Flash Flood Warning 9, NWS Tucson, AZ

156 
WGUS75 KTWC 211001
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
301 AM MST SAT JUL 21 2018

AZC019-211115-
/O.CON.KTWC.FF.W.0009.000000T0000Z-180721T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
301 AM MST SAT JUL 21 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 AM MST FOR
NORTHEASTERN PIMA COUNTY...

At 257 AM MST, Doppler radar indicated that the heavy rain has ended 
across the warned area. Light to locally moderate rain will continue 
for the next half hour. Spotters and rain gauges indicated that up 
to two inches had fallen earlier this morning which may produce 
flash flooding, especially inside of Catalina State Park.

Some locations that will experience flooding include...
Catalina State Park and Catalina. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

&&

LAT...LON 3245 11078 3238 11079 3238 11094 3246 11092

$$

729 
WGUS75 KTWC 211108
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
408 AM MST SAT JUL 21 2018

AZC019-211116-
/O.EXP.KTWC.FF.W.0009.000000T0000Z-180721T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
408 AM MST SAT JUL 21 2018

...THE FLASH FLOOD WARNING FOR NORTHEASTERN PIMA COUNTY WILL EXPIRE
AT 415 AM MST...

The heavy rain has ended and flood waters are likely receding. 
Flooding is no longer expected to pose a threat.

LAT...LON 3245 11078 3238 11079 3238 11094 3246 11092

$$

Area Forecast Discussion
National Weather Service Tucson AZ
900 PM MST Fri Jul 20 2018

.SYNOPSIS...Isolated to scattered thunderstorms will continue this
tonight and again Saturday afternoon and evening. Then high pressure
will strengthen over the region late this weekend into early next
week resulting very little storm activity and much warmer
temperatures. High temperatures Monday into Wednesday will be much
warmer than normal and likely reaching record levels at some
locations.

&&

.DISCUSSION...Thunderstorms brought some quarter size hail to parts
of Sierra Vista and Corona De Tucson this afternoon. The
thunderstorm activity had diminished this evening, but another round
of storms will be possible tonight. Latest radar and satellite
imagery suggested that this next round was already starting to flare
up across Cochise and Graham counties. The steering flow was from
the east which will track storms westward toward the lower deserts
tonight. Latest HRRR also supported the notion of more showers and
thunderstorms overnight. Current forecast already conveyed this
scenario of nighttime storms, so no updates necessary this evening.

&&

.AVIATION...Valid through 22/06.
ISOLD to SCT TSRA will continue well into this evening and
potentially through 21/10Z before with cloud bases 8-10k ft AGL.
Some clearing expected after 21/12Z then ISOLD-SCT TSRA After an
active thunderstorm day for parts of southeast Arizona, especially
around Sierra Vista and Corona De Tucson where several reports of
quarter size hail were received.will redevelop again after 21/19Z
east and south of KTUS. Outside of strong and erratic TSRA outflows,
surface winds remain below 12 kts through the period. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Isolated to Scattered thunderstorms will continue
into the overnight hours then fire up again east and south of Tucson
Saturday afternoon, although they should be fewer in number. Upper
level high pressure will build over the region significantly
suppressing thunderstorms Sunday through Tuesday so they will be
tough to come by at all outside of the White Mountains although
dewpoints will remain at respectable levels. However, this high will
bring near or record level heat to the area Monday through at least
Tuesday. Later in the week the high shifts to the west allowing
monsoon moisture to begin returning to the area. Winds typically
light for mid-summer with the exception of strong gusty winds near
thunderstorms.

&&

.PREV DISCUSSION...On Saturday, we will gradually begin to
transition to a less favorable thunderstorm environment thanks to
upper level high pressure that will build westward from Texas this
weekend. Still expecting some storms Saturday, just fewer in number
and more limited to higher terrain east and south of Tucson. Also
may end up with a fair amount of cloud cover through the morning
which would hinder development.

Sunday the high approaches and settles overhead Monday through
Tuesday. Sunday there will be very limited convection then Monday
and Tuesday will not likely see much of any development thanks to
the subsidence and mid-level warming. That said, that warming will
impact our temperatures significantly. Heights and temperatures
700mb and above are forecast to be at or above the 99th percentile
for this time of year which translates to hot temperatures Monday,
Tuesday and possibly Wednesday. Unlike June when dewpoints are
typical very low they will be higher this event which will make it
feel warmer yet. We already have an Heat Warning in effect and that
looks great.
There is some question for Wednesday as it will depend on how fast
the monsoon moisture returns over the area behind the departing high.
At a later time we may need to expand the warning into Wednesday at
least for western parts of the area.

By the end of the week temperatures should return to "normal" with
moisture providing for some storms once again.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
  Excessive Heat Warning from 10 AM Monday to 8 PM MST Tuesday for
  AZZ501>509.

&&

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