Alert archive / Arizona / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 52, NWS Tucson, AZ

August 2, 2018Pima County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 2, 2018, 4:12 PM MST for Pima County, Arizona. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 2, 2018, 4:12 PM MST (23:12 UTC)
Expired: Aug 2, 2018, 5:00 PM MST
In force: 48 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Hail: 1.5 in
Wind: 70.0 mph

County Pima County, AZ

The radar

The Phoenix radar (KIWA), 111 km from the middle of the area, began a volume at 23:13 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Tuscon, AZ (KDMA), launched 12:00Z, 11.2 hours before the alert went out and 88 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 234 J/kg
Mixed-layer CIN: -280 J/kg
Mixed-layer LCL: 2343 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: -18 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

787 
WUUS55 KTWC 022312
SVRTWC
AZC019-030000-
/O.NEW.KTWC.SV.W.0052.180802T2312Z-180803T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tucson AZ
412 PM MST THU AUG 2 2018

The National Weather Service in Tucson has issued a

* Severe Thunderstorm Warning for...
  North central Pima County in southeastern Arizona...

* Until 500 PM MST.

* At 412 PM MST, a severe thunderstorm was located 13 miles east of
  Santa Rosa, or 26 miles north of Sells, and is nearly stationary.

  HAZARD...70 mph wind gusts and ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           considerable tree damage. Wind damage is also likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Santa Rosa, Sil Naggia and Ak Chin. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3229 11166 3213 11192 3231 11212 3246 11178
TIME...MOT...LOC 2312Z 139DEG 4KT 3230 11180 

HAIL...1.50IN
WIND...70MPH
 
$$

Meyer

1 follow-up statement

747 
WWUS55 KTWC 022332
SVSTWC

Severe Weather Statement
National Weather Service Tucson AZ
432 PM MST THU AUG 2 2018

AZC019-030000-
/O.CON.KTWC.SV.W.0052.000000T0000Z-180803T0000Z/
Pima-
432 PM MST THU AUG 2 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM MST
FOR NORTH CENTRAL PIMA COUNTY...

At 430 PM MST, an area of severe thunderstorms was located near and 
east of Santa Rosa, or 25 miles north of Sells, moving west at 5 
to 10 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Santa Rosa, Sil Naggia and Ak Chin. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3229 11166 3213 11192 3231 11212 3246 11178
TIME...MOT...LOC 2330Z 103DEG 9KT 3229 11195 

HAIL...1.00IN
WIND...60MPH
 
$$

Meyer

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tucson, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 2, 2:16 PM MST, 1 hour 56 minutes earlier.

Area forecast discussion, Aug 2, 2:16 PM MST, 1 hour 56 minutes before

Area Forecast Discussion
National Weather Service Tucson AZ
216 PM MST Thu Aug 2 2018

.SYNOPSIS...Expect scattered showers and thunderstorms through
tonight. Slow moving storms could produce areas of heavy rain.
Daily rounds of isolated to scattered thunderstorms can be
expected into next week. Temperatures will remain within slightly
above normal for early August.

&&

.DISCUSSION...Morning sounding showed 1.42 inches of precipitable
water but fairly weak winds aloft, so expect thunderstorm
outflows to be the primary means of thunderstorm propagation once
again this evening.

As mentioned in the mid morning discussion an outflow/gravity wave
from late night MCS over northern Sinaloa was seen in northern
Sonora this morning. Further interrogation of satellite data
showed this boundary instrumental in firing up the strong storm
over the Santa Rita Mts late this morning. That gravity wave has
continued to move rapidly north this afternoon.

Meanwhile, other storms trying to initiate in best instability in
Pima and Santa Cruz counties. These storms will be slow movers as
this area is close to the ridge axis. By evening, more storms are
anticipated in eastern areas as instability increases there. Not
confident that there will be quite as much upper level support for
eastern storms as earlier anticipated but there are still
indications that Sonoran MCS later this evening will push an
outflow northward to keep storms going in SE AZ into the nighttime
hours.

