Alert archive / Arizona / Flash Flood Warnings in 2019

Flash Flood Warning 119, NWS Phoenix, AZ

November 29, 2019Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Nov 29, 2019, 2:42 AM MST for Maricopa County, Arizona. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Nov 29, 2019, 2:42 AM MST (09:42 UTC)
Expired: Nov 29, 2019, 8:15 AM MST
In force: 6 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Flood severity: None

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 77 km from the middle of the area, began a volume at 09:46 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 (KTUS), launched 00:00Z, 9.7 hours before the alert went out and 198 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: 81 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 1542 m above ground
0-6 km bulk shear: 75 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 365 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning 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 flash flood warning went out at Nov 28, 11:27 PM MST, 3 hours 15 minutes earlier.

Area forecast discussion, Nov 28, 11:27 PM MST, 3 hours 15 minutes before

Area Forecast Discussion
National Weather Service Phoenix AZ
1127 PM MST Thu Nov 28 2019

.UPDATE...
Updated 06Z aviation discussion.

&&

.SYNOPSIS...
Rainfall will increase in coverage tonight as a strong low pressure
system moves into the Desert Southwest. There will also be very windy
conditions at times along with a slight chance of thunderstorms.
Snow levels will drop rapidly across Gila County Friday morning
and it will be cold enough for accumulating snow, generally above
4500 feet. Warmer and drier conditions are expected during weekend as
high pressure builds across the Rockies. Another low pressure system
will bring a chance of rain to the region midweek.

&&

.DISCUSSION...
The heaviest precipitation associated with the well-advertised
Pacific low pressure system has moved inland along the southern
California coast while further east across Arizona, showers early
this morning across Maricopa County didn't amount to much.

Latest visible satellite shows some breaks in the clouds across
western Arizona, which reveal thickening stratocu marching due
northward, embedded with an anomalously strong 40 kt low-level jet.
The HREF suggests the increasing instability across western Arizona
coupled with vorticity-forced ascent will result in a developing area
of shower activity late this afternoon and this evening, likely
stretching from Maricopa and La Paz Counties back into Yuma County.

Latest CAMs and global models depict the main batch of precipitation
stretching along a north-south line near the Colorado River Valley
late this afternoon and this evening. Given the 60-80 kt deep-layer
shear and modest instability, there is some potential for organized
convection, most likely in the form of a squall line. However, a
supercell cannot be ruled out as well. The strongest storms will be
capable of producing heavy rain, hail, and even severe wind gusts.
A brief tornado is also possible within any sustained supercells or
embedded circulations, particularly across Imperial and Yuma
counties.

The NAEFS 850 mb wind percentiles near 55 kt will approach
all-time records this evening across southwestern Arizona. With
widespread shower activity moving steadily across Arizona, it won't
be difficult to mix down gusts as high as 40-55 mph to the surface.
ECMWF-E and GEFS plumes have generally captured the potential for
stronger wind gusts and this is reflected in the latest forecast.
Heaviest rain across south-central Arizona will likely occur between
10 pm and 7 am. Little change was made to forecast QPF. Ensembles
continue to suggest rain totals will range from 1 to 1.5 inches
across the Phoenix area, with higher amounts to the north and east.

The heaviest precipitation will translate eastward into Gila County
Friday morning. A Winter Storm Warning remains in effect for
significant snow accumulations, generally above 4500 feet. Rainfall
will taper off quickly during the morning across the Phoenix area,
with clearing likely in the lower deserts during the afternoon.

In the wake of the low pressure system, a ridge will migrate
eastward across the Desert Southwest Saturday and amplify across the
Rockies Sunday. GEFS indicates mid-level heights will remain above
average through early next week, which will translate into above
normal temperatures Monday and Tuesday. There is increasing
likelihood another trough will impact the region during the midweek
period. Both the GEFS and ECMWF-E suggest the potential for
another 0.5-1.0 inch of rain. However, thicknesses point to a warm
system with above normal snow levels.

&&

.AVIATION...Updated at 0627Z.

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

Strong southerly winds with gusts up to 35 knots are expected
through 10Z as showers gradually increase in coverage and SCT-BKN
ceilings lower to around 4-5 kft. Isolated stronger gusts are
possible ahead of and along the front, particularly with any
convection that is able to mix down higher momentum air aloft
associated with a 50 knot low-level jet. Deeper convection is
generally not expected until the front arrives at the terminals
closer to 10-11Z, along which there should be enough instability
and frontal forcing to produce isolated thunderstorms within a
line of convection. A brief period of IFR-MVFR visibilities and
ceilings are expected with this convective line, with widespread
rain showers behind it through 16-17Z. Southerly wind gusts in
excess of 35 knots will be possible along and ahead of the front,
with westerly wind gusts up to 25 knots expected behind the front.
Ceilings should improve tomorrow with a slight chance of showers
and possibly an elevated thunderstorm or two in the afternoon, but
confidence is too low to include them in the TAF at this time.

