Areal Flood Warning 8, NWS Tucson, AZ

961 
WGUS85 KTWC 241853
FLSTWC

Flood Statement
National Weather Service Tucson AZ
1153 AM MST Sat Jul 24 2021

AZC021-241903-
/O.CAN.KTWC.FA.W.0008.000000T0000Z-210724T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pinal AZ-
1153 AM MST Sat Jul 24 2021

...FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN PINAL COUNTY...

Flood waters from the Santa Cruz and Green Wash have receded. 
Additional light to moderate rainfall will continue with heavy flow 
in streams and washes as well as ponding in poor drainage areas. 
Please continue to heed remaining road closures.

LAT...LON 3275 11163 3274 11162 3271 11152 3263 11141
      3260 11140 3254 11147 3253 11155 3258 11168
      3263 11173 3265 11175 3272 11183 3276 11188
      3279 11188 3279 11177 3276 11178 3276 11174
      3272 11174 3274 11167

$$

WJM

Area Forecast Discussion
National Weather Service Tucson AZ
258 PM MST Fri Jul 23 2021

.SYNOPSIS...

After an active night and early morning, very little shower
activity has occurred today. This will likely be short lived, as
more precipitation is expected to start back up this evening and
last into the overnight hours.

&&

.DISCUSSION...

A slight lull in activity has allowed some of the flow in area
streams and washes to recede a little. However, CAMs and Ensemble
models are highlighting another round of heavy rainfall across SE
AZ beginning this evening and lasting into overnight. Some of the
activity may be convective in nature, but the biggest threats
remain flash flooding due to heavy rainfall.

We launched an 18 UTC sounding in hopes to get a better look at
the atmosphere. While there is plenty of moisture available, an
inversion above has kept the shower and thunderstorm activity to
a minimum today. The upper level low currently sitting over
central New Mexico will play a role in overcoming this inversion
by this evening.

Based on updated CBRFC forecasts this morning, we issued a Flood
Warning for portions of the Santa Cruz near Trico and downstream
to Eloy through 9pm this evening.

In collaboration with WPC and adjacent SW WFOs, we decided to
extend the Flash Flood Watch through Sunday night, to catch any
additional lingering flood issues that may arise.

After Sunday, things should start to dry out a bit, but lingering
threat of daily showers and thunderstorms will remain.

&&

.AVIATION...Valid through 25/00Z.SCT-BKN clouds at 8k-12k ft MSL
much of the period. Scattered to numerous SHRA/TSRA developing
this afternoon and remain into the nighttime period. Precipitation
is expected to continue into tomorrow. Expect brief MVFR
CIGS/VSBYS and mountain obscurations around TSRA along with gusty
outflow winds, potentially in excess of 45 kts with the strongest
storms. Otherwise, SFC wind generally less than 12 kts following
diurnal trends. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Periods of heavy rainfall are expected into the
weekend, with scattered to numerous showers and thunderstorms.
Flooding issues are expected to continue, due to part to saturated
soils. While in this pattern, showers and storms will be possible
throughout both the daytime and nighttime. Gusty winds in excess
of 40 mph and numerous lightning strikes may accompany stronger
storms. Daytime temperatures will remain below normal. 20-foot
winds will generally be less than 15 mph when not influenced by
thunderstorms. A bit of a reprieve from showers and storms is
possible the middle of next week.

&&

.HYDROLOGY...Given the chance for heavy rainfall and already
saturated soils the potential for flows in rivers and washes is
high. The latest river forecasts from the Colorado Basin River
Forecast Center show Sabino Creek, Pantano Wash near Vail, and
Santa Cruz River at Trico Road rising near or to flood stage later
today.

A couple of potential trouble areas to make note of...Finger Rock
and Sabino Canyon. Significant sediment and silt have moved around
the Finger Rock area with last nights activity, causing some
localized damage. Any additional high rainfall rates in this area
could cause more trouble. Sabino Canyon also is an area to keep an
eye on, where high rainfall rates could cause issues quickly.

Most river forecasts across southeast Arizona show
elevated stream flow over the weekend. With high enough rainfall
amounts other locations could reach flood stage and possibly out
of bank flow. Stream flow may also take longer to recede if basin
receives multiple days of rainfall. Potentially leading to
elevated stream flow into early next week.

River observations and forecasts can be found at the following
sites:
https://water.weather.gov/ahps2/index.php?wfo=twc
http://www.cbrfc.noaa.gov

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Sunday evening for AZZ501>515.

&&

Public...Singer
Aviation...Singer/Tripoli
Fire Weather....Singer/Guillet/Carpenter
Hydrology....Boyle/Singer

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