Flash Flood Warning 9, NWS Reno, NV

935 
WGUS75 KREV 182247
FFSREV

Flash Flood Statement
National Weather Service Reno NV
347 PM PDT Thu Aug 18 2022

CAC063-182257-
/O.EXP.KREV.FF.W.0009.000000T0000Z-220818T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Plumas CA-
347 PM PDT Thu Aug 18 2022

...FLASH FLOOD WARNING HAS EXPIRED FOR PLUMAS COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3989 12015 3987 12018 3987 12029 3989 12033
      3992 12029 3993 12024 3993 12019 3993 12012
      3991 12012

$$

TF

Area Forecast Discussion
National Weather Service Reno NV
228 AM PDT Thu Aug 18 2022

.SYNOPSIS...

Showers with a few weak embedded thunderstorms are rapidly
clearing from the west to the east early this morning. Additional
strong thunderstorms are possible this afternoon with gusty winds
and localized heavy rainfall. Storm chances decrease Friday onward
with drier southwest flow over the region. Temperatures will be
near to above normal with typical afternoon breezes returning this
weekend.

&&

.DISCUSSION...

Biggest change to the forecast is the cancellation of the Red Flag
Warning for northeast CA and far northern NV. Deep moisture is
present with plentiful rain showers. While a stray lightning
strike is still possible through morning, the limited lightning
activity and increased moisture negates the risk. See the Fire
Weather section below for additional details.

Plenty of rain showers out there as of the time of writing, with
deeper convection and embedded thunderstorms being observed near
and southeast of a Mammoth-Fallon line. KRNO has unofficially
broken the record for wettest August with 0.11" inches falling as
of 1 am, bringing the monthly total up to 1.66". The previous
record for the month of August was 1.65" in 1965. We'll have an
official overnight total at 5 am, and will update the monthly
total at that point. Additional rain is possible this afternoon if
a thunderstorm moves over the airport.

Negatively tilted shortwave lifts through the region this morning.
Rapid drying and clearing will occur behind the wave, with a mid-
upper level intrusion of dry air. This is already clearly showing
up in radar and satellite trends with precipitation clearing from
west to east and all areas clearing by 8-11 am. Lower level
moisture remains in place with PWATs running 150-180% of normal,
so we'll once again destabilize with afternoon heating. Increased
shear due to the shortwave could organize storms this afternoon,
especially in northeast CA and far northern NV where there is a
greater risk for strong storms. A few cells may also fire in
western Nevada near and east of US-95, with greater coverage into
central NV east, where the deeper moisture is present. The latest
HRRR is agreeing with this idea as well.

Drier and more stable air will limit thunderstorm activity Friday
into the weekend, with a 10-15% chance in the Eastern Sierra each
afternoon. Further drying is anticipated for the end of the
weekend into the start of next week with a deep trough pushing
into the PacNW, enhancing southwest flow over the region. Ensemble
meteograms along with NBM guidance indicate a slightly enhanced
zephyr Monday and Tuesday afternoons with gusts of 25-35 mph.

Longer range trends suggest temperatures will linger above normal,
with the monsoonal flow shunted well to the southeast and overall
drier conditions to finish out the month of August. -Dawn

&&

.AVIATION...

* Showers and a few embedded thunderstorms continue early this
  morning, rapidly clearing from west to east. As of 2 am,
  activity is limited east of a KSVE-KNFL-KHTH line, with a few
  isolated cells in the eastern Sierra in the vicinity of KMMH.
  This overnight activity will be out of the area between 14-18z
  this morning.

* A later period of convective development will initiate more
  storms this afternoon over northeast CA/northwest NV and the
  eastern Sierra. Stronger storms will be possible in northeast CA
  and northern NV, with gusty and erratic outflow winds 45+ kts
  and localized heavy rainfall. Anticipate lower cigs/vis in these
  storms with terrain obscuration. Winds may produce areas of
  blowing dust, but recent rainfall should minimize how much
  particulate matter is able to be lofted.

* Storm chances decrease this weekend as a more stable westerly
  upper flow increases over the region bringing VFR conditions to
  Sierra and western NV terminals. Thunderstorms that do form will
  be confined to the eastern Sierra with only a 10-15% chance for
  development.

-Dawn/Amanda

&&

.FIRE WEATHER...

**RED FLAG WARNING CANCELLED**

We have cancelled the Red Flag Warning for northeast CA and
northwest NV early this morning as plentiful rainfall and minimal
lightning have occurred overnight.

Showers and thunderstorms are anticipated to develop through
northeast CA and northern NV this afternoon, mainly in the 1 pm
to 9 pm time frame per HREF guidance. Stronger storms remain
possible with gusty and erratic outflow winds and localized heavy
rainfall. There is a lower risk of flash flooding given the faster
storm motions, however, we'll still need to watch the potential
for storms to train over the same area, bringing renewed flood
risks. Overall, storms should be wet, but as always, any
lightning brings concerns for new fire starts.

Wind gusts from storms today could exceed 50 mph, otherwise, general
NW wind gusts this afternoon will be under 15-20 mph. -Dawn

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

For more information from the National Weather Service visit...
http://weather.gov/reno