Flash Flooding and Damaging Winds in Nevada, July 1 to 2, 2016

Area Forecast Discussion
National Weather Service Las Vegas NV
1054 PM PDT THU JUN 30 2016

.SYNOPSIS...Monsoonal moisture that has spread up from northern
Mexico will fuel thunderstorms across the Mojave Desert region...
especially during the afternoon and evening hours through Saturday.
Temperatures will trend downward due to the increase in cloud cover.
Drier air is expected to work into the region early next week
pushing monsoonal moisture east of the area. This will also allow
for a warming trend with temperatures about 3 to 5 degrees above
normal by Monday.
&&

.UPDATE...Scattered showers and thunderstorms have increased over
portions of Death Valley, southern Nye and extreme northern San
Bernardino Counties this evening. This area had very little weather
earlier in the day and instability is quite high in those areas.
CAPE values are generally around 2000-3000 J/KG with LI's around
-1/-3. Hail will be a concern with any storm this evening along with
flash flooding. Upper level winds are fairly light and this will
lead to slow moving storms. Thunderstorm activity is expected to
last much of the night.

.AVIATION...For McCarran...Erratic winds from several storm outflows
have occurred this evening, making for a low-confidence forecast.
However, trend seems to be for winds becoming light/variable
overnight. Southeast winds expected to commence tomorrow with speeds
around 10 kts. Chance of storms continues tomorrow, with best
chances in the afternoon and evening. Potential air traffic impacts
are substantial, with chances of convection at the terminal and
in the flight corridors.

For the rest of southern Nevada...northwest Arizona...and southeast
California...Storms continue late this evening in Inyo, Nye, and San
Bernardino Counties. Winds near storm outflows are
gusty/erratic,while outside of these areas mostly terrain-driven and
below 10 kts. Expect SE winds to develop tomorrow in most of the
region with more chances of storms, especially during the
afternoon/evening, with associated locally lower CIGs, reduced
visibility, and convective turbulence.
&&

.PREV DISCUSSION...
315 PM PDT THU JUN 30 2016

.SHORT TERM...through Saturday night.

Scattered to numerous thunderstorms have erupted over southern
Nevada and northwest Arizona thanks to the influx of low level
moisture we received this morning from a widespread push of
southeast flow below 700 mb. Surface heating and a boundary
associated with a disturbance moving from southeast Nevada into
southwest Utah helped initiate and intensify the thunderstorms and
we should see convection expand this afternoon and evening across
southern Nevada and northwest Arizona due to boundary interactions.
Convection will diminish overnight but probably not die completely
due to the moist and unstable environment.

Similarly moist and unstable conditions will exist over the same
area through Friday so we can expect scattered to numerous
thunderstorms Friday afternoon. Dry mid to upper level flow should
help clear mid to high level debris clouds overnight and allow for
full surface heating again Friday. Saturday will see a slight
decrease in thunderstorm coverage from west to east as dry westerly
flow starts to spread over southern Nevada.

.LONG TERM...Sunday through Wednesday.

Models remain consistent with Previous runs showing a significant
decrease in moisture on Sunday followed by dry weather areawide
Monday through Wednesday. Weak troughing passes through California
Sunday and through Nevada Monday, turning the flow more westerly and
flushing out the monsoon moisture from our area. This will eliminate
rain chances, knock surface dewpoints back down into the 20s and
30s, and also allow temperatures to climb back to several degrees
above normal. Longer range models hint at moisture possibly
returning around the end of the week, but there is plenty of time to
watch this.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather according to standard operating procedures.
Flash flooding will be a concern with any thunderstorm today
especially across Mohave, Clark, and eastern San Bernardino
Counties.
&&

Update...Gorelow
Short Term...Adair
Long Term...Morgan
Aviation...Shafer

For more forecast information...see us on our webpage:

http://weather.gov/lasvegas or follow us on Facebook and Twitter

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
916 PM PDT THU JUN 30 2016

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

0700 PM     FLASH FLOOD      1 SSW BULLHEAD CITY     35.09N 114.61W
06/30/2016                   MOHAVE             AZ   PUBLIC

            SWIFTLY FLOWING WATER AT LEAST SIX INCHES
            DEEP COVERING PORTIONS OF CHAPARRAL DRIVE IN
            BULLHEAD CITY. REPORT RELAYED VIA SOCIAL
            MEDIA. TIME ESTIMATED BASED ON RADAR.

&&

CMS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1029 PM PDT THU JUN 30 2016

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

0930 PM     FLASH FLOOD      14 NNW NEEDLES          35.04N 114.69W
06/30/2016                   SAN BERNARDINO     CA   LAW ENFORCEMENT

            CALIFORNIA HIGHWAY PATROL REPORTS FLASH
            FLOODING AT NEEDLES HIGHWAY AND RIVER ROAD.
            SEVERAL ADJACENT COUNTY ROADS ARE ALSO
            WASHED OUT. START TIME OF 730 PM PDT AND
            ONGOING AT REPORT TIME OF 930 PM PDT.

&&

CMS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1035 PM PDT THU JUN 30 2016

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

1006 PM     FLASH FLOOD      1 WNW NEEDLES           34.85N 114.63W
06/30/2016                   SAN BERNARDINO     CA   LAW ENFORCEMENT

            CALIFORNIA HIGHWAY PATROL REPORTS US HIGHWAY
            95 IS CLOSED AT INTERSTATE 40 OWING TO HEAVY
            RAIN AND FLASH FLOODING.

&&

CMS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1146 PM PDT THU JUN 30 2016

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

1144 PM     HAIL             1 WNW PAHRUMP           36.21N 116.00W
06/30/2016  U1.00 INCH       NYE                NV   TRAINED SPOTTER

            SPOTTER IN PAHRUMP REPORTED HAIL UP TO THE
            SIZE OF A QUARTER.

&&

ASG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1243 AM PDT FRI JUL 1 2016

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

1213 AM     FLASH FLOOD      11 SW MERCURY           36.55N 116.13W
07/01/2016                   NYE                NV   DEPT OF HIGHWAYS

            STATE ROUTE 160 IS CLOSED FROM MILE MARKER
            32 TO U.S. 95 DUE TO FLOODING. DISTANCE IS
            ABOUT 2 MILES. .

&&

ASG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
110 AM PDT FRI JUL 1 2016

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

1130 PM     FLASH FLOOD      9 NNW FURNACE CREEK     36.57N 116.92W
06/30/2016                   INYO               CA   LAW ENFORCEMENT

            CHP REPORTED FLASH FLOODING ON STATE ROUTE
            190 IN DEATH VALLEY NATIONAL PARK BETWEEN
            DAYLIGHT PASS CUTOFF TO COW CREEK. TIME
            ESTIMATED BASED ON RADAR DATA.

&&

JH