023 FXUS65 KREV 152114 AFDREV Area Forecast Discussion National Weather Service Reno NV 214 PM PDT Sun Jun 15 2025 .KEY MESSAGES... * A trough moving through the area tomorrow will lead to periods of gusty winds, resulting in areas of critical fire weather conditions. * Typical June temperatures and dry weather prevail through Tuesday, with moderate HeatRisk returning by Wednesday and Thursday. * Stronger winds and cooler conditions still appear to return by the end of this week. && .DISCUSSION... No significant changes in the forecast as everything still looks to be on track with the latest model runs. We remain under a southwesterly flow bringing warm and dry air to the region this afternoon and evening. By tomorrow an upper level trough arrives to the area with its associated cold front pushing through sometime in the late afternoon and evening. Therefore, expect cooler afternoon highs, just 3-5 degrees lower, with the intrusion of cooler air. However, winds will be the main concern. Winds start from the southwest in the late morning with speeds in the 10-15 mph range and gusting to 20-25 mph, as we get into the mid-afternoon to early evening winds become from the west and finally to the northwest. Wind speeds will peak in this timeframe too, with gusts increasing to 25-35 mph. Wind prone areas and mountain ridges will have stronger gusts up to 45-55 mph. The chances of exceeding 35 mph south of I-80 are around 60-90%. These winds bring travel, recreation, fire and aviation impacts. This will lead to a lake wind advisory for lakes western NV and Mono county on Monday. For fire weather info, please look at the Fire Weather section below. The northern portions of Lassen into Modoc counties may see a stray shower or thunderstorm, or two. The probability is low around 5 to 10% at the most, as only one or two members of the HREF are indicating this activity. Weak ridging and a quasi-zonal pattern will replace the trough Tuesday and Wednesday. This will lead to a quick warm up, especially by Wednesday. Wednesday PM temps will be in the mid to upper 90s for western NV and NE CA valleys, while the Sierra and other higher elevation areas will be in the mid-70s to mid-80s. This is around 10 degrees above average with a moderate HeatRisk in most places. At least this heat will not last long, as the next system starts approaching the region early on Thursday. There is still some uncertainty with the ensembles and global models about the timing and placement of the next upper trough that will pass through the PacNW and the Great Basin. It looks like we will have an initial wave on Thursday, followed by the main and deeper system between Friday and Sunday. Again the main concern is still winds. The probability for gusts exceeding 40 mph starts around 40%, but goes up to 60-90% across a vast portion of the region both on Thursday and Friday. Temperatures will take a hit, as afternoon highs drop to below average for late June. Max temps will be around 10-15 degrees below average. In other words, we will go from the mid-upper 90s to the upper-70s to mid-80s in western NV. -HC && .AVIATION... VFR conditions continue through the foreseeable future. Wind will be light and VRB overnight and early morning, then roughly between 19Z Sun-03Z Mon become from the west and southwest 10-15 kts and gusting to 20-25 kts. Stronger winds are very likely on Monday with the passage of a cold front, especially for western NV and the eastern Sierra south of the Tahoe area. Sustained west/southwest winds 15-20 kts with gusts of 25-30 kts in the late morning will turn slowly northwest during the day. Mountain wave turbulence and LLWS is expected, especially near the Sierra. -McKellar/HC && .FIRE WEATHER... An upper level trough and associated dry cold front will be moving through the Great Basin tomorrow. The overlap of gusty winds and very low relative humidity accompanied by poor overnight recoveries has led to the upgrade of the Fire Weather Watch into a Red Flag Warning between 1 PM and 11 PM Monday for zones 420, 421 and 429 in NV. Zones 423 and 274 are pretty much hitting criteria for 3+ hours too, but the fuels may not be entirely there. We will reassess later if we need to include them. Anyway, winds are expected to be from the west and southwest between 15-25 mph with gusts up to 45 mph along with minimum relative humidity between 5-15% and overnight recoveries in the 15-30% range. Winds become from the northwest behind the frontal passage after 6 PM. There is a 5-10% chance for showers and thunderstorms in NE CA between 3 to 7 PM. Any storm could create gusty and erratic winds with gusts up to 35 mph. Our next period of concern starts on Thursday through the weekend, with Friday appearing to be the day with the highest risk. A stronger upper level system passing through brings gusty winds, possibly stronger than what we are expecting tomorrow. Those winds coupled with a long stretch of very dry conditions and a couple of hot days will increase the fire weather risk to critical again. -HC && .REV Watches/Warnings/Advisories... NV...Red Flag Warning from 1 PM to 11 PM PDT Monday NVZ420-421-429. Lake Wind Advisory from 1 PM to 10 PM PDT Monday NVZ001-003-004. CA...Lake Wind Advisory from 1 PM to 10 PM PDT Monday CAZ073. && $$