The upper level ridge of high pressure will meander around for the
next few days. First it will shift south and west, but ultimately
to our north early next week, although there are differences in
models solutions concerning how far north and consequently how
deep of an moist easterly flow will set up over SE AZ. Overall,
can not really rule out storms on any day as moisture will remain
adequate, but there could be a ramp up in activity next week.

&&

.AVIATION...Valid through 04/00Z. ISOLD to SCT TSRA will occur
into the night time hours and TSRA will develop again Friday
afternoon. Brief periods of MVFR conditions are possible. Typical
diurnal wind trends with speeds less than 12 kts will continue
except for gusty and erratic thunderstorm outflows. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Sufficient moisture typical of early August remains
in place through the forecast, with daily afternoon/evening
thunderstorms continuing. Humidities will recover well each night
and only drop to around 20-30 percent each afternoon. Outside of
thunderstorm induced gusts, expect diurnal trends with speeds of 15
mph or less.

&&

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

&&

KD

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weather.gov/Tucson

In the hours before

Special weather statement, Aug 2, 11:40 AM MST, 4 hours 32 minutes before

Special Weather Statement
National Weather Service Tucson AZ
1140 AM MST THU AUG 2 2018

AZZ503-504-507-513-021915-
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-Tucson Metro Area including Tucson/Green
Valley/Marana/Vail-
1140 AM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PIMA AND NORTH
CENTRAL SANTA CRUZ COUNTIES UNTIL 1215 PM MST...

At 1138 AM MST, Doppler radar was tracking a strong thunderstorm 14
miles southeast of Green Valley over the Santa Rita Mountains. This
storm was nearly stationary.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Madera Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3161 11079 3171 11094 3185 11075 3178 11066
TIME...MOT...LOC 1838Z 221DEG 3KT 3173 11080

KD

Special weather statement, Aug 2, 12:20 PM MST, 3 hours 52 minutes before

Special Weather Statement
National Weather Service Tucson AZ
1220 PM MST THU AUG 2 2018

AZZ507-513-021945-
Upper San Pedro River Valley including Sierra
Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including
Bisbee/Canelo Hills/Madera Canyon-
1220 PM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL PIMA AND
NORTHEASTERN SANTA CRUZ COUNTIES UNTIL 1245 PM MST...

At 1220 PM MST, Doppler radar was tracking a strong thunderstorm 15
miles southeast of East Sahuarita, or 17 miles east of Green Valley.
This storm was nearly stationary.

Dime size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Highway 83 north of Sonoita.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3170 11071 3172 11078 3186 11073 3193 11061
      3182 11056
TIME...MOT...LOC 1920Z 226DEG 4KT 3179 11072

KD

Special weather statement, Aug 2, 2:48 PM MST, 1 hour 24 minutes before

Special Weather Statement
National Weather Service Tucson AZ
248 PM MST THU AUG 2 2018

AZZ502-503-515-022230-
Tohono O'odham Nation including Sells-Upper Santa Cruz River and
Altar Valleys including Nogales-Baboquivari Mountains including Kitt
Peak-
248 PM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL PIMA COUNTY UNTIL
330 PM MST...

At 246 PM MST, Doppler radar was tracking a strong thunderstorm 15
miles southeast of Kitt Peak, or 18 miles northwest of Arivaca,
moving west at 5 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Fresnal Canyon and Junction Of Highway 286 And Arivaca Road.

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 3186 11138 3168 11137 3162 11159 3184 11170
TIME...MOT...LOC 2146Z 077DEG 5KT 3175 11148

Meyer

Special weather statement, Aug 2, 3:04 PM MST, 1 hour 8 minutes before

Special Weather Statement
National Weather Service Tucson AZ
304 PM MST THU AUG 2 2018

AZZ502>504-515-022245-
Tohono O'odham Nation including Sells-Upper Santa Cruz River and
Altar Valleys including Nogales-Baboquivari Mountains including Kitt
Peak-Tucson Metro Area including Tucson/Green Valley/Marana/Vail-
304 PM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL PIMA COUNTY UNTIL 345 PM
MST...

