Flash Flood Warning 48, NWS Tucson, AZ

540 
WGUS75 KTWC 232121
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
221 PM MST TUE OCT 23 2018

AZC019-232315-
/O.CON.KTWC.FF.W.0048.000000T0000Z-181023T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
221 PM MST TUE OCT 23 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM MST FOR
EAST CENTRAL PIMA COUNTY...

At 220 PM MST, Doppler radar indicated thunderstorms producing areas 
of rain across the warned area with rain amounts up to 2 inches 
since late this morning. Flash flooding is expected to be ongoing 
across the area. 

Some locations that will experience flooding include...
Green Valley, Sahuarita, Three Points, Valencia West, Drexel Heights,
Summit, East Sahuarita, Tucson Estates, San Xavier Mission, Ryan
Field and San Pedro.

This includes the following highways...
 Interstate 19 between mile markers 31 and 58.
 Route 86 between mile markers 139 and 163.
 Route 286 between mile markers 24 and 45.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3220 11127 3212 11098 3197 11095 3173 11099
      3173 11143 3215 11155

$$

GL

682 
WGUS75 KTWC 232311
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
411 PM MST TUE OCT 23 2018

AZC019-232321-
/O.EXP.KTWC.FF.W.0048.000000T0000Z-181023T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
411 PM MST TUE OCT 23 2018

...THE FLASH FLOOD WARNING FOR EAST CENTRAL PIMA COUNTY WILL EXPIRE
AT 415 PM MST...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3220 11127 3212 11098 3197 11095 3173 11099
      3173 11143 3215 11155

$$

AH

Area Forecast Discussion
National Weather Service Tucson AZ
940 AM MST Tue Oct 23 2018

.SYNOPSIS...Numerous showers and thunderstorms today with greatest
coverage from Tucson eastward. Some thunderstorms may produce large
hail and damaging winds. Showers and thunderstorms ending this
evening with dry conditions late tonight. There is a slight chance
of showers and thunderstorms Wednesday east of Tucson followed by
dry conditions area wide Wednesday night into next Monday.

&&

.DISCUSSION...Scattered showers and thunderstorms were occurring
across Cochise County northward into southern Graham/Greenlee
Counties at this time. Meanwhile, isolated showers/tstms were also
occurring from the Tucson metro area northward into southeast Pinal
County. A storm spotter reported hail to one half inch diameter near
Ryan Airfield (southwest Tucson) around 910 am MST. Cell movements
were nely 15-20 kts.

A mid/upper trough axis extended from western Nevada southward into
southern California this morning. Meanwhile, the Storm Prediction
Center Mesoscale Analysis valid 16Z depicted an axis of 1000 J/kg
MLCAPE extended from near Nogales northward to just west of Tucson.
A broad area of 500-1000 J/kg encompassed much of southeast Arizona.
23/12Z KTWC sounding total precip water value of 1.07 inches was
nearly identical to 24 hours ago. However, this sounding was
markedly more unstable as per various parameters (e.g. MLCAPE of
1007 J/kg) versus 24 hours ago.

Numerous showers and thunderstorms will occur across much of
southeast Arizona into this evening. The exception is across western
Pima County where precip-free conditions will prevail. As per the
1107 am CDT/907 am MST Storm Prediction Center Day 1 Convective
Outlook, the primary threats the rest of today are gusty winds and
marginally severe hail. A weakening shear environment will occur as
the mid/upper trough approaches from the west. There is also a
localized flash flood threat as per the latest NWS Weather
Prediction Center Mesoscale Precipitation Discussion.

Several HRRR solutions as well as the 23/12Z Univ of AZ WRF-NAM
depict showers/tstms to decrease in coverage/intensity early this
evening as the bulk of precip is progged to mostly end around 24/06Z
or shortly thereafter. This timing is coincident with the mid/upper
trough axis depicted to move via various models to move into
southwest New Mexico by daybreak Wednesday. High temps today are
forecast to be mainly within a couple of degrees of normal.

Please refer to the additional sections for further detail.

&&

.AVIATION...Valid through 24/18Z.
Numerous -TSRA/-SHRA into early this evening. Some +TSRA may occur
at times with hail and gusts approaching 50 kts. Scattered -TSRA
and -SHRA mainly east of KTUS early this evening with most precip
ending by daybreak Wednesday. Isolated -TSRA/-SHRA mainly near White
Mountains northeast of KSAD toward end of period.

Otherwise, cloud decks mostly 4k-8k ft AGL becoming 6k-10k ft AGL
around 24/06Z and continuing into Wednesday morning. Surface wind
mainly sely/sly 5-15 kts with gusts near 25 kts apart from
thunderstorm gusts. Surface wind after 24/06Z variable in direction
less than 12 kts. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A slow moving weather system will produce showers
and thunderstorms again today. Some storms will be capable of
producing localized heavy rainfall, large hail and wind gusts in
excess of 50 mph. Storm coverage will extend mainly from central Pima
County toward the east. By Wednesday, slight chances for rainfall
will be limited to Fire Zones 152 and 153. Dry conditions then occur
Thursday through the upcoming weekend. Outside of strong convective
gusts today, 20-ft winds will remain below 15 mph through the
forecast period.

