Alert archive / Arizona / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 29, NWS Flagstaff, AZ

July 19, 2018Yavapai County, Arizona

NWS Flagstaff, AZ issued this severe thunderstorm warning at Jul 19, 2018, 5:15 PM MST for Yavapai County, Arizona. It was in force for 30 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 19, 2018, 5:15 PM MST (00:15 UTC)
Expired: Jul 19, 2018, 5:45 PM MST
In force: 30 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 53 km from the middle of the area, began a volume at 00:18 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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 0.3 hours before the alert went out and 72 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2260 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 17 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

887 
WUUS55 KFGZ 200015
SVRFGZ
AZC025-200045-
/O.NEW.KFGZ.SV.W.0029.180720T0015Z-180720T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Flagstaff AZ
515 PM MST THU JUL 19 2018

The National Weather Service in Flagstaff has issued a

* Severe Thunderstorm Warning for...
  Yavapai County in west central Arizona...

* Until 545 PM MST

* At 514 PM MST, a severe thunderstorm was located over Camp Verde,
  moving north at 15 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Expect damage to roofs, siding, and trees. 

* Locations impacted include...
  Camp Verde, Mcguireville, Montezuma Well, Montezuma Castle National
  Monument, Rimrock, Middle Verde, Lake Montezuma, V Bar V Visitors
  Center and Clear Creek Campgrounds.

This includes the following highways...
 Interstate 17 between mile markers 286 and 297.
 State Route 260 between mile markers 217 and 232.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3449 11170 3451 11191 3463 11190 3469 11179
      3466 11169
TIME...MOT...LOC 0014Z 181DEG 12KT 3456 11181 

HAIL...0.88IN
WIND...60MPH
 
$$

1 follow-up statement

298 
WWUS55 KFGZ 200046
SVSFGZ

Severe Weather Statement
National Weather Service Flagstaff AZ
546 PM MST THU JUL 19 2018

AZC025-200054-
/O.EXP.KFGZ.SV.W.0029.000000T0000Z-180720T0045Z/
Yavapai-
546 PM MST THU JUL 19 2018

...THE SEVERE THUNDERSTORM WARNING FOR YAVAPAI COUNTY WILL EXPIRE AT
545 PM MST...
                
The severe thunderstorm that was just east of Camp Verde, which 
prompted the warning, has weakened below severe limits. The warning 
will be allowed to expire. Heavy rain is still occurring with this 
storm, from just east of Camp Verde, toward the Bullpen area.

LAT...LON 3449 11170 3451 11191 3463 11190 3469 11179
      3466 11169
TIME...MOT...LOC 0044Z 181DEG 12KT 3466 11181 

$$

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 Flagstaff, AZ wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 19, 2:53 PM MST, 2 hours 22 minutes earlier.

Area forecast discussion, Jul 19, 2:53 PM MST, 2 hours 22 minutes before

Area Forecast Discussion
National Weather Service Flagstaff AZ
253 PM MST Thu Jul 19 2018

.SYNOPSIS...Expect afternoon and evening showers and thunderstorms
through at least Saturday. The greatest coverage and highest
potential for stronger storms will be over the Mogollon Rim and
Yavapai County where areas of heavy rain could produce localized
flooding. Warmer afternoon temperatures and less storm coverage
may start on Sunday.

&&

.DISCUSSION...Showers and thunderstorms developed over the higher
terrain of northern Arizona by late morning. Most storms are
moving slowly to the west this afternoon with some areas receiving
heavy to very heavy rain and hail. Local street flooding and
flowing and washes have also been reported under the stronger
storms.

Storms will decrease some after dark tonight...but some storms
will continue well past midnight.

For Friday and Saturday, the subtropical high pressure re-
centers near Four Corners on Friday. This puts northern Arizona
in very light south to southeast flow pattern with rich monsoon
moisture through Saturday. Expect primarily afternoon and evening
showers and thunderstorms with storms moving very slowly from
south to north. Heavy rain and flash flooding will be the main
storm threats.

From Sunday through Thursday...The ridge of high pressure slowly
moves westward over Arizona. This will decrease the southerly
flow of deep moisture into Arizona. Temperatures will also
increase high temperatures to above average levels.

&&

.AVIATION...For the 00Z package...NUMRS SHRA/TSRA with MVFR/IFR
conditions and gusty winds through 02Z. VFR conditions outside of
storms. ISOLD-SCT -SHRA/-TSRA after 02Z. Storms will develop again
Friday after 17Z becoming SCT-NMRS SHRA/TSRA with ISOLD +TSRAGR by
19Z-20Z. Convective activity most wdsprd after 21Z. Strongest
storms will produce localized MVFR/IFR conditions and wind gusts
to 50kts. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...An active monsoon pattern with scattered to
numerous slow moving thunderstorms will continue through Saturday.
Heavy rain and erratic thunderstorm winds will be the main threats.
Outside of thunderstorms, winds will generally be light.

