Heat in Arizona, August 29 to 30, 2022

Area Forecast Discussion
National Weather Service Tucson AZ
923 AM MST Mon Aug 29 2022

.SYNOPSIS...As high pressure strengthens north of the area, we'll
see hotter afternoons the first half of the week. Some drying as
well with fewer storms as a result. We'll see a day or two where
storm chances pick up again, but overall storm coverage should be
down this week compared to recent weeks.

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.DISCUSSION...Current forecast looked on track so no updates
necessary this morning. Please refer to the previous discussion in
this product for more details.

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.AVIATION...Valid through 30/12Z.
Mostly clear this morning. Isolated SHRA/TSRA developing after
29/19Z with SCT-BKN 110-150 associated with storms. Clearing again
after 30/03Z. Strong gusty outflows with thunderstorms, otherwise
normal diurnal wind trends generally less than 10 kts. Aviation
not updated for TAF amendments.

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.FIRE WEATHER...Fewer storms around to start the week as we see a
drying trend (with eastern areas seeing the most drying). Primary
threats will be strong winds and lightning with heavy rainfall on
a smaller scale compared to recent weeks. Outside of thunderstorm
activity, wind trends will remain light and favor a west to
northwest direction early in the week, with an easterly flow
that's breezy at times beginning Wednesday afternoon.

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.PREV DISCUSSION.../Issued at 255 AM MST Mon Aug 29/
A broad westerly to northwesterly flow has developed as expected,
with the flow reversal shutting off access to deeper moisture pools.
Boundary layer moisture will try to recycle again today but is
getting shallower and we will probably see some modest dewpoint
cratering this afternoon. Precipitable water values will struggle to
keep up with seasonal climatology, with 1 to 1.1 inches east to 1.4
inches west. Not many storms expected for today with any buildups
likely restricted to sky islands, and poor support for valleys.

With a more amplified pattern building, the resulting strong ridge
through much of the west will push temperatures up several degrees
over the next few days; likely around 3 to 6 degrees above climo for
most of our area.

As the high center reconsolidates over the Great Basin to our
northwest, the resulting storm level flow will veer
northeasterly/easterly, which sets up an interesting scenario as
early as Tuesday afternoon. As previously discussed, the upstream
flow around the high would continue to tend to erode moisture on its
own, however this pattern will also open us back up to easterly wave
activity. One such feature will try to build across northern
Chihuahua and Sonora this week, and if we have enough moisture to
fire storms off the Mogollon Rim, the resulting organized outflows
would propagate into a more favorable valley moisture regime as they
push toward the west and southwest. With uncertainty about available
moisture, it's a tough thing to hang your hat on. We could even see
a scenario where we see a modest moisture return from the south
through the lower deserts while our eastern areas get a little too
dry to support valley storm propagation. The result would be that
both Sonora and western Arizona could end up with an overall busier
pattern than SE AZ.

Best guess continues to be that at least part of our area will pick
back up after Tuesday or Wednesday. Either way, our focus will begin
to shift away from widespread heavy rain potential to a late season
emphasis on fewer but sometimes stronger storms.

Finally, keep an eye on the tropics. 'Tis the season for average
origination points a little further north for eastern Pacific storms.

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