Severe Thunderstorm Warning 46, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
202 PM MST Fri Jul 28 2023

.SYNOPSIS...
An excessive heat warning remains in effect across portions of
the region through this evening. Isolated to scattered mainly
afternoon and evening showers and thunderstorms today, then an
increase in moisture this weekend into early next week should
result in cooler afternoon temperatures and more numerous and
wetter showers and thunderstorms.

&&

.DISCUSSION...
Another excessively hot day across many of the lower deserts today
with the strong upper ridge centered over western New Mexico. As
of this writing, the majority of the convective activity remains
over the Mogollon Rim and toward Mount Graham. This activity
should slowly start to shift southwestward as convection becomes
more outflow dominant. We are also expecting activity to start up
near Santa Cruz County in the next few hours. With the west to
southwest flow in place, we could see another day of convective
activity impacting the Tucson metro around and after sunset.

We continue to track a tropical wave currently evident on
satellite imagery in the western Gulf of Mexico. The forecast is
for this wave to track west across Mexico, round the base of the
upper ridge, and eventually track northward across western Arizona
early next week. At the very least, this system should bring about
increased shower/thunderstorm coverage and modestly cooler
temperatures. The best potential for more widespread thunderstorms
appears to be Sunday, but everyday Saturday through Monday should
resemble more closely to what we would normally expect this time
of year with respect to thunderstorm activity.

Atmospheric moisture decreases in the wake of the easterly wave.
While daily chances of thunderstorms will persist, the coverage
won't be as high as it will be over the weekend.

&&

.AVIATION...valid through 29/12Z.
SCT-BKN mid and high-level clouds developing this afternoon.
Isolated to scattered SHRA/TSRA are expected potentially
impacting KTUS, KDUG, and KOLS through 29/06Z. Gusty outflow winds
to 40+ kts along with VSBY reductions to 3SM or less are possible
with TSRA. Outside of thunderstorm outflows, afternoon SFC winds
will be NWLY around 15 kts. Aviation discussion not updated for
TAF amendments.

&&

.FIRE WEATHER...
Isolated to scattered afternoon and evening showers and
thunderstorms are expected across portions of southeast Arizona
this afternoon before an increase in coverage and rainfall
potential is expected this weekend. Storms will be capable of
producing strong, gusty and erratic outflow winds of 45 mph or
more. Although sustained 20-foot winds will generally be less than
15 mph today, afternoon gusts to around 25 mph may occur. Much
above normal temperatures are expected again today with high
temperatures lowering a few degrees over the weekend and into the
middle of next week. Valley min RH readings will generally range
between 15-25% today and Saturday, then 20-30% for Monday and
Tuesday before drying out to 15-25% on Wednesday and 10-20% for
Thursday and Friday.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 10 PM MST this evening for
AZZ504>506-509.

&&

Public...Dang
Aviation...Dang
Fire Weather....Dang

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Special Weather Statement
National Weather Service Tucson AZ
334 PM MST Fri Jul 28 2023

AZZ506-507-509-511-282300-
Upper Gila River and Aravaipa Valleys including
Clifton/Safford-Southeast Pinal County including
Kearny/Mammoth/Oracle-Upper San Pedro River Valley including Sierra
Vista/Benson-Galiuro and Pinaleno Mountains including Mount Graham-
334 PM MST Fri Jul 28 2023

...A strong thunderstorm will impact portions of west central Graham
and east central Pinal Counties through 400 PM MST...

At 333 PM MST, Doppler radar was tracking a strong thunderstorm 9
miles southeast of Aravaipa Canyon Wilderness, or 15 miles east of
Mammoth, moving northwest at 20 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Aravaipa Canyon Wilderness and Klondyke.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3280 11022 3264 11044 3294 11072 3314 11046
TIME...MOT...LOC 2233Z 134DEG 19KT 3281 11040

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

KGD