Heat in Arizona, September 2, 2022

Area Forecast Discussion
National Weather Service Tucson AZ
959 AM MST Fri Sep 2 2022

.SYNOPSIS...Temperatures will remain near to a bit above average
into the middle of next week with a breezy east wind at times.
Isolated to scattered thunderstorms are possible the next few
afternoons as storms develop over the Rim country and move southwest.
An increase in moisture and better storm chances are possible next
week.

&&

.DISCUSSION...Latest mid/upper level pattern places the anomalously
strong subtropical high over the Great Basin with southeast Arizona
under east to northeasterly flow aloft. The pattern is quite
favorable today for Mogollon Rim storms to propagate southwestward
into valley locations. Moisture values are once again a bit on the
marginal side but just enough for some increased storm coverage
compared to the past few days. CAMs are in good agreement that a
broken line of storms will develop across the Mogollon Rim/White
Mountains in the early afternoon and push SW. Latest SPC Day 1
outlook places a slight risk mainly just to the north and west of
our CWA with much of the western 2/3rds of our forecast area in a
marginal risk of severe thunderstorms. Main concern is strong gusty
winds with DCAPE values in excess of 1500 J/KG. With the HREF
showing >50 pct probabilities of winds in excess of 30 kts to the
north and west of Tucson, blowing dust from outflow winds will also
be a concern late this afternoon into the evening. In coordination
with WFO Phoenix, we went ahead and hoisted a blowing dust advisory
for portions of Pinal County, the T.O. Nation and Western Pima
County from 4 pm through 10 pm. It does look like the Tucson Metro
will be on the southern fringes of the activity with gusty outflow
winds the main concern. PoPs remain fairly low given the anticipated
broken line of storms and quick movement. Separately, a few storms
are possible right along the International border this afternoon.
Remainder of forecast remains unchanged. See previous discussion
below for additional information.

&&

.AVIATION...Valid through 03/12Z.
SKC-SCT clouds above 10k ft MSL. ISOLD to SCT -SHRA/-TSRA btwn
02/21z and 03/06z with storms dvlpg over higher trrn and
propagating to the SW. Wind gusts near any -TSRA could exceed 40
kts otherwise expect east winds 10 to 15 kts. Aviation not
updated for TAF amendments.

&&

.FIRE WEATHER...A chance of storms developing off the Rim and
drifting SW into this evening. A slight chance of storms this
weekend. Primary threats will be strong gusty winds and lightning
as storms will move fast enough to avoid prolonged heavier rains.
There is potential for an increase in moisture areawide next week
for more shower and thunderstorm activity.

&&

.PREV DISCUSSION...Thursday evening upper air chart placed center of
500 mb high over NV with E/NE flow over the forecast area. Last
night a line of thunderstorms developed in central Gila county and
marched there way SW between Phoenix and Marana before dissipating
across southwestern deserts earlier this morning. There is the
possibility that we may see a repeat of that again late this
afternoon into this evening but a little further south and east with
storms develop on the rim and propagate to the SW. SPC has Pinal and
most of Pima county under marginal risk for severe storms today with
00z HREF showing a 10-30% chance of wind gusts >50kts across Pinal
county this evening. Kept patchy blowing dust in the forecast mainly
NW-W of Tucson.

This weekend: The strength of the upper high will keep deeper
tropical moisture from 11E bottled up to our south. Still linger
moisture around for a few storms both days, especially across the
Whites and along the International border.

Next week: Plenty of uncertainty with respects to a potential
inverted trof impacting the area early in the new week and then the
threat of increase moisture later in the week from the tropics. I
didn't make any changes to the recommended initialization next week
due to the uncertainty. Confidence low.

High temperatures will remain on the warm side for early September.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...Blowing Dust Advisory from 4 PM
this afternoon to 10 PM MST this evening for AZZ501-502-505.

&&

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