At 303 PM MST, Doppler radar was tracking a strong thunderstorm just
south of Kitt Peak, or 18 miles east of Sells. This storm was nearly
stationary.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Kitt Peak, San Isidro and Pan Tak.

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 3208 11138 3186 11125 3184 11170 3203 11175
TIME...MOT...LOC 2203Z 104DEG 4KT 3189 11156

Meyer

Special weather statement, Aug 2, 3:08 PM MST, 1 hour 4 minutes before

Special Weather Statement
National Weather Service Tucson AZ
308 PM MST THU AUG 2 2018

AZZ502-022300-
Tohono O'odham Nation including Sells-
308 PM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL PIMA COUNTY UNTIL
400 PM MST...

At 308 PM MST, Doppler radar was tracking a strong thunderstorm 15
miles southwest of Sells, moving northwest at 5 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Vamori and Cowlic.

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 3168 11218 3188 11230 3192 11192 3166 11179
      3164 11204
TIME...MOT...LOC 2208Z 142DEG 6KT 3175 11204

Meyer

Special weather statement, Aug 2, 4:05 PM MST, 7 minutes before

Special Weather Statement
National Weather Service Tucson AZ
405 PM MST THU AUG 2 2018

AZZ502-504-022345-
Tohono O'odham Nation including Sells-Tucson Metro Area including
Tucson/Green Valley/Marana/Vail-
405 PM MST THU AUG 2 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL PIMA COUNTY UNTIL
445 PM MST...

At 403 PM MST, Doppler radar was tracking an area of strong
thunderstorms north of Sells over north central portions of the
Tohono O'Odham Nation, moving northeast at 5 to 10 mph.

Half inch hail and wind gusts up to 50 mph will be possible with
these storms, along with heavy rain.

Locations impacted include...
Santa Rosa, San Luis, Mountain Village, Santa Rosa Ranch, Covered
Wells, Anegam, Comobabi, Nolic, San Isidro, Sil Naggia, Ak Chin and
Queens Well.

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 3199 11164 3206 11216 3250 11213 3250 11178
      3233 11147
TIME...MOT...LOC 2303Z 217DEG 9KT 3220 11187

Meyer

The office that day

Everything else NWS Tucson, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 1, 5:00 PM MST	Special Weather Statement	TWC	Graham	30 min
Aug 1, 5:41 PM MST	Special Weather Statement	TWC	Santa Cruz	34 min
Aug 1, 5:59 PM MST	Special Weather Statement	TWC		46 min
Aug 1, 6:30 PM MST	Special Weather Statement	TWC	Santa Cruz	30 min
Aug 1, 7:19 PM MST	Special Weather Statement	TWC		41 min
Aug 1, 7:27 PM MST	Severe Thunderstorm Warning	TWC	Pima	48 min
Aug 1, 7:59 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	46 min
Aug 1, 8:14 PM MST	Severe Thunderstorm Warning	TWC	Pima	46 min
Aug 1, 8:25 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	110 min
Aug 1, 8:44 PM MST	Flash Flood Warning	TWC	Pima, Pinal	2 hr
Aug 1, 9:17 PM MST	Flash Flood Warning	TWC	Pima	118 min
Aug 1, 9:21 PM MST	Special Weather Statement	TWC	Pima	54 min
Aug 2, 11:40 AM MST	Special Weather Statement	TWC	Santa Cruz	35 min
Aug 2, 12:20 PM MST	Special Weather Statement	TWC	Santa Cruz	25 min
Aug 2, 2:48 PM MST	Special Weather Statement	TWC	Pima	42 min
Aug 2, 3:04 PM MST	Special Weather Statement	TWC	Pima	41 min
Aug 2, 3:08 PM MST	Special Weather Statement	TWC	Pima	52 min
Aug 2, 4:05 PM MST	Special Weather Statement	TWC	Pima	40 min
Aug 2, 4:38 PM MST	Severe Thunderstorm Warning	TWC	Pima	37 min

Nearby

Severe Thunderstorm Warnings in Arizona, 2018 Every severe thunderstorm warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.