Alert archive / Arizona / Special Weather Statements in 2016

Special Weather Statement, NWS Phoenix, AZ

August 19, 2016

NWS Phoenix, AZ issued this special weather statement at Aug 19, 2016, 8:14 PM MST. It was in force for 31 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 19, 2016, 8:14 PM MST (03:14 UTC)
Expired: Aug 19, 2016, 8:45 PM MST
In force: 31 min
Issued by: NWS Phoenix, AZ

The radar

The Yuma radar (KYUX), 134 km from the middle of the area, began a volume at 03:15 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

Phoenix, AZ (KPSR), launched 00:00Z, 3.2 hours before the alert went out and 139 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: 88 J/kg
Mixed-layer CIN: -140 J/kg
Mixed-layer LCL: 3007 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: -23 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Phoenix, AZ wrote its last area forecast discussion before this special weather statement went out at Aug 19, 2:10 PM MST, 6 hours 4 minutes earlier.

Area forecast discussion, Aug 19, 2:10 PM MST, 6 hours 4 minutes before

Area Forecast Discussion
National Weather Service Phoenix AZ
210 PM MST FRI AUG 19 2016

.SYNOPSIS...
Temperatures will remain near to slightly above the seasonal average
through early next week. Modest moisture levels will persist through
the weekend, and into early next week, with occasional spotty
thunderstorm chances. The primary threats from any of these storms
will be gusty winds, patchy blowing dust, and very isolated heavy
rainfall. The passage of a weather system during the middle of next
week should allow some warming and drying across the region.

&&

.DISCUSSION...

Tonight through Monday...

After another active late night/early morning period, we are seeing
a break in the thunderstorm activity at this hour across most of our
cwa. The shortwave that moved across our cwa last night/early this
morning is now moving off to our east. In its wake, we are seeing a
bit of convergent flow across south-central and SW AZ (as seen on
the latest SPC 500mb mesoscale analysis). This convergent flow is
likely keeping convective development from occurring over this region
at this time. Further west, in more favorable flow aloft ahead of
the next shortwave that is just now ejecting eastward out of a quasi-
stationary upper low that continues to spin just off the southern CA
coast, we are now starting to see a few storms developing over
Joshua Tree NP.

As far as the forecast for the rest the afternoon through tonight is
concerned, it appears that subsidence aloft will likely inhibit
convective development over south-central AZ this afternoon/evening.
On the other hand, a combination of greater low-level moisture (sfc
dewpoints up in the 60s), the presence of a weak jet max, and an
approaching shortwave is expected to enhance chances for storms
across SW AZ and SE CA, especially around the Yuma area. In fact,
the latest SPC mesoscale analysis is showing a MLCAPE bullseye of
1000 J/kg or greater over that region. Thus, have raised pops for
that region for the evening/overnight hours. As far as South-Central
AZ is concerned, the presence of a bit of a cap between 600 and 700
mb and less available moisture through the column means that it will
likely take some rather robust outflows from the north to produce
any thunderstorms, thus keeping pops over that region well down in
the slight chance range.

There is growing evidence that thunderstorm activity will become
more expansive Saturday afternoon along the Mogollon Rim and White
Mountains as the moisture axis shifts east ahead of the main
positively tilted trough. Certainly, much of Gila County would stand
to receive better convective coverage under such an evolution, but
once again signals are mixed whether outflow boundaries would be
sufficient to spark organized storms at lower elevations. Much of
the activity Saturday may be dependent on storm scale evolution
tonight and potential modification of the environmental moisture
profiles. Should deeper 10 g/kg mixing ratios materialize in the
face of steep outflow boundaries, then storm formation would be
favored although ensemble means are still not optimistic.

Tuesday through next Friday...

Operational models continue to show the aforementioned positively
tilted trough reinforced by upstream energy sweeping through the
forecast area in the strong westerly flow next Tuesday. While the
approach of the wave and height falls could spur a convectively
active period Monday afternoon/evening, this shortwave passage
should also act to scour the remaining residual moisture east for
the forecast area and place the entire region into subsident NW
flow. With agreement among the majority of medium range models and
conceptual pattern recognition, the middle of next week should be
convectively inactive with temperatures warming moderately.

&&

.AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL:

Breezy westerly component winds are in store today with afternoon
and early evening gusts of 17 to 20 kts. There is a slight chance of
rain showers and thunderstorms this afternoon and tonight although
there was not enough confidence on their likelihood and exact timing
to include them in the TAFS. Outflow boundaries, most likely from
the west or north from distant storms, could also produce some
occasionally gusty winds this afternoon and tonight. Skies will be
partly cloudy with occasional mid to high cloud cigs developing this
evening from 10 to 25K ft. There is also a slight chance that
isolated patchy dust could reduce some slant range visibilities this
afternoon and evening.

Southeast California/Southwest Arizona including KIPL and KBLH:

Skies will be clear to partly cloudy with few to sct mid and high
level clouds along with light and variable and westerly component
winds. There is also a slight chance of thunderstorms although there
was not enough confidence on their likelihood and timing to include
them in the TAFS. Outflows from distant thunderstorms this afternoon
and evening could also produce variable gusty winds and a slight
chance of reduced slant range visibilities due to patchy dust.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Monday through Friday...

