605
FXUS65 KREV 012116
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
216 PM PDT Sat Jun 1 2024

.SYNOPSIS...

Above average temperatures and mainly dry conditions will persist
through early next week with a couple of weak weather systems
enhancing afternoon winds and allowing for precipitation chances
later today and Monday within northern portions of the region.
Confidence is high in a significant warmup for the middle to late
portions of next week as highs approach 100 degrees in the hottest
western NV valleys, with afternoon thunderstorms also possible in
the later half of next week.

&&

.DISCUSSION...

Key Points:

* Above normal temperatures continue today along with mostly dry
  conditions with the exception of a 10-20% chance of isolated
  showers for areas north of I-80 later this afternoon.

* While dry conditions are anticipated on Sunday, the region sees
  more chances for isolated showers for areas north of I-80 on
  Monday with the entire CWA expecting 30-40 mph wind gusts possible
  generally out of the west.

* Triple digit (or close to it) day high temperatures are possible
  within the region on Wednesday through Friday along with some
  diurnal showers/thunderstorms in some portions on Thursday through
  Saturday.

Current satellite imagery shows some clouds developing in areas
along and north of I-80 within the region with radar data reporting
some isolated showers within Lassen County this afternoon. As the
latest RAP analysis of the upper air pattern over the CWA shows a
weak trough over the CWA, the 18Z HRRR forecasts some isolated
light showers possible (10-20% chance) in northern Lassen, Washoe,
and Pershing counties along a convergence zone where clouds are
currently developing through almost 8 PM PDT. There is a chance
though that this precipitation may just be virga due to drier air
layer seen closer to the surface. West-northwesterly winds gusting
up to around 25-30 mph are expected within the CWA through this
evening before dying down overnight.

On Sunday, forecast guidance shows the upper air trough moving to
the west allowing for a northwesterly upper air flow over the CWA as
a weak upper air ridge trails the trough. This will allow for warm
temperatures, dry conditions, and breezy afternoon winds out of the
west-northwest throughout the region. For Monday, models depict
another trough passing through the northwestern CONUS placing the
CWA underneath its base during the afternoon hours. Enhanced
zephyr breezes are expected once again at the surface on Monday as
a result with winds gusting up to around 30-40 mph in the
afternoon and evening hours (possible Lake Wind Advisory?). Models
also show precipitation chances between 10-50% within the
northern half of the CWA during the morning hours with the higher
chances closer to the OR border around where a cold front sets up.
Daytime high temperatures on Monday look to cool slightly as a
result ranging between the upper 60s and middle 80s.

For the remaining days of next week, ensemble guidance shows a
ridge moving over the CWA on Tuesday and Wednesday before the CWA
starts to take a southwesterly flow aloft on Thursday being
underneath the western portion of the upper air ridge. This flow
then looks to turn more southerly late Friday into Saturday as a
trough moves over the Pacific Coast and pushes the ridge eastward.
At the surface, daytime high temperatures look to get hotter with
portions of the CWA nearing the 90 degree mark on Tuesday. On
Wednesday, the latest NBM probabilities show around an 80-95%
chance of daytime highs at 90 degrees or above within western NV
and a portion of adjacent CA. The coverage of these probabilities
increases on Thursday while there is also around a 20-50% chance
for highs to reach 100 degrees or above in some portions of
western NV. NBM probabilities for daytime high temperatures of 90
degrees or higher for Friday and next Saturday look once again to
be between 70-90% for western NV and portions of adjacent CA. The
latest ECMWF Extreme Forecast Index (EFI) for MaxT looks to be
between 0.7-0.9 on Wednesday through Friday, so this also signals
the potential for above normal and hot temperatures. Please
prepare now for this upcoming risk for this heat while you can!
Models also show the potential for more precipitation chances
towards the tail end of next week though there is still some
uncertainty in coverage and probability at this time. The ECMWF
EFI for CAPE shows a bulls-eye near Lake Tahoe and also down in
Mono County on Friday, so these areas may be at a higher risk to
see some convection. Will continue to monitor this and update the
forecast as needed.

.AVIATION...

VFR conditions will prevail throughout the rest of today and into
Sunday. Increased winds out of the westerly winds expected this
afternoon for most TAF sites (southwesterly for KMMH), with gusts
peaking around 25-30 kts between 20-06Z. Some brief light to
moderate turbulence may be possible during that time as well.
Northern portions of the CWA may see a slight chance for an isolated
shower or two later this afternoon and evening.

&&

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

$$