Severe Thunderstorm Warning 91, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
1010 AM MST Sun Sep 1 2019

.SYNOPSIS...Happy first day of meteorological fall. The favorable
weather pattern for daily afternoon and evening thunderstorms
will remain in place through at least the middle of the upcoming
week. Expect temperatures to remain above average through the
week.

&&

.DISCUSSION...On this first morning of meteorological Fall,
infrared and visible satellite imagery showed mostly clear
conditions across southern Arizona. Further south thunderstorms
were developing across central Baja while a thunderstorm complex
was weakening across the southern Gulf of CA. These were
associated with an inverted trof moving through that area. Closer
to home the 12z upper air charts placed the upper high near the
four corners with favorable easterly flow over the area. In fact
the 12z Tucson sounding showed rather brisk 15-25 kt mid-level
steering flow. PWAT values this morning ranged from 0.70" across
the White mountains to 1.3" over Tucson to 1.6" across western
Pima county.

Latest CAM runs indicate two areas of concern today. One being
across central/western Pima county where models show increasing
upper level divergence this afternoon. With PWAT values over 1.5"
wet microbursts are likely. The second area of concern this
afternoon into this evening is from Tucson north as thunderstorms
move off the higher terrain. Outside of the severe potential,
with SPC having the most of the area under marginal to slight
risk, strong outflows will produce areas of blowing dust mainly
west and northwest of Tucson. Highs today similar to yesterday.

&&

.AVIATION...Valid through 02/12Z.
ISOLD-SCT TSRA/SHRA return this afternoon and evening. Cloud decks
are generally FEW-SCT AOA 12k ft MSL except near TSRA where it
may be BKN between 8-10k ft MSL. SFC wind less than 12 kts thru
the forecast period and either variable in direction or favoring
an ELY/SELY direction. Gusty winds possible near TSRA/SHRA.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A favorable flow regime combined with adequate
moisture will result in the daily cycle of mainly afternoon and
evening isolated to scattered showers and thunderstorms this weekend
and into at least the middle of this week. Expect gusty and
erratic winds with the stronger thunderstorms. Otherwise, 20-foot
winds will be terrain driven mainly under 15 mph.

&&

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

&&

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PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
910 AM MST SUN SEP 1 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 PM     TSTM WND DMG     SAINT DAVID             31.90N 110.22W
08/31/2019                   COCHISE            AZ   PUBLIC

            SPOTTER REPORTS SEVERAL LARGE TREES SNAPPED
            AT THE BASE ALONG MILLER LANE IN SAINT
            DAVID. OTHER LARGE TREES WITH 6+ INCH
            BRANCHES BROKEN. TWO WINDOWS BLOWN OUT.
            METAL ROOF LIFTED AND BENT IN ONE CORNER.

&&

Special Weather Statement
National Weather Service Tucson AZ
130 PM MST Sun Sep 1 2019

AZZ505-506-012115-
Southeast Pinal County including Kearny/Mammoth/Oracle-South Central
Pinal County including Eloy/Picacho Peak State Park-
130 PM MST Sun Sep 1 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL PINAL COUNTY UNTIL
215 PM MST...

At 129 PM MST, Doppler radar was tracking a strong thunderstorm 13
miles northwest of Saddlebrooke, or 8 miles northeast of Red Rock,
moving west at 15 mph.

Wind gusts of 50 mph and blowing dust will be possible with this
storm.

Locations impacted include...
Eloy, Picacho, Picacho Peak State Park, Red Rock and Cactus Forest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3251 11134 3267 11172 3299 11131 3262 11089
TIME...MOT...LOC 2029Z 093DEG 11KT 3265 11110

Zell

Special Weather Statement
National Weather Service Tucson AZ
148 PM MST Sun Sep 1 2019

AZZ502>504-515-012145-
Tohono O'odham Nation including Sells-Upper Santa Cruz River and
Altar Valleys including Nogales-Baboquivari Mountains including Kitt
Peak-Tucson Metro Area including Tucson/Green Valley/Marana/Vail-
148 PM MST Sun Sep 1 2019

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL PIMA COUNTY UNTIL 245 PM
MST...

At 147 PM MST, Doppler radar was tracking a strong thunderstorm near
Three Points moving west at 15 mph.

Wind gusts of 50 mph and blowing dust will be possible with this
storm.

Locations impacted include...
Three Points, Kitt Peak, San Pedro and Pan Tak.

LAT...LON 3210 11121 3191 11129 3196 11169 3224 11156
TIME...MOT...LOC 2047Z 106DEG 13KT 3202 11135