FXUS65 KREV 110928

Area Forecast Discussion
National Weather Service Reno NV
128 AM PST Mon Dec 11 2023


High pressure will continue to produce dry weather conditions,
valley inversions, and near average temperatures this week.
Easterly breezes increasing overnight Tuesday into Wednesday will
bring bitter cold conditions across the Sierra crest. Otherwise,
dry conditions look to continue at least through the end of next



The few light showers skirting along the CA-OR-NV border this
morning with a weakly forced short wave trough will continue to push
off east into northern NV. Ok....now that’s good. No sooner these
showers dance north of the NV border, another dry short wave trough
dropping south back-door like across the Great Basin region on
Tuesday will spin up a close low circulation that eventually
settles into southern NV later Tuesday night into Wednesday
morning. Ok....now that’s better!

The ensuing shift in the flow aloft to north-northeast will
challenge the persistence of strong valley inversions that were
allowed to strengthen the last several days under the influence of
widespread high pressure. Don’t expect the influence of high
pressure over the region to wane much with passage of these upper
troughs. But it will weaken just enough to allow some modest
improvement in ventilation of lower valley areas through midweek.
Further improvement in air quality and haze will keep step with an
increasing easterly flow that brings gusty conditions across
Sierra ridgetops late Tuesday night into Wednesday morning.
Ridgetop winds at times will peak at 40-45 mph and bring that
extra cold chill across the Sierra high country. Winter weather
enthusiasts take heed, add those extra layers if you’re feeling
extra adventurous! Dry conditions, light winds, and strengthening
of valley inversions will return with the shift of a sharp upper
ridge axis into the western US later this week.

The next upstream signal for any precipitation so far doesn’t look
very impressive at this time. Even the winds look to remain
mostly light with dry conditions continuing through the weekend.
Ensemble simulations still motion toward early next week with Dec
18-19th being the dates to Que-in on for a wetter solution. EC/GFS
ensemble simulations, however, are throwing out a variety of
solutions where the next Pacific system ventures towards the west
coast and either cuts-off, then slowly dig south, or splits with
energy and moisture directed into the Pacific Northwest and
southern CA. Once confidence with guidance improves, we’ll update
you as soon as possible. -Amanda



* Generally, VFR conditions will prevail through Monday main
  terminals. Due to persistent valley inversions, lower valley
  terminals will see hazy conditions and reduced slant range
  visibility issues. The only exception will be KTRK and KTVL,
  which will again see development of patchy early morning FZFG.

* Enhanced easterly ridgetop breezes (FL100) will increase across
  Sierra ridgetops overnight Tuesday with gusts peaking 30-40 kts.
  This may increase turbulence and brief periods of LLWS for areas
  west of the Sierra crest. -Amanda


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