High temperatures will be
near normal today and Tuesday with additional lowering to around
3 to 6 degrees below normal Wednesday and Thursday before
temperatures warm again into the weekend.

&&

.DISCUSSION...
As of 2 PM, thunderstorms are beginning to initiate in the
expected areas in the White and Chirichua Mountains. Activity is
expected to increase in coverage and intensity this afternoon
and evening. The multi-hazard impacts of severe winds and flash
flooding are still on track.

Looking to tomorrow, there can be another day of multi-hazard
impacts of severe wind and flash flooding. For the strong to
severe winds, the latest 11/15Z U of A WRF HRRR (usually the
most bullish of the models) is showing the potential for a line
of thunderstorms forming forming from initial activity the
Huachucha Mountains/Santa Cruz County moving northwest towards
the Tucson Metro into Central Pima and Pinal Counties. This is
the reasonable worst case scenario, with the more likely
scenario being thunderstorms being strong to severe but more
scattered in nature, not in a formal line. The 11/12Z HREF is
showing a 10% probability of 50 kts within 40 km in mainly
Cochise County with this run. I wouldn`t be surprised if future
HREF runs spreads this contour westward as it accounts for the
HRRR`s latest runs that are latching onto more activity and
stronger outflow winds. Moisture from the west and south moves
back into the eastern valleys, allowing for more of a flash
flood threat for areas Tucson eastward. The 11/12Z HREF is
highlighting these areas for 3 hour probabilities of storm
totals between 1-2 inches, with a localized threat for 3 inches.

The elevated monsoonal pattern continues into Thursday this week
with day to day variability. With the high pressure staying in
the four corners region, the easterly flow aloft will keep the
ability for the afternoon/early evening activity to move out of
the area and allow for the atmosphere to recharge each night.
The only caveat to this would be any overnight convection that
could hamper and/or shut down the activity for the next day.

On the bright side, the increased thunderstorm activity will
`cool` high temperatures, especially Tuesday through Thursday.
Temperatures begin to warm up Friday into early next week.

&&

.AVIATION...Valid through 12/00Z.
Now thru 11/06z, SCT -SHRA/-TSRA with clouds 8-12k ft AGL.
Isold vsbys 1SM +TSRA. Gusty erratic winds of 35-50 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. Aft 11/06z, ISOLD -SHRA mainly W of KTUS
diminishing. Lower cloud decks also diminishing. SFC winds light
and terrain driven after 11/06Z. Additional SHRA/TSRA chances
aft 11/18Z thru the end of the period. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...
Expect daily afternoon and evening showers and thunderstorms
through Thursday with less coverage Friday into next 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 2 PM MST this afternoon through this evening
for AZZ501>506-514-515.

Flood Watch from 2 PM MST Tuesday through 11 PM MST Tuesday for
AZZ503-504-507>509-511>514.

&&

$$

JT

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