Flash Flood Warning 112, NWS Tucson, AZ

905 
WGUS75 KTWC 202113
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
213 PM MST Sat Aug 20 2022

AZC019-202123-
/O.EXP.KTWC.FF.W.0112.000000T0000Z-220820T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
213 PM MST Sat Aug 20 2022

...FLASH FLOOD WARNING WILL EXPIRE AT 215 PM MST THIS AFTERNOON FOR 
NORTHEASTERN PIMA COUNTY...

Gauges along the CDO have receded, but some residual flood waters 
will remain in the channel while it gradually decreases. Please 
continue to heed remaining road closures.

A Flood Watch remains in effect until 1100 PM MST Saturday for a 
portion of Southeast Arizona.

LAT...LON 3233 11108 3235 11104 3238 11101 3242 11095
      3248 11091 3248 11088 3241 11092 3237 11099
      3231 11106

$$

RAH

Area Forecast Discussion
National Weather Service Tucson AZ
944 AM MST Sat Aug 20 2022

.SYNOPSIS...Shower and thunderstorm chances will continue into
next week with a continued uptick in activity today. The main
threats will be strong gusty winds and heavy rainfall especially
today. Otherwise, temperatures will be 5-10 degrees below normal
into early next week.

&&

.DISCUSSION...Showers and a few thunderstorms continued to increase
in coverage this morning with several flood/flash flood related
advisories and warnings in effect. Latest models suggested that the
bulk of the shower and thunderstorm activity will shift eastward
during the afternoon and evening. Already seeing indications of this
as a band of light to moderate rainfall was developing across
northern Cochise, central and southern Graham, and southern Greenlee
counties. As the heavier rainfall becomes more focused across the
eastern CWA into western NM, there will be a concern for elevated
flows in the Gila River system. Latest RFC forecast showed most of
the stages on the Gila River cresting below flood stage on Monday.
Otherwise, the Flood Watch remains in effect through 11 PM MST this
evening. Will likely make some adjustments to the watch area on the
afternoon package. Otherwise, the current forecast looked on track.
Please refer to the previous discussion section in this product for
more details.

&&

.AVIATION...Valid through 21/18Z.
Slow moving low pressure system over the area will continue to bring
scattered to broken cloud clds, with CIGs down to 3k-6k ft possible
at KOLS for a few hours early in the period. ISOLD/SCT SHRA will
continue through the period with a few embedded TSRA possible in the
area from 20/18Z-20/23Z. Stronger showers and storms could reduce
visibilities in heavy downpours, briefly lower CIGS to 3k-6k ft AGL,
and/or produce gusts of 40+ kts even if only in the vicinity of the
terminal. Otherwise, winds following diurnal trends at speeds of
10kts or less can be expected. Aviation discussion not updated for
TAF amendments.

&&

.FIRE WEATHER...Monsoonal thunderstorm activity will remain elevated
through the weekend with rounds of showers and thunderstorms
expected each day. Primary threats include strong winds, lightning,
and flash flooding. Outside of thunderstorm activity, wind trends
will remain light and follow typical diurnal trends.

&&

.PREV DISCUSSION...\Issued at 228 AM MST Sat Aug 20 2022\
Current radar shows scattered showers across southeast Arizona. Area
gauges at washes and rivers have started to come down from their
peaks caused by earlier rainfall. Water vapor shows a few upper
level lows in the region. One is over the central Sonora Coast,
another is over east central Arizona, and the third is moving into
southern Utah. Models slowly drift the low over Sonora northward,
with the low in Arizona moving off into New Mexico. Mesoanalysis
shows fairly strong upper level divergence over most of southern
Arizona, which will aid in increasing shower activity early this
morning. PWAT values are near record levels with the KTWC 20/00Z
sounding recording 1.98". This anomalous moisture combined with the
upper level forcing from the low will lead to a continued threat of
widespread heavy rainfall and flash flooding today. Runoff from
storms will also likely lead to a flood threat for area rivers and
larger washes.

By Sunday the low over Sonora weakens considerably as high pressure
begins to build back into the Southwest. This high pushes the low
over Utah into Colorado and briefly puts Arizona in northwesterly
mid-level flow. Moisture does decrease a little but will still be
above normal. Expect scattered convection with a more localized
flash flooding threat. Soil moisture will be very high, so it won't
take much rain to cause runoff.

Early next week the high slowly migrates back into the Great Basin.
Thunderstorm activity looks to decrease some as the area loses some
of its moisture. But there will still be enough around for daily
afternoon/evening isolated to scattered showers and thunderstorms.

Temperatures will be well below normal today and continue to be
below normal through Monday. Tuesday onward temperatures will be
normal to just below normal.

&&

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

&&

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