Heat in Arizona, August 7 to 10, 2023

Area Forecast Discussion
National Weather Service Tucson AZ
921 AM MST Mon Aug 7 2023

.SYNOPSIS...Somewhat more typical monsoon weather is expected this
week with temperatures running closer to normal with scattered
afternoon and evening thunderstorms across much of southeast
Arizona.

&&

.DISCUSSION...The 12z 500 mb chart placed the center of a strong
high over the Texas Big Bend with southwest flow aloft over the
area. Mid-level temperatures have also cooled in the past 24
hours, to -4 to -5 C versus -2C. PW values are significantly
higher versus 24 hours ago also with values mostly ranging from 1"
to 1.6" with localized areas up to 1.8". 16z infrared satellite
imagery showed partly to mostly cloudy conditions across eastern
half of the forecast areas with radar showing a few light showers
or virga.

Today will be a bit more active with localized severe storms and
heavy rainers this afternoon and evening, mostly east of a
Safford to Tucson to Nogales line with a focus on Cochise county.
Latest HRRR hinting at outflows pushing north from evening
Sororan storms keeping chance of elevated storms into the
overnight hours.

Oh, and this is nice to say. Highs today will be COOLER versus
Sunday by 3 to 7 degrees depending on location, but still running
several degrees above normal.

&&

.AVIATION...Valid through 08/12Z.
Afternoon -SHRA/-TSRA are possible for the whole forecast area. Sfc
winds around -SHRA/TSRA are possible at producing FEW-SCT Clouds vAOA
10-15k and SCT-BKN AOA 20k AGL for areas south and east of Tucson
thru 07/13Z and again from 08/0Z thru the end of the period.
Otherwise SKC conditions. Sfc winds NW-WLY 10-15 kts gusting up to
25kts from 07/21Z thru 08/03Z, otherwise follow diurnal trends and
generally remain under 10 kts. Aviation discussion not updated for
TAF amendments.

&&

.FIRE WEATHER...Daily rounds of showers and thunderstorms each
afternoon through the weekend. Any storms that do form are capable
of producing erratic and gusty outflows. Daytime temperatures remain
a few degrees above normal before increasing next weekend. Minimum
RH in the lower elevations range from 20-35% and 40-50% in the higher
elevations today and decreasing to 10-20% and 20-30% by the weekend.

&&

.CLIMATE...The consecutive day streak of highs 100 degrees or
hotter in Tucson stands at 52 days. The probabilities each day
this week of NOT hitting 100 degrees is less than 10%.

&&

.PREV DISCUSSION...The upper level high that has dominated our
weather with very hot temperatures continues to weaken a bit and
drift east. The southerly flow that developed over the area
continues to advect moisture into Arizona with PWs on the rise.
The result of these changes will be cooler, closer to normal,
temperatures and scattered afternoon and evening showers and
thunderstorms through the work week. As is typical in this
scenario, the convective potential each day will partly depend on
the previous day/evenings convection.

Next weekend an upper low is forecast to develop just off the
California coast and will play a roll in the amount of storm
coverage we will have. If the flow overhead becoming more
southwesterly then there will be gradual drying and a decrease in
storm coverage.

Then the early part of the following week we could see a more
pronounced warming and drying trend once again. Plenty of time to
see how that may or may not unfold.

&&

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

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