Flash Flood Warning 28, NWS Phoenix, AZ

099 
WGUS75 KPSR 310727
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1227 AM MST Wed Jul 31 2019

AZC012-013-311045-
/O.CON.KPSR.FF.W.0028.000000T0000Z-190731T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-Maricopa AZ-
1227 AM MST Wed Jul 31 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM MST FOR
EAST CENTRAL LA PAZ AND MARICOPA COUNTIES...

At 1216 AM MST, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain over the warned area. Up to two
inches of rain has already fallen with up to an additional inch of
rain per hour possible. Flash flooding is expected to begin shortly.

Flash flooding will remain over mainly rural areas of east central La
Paz and Maricopa Counties including Harquahala and Salome Road.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

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 3374 11333 3369 11330 3348 11301 3330 11312
      3353 11357 3375 11355

$$

LJH

706 
WGUS75 KPSR 310803
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
103 AM MST Wed Jul 31 2019

AZC012-013-311045-
/O.CON.KPSR.FF.W.0028.000000T0000Z-190731T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-Maricopa AZ-
103 AM MST Wed Jul 31 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM MST FOR
EAST CENTRAL LA PAZ AND MARICOPA COUNTIES...

At 101 AM MST, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain over the warned area. Flash 
flooding is expected to begin shortly. Since 1230 am, rain has 
decreased somewhat in the warned area but locally heavy rain will 
continue into the early mornng. Radar indicated that very heavy rain 
fell along Interstate 10 earlier and flash flooding or flooding is 
possible near or on the interstate.

Flash flooding will remain over mainly rural areas of east central La
Paz and Maricopa Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

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 3374 11333 3369 11330 3354 11310 3334 11319
      3353 11357 3375 11355

$$

CB

785 
WGUS75 KPSR 311022
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
322 AM MST Wed Jul 31 2019

AZC012-013-311045-
/O.CON.KPSR.FF.W.0028.000000T0000Z-190731T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-Maricopa AZ-
322 AM MST Wed Jul 31 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM MST FOR
EAST CENTRAL LA PAZ AND MARICOPA COUNTIES...

At 320 AM MST, Doppler radar and automated rain gauges indicated 
thunderstorms had mostly ended over the warned area. Significant 
rain fell earlier in the warned area along the Interstate 10 
corridor and as such flash flooding is still possible. Thus the 
warning will be allowed to continue.

Flash flooding will remain over mainly rural areas of east central La
Paz and Maricopa Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

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 3374 11333 3369 11330 3354 11310 3334 11319
      3353 11357 3375 11355

$$

CB

Area Forecast Discussion
National Weather Service Phoenix AZ
1015 PM MST Tue Jul 30 2019

.UPDATE...
Updated short-term forecast to refine PoPs/QPF. Precipitation has
increased in coverage this evening, associated with an MCV across
central Arizona and a larger inverted trough across northern
Sonora. Also extended Flash Flood Watch into Wednesday morning
based on consensus from CAMs.

&&

.SYNOPSIS...
A significant increase in thunderstorm activity is expected in the
tonight through Wednesday time frame...mainly for Arizona. Locally
heavy rain is expected which brings the potential for flash
flooding. There is also potential for strong winds and blowing
dust as well. Significantly cooler temperatures can be expected
on Wednesday. A drying and warming trend will occur later in the
week, though slight chances for thunderstorms will continue each
day...mainly over the higher terrain of south-central Arizona.

&&

.DISCUSSION...
Storms are percolating over the higher terrain and far southern
Arizona - a bit slower than previously anticipated due to
lingering cloud cover. There are at least a couple of small scale
cyclonic circulations in the flow over/near AZ. One of the them is
moving from southern Maricopa/western Pima into Yuma County.
Another is moving from Pinal into Gila County and yet another is
centered over the Gulf of California near San Carlos Sonora. The
first two may be factors in the activity this afternoon/evening
(especially the second one) and the third one will be a factor
later tonight and Wednesday morning (especially for southwest AZ
and western Maricopa). Precipitable water values are quite high
over southwest AZ and trend down east and north of there.

