Alert archive / Arizona / Special Weather Statements in 2018

Special Weather Statement, NWS Tucson, AZ

July 17, 2018Pima County, Arizona

NWS Tucson, AZ issued this special weather statement at Jul 17, 2018, 9:39 PM MST for Pima County, Arizona. It was in force for 51 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: Jul 17, 2018, 9:39 PM MST (04:39 UTC)
Expired: Jul 17, 2018, 10:30 PM MST
In force: 51 min
Issued by: NWS Tucson, AZ

County Pima County, AZ

The radar

The Tucson radar (KEMX), 104 km from the middle of the area, began a volume at 04:43 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.

The nearest sounding before it

Tuscon, AZ (KDMA), launched 00:00Z, 4.7 hours before the alert went out and 80 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: 46 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 3087 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 45 m²/s²
0-3 km storm-relative helicity: 63 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Jul 17, 9:05 PM MST, 34 minutes earlier.

Area forecast discussion, Jul 17, 9:05 PM MST, 34 minutes before

Area Forecast Discussion
National Weather Service Tucson AZ
905 PM MST Tue Jul 17 2018

.SYNOPSIS...Plenty of moisture and instability will remain in
place to support daily showers and thunderstorms through at least
the middle of the week. Partial drying from the east may lead to
reduced thunderstorm coverage by the weekend, along with hotter
temperatures.

&&

.DISCUSSION...Thunderstorms continue this evening mainly SW of
Tucson where greatest instability resides, but a couple of storms
even occurring over the Rim at this hour. 00z sounding showed
increased easterly mid level flow which is aiding in storm
intensities, increasing storm movement and providing increased
potential for strong wind gusts. HRRR has been verifying well
since late this afternoon and continues to show that thunderstorms
will continue to move across primarily western and central Pima
County into the overnight hours. Cannot completely rule out a
stray shower or storm in the Tucson Metro eastward through at
least midnight. Will keep the 10 percent chances there as in the
going forecast.

&&

.AVIATION...Valid through 19/06Z.
Isolated to scattered SHRA/TSRA mainly west of KTUS and near the
International Border through the night. The Wednesday morning
hours should be dry but at least ISOLD TSRA coverage is expected
again after 18/19z. Cloud bases 8k-12k ft AGL with SCT- BKN
clouds above 20k. Winds remain below 12 kts through the period,
with stronger gusts possible around TSRA. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...A shift in the weather pattern will begin to
take place, bringing in drier air and reducing rain chances.
However, isolated storms could still develop, especially over the
higher terrain. Temperatures also gradually warm through the week.
20-ft winds remain below 15 mph, although the Upper Gila River
Valley will experience gustier northwesterly winds at times.

&&

.PREV DISCUSSION...The upper low moving through Sonora, Mexico
along with the northern extent of the inverted trough passing
through Arizona was showing up nicely in Satellite water vapor
imagery. Showers and a few thunderstorms were developing this
afternoon in the vicinity of this upper low and across far western
Pima county. This general area will be the main focus of showers
and thunderstorm this evening and tonight. Cannot rule out a few
thunderstorms farther north though. Otherwise, high pressure aloft
will become established over the Great Basin region around
Wednesday before shifting over the Desert Southwest this coming
weekend. This adjustment in the position of the upper high will
result in some warming and drying aloft by the end of the week.
This warmer and drying will eventually translate to less
thunderstorm activity and hotter daytime temperatures by the
weekend.

&&

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

&&

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

In the hours before

Special weather statement, Jul 17, 6:18 PM MST, 3 hours 21 minutes before

Special Weather Statement
National Weather Service Tucson AZ
618 PM MST TUE JUL 17 2018

AZZ501-502-180200-
Tohono O'odham Nation including Sells-Western Pima County Including
Ajo/Organ Pipe Cactus National Monument-
618 PM MST TUE JUL 17 2018

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL PIMA COUNTY UNTIL
700 PM MST...

At 617 PM MST, Doppler radar was tracking a strong thunderstorm near
Organ Pipe National Monument, or 51 miles west of Sells, moving west
at 20 mph.

Wind gusts of 50 mph and blowing dust will be possible with this
storm.

Locations impacted include...
Organ Pipe National Monument and Lukeville.

LAT...LON 3206 11295 3200 11264 3184 11268 3195 11305
TIME...MOT...LOC 0117Z 106DEG 19KT 3195 11275

Zell

Special weather statement, Jul 17, 8:30 PM MST, 1 hour 9 minutes before

Special Weather Statement
National Weather Service Tucson AZ
830 PM MST TUE JUL 17 2018

AZZ502>504-515-180415-
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-
830 PM MST TUE JUL 17 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PIMA COUNTY UNTIL
915 PM MST...

At 830 PM MST, Doppler radar was tracking a strong thunderstorm over
Three Points, or 23 miles northwest of Green Valley, moving northwest
at 25 mph.

Wind gusts of 50 mph and blowing dust will be possible with this
storm.

Locations impacted include...
Three Points, Kitt Peak, Valencia West, Tucson Estates, Santa Rosa
Ranch, Ryan Field, Pan Tak, San Pedro and Queens Well.

LAT...LON 3184 11132 3194 11162 3226 11179 3233 11140
      3212 11109
TIME...MOT...LOC 0330Z 117DEG 23KT 3206 11132

Zell

Special weather statement, Jul 17, 9:39 PM MST, 0 minutes before

Special Weather Statement
National Weather Service Tucson AZ
939 PM MST TUE JUL 17 2018

AZZ502>504-515-180530-
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-
939 PM MST TUE JUL 17 2018

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL PIMA COUNTY UNTIL 1030 PM
MST...

At 938 PM MST, Doppler radar was tracking an area of strong
thunderstorms from west of Three Points to north of Sells, moving
west at 15 mph.

Wind gusts of 50 mph and blowing dust will be possible with these
storms.

Locations impacted include...
Sells, Kitt Peak, Santa Rosa Ranch, Little Tucson, Pan Tak, San
Pedro, Topawa, Big Fields, Cowlic, Artesa, Comobabi, Nolic and San
Isidro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3212 11140 3195 11140 3170 11198 3198 11221
      3216 11199
TIME...MOT...LOC 0438Z 093DEG 13KT 3204 11148

Zell

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 6:18 PM MST	Special Weather Statement	TWC		42 min
Jul 17, 6:57 PM MST	Severe Thunderstorm Warning	TWC	Santa Cruz	21 min
Jul 17, 8:30 PM MST	Special Weather Statement	TWC	Pima	45 min
Jul 17, 8:40 PM MST	Severe Thunderstorm Warning	TWC	Pima	35 min
Jul 17, 9:48 PM MST	Areal Flood Advisory	TWC	Pima	117 min
Jul 17, 9:58 PM MST	Severe Thunderstorm Warning	TWC	Pima	47 min
Jul 17, 11:48 PM MST	Areal Flood Advisory	TWC	Pima	117 min
Jul 18, 3:03 AM MST	Severe Thunderstorm Warning	TWC	Pima	42 min
Jul 18, 1:08 PM MST	Special Weather Statement	TWC	Santa Cruz	67 min
Jul 18, 4:08 PM MST	Special Weather Statement	TWC	Santa Cruz	37 min

Nearby

Special Weather Statements in Arizona, 2018 Every special weather statement 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.