&&

.PREV DISCUSSION /229 AM MST/...It should end up being an
interesting day with the way things are setting up. The upper low
that has basically been over southern California the last few days
has set the stage by generating a very moist and unstable air mass
over the region. Now this feature is on the move and will slowly
move across Arizona later today into tonight and will provide the
dynamics to trigger thunderstorms today.

Depending on the minor (but important) details of the forcing there
could be multiple rounds of convection and that is suggested in the
various CAM (Convective Allowing Model) solutions. Each of the CAM
models has their own take on the details, however the main idea is
the same with plenty of thunderstorm activity today from fairly
early in the day into the evening. With the available instability,
wind shear and forcing, some of the thunderstorms are expected to be
severe, meaning producing large hail and/or damaging winds. The
primary area of concern for the stronger storms is east of a Sasabe
to Casa Grande line all the way into western New Mexico. For visual
reference see the Day 1 Convective Outlook from SPC. Like Monday,
there could also be local flash flooding issues especially if heavy
rains fall over already very wet areas. It should be a dynamic day,
one where you will need to stay tuned to the latest forecasts,
statements and warnings.

This evening the focus of the convection will be forced to the
eastern part of the forecast area as the upper trough moves east and
the threat of strong storms will be over for Arizona before
midnight. Then we begin the slow process of drying out and
stabilizing the atmosphere. By Wednesday afternoon things should
have settled down enough to limit activity to just a few isolated
rain showers over the White mountains and near the New Mexico border
area.

Thursday into the weekend more significant drying takes hold with NW
flow aloft ahead of an upper level ridge that will eventually build
overhead late in the weekend. So, looking at mostly clear skies
Thursday onward with gradually warming temperatures and afternoon
highs peaking 5-10 degrees warmer than normal by Sunday. There is
some potential for a little unsettled weather early next week but
that is a problem to deal with another day.

&&

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

&&

Francis
PREVIOUS DISCUSSION...Cerniglia

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Special Weather Statement
National Weather Service Tucson AZ
920 AM MST TUE OCT 23 2018

AZZ504-514-231645-
Santa Catalina and Rincon Mountains including Mount
Lemmon/Summerhaven-Tucson Metro Area including Tucson/Green
Valley/Marana/Vail-
920 AM MST TUE OCT 23 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PIMA COUNTY UNTIL
945 AM MST...

At 920 AM MST, trained weather spotters reported a strong
thunderstorm near Tucson Estates, or 8 miles west of Tucson, moving
north at 25 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Tucson, Oro Valley, Marana, Tortolita, Flowing Wells, Drexel Heights,
Tucson Estates, Valencia West, Casas Adobes, South Tucson, Ryan
Field, Dove Mountain, Catalina State Park, San Xavier Mission,
Catalina Foothills and Picture Rocks.

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 3209 11097 3211 11122 3247 11117 3245 11087
TIME...MOT...LOC 1620Z 192DEG 21KT 3223 11109

GL

Special Weather Statement
National Weather Service Tucson AZ
956 AM MST TUE OCT 23 2018

AZZ502-504-507-514-231800-
Santa Catalina and Rincon Mountains including Mount
Lemmon/Summerhaven-Tohono O'odham Nation including Sells-Upper San
Pedro River Valley including Sierra Vista/Benson-Tucson Metro Area
including Tucson/Green Valley/Marana/Vail-
956 AM MST TUE OCT 23 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PIMA COUNTY UNTIL
1100 AM MST...

At 955 AM MST, Doppler radar was tracking a strong thunderstorm near
Tanque Verde, or 9 miles east of Tucson, moving northeast at 25 mph.
Numerous other strong thunderstorms were developing across the
Tucson Metro area as well, moving northeast at 25 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Tucson, Oro Valley, Marana, Tortolita, Summit, Tucson Estates,
Drexel-Alvernon, Valencia West, Flowing Wells, Littletown, Drexel
Heights, Three Points, Casas Adobes, Tanque Verde, South Tucson,
Vail, Mount Lemmon/Summerhaven, Ryan Field, Dove Mountain 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.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3201 11048 3203 11134 3250 11129 3249 11046
TIME...MOT...LOC 1655Z 207DEG 21KT 3221 11078

GL

Special Weather Statement
National Weather Service Tucson AZ
1015 AM MST TUE OCT 23 2018

AZZ503-507-513-231815-
Upper San Pedro River Valley including Sierra
Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including
Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar
Valleys including Nogales-
1015 AM MST TUE OCT 23 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL SANTA CRUZ COUNTY UNTIL
1115 AM MST...

At 1015 AM MST, Doppler radar was tracking a strong thunderstorm over
Nogales, moving northeast at 30 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Nogales, Rio Rico Northeast, Rio Rico Southwest, Rio Rico Northwest,
Tubac, Tumacacori-Carmen, Rio Rico Southeast, Patagonia, Pena Blanca
Lake, Tumacacori, Rio Rico, Kino Springs, Patagonia Lake, Sonoita,
Elgin and Amado.

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 3136 11115 3167 11108 3167 11054 3133 11071
      3133 11108
TIME...MOT...LOC 1715Z 205DEG 26KT 3134 11091

GL