Southeast California/Southwest Arizona including KIPL and KBLH:

Light to moderate rain showers will continue through 08-09Z at
KBLH and 12Z at KIPL behind the front with BKN-OVC ceilings
generally staying above 5-6 kft. Further east over eastern Yuma
and La Paz Counties, scattered showers and a few thunderstorms
are expected to develop ahead of a frontal line of convection over
the next few hours before moving into south central Arizona.
Frequent southerly 30-40 knot wind gusts with isolated stronger
gusts are expected ahead of and along the front, particularly with
any convection that is able to mix down higher momentum air aloft
associated with a 50 knot low-level jet. Shower activity will end
from W-NW to E-SE on Friday morning as skies gradually clear with
westerly wind gusts up to 35 knots during the afternoon.

&&

.FIRE WEATHER...
Saturday through Wednesday:
Below normal temperatures Saturday will warm to near normal by
Monday under slow drying conditions and light winds. Moisture
levels should remain fairly elevated through early next week with
minimum RH values mostly above 35 percent. The next low pressure
system then looks to approach from the west late Tuesday into
Wednesday bringing increased moisture, rain chances, and breezy
conditions later Wednesday

&&

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

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flash Flood Watch through Friday afternoon for AZZ534-537>563.

     Wind Advisory until 4 AM MST Friday for AZZ534-537>544-546-
     548>551-553>555-559.

     Wind Advisory until 9 AM MST Friday for AZZ545-547-552-556>558-
     560>563.

     Winter Storm Warning until midnight MST Friday night for AZZ557-
     558-563.

     Flash Flood Watch until 5 AM MST Friday for AZZ530>533-535-536.

     Wind Advisory until midnight MST tonight for AZZ530>533-535-536.

CA...Flash Flood Watch until 4 AM PST Friday for CAZ569.

     Wind Advisory until 11 PM PST this evening for CAZ562-564-565-
     569-570.

     Winter Storm Warning until 4 AM PST Friday for CAZ560.

     Wind Advisory from 2 AM to 3 PM PST Friday for CAZ560.

&&

DISCUSSION...Hirsch
AVIATION...Hopper
FIRE WEATHER...Kuhlman

In the hours before

Local storm report, Nov 28, 9:53 PM MST, 4 hours 49 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
953 PM MST THU NOV 28 2019

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

0834 PM     FLASH FLOOD      4 WNW FELICITY          32.76N 114.84W
11/28/2019                   IMPERIAL           CA   DEPT OF HIGHWAYS

            OGILBY ROAD CLOSED FROM I-8 TO CALIFORNIA
            STATE ROUTE 78 DUE TO FLOODING PER
            CALIFORNIA HIGHWAY PATROL.

&&

LJH

Local storm report, Nov 28, 10:09 PM MST, 4 hours 33 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1009 PM MST THU NOV 28 2019

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

0822 PM     FLASH FLOOD      5 S QUARTZSITE          33.60N 114.22W
11/28/2019                   LA PAZ             AZ   LAW ENFORCEMENT

            ALL WASHES FLOODED OUT ALONG HIGHWAY 95 FROM
            MILE POST 90 NORTH TO QUARTZSITE PER LA PAZ
            COUNTY SHERIFFS OFFICE; POINT OF REPORT AT
            FRENCH CREEK IN THE MIDDLE OF THE FLOODED
            AREA.

&&

LJH

Local storm report, Nov 29, 1:41 AM MST, 1 hour 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
141 AM MST FRI NOV 29 2019

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

1124 PM     FLASH FLOOD      2 SSW VICKSBURG         33.71N 113.77W
11/28/2019                   LA PAZ             AZ   LAW ENFORCEMENT

            ***DELAYED REPORT***...TWO VEHICLES STUCK IN
            WASH ALONG VICKSBURG ROAD WITH WATER UP TO
            THE BOTTOM OF ITS CAR DOOR WINDOWS; RELAYED
            BY LA PAZ COUNTY S.O.

&&

LJH

Local storm report, Nov 29, 1:45 AM MST, 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
145 AM MST FRI NOV 29 2019

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

1253 AM     FLASH FLOOD      4 NW VICKSBURG          33.78N 113.80W
11/29/2019                   LA PAZ             AZ   LAW ENFORCEMENT

            WASHES RUNNING ALONG STATE ROUTE 72 AND
            BECOMING IMPASSABLE AT MILE POSTS 35, 43,
            AND 45; RELAYED BY LA PAZ COUNTY S.O.

