Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
511 FXUS65 KREV 090903 AFDREV Area Forecast Discussion National Weather Service Reno NV 103 AM PST Tue Dec 9 2025 .KEY MESSAGES... * Dry weather and near record warmth expected this week. * Hazy skies and minor reductions in air quality possible each morning across lower urban valleys. * Next week may bring periods of increased winds and precipitation chances, but confidence remains low. && .DISCUSSION... A strong upper level ridge off the CA coast and extending across much of CA-NV will keep dry conditions going through at least this weekend, with the main storm track remaining over the Pacific Northwest. Unseasonable warmth will prevail with 850-700 mb layer temperatures rising by about 3-4 degrees C compared to yesterday. While light winds will limit mixing, this low level warmup will allow highs to climb above 60 degrees across most lower elevations west of US-95 and also into many Sierra communities today through Thursday. Record highs at Reno and South Lake Tahoe airports are well within reach, especially today (65 and 58 degrees, respectively) and Thursday (64 and 59 degrees), while Wednesday`s current records of 67 at KRNO and 63 at KTVL will be a bit more of a challenge to reach. A slight westward shift of the ridge axis from Friday-Sunday will bring a slight cooling, but highs will remain 10-15 degrees above average. While we`re in this strong ridging pattern, cloud cover will be limited to occasional passing swaths of cirrus mainly north of I-80. Due to low-level inversions, expect valley haze (and patchy fog for valleys around Truckee) each morning this week before dispersing by the early afternoon hours. For next week, medium range guidance has been hinting at a potential change to a more active weather pattern with periods of increasing winds and valley rain/mountain snow. However, the majority of the ensemble data is now trending toward a longer delay before this change occurs. A weakening trough passage could still make a small dent in the prevailing ridge next Monday or Tuesday, but the most likely result is low-end (15-30%) light shower chances from the Sierra crest northward to the OR border and an uptick in SW winds mainly for higher elevations. Then after this system exits, signals are pointing toward a rebuilding ridge through at least the middle of next week. Given daily fluctuations with wetter/drier trends as each ensemble guidance run arrives, the confidence in the evolution of next week`s overall weather pattern remains on the low side. MJD && .AVIATION... Minimal weather concerns for aviation this week as high pressure maintains VFR conditions and light breezes. Conditions remain favorable (50-70% chance) for patchy FZFG formation at KTRK during the next few mornings, mainly between 10-16Z. Haze from valley inversions could produce minor reductions in slantwise visibility each morning this week, primarily for W NV sites. MJD && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$