FXUS65 KREV 110928 AFDREV Area Forecast Discussion National Weather Service Reno NV 128 AM PST Mon Dec 11 2023 .SYNOPSIS... 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 weekend. && .DISCUSSION... 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 && .AVIATION... * 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 && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$