An upper level trough tracking across the region from the west will
bring a chance of thunderstorms and wetting rain from Monday evening
through Tuesday morning from the south central deserts to the high
country. Maximum temperatures will be near normal during the period
except for Tuesday when they will dip to slightly below normal. Some
drying on Wednesday will cause minimum RH levels to fall to 13 to 16
percent range in SE CA and the 15 to 21 percent range elsewhere on
Wednesday before recovering slightly on Thursday and Friday. Expect
gusty outflow winds from isolated to scattered thunderstorms Monday
evening and Tuesday morning along with breezy westerly winds Tuesday
afternoon with gusts of 17 to 22 mph. Overnight recoveries will be
fair in southeast CA to good elsewhere.

&&

.FIRE WEATHER...
Sunday through Thursday...
Very typical mid August temperatures will persist through the most
of next week, with drier westerly flow gradually displacing moisture
and thunderstorm chances. Wetting rain chances will favor central
Arizona early in the week with little chance of any showers by the
middle of the week. Minimum humidity levels will range from 15 to 20
percent at lower elevations to 20 to 30 percent over mountainous
terrain. Overnight recovery will be good to excellent. Aside from
stronger wind gusts near thunderstorms, only occasional upslope
gustiness will prevail.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters are encouraged to report based on standard operating
procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.

&&

Visit us on Facebook...Twitter...and at weather.gov/phoenix

DISCUSSION...Percha/MO
AVIATION...Sawtelle
FIRE WEATHER...Sawtelle

In the hours before

Local storm report, Aug 19, 6:10 PM MST, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
610 PM MST FRI AUG 19 2016

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

0609 PM     DUST STORM       1 NW IMPERIAL           32.85N 115.57W
08/19/2016                   IMPERIAL           CA   STORM CHASER

            CHASER REPORTS VISIBILITIES BELOW 1/8 OF A
            MILE IN IMPERIAL. .

&&

BH

Special weather statement, Aug 19, 6:11 PM MST, 2 hours 3 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
611 PM MST FRI AUG 19 2016

AZZ020-CAZ031-033-200200-
LOWER COLORADO RIVER VALLEY AZ AZ-IMPERIAL COUNTY CA-
LOWER COLORADO RIVER VALLEY CA CA-
611 PM MST FRI AUG 19 2016

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  SOUTHWESTERN LA PAZ AND EAST CENTRAL IMPERIAL COUNTIES

UNTIL 700 PM MST/700 PM PDT/

AT 611 PM MST/611 PM PDT/...DOPPLER RADAR WAS TRACKING A STRONG
THUNDERSTORM 15 MILES SOUTH OF CIBOLA...OR 18 MILES NORTHWEST OF
MARTINEZ LAKE...MOVING SOUTH AT 10 MPH.

DIME SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM. THIS STORM IS ALSO PRODUCING HEAVY RAIN.

BLOWING DUST FROM THE STORM IS ALSO POSSIBLE.

LOCATIONS IMPACTED INCLUDE...
GLAMIS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LOCALLY DENSE BLOWING DUST IS POSSIBLE.  IF YOU ENCOUNTER BLOWING
DUST WHILE DRIVING...PULL OVER AS FAR OFF THE ROADWAY AS POSSIBLE AND
PARK. TURN OFF YOUR HEADLIGHTS AND KEEP YOUR FOOT OFF THE BRAKE.

&&

LAT...LON 3322 11481 3322 11460 3290 11456 3283 11455
      3293 11506 3299 11510
TIME...MOT...LOC 0111Z 002DEG 8KT 3313 11474

AD

Local storm report, Aug 19, 6:26 PM MST, 1 hour 48 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
626 PM MST FRI AUG 19 2016

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

0624 PM     DUST STORM       3 E ALAMORIO            32.98N 115.41W
08/19/2016                   IMPERIAL           CA   TRAINED SPOTTER

            BLOWING DUST, VISIBILITY 1/8 MI.

&&

NWS PHOENIX AZ
IRIS SYSTEM

Special weather statement, Aug 19, 7:03 PM MST, 1 hour 11 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
703 PM MST FRI AUG 19 2016

AZZ025-026-CAZ031-033-200245-
SOUTHWEST DESERTS AZ-YUMA/MARTINEZ LAKE AND VICINITY AZ-
IMPERIAL COUNTY CA-LOWER COLORADO RIVER VALLEY CA CA-
703 PM MST FRI AUG 19 2016

...SPECIAL WEATHER STATEMENT...

AT 701 PM MST/701 PM PDT/...DOPPLER RADAR WAS TRACKING A LINE OF
STRONG WINDS ALONG A LINE EXTENDING FROM 7 MILES SOUTH OF MARTINEZ
LAKE TO NEAR WINTERHAVEN TO 12 MILES NORTH OF ALGODONES DUNES...AND
MOVING SOUTHWEST AT 15 MPH.

