Flash Flood Warning 25, NWS Tucson, AZ

929 
WGUS75 KTWC 231824
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1124 AM MST THU AUG 23 2018

AZC023-232100-
/O.CON.KTWC.FF.W.0025.000000T0000Z-180823T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz-
1124 AM MST THU AUG 23 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM MST FOR
SOUTH CENTRAL SANTA CRUZ COUNTY...

At 1120 AM MST, Heavy rains have caused flooding on the Nogales 
Wash.  The wash is currently running around 2 feet above flood stage 
and continues to rise. Rains continue in the area so the wash will 
continue to run at or above flood stage into the early afternoon. 
The flood wave will continue northward toward Rio Rico where it 
dumps into the Santa Cruz. 

Some locations that will experience flooding include...
Nogales and Rio Rico.

Flood waters are moving down the Nogales Wash from Nogales to Rio 
Rico. 

This includes the following highways...
 Interstate 19 between mile markers 1 and 11.
 Route 82 between mile markers 1 and 3.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3147 11101 3147 11094 3133 11088 3133 11098

$$

Cerniglia

816 
WGUS75 KTWC 231932
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1232 PM MST THU AUG 23 2018

AZC023-231936-
/O.CAN.KTWC.FF.W.0025.000000T0000Z-180823T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz-
1232 PM MST THU AUG 23 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL SANTA CRUZ COUNTY IS
CANCELLED...

The heavy rain over and around the Nogales area has ended and the 
flood waters have been reported to be receding by local officials. 
The Nogales Wash gauge has also dropped below flood stage shortly 
before noon.  

While flooding is no longer expected to pose a threat to life and 
property high water will take some time to recede so please continue 
to heed any remaining road closures.

LAT...LON 3147 11101 3147 11094 3133 11088 3133 11098

$$

Cerniglia

Area Forecast Discussion
National Weather Service Tucson AZ
1009 AM MST Thu Aug 23 2018

.SYNOPSIS...Abundant moisture will provide elevated shower and
thunderstorm chances into the weekend. Some storms will produce
heavy rain and gusty winds. We may start to see some drying early
next week with fewer storms. Temperatures will run near or slightly
below normal for late August.

&&

.DISCUSSION...Morning sounding was primed for action with abundant
instability, well above average moisture and very little storm
steering winds (less than 5 kts). We have upper level divergence
over the area providing lift and the result is what is already
happening out the window, widespread storm development with
locally heavy rains to 4" per hour rainfall rates. Based on that
and a glance at the latest CAM solutions being verified by the
real weather, I already hoisted a Flash Flood Watch for much of
the area into this evening. Not going to be much time for a deep
look into the longer range forecast so not expecting big changes
there although I will send a quick update out this morning for the
first 24 hours.

&&

.AVIATION...Valid through 24/18Z.
Scattered to numerous TSRA/SHRA, with an increase this afternoon.
MVFR and local IFR conditions in very heavy rain with brief gusts
approaching 50 kts with strongest TSRA. Otherwise, cloud decks
generally 8k- 15k ft AGL and surface wind variable in direction
mainly less than 12 kts into Thursday evening. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...A favorable pattern for thunderstorm development
will continue into this weekend. Expect heavy rainfall to occur at
times. Terrain driven 20-ft winds persist at less than 15 mph,
except gusty and erratic winds near thunderstorms. A gradual drying
trend with less daily thunderstorm coverage may occur next week.

&&

.PREV DISCUSSION... /issued 241 AM MST Thu Aug 23 2018/
Deep moisture is in place over Southeast Arizona, with a high
pressure center consolidated just east of our area and a favorable
southerly flow over the area. Precipitable water values between
1.6 and 1.8 inches are well above the 90th percentile for late
August. Add in a mid level impulse immediately south of our area
in northern Sonora, and upper level diffluence on the eastern
periphery of the upper ridge axis and we have a good recipe for
showers and thunderstorms that don't follow a typical diurnal
cycle. Plenty of convection around this morning, with a chance of
showers and thunderstorms continuing into the evening hours. With
this much moisture and relatively modest storm movement, the main
focus will continue to be an elevated risk for heavy rainfall and
localized flooding issues.

We'll continue to maintain enough moisture for a decent chance of
showers and thunderstorms into the weekend. A trough pushing
through the northern Great Basin may introduce a westerly
component to the flow over at least western and northern portions
of our area early next week. Probably enough to slow storm
development once again, especially if the high responds by
temporarily elongating back westward in an east-west oriented
axis. If the trough gets deep enough early next week, the ridge
might even sink to a blocking position over northern Sonora. That
would bring a day or two of zero storm coverage by Wednesday or
Thursday.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 8 PM MST this evening for AZZ502>515.

&&

PUBLIC...Cerniglia/Meyer
AVIATION....Rasmussen
FIRE WEATHER...Rasmussen

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