The precipitable water values and the disturbances create the
potential for heavy rain and in turn flash flooding. Thus,
expanded the Flash Flood Watch northward to cover nearly all of
our Arizona zones. A limiting factor is that steering flow is
roughly southeasterly at 15 knots. Such movement may actually
hinder the more serious flooding (less residence time over a given
area) but it may help the severe potential (marginally). The CAMs
and HREF have been hitting on Pima County being very active and
producing a large area of outflow. They have also been depicting
at least isolated activity over the higher terrain areas to our
northeast through southeast. From there, they have been depicting
development over metro Phoenix this evening with activity
tracking to southwest AZ (especially La Paz County) later this
evening (weakening in the process). With the outflows comes the
potential for blowing dust. Issued a long-fused blowing dust
Advisory in advance of the dust in order to provide a heads up to
where we think the blowing dust will be most likely.

As is always the case, if we don't have quite enough of one
ingredient or another, then things don't wind up panning out as
anticipated. The fact that surface dew points are at (and above)
60 degrees in the mid afternoon is encouraging. It could be that
we don't get quite enough surface heating and/or the outflows
don't get quite strong enough. A key for our the lower elevations
of south-central AZ (including metro Phoenix) tonight will be how
active things get over Pima County (coverage and strength of
storms). Secondarily will be storm development over northern Pinal
and southern Gila. But overall, there are to many factors in play
to think northing will happen over the next 24 hours. Time will
tell. There is less uncertainty in the forecast for southeast
California as there is good model agreement that storm activity
will not go very far west of the Lower Colorado River Valley.

By Thursday, a gradual drying trend will commence as south-
southwesterly flow aloft strengthens across southern California
and western Arizona. However, enough moisture will remain in place
to support slight chances of thunderstorms across south-central
Arizona, especially over the higher terrain north and east of
Phoenix. These chances will continue into the weekend, amidst a
warming trend, as high pressure aloft redevelops and strengthens
over New Mexico.

&&

.AVIATION...Updated at 0010 UTC.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Scattered showers and thunderstorms will be expected through 03Z
at the Phoenix terminals as southerly to westerly winds become
overtaken by easterly outflows within the next hour by 01Z. Wind
gusts with the outflows will be around 25-30 knots, with stronger
40-60 knot gusts possible within thunderstorm microbursts. The
biggest uncertainty in over the next few hours is whether the
storms in the East Valley will congeal into a line that is able to
persist into KPHX, KDVT and the West Valley or if it will weaken
into shower activity due to a weak midlevel stable layer. For now,
we have thunderstorms in the TAFs through 02-03Z for the Phoenix
sites with VCSH after that into the overnight hours as convective
potential will be dependent on how much we become worked over by
the current storms. Easterly to southerly winds are currently
expected to persist through mid-afternoon on Wednesday, but this
will be dependent on how widespread shower activity is tonight and
how much BKN to OVC decks above 8 kft persist into tomorrow,
which will most likely inhibit convection tomorrow to some extent.

Southeast California/Southwest Arizona including KIPL and KBLH:
Chances for precipitation today in the western deserts is rather
low; any showers or storms that form will be quite isolated. For
the most part, expect SCT-BKN mid and high level decks for the 24
hour TAF period with bases mostly aoa 10k feet. Winds will favor
the south at KBLH with speeds over 20 kts at times today. Winds to
favor the southeast through the 24 hours period at KIPL with
gustiness possible during the afternoon allowing winds to peak
over 20 kts as well. Overnight tonight chances for showers will
increase along the lower Colorado River and at the KBLH TAF site.
We continue to maintain VCSH after 06Z in the KBLH TAF, with some
thunderstorm potential that is too low to mention at this time.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Friday through Tuesday: Moisture and instability continue to
decline on Friday with little change through Tuesday. However,
there will be at least a slight chance of storms continuing
over the the higher terrain of south-central AZ. Minimum
humidities will dip below 15% over southeast California but
remain at or above 15% east of there. Overnight recovery will
remain fair to good (excellent for higher terrain of south-central
AZ). Winds overall will follow familiar diurnal patterns favoring
southwest and west in the afternoons and evenings.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flash Flood Watch until 8 AM MST Wednesday for AZZ531-533>555-
     557>559-561-562.