WINDS 30 FROM 40 MPH WILL BE POSSIBLE WITH THESE STORMS. BLOWING
DUST IS ALSO POSSIBLE.

LOCATIONS IMPACTED INCLUDE...
YUMA...SOMERTON...GADSDEN...FORTUNA FOOTHILLS...BLAISDELL...ARABY...
GORDON'S WELL...ANDRADE...ALGODONES DUNES...WINTERHAVEN AND KINTER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LOCALLY DENSE BLOWING DUST IS POSSIBLE.  IF YOU ENCOUNTER BLOWING
DUST WHILE DRIVING...PULL OVER AS FAR OFF THE ROADWAY AS POSSIBLE AND
PARK. TURN OFF YOUR HEADLIGHTS AND KEEP YOUR FOOT OFF THE BRAKE.

&&

LAT...LON 3251 11482 3255 11479 3256 11481 3262 11481
      3266 11475 3272 11472 3269 11511 3277 11520
      3301 11487 3286 11461 3294 11432 3240 11450
TIME...MOT...LOC 0201Z 038DEG 12KT 3287 11446 3281 11466 3292 11485

AD

Special weather statement, Aug 19, 7:28 PM MST, 46 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
728 PM PDT FRI AUG 19 2016

CAZ033-200300-
IMPERIAL COUNTY CA-
728 PM PDT FRI AUG 19 2016

...SPECIAL WEATHER STATEMENT...

AT 727 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 13
MILES NORTH OF ALGODONES DUNES...OR 24 MILES NORTHWEST OF YUMA...
MOVING WEST AT 15 MPH.

WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH THIS STORM. THIS
STORM IS CAPABLE OF PRODUCING HEAVY RAIN.

LOCATIONS IMPACTED INCLUDE...
GLAMIS.

LAT...LON 3304 11486 3287 11478 3273 11508 3300 11518
TIME...MOT...LOC 0227Z 068DEG 14KT 3293 11491

AD

Special weather statement, Aug 19, 8:14 PM MST, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
814 PM MST FRI AUG 19 2016

AZZ026-027-200345-
SOUTHWEST DESERTS AZ-SOUTHWEST MARICOPA COUNTY AZ-
814 PM MST FRI AUG 19 2016

...SPECIAL WEATHER STATEMENT...

AT 813 PM MST...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER
SENTINEL...OR 31 MILES WEST OF GILA BEND...MOVING EAST AT 15 MPH.

HEAVY RAINS AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
INTERSTATE 8...SENTINEL...DATELAND AND PALOMA.

LAT...LON 3267 11350 3291 11356 3304 11293 3276 11287
TIME...MOT...LOC 0313Z 265DEG 12KT 3286 11321

AD

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 19, 5:13 PM MST	Blowing Dust Advisory	PSR		75 min
Aug 19, 5:31 PM MST	Special Weather Statement	PSR		44 min
Aug 19, 6:14 PM MST	Severe Thunderstorm Warning	PSR	Yuma	31 min
Aug 19, 6:44 PM MST	Blowing Dust Advisory	PSR		76 min
Aug 19, 7:03 PM MST	Special Weather Statement	PSR		42 min
Aug 19, 8:19 PM MST	Areal Flood Advisory	PSR	Maricopa, Yuma	3 hr
Aug 19, 8:50 PM MST	Areal Flood Warning	PSR	Maricopa, Yuma	3 hr
Aug 19, 8:53 PM MST	Special Weather Statement	PSR		52 min
Aug 19, 9:50 PM MST	Special Weather Statement	PSR	Yuma	40 min
Aug 19, 10:15 PM MST	Blowing Dust Advisory	PSR		9 min
Aug 19, 10:21 PM MST	Dust Storm Warning	PSR		99 min
Aug 20, 3:46 PM MST	Special Weather Statement	PSR		59 min
Aug 20, 4:09 PM MST	Special Weather Statement	PSR	La Paz	66 min
Aug 20, 4:22 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	23 min
Aug 20, 4:53 PM MST	Special Weather Statement	PSR	Gila	67 min
Aug 19, 5:03 PM MST	Areal Flood Advisory	PSR	Riverside	117 min
Aug 19, 5:34 PM MST	Special Weather Statement	PSR	Riverside	26 min
Aug 19, 5:44 PM MST	Special Weather Statement	PSR	Imperial	31 min
Aug 19, 6:11 PM MST	Special Weather Statement	PSR	Imperial	49 min
Aug 19, 6:28 PM MST	Dust Storm Warning	PSR		92 min
Aug 19, 7:28 PM MST	Special Weather Statement	PSR	Imperial	32 min
Aug 20, 2:27 PM MST	Special Weather Statement	PSR	Riverside	33 min
Aug 20, 2:46 PM MST	Severe Thunderstorm Warning	PSR	Riverside	44 min
Aug 20, 3:55 PM MST	Areal Flood Advisory	PSR	Riverside	3 hr

Nearby

Special Weather Statements in Arizona, 2016 Every special weather statement in 2016

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.