Flash Flood Warning 28, NWS Tucson, AZ

795 
WGUS75 KTWC 012107
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
207 PM MST SAT SEP 1 2018

AZC009-012200-
/O.CON.KTWC.FF.W.0028.000000T0000Z-180901T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Graham-
207 PM MST SAT SEP 1 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 300 PM MST FOR
SOUTH CENTRAL GRAHAM COUNTY...

At 202 PM MST, Doppler radar and automated rain gauges indicated 
that over 1.5 inches of rain have fallen over Mt. Graham in the last 
2 hours. This includes portions of the Frye Fire burn scar. Flash 
flooding is already occurring, with a 3 foot rise recorded on Ash 
Creek in the last hour. Additional rainfall will be possible this 
afternoon.

Some locations that will experience flooding include...
Fort Grant, Frye Mesa Dam, Ash Creek and Mount Graham. 

This includes the following streams and drainages...Underwood Wash...
Stockton Wash...Twilight Creek...Aravaipa Creek...Two E Wash...Gibson
Creek...Fresnal Wash...Sheep Wash...Ash Creek...Marijilda Wash...
Bigler Wash...Noon Creek...High Creek...Frye Creek...Jacobson
Creek...Gila River and Kennedy Falls Wash.

This includes Route 266 between mile markers 125 and 126.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

This warning includes areas in or below a wildfire burn scar.
Rainfall on burned areas can cause increased flash flooding, debris
flows, mud slides, and rock slides. Take action now to protect
yourself from the effects of flash flooding and remember, Turn
Around, Don't Drown!

&&

LAT...LON 3279 10981 3267 10972 3260 10994 3276 11015
      3282 10997

$$

ECC

177 
WGUS75 KTWC 012158
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
258 PM MST SAT SEP 1 2018

AZC009-012204-
/O.EXP.KTWC.FF.W.0028.000000T0000Z-180901T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Graham-
258 PM MST SAT SEP 1 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL GRAHAM COUNTY WILL
EXPIRE AT 300 PM MST...

The heavy rain which prompted the flash flood warning has ended and 
flood waters are receding. Flooding is no longer expected to pose an 
immediate threat. However, additional showers and storms may still 
occur through this evening over portions of the Frye Fire burn scar 
and Mt. Graham. Please continue to heed any remaining road closures.

LAT...LON 3279 10981 3267 10972 3260 10994 3276 11015
      3282 10997

$$

ECC

Area Forecast Discussion
National Weather Service Tucson AZ
935 AM MST Sat Sep 1 2018

.SYNOPSIS...Expect isolated to scattered showers and thunderstorms
especially from Tucson eastward through Labor Day. Daytime
temperatures will generally be a few degrees below normal. A gradual
drying trend will then occur later next week, with the bulk of
thunderstorms mainly east of Tucson.

&&

.DISCUSSION...There has been quite a bit of thunderstorm activity
across east-central and Northeast Arizona over the past 6 hours as
a few vorticity lobes track thru the the southern periphery of an
upper trough positioned over Nevada/Utah. The favorable dynamics
with this upper feature this morning are currently N and NE of our
CWA in NE AZ and WRN NM. However, as the upper trough begins
to sag south, it will result in another upper diffluent field
establishing itself across the eastern portions of the forecast area
this afternoon into Sunday. The 01/12Z KTWC upper air sounding
indicated ample moisture still present in the lower-to-middle
layers of the atmosphere with a PWAT value of 1.40 inches. It also
indicated the warm air layer aloft last evening has eroded away,
allowing for a more favorable environment for sustained convection.

The majority of the Hi-Res models are in agreement with convection
firing up from Tucson east this afternoon. Given the developing
diffluent field aloft, I am leaning more toward the 01/12Z UofA
WRFNAM solution which maintains convection overnight, especially
along the AZ and New Mexico border. This is also reflected to a
lesser extent by the 01/12Z HRRR and 01/12Z HREF ARW models. Given
the moist airmass in effect, we will likely have to pay attention to
rainfall amounts along the AZ/NM border resulting in minor small
stream flooding issues(FLS) through Sunday.

Otherwise...the mean upper trough remains over SE AZ Monday and
slowly nudges to the east by the middle of next week as the upper
ridge in the Eastern Pacific shifts NE into California. Although
this would keep the WRN portions of the forecast area dry this week,
enough instability will exist to the east of Tucson...especially if
this trough phases up with an inverted trough west moving along the
southern periphery of the upper high moving into the Great Basin
next weekend.

&&

.AVIATION...Valid through 02/18Z. Scattered -TSRA/-SHRA KTUS
vicinity eastward into Sunday. Isolated -TSRA/-SHRA may also occur
west of KTUS this afternoon. SCT-BKN clouds 8k-12k ft AGL
areawide, with clearing west of Tucson late tonight. Surface wind
variable in direction mainly less than 12 kts, though brief gusts to
40 kts near TSRA. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Scattered thunderstorms east of Tucson with lesser
coverage and precipitation chances west of Tucson through Labor Day.
A gradual drying trend will evolve to isolated thunderstorms mostly
east of Tucson by the middle of the upcoming week. Expect terrain
driven 20-foot winds at less than 15 mph, except brief strong gusts
near thunderstorms.

&&

.PREV DISCUSSION...A cluster of thunderstorms managed to develop
after midnight near the San Carlos Reservoir, and were tracking
eastward through the Upper Gila River Valley at this time. Latest
HRRR solution picked up on this area of rainfall and showed an area
of further development along the Rim into the White Mountains
through daybreak. Thereafter, the HRRR showed some scattered showers
and thunderstorms developing across southeast Arizona from near
Tucson and east through southeast of there after 18Z today. Both the
ECMWF and GFS models continued to suggest a noticeable upswing in
thunderstorms today and more so Sunday into early Monday as the tail
end of a system swings through the state. Along with the increase in
rain chances, daytime temperatures will drop a few degrees on today
and level off next week with readings near normal. Drier conditions
will return by Tuesday, with most of the thunderstorm activity
remaining confined to far eastern Arizona and the mountains.

&&

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

&&

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Special Weather Statement
National Weather Service Tucson AZ
1030 AM MST SAT SEP 1 2018

AZZ509-511-011815-
Upper Gila River and Aravaipa Valleys including
Clifton/Safford-Galiuro and Pinaleno Mountains including Mount
Graham-
1030 AM MST SAT SEP 1 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL GRAHAM COUNTY UNTIL
1115 AM MST...

At 1029 AM MST, Doppler radar was tracking a strong thunderstorm
over the Pineleno Mountains or 15 miles southwest of Safford, moving
east at 5 mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Safford, Thatcher, Pima, Swift Trail Junction, Mount Graham and Frye
Mesa Dam.

LAT...LON 3257 10990 3278 11004 3300 10982 3278 10961
TIME...MOT...LOC 1729Z 265DEG 4KT 3274 10995

Special Weather Statement
National Weather Service Tucson AZ
1232 PM MST SAT SEP 1 2018

AZZ504-012000-
Tucson Metro Area including Tucson/Green Valley/Marana/Vail-
1232 PM MST SAT SEP 1 2018

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PIMA COUNTY UNTIL
100 PM MST...

At 1231 PM MST, Doppler radar was tracking a strong thunderstorm over
Tucson. This storm was nearly stationary.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Tucson, Drexel-Alvernon, Flowing Wells, Tanque Verde, South Tucson,
Catalina Foothills, Sabino Canyon and Davis-Monthan Air Force Base.

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 3216 11100 3229 11099 3234 11080 3214 11081
TIME...MOT...LOC 1931Z 272DEG 4KT 3221 11093