Special Weather Statement, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
345 PM MST Wed Aug 11 2021

.SYNOPSIS...Scattered showers and thunderstorms continue today and
Thursday. A disturbance moving in from the east Friday into the
weekend will increase convection for much of southeast Arizona. Some
storms will generate strong winds and heavy rain which will result
in continued flooding concerns and localized storm damage.
Temperatures remain below normal over the next several days.

&&

.DISCUSSION...Showers and thunderstorms pretty much on track as we
expected south and east of Tucson this afternoon. A few issues with
water as we've seen rainfall rates around 1+" per hour in parts of
Santa Cruz County, though instantaneous rates at times have been
higher. Storm motions are slow and erratic, not surprising with the
weak steering flow observed on the morning sounding, contributing to
the flash flood threat. Storms continue into this evening, though
should wind down around the midnight hour if the CAM solutions are
to be trusted.

Thursday looks interesting with the potential for some storms out
west initially, but the bulk of activity looks to occur during the
late afternoon into the evening near the AZ/NM border. The focus for
convection looks to be on the western edge of an inverted trough
pushing west toward the area, not too unlike the disturbance which
brought us several days of rain just a few weeks ago. This time,
we'll also be working with some tropical moisture making its way up
the Gulf of California, which will reinforce our moisture levels by
Friday. The aforementioned disturbance will then rotate west across
our area Friday into Saturday, enhancing rainfall chances for almost
all of southeast Arizona. We're still assessing the flash flooding
threat, but would not be surprised to see headlines issued on
subsequent shifts if guidance continues increase our confidence
regarding this event. With little in the way of a break so far this
summer, the ground is well saturated and mainstem rivers are flowing
almost daily in conjunction with convection, so another prolonged
period of rain could cause some real problems depending on where the
heaviest rainfall occurs.

We might see a bit of a reprieve early next week in the wake of the
departing disturbance, but not enough to shut us down completely.
Southwesterly to southeasterly flow will continue to bring moisture
into the area for at least isolated chances for storms each
afternoon and evening through next Tuesday.

With plenty of moisture and cloud cover in the forecast into next
week, expect daytime temperatures to remain below normal values for
mid-August.

&&

.AVIATION...Valid through 13/00Z.
Mostly SCT-BKN 8-12k ft MSL this afternoon and overnight with some
gradual clearing Thursday morning. Isolated to scattered SHRA/TSRA
this afternoon and evening with less coverage overnight. Best
chances will be along the international border. Local MVFR
conditions and gusty winds with SHRA/TSRA. Outside of SHRA/TSRA, SFC
winds will be less than 10 kts following a normal diurnal flow of
sly/sely during the night/early morning and mainly wly/nwly late
morning through afternoon. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Ample moisture this week along with periodic
mid level disturbances will result in at least a mid grade monsoon
pattern. Given the higher levels of moisture and cloud coverage,
temperatures will be cooler this week. Strong, erratic winds and
locally heavy rainfall will be possible with any stronger storms
that develop. 20-foot winds will generally be less than 15 mph when
not influenced by thunderstorms.

&&

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

&&

Carpenter/Hardin

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson

Special Weather Statement
National Weather Service Tucson AZ
224 PM MST Wed Aug 11 2021

AZZ503-507-513-112145-
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-
224 PM MST Wed Aug 11 2021

...A strong thunderstorm will impact portions of southeastern Santa
Cruz County through 245 PM MST...

At 222 PM MST, Doppler radar was tracking a strong thunderstorm near
Patagonia, or 18 miles northeast of Nogales, moving northeast at 10
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...
Elgin.

This includes Route 83 between mile markers 17 and 23.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

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 3138 11072 3152 11078 3162 11056 3142 11048
TIME...MOT...LOC 2122Z 239DEG 16KT 3149 11066

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

TRIPOLI

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
332 PM MST WED AUG 11 2021

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

0326 PM     FLASH FLOOD      5 NW PIRTLEVILLE        31.40N 109.63W
08/11/2021                   COCHISE            AZ   LAW ENFORCEMENT

            KINGS HIGHWAY AND BROOKS ROAD ARE CLOSED
            FROM HIGHWAY 80 TO DOUBLE ADOBE ROAD CLOSED
            DUE TO FLOODING BY COUNTY LAW ENFORCEMENT.
            WHITEWATER DRAW CROSSES THESE ROADS.

&&

KJS

Special Weather Statement
National Weather Service Tucson AZ
356 PM MST Wed Aug 11 2021

AZZ501-502-112330-
Western Pima County Including Ajo/Organ Pipe Cactus National
Monument-Tohono O'odham Nation including Sells-
356 PM MST Wed Aug 11 2021

...A strong thunderstorm will impact portions of northwestern Pima
County through 430 PM MST...

At 356 PM MST, Doppler radar was tracking a strong thunderstorm 12
miles southeast of Ajo, moving east at 15 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Ajo, Gu Vo, Organ Pipe Cactus National Monument, Why, Charco 27,
Gunsight and Kuakatch.

This includes the following highways...
 Route 85 between mile markers 39 and 66.
 Route 86 between mile markers 53 and 70.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3208 11281 3241 11290 3249 11254 3205 11244
TIME...MOT...LOC 2256Z 255DEG 11KT 3222 11275

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

RH