Flash Flood Warning 328, NWS Las Vegas, NV

740 
WGUS75 KVEF 151835
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1135 AM PDT Sat Oct 15 2022

CAC071-NVC003-151845-
/O.CAN.KVEF.FF.W.0328.000000T0000Z-221015T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-Clark NV-
1135 AM PDT Sat Oct 15 2022

...FLASH FLOOD WARNING IS CANCELLED FOR SAN BERNARDINO COUNTY...

Flooding is no longer expected to pose a threat however, a Flood 
Watch remains in effect until 500 AM PDT Sunday for portions of San 
Bernardino County.

LAT...LON 3526 11459 3519 11442 3499 11433 3491 11453
      3490 11463 3494 11463 3496 11464 3499 11463
      3503 11464 3507 11460 3508 11461 3510 11465
      3512 11462 3513 11458 3514 11457 3518 11457

$$

AZC015-151945-
/O.CON.KVEF.FF.W.0328.000000T0000Z-221015T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
1135 AM MST Sat Oct 15 2022

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1245 PM MST THIS 
AFTERNOON FOR SOUTHWESTERN MOHAVE COUNTY...

At 1135 AM MST, Doppler radar indicated thunderstorms which produced 
heavy rain from Oatman to Fort Mohave. Flash flooding is possible in 
these areas. More thunderstorms approaching from the east could also 
continue the flash flood threat.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated rain gauges.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Bullhead City, Laughlin, Mesquite Creek, Oatman, Mojave Ranch 
  Estates, Mohave Valley and Willow Valley.

Flash Flooding of Silver Creek Road and Bullhead Parkway east of the 
Fort Mohave area are likely to see washes with flowing water 
impacting them in several locations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3526 11459 3519 11442 3499 11433 3491 11453
      3490 11463 3494 11463 3496 11464 3499 11463
      3503 11464 3507 11460 3508 11461 3510 11465
      3512 11462 3513 11458 3514 11457 3518 11457

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

TB3

048 
WGUS75 KVEF 151941
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1241 PM PDT Sat Oct 15 2022

AZC015-151951-
/O.EXP.KVEF.FF.W.0328.000000T0000Z-221015T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
1241 PM MST Sat Oct 15 2022

...FLASH FLOOD WARNING WILL EXPIRE AT 1245 PM MST THIS AFTERNOON FOR 
SOUTHWESTERN MOHAVE COUNTY...

The thunderstorms that produced the heavy rain have moved out of the 
area. Flooding from these storms are no longer expected to pose a 
threat. Please continue to heed any road closures.

Remember, a Flood Watch remains in effect until 500 AM MST Sunday 
for Mohave County and further warnings may be needed if more 
activity moves into the area.

LAT...LON 3526 11459 3519 11442 3499 11433 3491 11453
      3490 11463 3494 11463 3496 11464 3499 11463
      3503 11464 3507 11460 3508 11461 3510 11465
      3512 11462 3513 11458 3514 11457 3518 11457

$$

TB3

Area Forecast Discussion
National Weather Service Las Vegas NV
820 AM PDT Sat Oct 15 2022

.SYNOPSIS...An incoming low pressure system will bring widespread
rainfall to parts of the Mojave Desert and Northwest Arizona this
afternoon and tonight, mainly south of Las Vegas. Showers will
linger over northwest Arizona Sunday before the low pushes eastward.
Dry and warm conditions will resume across the region Monday through
at least the middle of the week.
&&

.UPDATE...Ingredients coming together this morning for what will
shape up to be a very active afternoon and evening across the Mojave
Desert region. Cut-off low off the northern Baja Coast will begin to
push inland by this afternoon with an increasingly diffluent flow
aloft overspreading the region and a southerly moisture tap pumping
instability northward. Already beginning to see signs of this
transition with a band of morning convection lifting into the lower
Colorado River Valley near Lake Havasu, largely driven by the
increasing divergence aloft interacting with a plume of enhanced
700mb moisture.  CAM guidance did not have this initial band very
well initialized, so made some morning edits to boost PoPs in our
southern zones to account for this, as well as bump the start time
of the Flash Flood Watch for our southern border zones to 15z.

Still anticipate the main show will come later in the afternoon when
the low creeps closer and better instability becomes realized with
daytime heating.  Forecast Mixed Layer CAPE values will climb into
the 500-1500 j/kg range by the afternoon, particularly along and
south of I-40, and a few severe thunderstorms may be possible with
hail and wind given the enhanced shear in place and fairly steep
lapse rates. SPC maintains a marginal risk for severe thunderstorms
across much of the forecast area south of Las Vegas.