CA...None.
&&

UPDATE...Hirsch
DISCUSSION...AJ/Rogers
AVIATION...Hopper/Hernandez
FIRE WEATHER...AJ

Special Weather Statement
National Weather Service Phoenix AZ
600 PM MST Tue Jul 30 2019

AZZ551-553-310145-
Northwest Pinal County AZ-Southeast Valley/Queen Creek AZ-
600 PM MST Tue Jul 30 2019

...SIGNIFICANT WEATHER ADVISORY FOR MARICOPA AND PINAL COUNTIES UNTIL
645 PM MST...

At 600 PM MST, Doppler radar was tracking a strong thunderstorm over
Bapchule, or near Sun Lakes, moving northwest at 15 mph.

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

Locations impacted include...
Chandler, Casa Grande, Sun Lakes, Bapchule, Olberg, Sacaton and
Santan.

This includes the following highways...
AZ Interstate 10 between mile markers 169 and 187.
AZ Route 87 between mile markers 145 and 160.
AZ Route 347 between mile markers 179 and 181.

LAT...LON 3301 11166 3293 11186 3315 11204 3326 11175
TIME...MOT...LOC 0100Z 155DEG 11KT 3316 11190

Hirsch

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
613 PM MST TUE JUL 30 2019

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

0500 PM     FLASH FLOOD      2 NNW APACHE JUNCTION   33.44N 111.56W
07/30/2019                   PINAL              AZ   911 CALL CENTER

            IRONWOOD AND LOST DUTCHMAN INTERSECTION
            FLOODING. LOW CLEARANCE VEHICLES REPORTED
            GETTING STUCK IN CERTAIN SPOTS ON THE ROAD.

&&

DSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
631 PM MST TUE JUL 30 2019

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

0510 PM     TSTM WND DMG     3 NE MESA               33.45N 111.79W
07/30/2019                   MARICOPA           AZ   BROADCAST MEDIA

            LARGE TREE (APPROXIMATELY 1-2 FT DIAMETER)
            DOWN IN RESIDENTIAL YARD.

&&

DSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
903 PM MST TUE JUL 30 2019

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

0815 PM     HEAVY RAIN       4 N GLOBE               33.45N 110.77W
07/30/2019  M0.73 INCH       GILA               AZ   PUBLIC

            SPOTTER REPORTED/MEASURED 0.73 INCHES OF
            RAINFALL IN A 30 MINUTE TIME FRAME.

&&

DSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1025 PM MST TUE JUL 30 2019

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

1001 PM     HEAVY RAIN       6 ENE SUN LAKES         33.24N 111.78W
07/30/2019  M0.65 INCH       MARICOPA           AZ   TRAINED SPOTTER

            SPOTTER REPORTED 0.65 INCHES OF RAIN FELL IN
            17 MINUTES. MINOR STREET FLOODING AND WATER
            IN THE RETENTION AREAS ALSO REPORTED.

&&

SDB

Special Weather Statement
National Weather Service Phoenix AZ
1108 PM MST Tue Jul 30 2019

AZZ533-538-310645-
Tonopah Desert AZ-Central La Paz AZ-
1108 PM MST Tue Jul 30 2019

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL LA PAZ AND MARICOPA
COUNTIES UNTIL 1145 PM MST...

At 1106 PM MST, Doppler radar was tracking a strong thunderstorm 23
miles southeast of Salome, or 25 miles west of Tonopah, moving west
at 15 mph.

Winds in excess of 40 mph will be possible with this storm. Dense
blowing dust may be possible as well.

This storm will remain over mainly rural areas of east central La
Paz and Maricopa Counties. This includes AZ Interstate 10 between
mile markers 51 and 74.

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.

&&

LAT...LON 3360 11325 3340 11331 3344 11373 3370 11365
TIME...MOT...LOC 0606Z 104DEG 15KT 3351 11337

CB