&&

LJH

Local storm report, Nov 29, 1:50 AM MST, 52 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
150 AM MST FRI NOV 29 2019

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

1249 AM     NON-TSTM WND GST 1 SSE SKY HARBOR AIRPOR 33.43N 112.01W
11/29/2019  M51 MPH          MARICOPA           AZ   ASOS

            PEAK SOUTHERLY WIND GUST OBSERVED AT SKY
            HARBOR; FREQUENT GUSTS BETWEEN 40-50 MPH
            OVER THE PAST COUPLE HOURS.

&&

LJH

Local storm report, Nov 29, 2:07 AM MST, 35 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
207 AM MST FRI NOV 29 2019

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

0142 AM     FLASH FLOOD      4 WSW BLYTHE            33.59N 114.66W
11/29/2019                   RIVERSIDE          CA   DEPT OF HIGHWAYS

            ROADWAY FLOODING REPORTED BY CALIFORNIA
            HIGHWAY PATROL AT STATE ROUTE 78 AND SEELEY
            RD.

&&

LJH

The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 28, 5:51 PM MST	Severe Thunderstorm Warning	PSR	La Paz	24 min
Nov 28, 6:15 PM MST	Severe Thunderstorm Warning	PSR	La Paz	45 min
Nov 28, 6:16 PM MST	Severe Thunderstorm Warning	PSR	La Paz	44 min
Nov 28, 7:30 PM MST	Areal Flood Advisory	PSR	La Paz	4 hr
Nov 28, 7:52 PM MST	Flash Flood Warning	PSR	La Paz, Yuma	8 hr
Nov 28, 7:59 PM MST	Flash Flood Warning	PSR	La Paz, Yuma	6 hr
Nov 28, 9:53 PM MST	Flash Flood Warning	PSR	La Paz, Yuma	4 hr
Nov 28, 11:20 PM MST	Areal Flood Advisory	PSR	La Paz, Yuma	4 hr
Nov 28, 11:36 PM MST	Flash Flood Warning	PSR	La Paz	4 hr
Nov 29, 12:04 AM MST	Flash Flood Warning	PSR	La Paz, Maricopa	5 hr
Nov 29, 12:27 AM MST	Areal Flood Advisory	PSR	Yuma	4 hr
Nov 29, 1:24 AM MST	Flash Flood Warning	PSR	Maricopa	7 hr
Nov 29, 2:01 AM MST	Flash Flood Warning	PSR	Maricopa, Yuma	5 hr
Nov 29, 2:34 AM MST	Severe Thunderstorm Warning	PSR	Maricopa	26 min
Nov 29, 2:55 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Nov 29, 3:27 AM MST	Flash Flood Warning	PSR	Maricopa	5 hr
Nov 29, 3:45 AM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	30 min
Nov 29, 4:01 AM MST	Tornado Warning	PSR	Maricopa	14 min
Nov 29, 4:18 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Nov 29, 4:41 AM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	34 min
Nov 29, 4:44 AM MST	Tornado Warning	PSR	Maricopa, Pinal	12 min
Nov 29, 4:57 AM MST	Areal Flood Warning	PSR	La Paz, Maricopa, Yuma	6 hr
Nov 29, 5:07 AM MST	Flash Flood Warning	PSR	Gila, Maricopa, Pinal	6 hr
Nov 29, 5:12 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Nov 29, 5:18 AM MST	Severe Thunderstorm Warning	PSR	Pinal	27 min
Nov 29, 7:12 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Nov 29, 7:22 AM MST	Flash Flood Warning	PSR	Gila, Pinal	4 hr
Nov 29, 8:10 AM MST	Areal Flood Warning	PSR	Maricopa	6 hr
Nov 29, 8:33 AM MST	Areal Flood Warning	PSR	Maricopa	6 hr
Nov 29, 8:53 AM MST	Areal Flood Warning	PSR	Gila	36 hr
Nov 29, 11:14 AM MST	Areal Flood Warning	PSR	Gila, Maricopa, Pinal	3 hr
Nov 29, 1:31 PM MST	Special Weather Statement	PSR	Pinal	29 min
Nov 29, 2:12 PM MST	Special Weather Statement	PSR	Pinal	33 min
Nov 29, 2:45 PM MST	Special Weather Statement	PSR	Pinal	30 min
Nov 28, 5:45 PM MST	Severe Thunderstorm Warning	PSR	Riverside	30 min
Nov 28, 6:22 PM MST	Areal Flood Advisory	PSR	Imperial, Riverside	3 hr
Nov 28, 6:54 PM MST	Flash Flood Warning	PSR	Imperial	4 hr
Nov 28, 10:59 PM MST	Areal Flood Warning	PSR	Imperial	6 hr

Nearby

Flash Flood Warnings in Arizona, 2019 Every flash flood warning in 2019

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.