Flash Flood Warning 18, NWS Las Vegas, NV

935 
WGUS75 KVEF 232033
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
133 PM PDT Sun Aug 23 2020

NVC003-232230-
/O.CON.KVEF.FF.W.0018.000000T0000Z-200823T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
133 PM PDT Sun Aug 23 2020

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM PDT THIS 
AFTERNOON FOR NORTHERN CLARK COUNTY...

At 131 PM PDT, Doppler radar indicated thunderstorms continuing to 
dump heavy rain on the Sheep Range. Radar estimated that two to 
three inches of rain had already fallen. Flash flooding is ongoing 
or expected to begin shortly.

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

SOURCE...Doppler radar.

IMPACT...Life threatening flash flooding of creeks, streams, and
         washes.

Some locations that will experience flash flooding include...
  Hayford Peak.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3670 11532 3685 11530 3685 11503 3660 11500
      3660 11534

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

$$

CM

918 
WGUS75 KVEF 232119
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
219 PM PDT Sun Aug 23 2020

NVC003-232230-
/O.CON.KVEF.FF.W.0018.000000T0000Z-200823T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
219 PM PDT Sun Aug 23 2020

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM PDT THIS 
AFTERNOON FOR NORTHERN CLARK COUNTY...

At 217 PM PDT, Doppler radar indicated thunderstorms continuing to 
produce heavy rain over the Sheep Range. The storms have drifted 
slightly west, and water is likely now flowing down both the west 
and east side of the range.

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

SOURCE...Doppler radar.

IMPACT...Life threatening flash flooding of creeks, streams, and
         washes.

Some locations that will experience flash flooding include...
  Hayford Peak.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3670 11532 3685 11530 3685 11503 3660 11500
      3660 11534

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

$$

CM

780 
WGUS75 KVEF 232221
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
321 PM PDT Sun Aug 23 2020

NVC003-232231-
/O.EXP.KVEF.FF.W.0018.000000T0000Z-200823T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
321 PM PDT Sun Aug 23 2020

...FLASH FLOOD WARNING WILL EXPIRE AT 330 PM PDT THIS AFTERNOON FOR 
NORTHERN CLARK COUNTY...

Heavy rain on the Sheep Range had ended. However, water was likely 
still flowing down the east side of the range. Anyone planning to go 
up there this afternoon and evening should be prepared for lots of 
water and mud on the trails.

LAT...LON 3670 11532 3685 11530 3685 11503 3660 11500
      3660 11534

$$

CM

Area Forecast Discussion
National Weather Service Las Vegas NV
500 AM PDT Sun Aug 23 2020

.SYNOPSIS...Thunderstorms remain a threat for Southern Nevada and
Northwest Arizona again today. Some storms may produce gusty winds
and small hail. Otherwise sunny and hot. Dry air begins working
in the area from the southwest late Monday into Tuesday and
thunderstorm chances diminish. Temperatures will remain several
degrees above average.
&&

.SHORT TERM...Sunday through Monday Night.
Current Mesoscale Analysis over the CWA tonight indicates a great
deal of mid-level instability exists to aid thunderstorm activity
again today. The question is where will this activity be focused.
The best chances for initiation of afternoon convection is
expected mainly across Clark, northern Mohave and Lincoln
Counties. This area is at the leading edge of a low level moisture
push and underneath an area of stout mid-level laps rates.
Similar to yesterday, the threat for small (and at times large)
hail remains today at CAPE values between the -10 to -20 degree C
level are on the order of 300-500 J/kg. CAMS also indicating a
fair amount of strong updrafts as well. Given the hail that fell
on Saturday south of Las Vegas, it seems reasonable to occur again
today. Despite the lack of strong wind gusts yesterday, the
threat for strong winds today cannot be ruled out either. Flooding
is always a threat now that enough moisture has working into the
area and the Monsoon is now in swing.

Another area of concern is northern Inyo County in California.
Convective activity is expected along the east Sierra this
afternoon as well. Instability and threats with these storms area
not strong as their eastern counterparts. However, these storms
will be capable of strong gusty winds, lightning and small hail.

Monday begins a transition day as westerly flow begins to move
into the area. The atmosphere will stabilize somewhat. Although
we cannot rule out a few showers and thunderstorms in the
afternoon. These will not be nearly as strong as on Sunday.
Excessive Heat becomes a factor for southern Mohave County and
the lower Colorado River Valley on Monday, lasting into Tuesday.
For that reason, an Excessive Heat Warning will be issued for
these zones.

By Tuesday, the overall flow across the region starts turning
southwest, which will bring drier air into the region. It should
be a gradual push of drier air, with precipitation chances
retreating east into Arizona more and more each day through the
second half of the week. Still some uncertainty to how long the
drier air will remain over the region, though long range models
are trending drier and even have westerly flow over the desert
Southwest for next weekend which will squash the high over the
Four Corners. Could monsoon 2020 be short lived? Unsure. Will
continue to watch model trends. Overall for the second half of
next week, currently expecting occasional afternoon breezes with
temperatures nearly steady each day, running about 5-8 degrees
above normal for this time of the year.
&&

.AVIATION...For McCarran...While yesterday's TSRA development around
the valley did not result in any direct impacts to the terminal,
another possibility for TSRA impacts may occur again this afternoon.
While still low confidence, many indicators continue to show the
potential for strong gusty outflow resulting in variable and strong
winds after 21Z this afternoon. Because of this low confidence but
possible significant impact, opted to include this in the TAF to
highlight the impact window for planning purposes, but this may need
to be removed in the 18Z TAF or via amendments. By nightfall, a
brief period of gusty southeast winds are possible before becoming
light and variable by midnight.

For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated to scattered TSRA again looks possible across
the region this afternoon with a few more terminals with a
possibility of experiencing outflow wind impacts. KVGT/KHND/KBIH all
have the greatest potential after 21Z this afternoon. Elsewhere low
impacts are expected as storms should stay clear of KDAG/KIGM/KEED.
Can't rule out some outflow eventually making it to these sites
later in the evening but confidence too low to include in the TAF.

&&

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

Short Term: Lericos
Long Term: Nickerson
Aviation: TB3

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