Special Weather Statement, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
209 PM MST Tue Jul 27 2021

.SYNOPSIS...Isolated to scattered storms are expected this and
tomorrow before a more active weather period begins Thursday into
the weekend. High temperatures will run near to a few degrees below
seasonal normals.

&&

.DISCUSSION...Isolated to scattered showers and thunderstorms were
developing this afternoon across parts of SE AZ. Latest high
resolution models were advertising more activity through this
evening compared to yesterday. The main feature supporting this
increase in activity was a weak disturbance tracking westward
underneath the upper high centered over Great Plains. The main
threats from the stronger thunderstorms will be locally heavy
rainfall and strong wind gusts. Models favored a decrease in
thunderstorms on Wednesday before the focus shifts to another period
of heavy rain starting Thursday into the weekend. An upper low
centered over the Gulf of Mexico south of Brownsville TX today will
track westward and approach the region on Thursday. Returning
moisture along with upper difluence in advance of this upper low
will increase the heavy rainfall threat Thursday afternoon into
Thursday night. Thereafter, a fair amount of uncertainty remained
with the track of this feature as it weakens over northern Mexico on
Friday. At any rate, at some point remnants of the upper low will
lift northward through parts of AZ around late Friday into Saturday.
Overall, this scenario will not be as impressive as last week and
weekend, but with the ground saturated in many areas and flowing
water already in normally dry washes there will likely be local
impacts again.

&&

.AVIATION...Valid through 29/00Z.
FEW/SCT clouds 8k-12k ft AGL this afternoon and evening with gradual
clearing overnight. Isolated to scattered SHRA/TSRA with +TSRA
possible from KTUS south to KOLS and eastward this afternoon and
evening. Brief MVFR conditions may be possible in the stronger
storms. Gusty outflow winds are likely with KTUS possibly seeing
late afternoon gusty outflows from the south/southwest. Gusts to
35kts+ possible. Otherwise expect sfc winds below 10 kts. Storm
activity will gradually diminish around sunset. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
be possible each afternoon and evening through Wednesday.
Precipitation chances then increase going into the upcoming weekend.
Gusty, erratic winds and locally heavy rainfall will accompany any
storms that develop. High temperatures will be near to slightly
below normal through Friday, lowering to below normal levels this
weekend. 20-foot winds will generally be less than 15 mph when not
influenced by thunderstorms.

&&

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

&&

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Special Weather Statement
National Weather Service Tucson AZ
156 PM MST Tue Jul 27 2021

AZZ503-507-513-272145-
Upper San Pedro River Valley including Sierra
Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including
Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar
Valleys including Nogales-
156 PM MST Tue Jul 27 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN COCHISE AND
SOUTHEASTERN SANTA CRUZ COUNTIES UNTIL 245 PM MST...

At 156 PM MST, Doppler radar was tracking a strong thunderstorm 7
miles west of Parker Canyon Lake, or 20 miles west of Sierra Vista,
moving west at 15 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Patagonia, Parker Canyon Lake, Fort Huachuca and Canelo.

LAT...LON 3155 11043 3135 11047 3143 11085 3164 11077
TIME...MOT...LOC 2056Z 103DEG 14KT 3147 11058

AH

Special Weather Statement
National Weather Service Tucson AZ
215 PM MST Tue Jul 27 2021

AZZ503-504-507-513-272200-
Upper San Pedro River Valley including Sierra
Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including
Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar
Valleys including Nogales-Tucson Metro Area including Tucson/Green
Valley/Marana/Vail-
215 PM MST Tue Jul 27 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PIMA AND NORTH
CENTRAL SANTA CRUZ COUNTIES UNTIL 300 PM MST...

At 215 PM MST, Doppler radar was tracking a strong thunderstorm 8
miles west of Sonoita, or 15 miles east of Tubac, moving west at 15
mph.

Winds in excess of 40 mph and pea sized hail will be possible with
this storm.

Locations impacted include...
Tubac, Sonoita and Madera Canyon.

LAT...LON 3184 11057 3157 11070 3164 11106 3189 11092
TIME...MOT...LOC 2115Z 103DEG 14KT 3167 11080

AH