As mentioned in previous discussions, there will be a sharp
northward gradient where precipitation fizzles, likely aligning with
the I-15 corridor in San Bernardino County, and the I-40 corridor in
Mohave County. While thunderstorms will impact Clark county this
afternoon, they will mainly be focused south of the Las Vegas Valley.

-Outler-

&&

.SHORT TERM...Today through Sunday night.

The clear skies across our region this morning are still expected to
fill in this afternoon from Las Vegas southward as numerous showers
and thunderstorms develop initially south of I-40 early this
afternoon then expand over central Mohave County, far southern Clark
County and much of eastern and southern San Bernardino County late
this afternoon and overnight. Storm-generating culprit is the
circulation that could be seen on satellite imagery early this
morning just off the SoCal Coast. Even though only isolated
thunderstorms were occuring well off shore, this system will move
inland over northern Baja late this afternoon and evening and bring
the diffluent northeast quadrant of the system over the
aforementioned areas. This will provide broad upward forcing and
destabilization to interact with precipitable water values
increasing to 1-1.25 inches resulting in numerous showers and
thunderstorms. Individual storm movement around the northern
periphery of the counterclockwise circulation will be generally east
to west around 15-20 mph. So, storms should not sit over any one
area for too long. But rainfall rates over 1 inch per hour will be
possible and some areas may see training cells which will increase
the threat of flash flooding. In addition to heavy rain, the HREF is
indicating the potential for strong thunderstorm winds gusts with a
50-70 percent probability of speeds greater than 35 mph from 00Z-06Z
this evening over most areas south of the Las Vegas Valley.

The Flash Flood Watch already in effect from this afternoon through
late tonight was expanded to include the Mojave National Preserve of
San Bernardino County which contains many flood-prone roads. The
latest HRRR and HREF indicate storms will dissipate over most of San
Bernardino County and the Colorado River Valley between 09Z and 12Z
so the end time of 12Z for the Flash Flood Watch looks good for
those areas. The end time of 18Z for central and southern Mohave
County also is supported by the HREF trends.

Chances for precipitation end over northwest Arizona by late Sunday
afternoon as the system pulls away into New Mexico and tranquil
weather will return for all areas Sunday night. High temps today
will be a few degrees lower Friday then readings will drop an
additional 5-7 degrees on Sunday.

.LONG TERM....Monday through Friday.

The weekend low will be out of the area by Monday, leaving us under
a amplified ridge. As a result, things dry out and temperatures warm
begin to warm. However, the warming trend will be halted by mid-to-
late week as another cut-off low slips under the ridge. Ensemble
guidance continues to be in good agreement with the low's formation
and trajectory. Forecast PWATs aren't quite as high as those
forecast with this weekend's system, but some light precipitation
looks to be possible in our southern areas. Temperatures to remain
generally at or a little above normal through the period.
&&

.AVIATION...For Harry Reid...Winds will remain light and are
expected to follow typical diurnal directional trends through 00Z.
After 00Z, there is a chance for southeasterly outflow winds will
push into the Las Vegas Valley and make it to the terminal area.
Currently, confidence in the timing and speeds of these winds are
low. However, by 06/07Z winds will have decreased to 10 knots or
less and will have shifted to the south-southwest. Cloud cover will
gradually increase through the morning, with cloud cover becoming
broken around 20Z this afternoon. Cloud bases will range from 12 kft
to 20 kft during the afternoon and evening. Shower and thunderstorm
activity in the valley itself currently appears to be unlikely. The
most likely impacts from the showers and thunderstorms across the
region will be the aforementioned outflows winds.

For the rest of southern Nevada, northwest Arizona and southeast
California...Similar to KLAS, KVGT and KHND will favor diurnal
directional trends with relatively light winds through approximately
00Z. Around 00Z the Las Vegas Valley TAF sites will have the
potential to see gusty southeasterly outflow winds impact the
terminal areas. Winds at KEED and KIFP will remain light and
variable through later this morning/early this afternoon. Between 19-
21Z, KEED and KIFP will see winds begin to pick up and with the wind
directions shifting to the southeast and southwest, respectively.
Thunderstorm activity will begin impacting the Colorado River Valley
TAF sites around 21Z this afternoon. Variable gusty winds up to 45
knots, rain, 8 kft cloud bases, and thunder are expected to
accompany these storms. Winds at KDAG will remain westerly through
18Z when it will flip to the east with 20 knot gusts. Convective
activity is expected to impact KDAG beginning around 22Z with 40+
knot gusts, rain, thunder, and 10 kft cloud bases expected to
accompany this convection. Storms are expected to persist through at
least 06Z for KEED, KIFP, and KDAG. KBIH will follow typical diurnal
trends with wind speeds remaining under 10 knots.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

SHORT TERM...Adair
LONG TERM...Woods
AVIATION...Stessman

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