Sunday through Tuesday...Thunderstorm chances will continue each day
through the weekend into early next week. There is a possibility of
a slight downturn in activity sometime next week with a warming
trend.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...MAS
AVIATION...MAS
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff

In the hours before

Local storm report, Jul 19, 1:36 PM MST, 3 hours 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
136 PM MST THU JUL 19 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0126 PM     HAIL             3 S FLAGSTAFF MALL      35.18N 111.58W
07/19/2018  E1.00 INCH       COCONINO           AZ   NWS EMPLOYEE

&&

MCT

Local storm report, Jul 19, 2:36 PM MST, 2 hours 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
236 PM MST THU JUL 19 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     HEAVY RAIN       1 ESE FLAGSTAFF MALL    35.22N 111.57W
07/19/2018  E4.57 INCH       COCONINO           AZ   MESONET

            ALERT RAIN GAUGE NEAR FLAGSTAFF MALL. THE
            DURATION OF THE HEAVY RAIN EVENT WAS 1 HOUR
            45 MINUTES.

&&

MCT

Local storm report, Jul 19, 2:48 PM MST, 2 hours 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
248 PM MST THU JUL 19 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0211 PM     FLASH FLOOD      2 E DOWNTOWN FLAGSTAFF  35.20N 111.61W
07/19/2018                   COCONINO           AZ   PUBLIC

            REPORT WITH VIDEOS FROM TWITTER SHOW
            ESTIMATED 2.5 TO 3 FEET OF FLOWING WATER IN
            WASH ALONG SIDE 4TH STREET/BUTLER AVE
            INTERSECTION (SWITZER WASH).

&&

MCT

Local storm report, Jul 19, 3:11 PM MST, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
311 PM MST THU JUL 19 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0130 PM     FLASH FLOOD      1 E FLAGSTAFF MALL      35.22N 111.57W
07/19/2018                   COCONINO           AZ   PUBLIC

            REPORT FROM TWITTER WITH PHOTOS OF FLOODED
            PARKING LOT AT VOLKSWAGEN DEALERSHIP. WATER
            UP TO THE HOOD OF VEHICLES. ESTIMATED 2 FEET
            DEEP. THE TIME WAS ESTIMATED BETWEEN 1:00 TO
            2:00 PM.

&&

MCT

Special weather statement, Jul 19, 4:40 PM MST, 35 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
440 PM MST THU JUL 19 2018

AZZ004-005-009-200030-
Kaibab Plateau-Marble and Glen Canyons-Northeast Plateaus and Mesas
Hwy 264 Northward-
440 PM MST THU JUL 19 2018

...SIGNIFICANT WEATHER ADVISORY FOR COCONINO COUNTY UNTIL 530 PM
MST...

At 439 PM MST, National Weather Service Doppler radar was tracking
developing thunderstorms from Page southward. These storms will
initially bring gusty winds to the greater Page area, including Lake
Powell and other recreation sites. Rainfall will follow.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Page, Big Five, LeChee, Marble Canyon, Lees Ferry, Antelope Canyon
Near Sr 98, Wahweap, Antelope Creek Basin, Lake Powell and Waterholes
Canyon.

LAT...LON 3700 11129 3677 11144 3678 11168 3700 11163
TIME...MOT...LOC 2339Z 205DEG 11KT 3694 11149

Special weather statement, Jul 19, 5:02 PM MST, 13 minutes before

Special Weather Statement
National Weather Service Flagstaff AZ
502 PM MST THU JUL 19 2018

AZZ007-008-200045-
Coconino Plateau-Yavapai County  Mountains-
502 PM MST THU JUL 19 2018

...SIGNIFICANT WEATHER ADVISORY FOR YAVAPAI AND COCONINO COUNTIES
UNTIL 545 PM MST...

At 502 PM MST, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Seligman, or 55 miles northwest of Chino Valley,
moving northwest at 10 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Fraziers Well and Hualapai Reservation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3582 11333 3582 11305 3554 11259 3531 11299
      3527 11333
TIME...MOT...LOC 0002Z 131DEG 9KT 3543 11298

JDS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 5:02 PM MST	Special Weather Statement	FGZ		43 min
Jul 19, 5:13 PM MST	Severe Thunderstorm Warning	FGZ	Gila	47 min
Jul 19, 5:56 PM MST	Severe Thunderstorm Warning	FGZ	Gila	49 min
Jul 19, 6:01 PM MST	Flash Flood Warning	FGZ	Gila	3 hr
Jul 19, 6:09 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Jul 19, 6:32 PM MST	Flash Flood Warning	FGZ	Navajo	3 hr
Jul 19, 6:42 PM MST	Special Weather Statement	FGZ		33 min
Jul 19, 6:42 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Gila, Yavapai	48 min
Jul 19, 7:27 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	48 min
Jul 19, 9:25 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Jul 20, 1:03 PM MST	Special Weather Statement	FGZ	Yavapai	27 min
Jul 20, 1:30 PM MST	Special Weather Statement	FGZ	Yavapai	30 min
Jul 20, 3:25 PM MST	Special Weather Statement	FGZ	Yavapai	35 min
Jul 20, 4:04 PM MST	Special Weather Statement	FGZ		26 min
Jul 20, 4:24 PM MST	Special Weather Statement	FGZ		36 min
Jul 20, 4:34 PM MST	Special Weather Statement	FGZ	Coconino	26 min
Jul 20, 4:59 PM MST	Special Weather Statement	FGZ		31 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.