Special Weather Statement, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
320 PM MST Sun Aug 1 2021

.SYNOPSIS...The overall trend in thunderstorm coverage will be
less for most of next week and focused south and east of Tucson.
High temperatures will trend up to near or slightly above normal
by midweek. Better coverage of showers and thunderstorms is
possible by next weekend.

&&

.DISCUSSION...Mainly isolated convection continues east of Tucson
and primarily over the higher terrain. Otherwise, most of the CWA
was under partly cloudy skies with temperatures in the upper 80s to
mid 90s across the lower elevations. Very weak and erratic flow
below H5 has prevented much storm movement into the valleys, and
stronger SWLY flow aloft has been shearing anvils off toward the NE.
The HREF members continue to advertise a day similar to Saturday in
terms of coverage, and I think there's an outside chance we could see
a few stronger cells develop with heavier rain cores and stronger
downdrafts/surface wind gusts. In fact, with storms being so bottom-
loaded, we have already seen some rainfall gauges report 1/4"-1/2"
in just 15 minutes.

For much of the upcoming week, high pressure to our south builds
north and west toward srn CA and the nrn Baja, tempering storm
chances to just low-grade monsoon activity. Of note however, the
potential for a mid-level vort max rounding the high and moving
across the White Mountains Monday afternoon, then south along the
AZ/NM border. Will look for potentially enhanced convection around
this feature while Sonora lights up to our south. There will be
potential for some outflows from the south to move into our border
areas late Monday night. If nothing else, it will reinforce our low-
level moisture field.

High pressure builds back north on Tuesday with some drying in the
mid-levels, then northeast overhead on Wednesday. This will bump
temperatures up to near or slightly above normal with limited storm
chances.

By Thursday and Friday, deterministic and ensemble solutions
elongate high pressure into the Four Corners with deeper easterly or
southeasterly flow for our area. This will help bring more of that
mid and upper level moisture back into play for a potential uptick
in convective coverage. It looks like we may get an assist from the
tropics as well with a potential surge up the Gulf of California,
especially Friday night into Saturday. As such, after peaking around
midweek expect highs dropping back below normal Friday into the
weekend.

&&

.AVIATION...Valid through 03/00Z.
FEW-SCT and occasionally BKN clouds 10k-14k ft MSL. ISOLD-SCT
SHRA/TSRA this afternoon and early evening, mainly E of KTUS. Clouds
decreasing areawide late this evening. Strong, gusty and erratic
wind gusts with TSRA to 40 kts, heavy downpours, and temporary MVFR
CIGS/VSBYS. Limited SHRA/TSRA chances on Monday afternoon, focused
NE of KTUS and over terrain, particularly the White Mountains.
Outside of TSRA outflows, SFC wind will generally remain less than
12 kts through the period. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Isolated to scattered showers and thunderstorms
are expected today, mainly south and east of Tucson, then a downward
trend in storm activity Monday through Wednesday when storm chances
will mainly be east of Tucson. An upswing in thunderstorm activity
is expected going into next weekend. Any thunderstorms that develop
will be capable of producing strong, gusty and erratic winds along
with locally heavy rainfall. RH values will remain well above
critical thresholds the next 7 days. Near normal high temperatures
through at least Thursday. 20-foot winds will generally be less than
15 mph when not influenced by thunderstorms.

&&

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

&&

Carpenter

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Special Weather Statement
National Weather Service Tucson AZ
1228 PM MST Sun Aug 1 2021

AZZ509-510-012015-
Upper Gila River and Aravaipa Valleys including Clifton/Safford-White
Mountains of Graham and Greenlee Counties including Hannagan Meadow-
1228 PM MST Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN GREENLEE COUNTY
UNTIL 115 PM MST...

At 1228 PM MST, Doppler radar was tracking a strong thunderstorm 12
miles south of Clifton, moving northeast at 5 mph.

Winds in excess of 45 mph will be possible with this storm.

Locations impacted include...
Duncan, York, Three Way and Guthrie.

LAT...LON 3269 10920 3293 10938 3305 10912 3289 10904
      3276 10905
TIME...MOT...LOC 1928Z 231DEG 6KT 3285 10922

AH

Special Weather Statement
National Weather Service Tucson AZ
242 PM MST Sun Aug 1 2021

AZZ509-510-012230-
Upper Gila River and Aravaipa Valleys including Clifton/Safford-White
Mountains of Graham and Greenlee Counties including Hannagan Meadow-
242 PM MST Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL GREENLEE COUNTY
UNTIL 330 PM MST...

At 241 PM MST, Doppler radar was tracking a strong thunderstorm 11
miles northwest of Mule Creek, or 18 miles northeast of Clifton.
This storm was nearly stationary.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

This storm will remain over mainly remote areas of east central
Greenlee County.

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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3316 10907 3327 10920 3337 10911 3330 10904
      3317 10905
TIME...MOT...LOC 2141Z 234DEG 3KT 3324 10909

Meyer

Special Weather Statement
National Weather Service Tucson AZ
345 PM MST Sun Aug 1 2021

AZZ509-012330-
Upper Gila River and Aravaipa Valleys including Clifton/Safford-
345 PM MST Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL GRAHAM COUNTY UNTIL 430
PM MST...

At 344 PM MST, Doppler radar was tracking a strong thunderstorm over
Roper Lake State Park, or near Safford, moving northeast at 10 mph.

Half inch hail and winds in excess of 45 mph will be possible with
this storm, along with heavy rain.

Locations impacted include...
Safford, Thatcher, Solomon, Roper Lake State Park, and Safford
Regional Airport.

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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3270 10969 3279 10984 3293 10980 3281 10953
TIME...MOT...LOC 2244Z 222DEG 7KT 3279 10973

Meyer