Special Weather Statement, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
147 PM MST Fri Jul 28 2017

.SYNOPSIS...Daily rounds of thunderstorms will continue through at
least this weekend with locally heavy rain and strong winds with
some storms. High temperatures will generally be a few degrees
below normal due to increased storm coverage.

&&

.DISCUSSION...Thunderstorms developing over mountains this
afternoon. Movement is WNW but is a little slower than Thursday.
Slower movement and a bit more moisture in this morning's sounding
(1.66 inches) will allow for heavy rain from individual storms
with rates 1 to 2 inches per hour easily attainable.

Satellite/models shows a number of upstream disturbances
available to act on moisture as they move across SE AZ through
this weekend. Of immediate concern is one that has already sparked
a large area of thunderstorms in NE Sonora/NW Chihuahua that is
moving northeast toward SE AZ. Expect this area to help keep
showers and thunderstorms going well into the evening, if not
overnight.

As mentioned, additional rounds of thunderstorms are expected
through the weekend. While ample moisture should remain in place
next week, the upper level high is forecast to recenter farther
west which may warm temperatures aloft enough to limit
thunderstorm coverage. At that time, high temperatures could
return to near normal, after being below normal through this
weekend.

&&

.AVIATION...Valid thru 30/00Z.
Sct to Num TSRA continuing thru 29/06z. Cloud decks generally 5k-
10k ft AGL with MVFR cigs/vsbys in TSRA. Isold/Sct SHRA/TSRA
overnight into Sat morning then another round of TSRA developing
Saturday afternoon. SFC wind variable in direction mainly less
than 12 kts, except in the vicinity of TSRA where gusts may exceed
40 kts. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...
Daily shower and thunderstorm chances will continue into next week
across most of southeast Arizona. Daytime temperatures will
generally be at or below normal. Elevated humidities will remain in
place through the weekend into next week with excellent overnight
recoveries. Outside of thunderstorm winds, expect 20-foot winds to
remain at or below 15 mph and follow typical upslope/down valley
diurnal patterns. Fire weather concerns are low through at least
late next week.

&&

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

&&

Drozd

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Special Weather Statement
National Weather Service Tucson AZ
218 PM MST FRI JUL 28 2017

AZZ503-504-282200-
Upper Santa Cruz River and Altar Valleys including Nogales-Tucson
Metro Area including Tucson/Green Valley/Marana/Vail-
218 PM MST FRI JUL 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN PIMA AND
NORTHWESTERN SANTA CRUZ COUNTIES UNTIL 300 PM MST...

At 216 PM MST, Doppler radar was tracking a group of strong
thunderstorms just west of Tubac and Amado. The storms are showing
very little movement.

Heavy rain and winds in excess of 40 mph will be possible with this
storm.

Locations impacted include...
Tumacacori-Carmen, Tubac, Rio Rico Northwest, Arivaca Lake,
Tumacacori and Amado.

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 3184 11112 3167 11106 3151 11103 3153 11131
      3183 11132
TIME...MOT...LOC 2116Z 101DEG 7KT 3167 11116

Cerniglia

Special Weather Statement
National Weather Service Tucson AZ
255 PM MST FRI JUL 28 2017

AZZ504-514-282230-
Santa Catalina and Rincon Mountains including Mount
Lemmon/Summerhaven-Tucson Metro Area including Tucson/Green
Valley/Marana/Vail-
255 PM MST FRI JUL 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR  UNTIL 330 PM MST...

At 255 PM MST, Doppler radar was tracking a strong thunderstorm over
Tanque Verde, or 9 miles east of Tucson. this storm was nearly
stationary.

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

Locations impacted include...
Tucson, Tanque Verde and Catalina Foothills.

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.

&&

LAT...LON 3232 11067 3217 11067 3222 11089 3233 11090
TIME...MOT...LOC 2155Z 077DEG 4KT 3226 11078

GL