Arizona, 2019

Flash Flooding in Arizona, December 4, 2019

December 4, 2019 · NWS VEF · 2 events in 1 county or zone

A Pacific storm system brought widespread rain and isolated flooding.

Where it happened

Every event with a place to put it. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

Deaths
0
Injuries
0
Property damage
$2,000
Crop damage
None recorded
Events
2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS VEF wrote it up.

A Pacific storm system brought widespread rain and isolated flooding.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Las Vegas, NV wrote its last area forecast discussion before the first event at Dec 4, 10:24 AM MST, 3 hours 59 minutes earlier.

Area forecast discussion, Dec 4, 10:24 AM MST, 3 hours 59 minutes before
Area Forecast Discussion
National Weather Service Las Vegas NV
924 AM PST Wed Dec 4 2019

.SYNOPSIS...Wet day in store for much of the region with
mountain snow confined to elevations above 7,000 feet. Improving
conditions are expected Thursday but another system will move in
late Friday into the weekend with additional mountain snow in the
Sierra and light shower activity possible across the Southern Great
Basin and higher terrain of the Mojave Desert.
&&

.UPDATE...Light rain showers have picked up across southern Nevada
and northwestern Arizona this morning. Light showers are expected to
continue through the morning as the brunt of the moisture pushes on
shore and through southeastern California. Region-wide,
precipitation has begun in the form of rain, though as temperatures
drop through the day in the higher elevations, precip should
transition into snow in the Sierra and Spring Mountains above 7000
ft. Regarding the Owens Valley, surface temperatures remained a few
degrees above freezing through the early morning hours resulting in
all-liquid precip. Temperatures will continue to increase in the
Owens Valley today, so chances of snowfall at this point are
unlikely.

Storm total rainfall amounts remain with a widespread 0.25-0.50" in
the forecast. An area of focus today will be the Morongo Basin. A
lot of the moisture is expected to wring out over the San Bernardino
Mountains before reaching the Morongo Basin. However, spill over is
possible, which would result in Yucca Valley and Morongo Valley with
overachieving rainfall amounts. We will keep an eye on this and
update as necessary.

No changes made to the forecast this morning as it looks to be in
good shape.
&&

.PREVIOUS DISCUSSION... /issued at 201 AM PST Wed Dec 4 2019/

.SHORT TERM...through Thursday.

The much anticipated storm system slated to bring widespread rain
and high elevation snow to the region today is still on track.
Current radar and satellite imagery indicate light, warm advection
driven shower activity already breaking out across the Mojave
Desert, with Daggett and Bicycle Lake both reporting light rain in
the past hour. Heavier rainfall is currently moving ashore across
coastal California and will gradually shift inland today. Dewpoint
depressions across most of the forecast area are within ten degrees,
so don't suspect it will take long to moisten the lower atmosphere
and start seeing reports of measurable rainfall.

Temperatures in the Owens Valley are currently hovering 1-3
degrees above the freezing mark, and suspect those temperatures
will hold through the morning. As such, aside from a brief
rain/snow mix this morning, anticipate most of the precipitation
in the Owens Valley and near Bishop will remain in the liquid
form, but will continue to monitor closely.

Elsewhere, precipitation amounts were generally unchanged
overnight, with a widespread 0.25-0.50" expected across the
region. Given the already moist lower atmosphere and tropical
origin of the incoming moisture, won't be surprised if we
overachieve a bit. There could also be a few very isolated
thunderstorms later this morning through the afternoon which could
result in briefly heavier rain rates, though coverage looks very
limited.

As precipitation shield shifts east tonight, next concern will be
lingering low level moisture and the potential for fog
development. Retained mention of patchy dense fog for the
overnight Wednesday into Thursday morning periods, especially for
valley locations. Surface winds will ultimately make or break the
fog potential, as some model guidance suggests winds remaining
just elevated enough to limit development beyond a low stratus
layer.

Drier conditions resume on Thursday, though scattered clouds will
linger across the area. Temperatures will hover near the seasonal
average across most of the region.

.LONG TERM...Friday through early next week.

Another closed low is progged to reach the Pacific NW by Saturday
and bring another round of Sierra snowfall Saturday through
Monday morning. The orientation of this next system is quite a bit
farther north and will be lacking the tropical moisture tap from
earlier in the week, so valley rainfall should be considerably
less impactful, if at all. However, the prospect for more winter
products may be on the horizon again for the higher elevations of
Inyo, Esmeralda, Nye, and Lincoln.

By early next week, a rather high amplitude ridge is progged to
set up over the western coast. This will likely keep weather
impacts minimal through at least the middle of next week.
&&

.HYDROLOGY...regarding the Taboose burn scar.
While this next system is expecting to bring widespread rainfall to
the region, rainfall rates in the vicinity of the Taboose burn scar
are expected to stay relatively light. Additionally, there could be
some effects due to rain falling on snow, but believe the impacts
along HWY 395 should be minimally impactful given the rates
expected.
&&

.AVIATION...For McCarran...CIGS will continue to lower today as a
low pressure system off the southern California coast moves inland
this morning and across southern Nevada this afternoon and tonight.
Expected impacts include low CIGs between 1k-1.5k feet in moderate
rain beginning between 12pm-1pm and lasting through 4pm-5pm before
steady rain is replaced by scattered light showers. There remains a
decent chance, CIGS could drop briefly to 500-700 feet at times.
Visibility during this time should generally be 3-5SM but could drop
to 1-2SM at times. 2-3k foot CIGS are expected overnight into
early Thursday morning with areas of fog possible within the
Las Vegas Valley before conditions vastly improve later Thursday
morning as the low moves further east.

For the rest of southern Nevada, northwest Arizona and southeast
California...A Pacific system off the southern California coast will
move inland this morning and across the forecast area this afternoon
and overnight. Widespread precipitation, mountain obscuration and
low CIGS are expected at all terminals. Ceilings between 3-5k feet
and rain will spread in from west to east between 12Z and 18Z
today with the brunt of the system impacting the region this
afternoon into the early evening. Precipitation coverage decreases
tonight but extensive low clouds will remain in some areas.
Locations that clear out could see areas of fog and low visibility
develop overnight tonight and into the early morning hours on
Thursday.
&&

.SPOTTER INFORMATION STATEMENT...Another system will move across
the area Today. Heavy rain, flooding, and snow reports are
encouraged, as well as reports of low visibility due to fog.
&&

UPDATE...Varian
DISCUSSION...Outler
AVIATION...Salmen

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter

The radar

The Las Vegas radar (KESX), 85 km away, was scanning. The volume nearest the first event began at 21:26 UTC.

Open the radar archive at this moment

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, Mohave

When
December 4, 2:23 PM MST to 4:00 PM MST
Where
Mohave County, 4.46 mi SSW of Golden Valley to 4.84 mi SSW of Golden Valley
Cause
Heavy Rain
Property damage
$1,000
Reported by
County Official
Coordinates
35.157, -114.236

Shinarump Dr was closed from Colorado Rd to Aztec Rd due to flooding.

Flash Flood, Mohave

When
December 4, 3:54 PM MST to 6:00 PM MST
Where
Mohave County, 3.07 mi NNE of Wikieup to 3.03 mi NNE of Wikieup
Cause
Heavy Rain
Property damage
$1,000
Reported by
County Official
Coordinates
34.742, -113.601

Pump Station Rd was closed from Highway 93 to Back Rd due to flooding.

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Arizona in 2019Every state in 2019This day in weather historyWarnings in Arizona, December 2019

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 869177, 869178.