Severe Thunderstorm Warning 111, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
327 PM MST Sat Aug 6 2022

.SYNOPSIS...A more favorable flow pattern for daily thunderstorms
will develop Sunday and persist through this coming week as the
upper high becomes centered over the Four Corners region. Daytime
temperature will remain near seasonable readings.

&&

.DISCUSSION...The upper-pattern is defined by a high pressure area
centered over NW Kansas with a ridge axis extending to the southwest
into SW Arizona...and an impressive inverted trough (as evidenced
with a beautiful swirl on the Water Vapor Satellite imagery) over
western portions of Texas.

Today/tonight is a transition day as the upper ridge axis continues
to lift north...allowing for the inverted trough to move west toward
SE Arizona. Although confidence is moderately high that Sunday will
be an active day across the entire forecast area, sometimes the
transition days can sneak up on us with stronger storms than
expected. In this case, the nose of the inverted trough doesn't
really begin to impact our neck of the woods until late this
evening/overnight...out of phase with peak surface
heating. I wouldn't be surprised to see a few storms get a bit frisky
this evening along the Arizona/Mexico border but confidence
is low with the coverage and intensity of the storms this
afternoon/tonight. It may be a situation that the majority
of the storm activity occurs after midnight with the increased
instability aloft.

The more favorable location tonight will be further south in Sonora
Mexico where a large complex is expected to develop. This system
will be important because it will help initiate a surge of
moisture to quickly move northward up the Gulf of California and
spill into the lower deserts of Arizona Sunday morning giving us a
key ingredient for heavy rainfall Sunday across the western
portions of the forecast area.

The inverted trough eventually moves into Southeast Arizona Sunday
afternoon...and is looking to be quite impactful for the region. The
dynamics associated with this feature, along with stronger shear and
the overall increase of surface moisture will result in enhanced
thunderstorm activity across all of Southeast Arizona, with a more
elevated potential for severe thunderstorms and/or flash flooding
over the typical Monsoon day.

The 12z SPC HREF (High Resolution Ensemble Forecast) has latched
onto a strong solution for our neck of the woods with a sustained
potential for wind gusts in excess of 50 kts from Tucson west Sunday
evening. This helps increase my confidence that we will experience
widespread blowing dust issues across Pima and Southeast Pinal
counties...including the potential for a Haboob formation.

In addition to the wind and blowing dust threat, the 12z SPC HREF 24
hour QPF LPMM or localized probability matched mean for 24 hour QPF
amounts indicated a large area between 1 and 2 inches of
rainfall tomorrow across Santa Cruz and Pima county. Given the
saturated soils across the area, this makes the potential
for flash flooding much greater. Ina ny event, tomorrow will be an
active and busy day.

Otherwise, rain chances will continue to be elevated this coming
week as a more favorable flow pattern develops with the upper high
becoming centered over the Four Corners region. Daytime temperatures
will remain near seasonable readings after today.

&&

.AVIATION...Valid through 08/00Z.
SCT-BKN clouds at 7k-10k ft AGL, with the clouds slowing diminishing
after midnight MST. SCTD SHRA/TSRA primarily between 06/23Z and
07/05Z. CIGS may briefly lower to 4k-6k ft AGL with the TSRA, along
with mountain obscurations and wind gusts to 40+ kts. Otherwise, SFC
wind generally less than 12 kts, favoring a NWLY/NLY direction
during the afternoon hours and variable in direction at other times.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...An active monsoon period is expected to continue
through the coming week, with daily rounds of scattered showers
and thunderstorms. The typical threats of strong gusty winds and
heavy rainfall remain, as well as the potential for precipitation
outside the normal afternoon/evening cycles. Wind trends are
otherwise light following a diurnal pattern.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson