Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
517 FXUS65 KREV 160929 AFDREV Area Forecast Discussion National Weather Service Reno NV 229 AM PDT Sun Jun 16 2024 .SYNOPSIS... * Gusty winds will impact fire potential and recreation this afternoon and evening. Gusty winds will persist for areas south of Hwy 50 Monday. * Much cooler conditions Monday and Tuesday. Tuesday morning lows will dip below freezing in Sierra valleys and near freezing for colder western NV valleys. * Warming trend for the second half of the week. Daytime highs for lower elevations will return to the 90s to around 100 by next weekend. && .DISCUSSION... Enhanced Breezes Today... * A weather system dropping southeast into the Pacific Northwest will swing a dry trailing edge of an attendant dry cold front across northern CA-NV. Hi-Res ensemble guidance projects increasing west-southwest winds ahead of the incoming system that contributes to wind gusts to 35-40 mph (50+ mph over Sierra Ridges) this afternoon that continues overnight through Monday morning. * Impacts to boating activities will surface 1-2 PM. With the enhanced breezes and continued dry conditions its advised to remain vigilant to prevent any sparking that leads to fire starts. Winds will shift to the northwest and north as the weather system passes further east into the central Great Basin. Winds may be slow to decouple and decrease with 30 mph gusts persisting through the overnight hours through Monday morning. In fact north winds will remain rather breezy for the Chalfant Valley into Mineral County Monday afternoon. Cooler Monday and Tuesday... * Following passage of the weather system, look for a few days of relief from the early summer heat with afternoon highs dropping into the mid to high 60s for Sierra locations, and mostly 70s for Monday and Tuesday in western NV valleys. * Light winds, little cloud cover, and dry air will encourage additional radiative cooling at the surface, and allow temperatures to drop into the mid-upper 20s in many Sierra valleys. * Across western NV there is a 10-20% chance of reaching freezing temperatures for cooler locations like the Carson and Smith valleys. Urban areas will still feel the refreshing morning chill Tuesday AM with lows in the 40s. Summer Rises Once More... High pressure builds into the West Coast through the second half of this week. The widespread subsiding air will not only coax drier conditions, but also return daytime highs to the more summer-like 90s by next weekend. A few lower western NV valleys may see afternoon highs topping the century make as well. Summer always finds a way to bump that heat engine up. Some ensemble simulations are even showing a slight increase in thunderstorm chances (~10%) over the Sierra and western NV through the latter half of the week. -Amanda && .AVIATION... * Breezy conditions return today with west-southwest winds gusting to 20-25 kts by late morning today after 17-18Z. Winds gusts will increase to 30-35 kts after 20-21Z as the dry trailing edge of a cold front passes across northern CA-NV this evening and overnight. Otherwise, expect persistent VFR flying conditions through the forecast period. Cooler, below average temperatures will mitigate elevated density altitude issues til mid-week. * Wind gusts will edge near 50-55 kts over Sierra Ridges with developing mountain waves east of the Sierra crest that encourage bumpy departures/arrivals from Sierra and western NV main terminals. Winds shift to the northwest and north overnight Sunday and early Monday with gusts 25-30 kts persisting into Monday across western NV. - Amanda && .FIRE WEATHER... * We have upgraded the fire weather watch to a warning for the Sierra Front and Western Nevada Basin & Range mid afternoon into this evening. Latest HREF and ECMWF EFI show a signal for a critical combination of gusty winds and low RH (west-southwest winds 15-25 mph with gusts to 30+ mph and RH 8-15%). * Winds will begin to increase late morning and early afternoon and enhance further during the late afternoon as gradients tighten and winds aloft increase ahead of incoming trough. A cold front will swing through this evening and begin to turn winds to the northwest. Cooler air will allow for humidity to slowly rise after sundown, but winds will likely remain elevated through the night. Duration of critical conditions will average 2 to 4 hours, but will locally last up to 6 hours. * Another period of critical conditions is possible across the Chalfant Valley and Mineral County (where fuels are receptive) Monday as northerly gradients remain strong and humidity levels stay low. Hohmann && .REV Watches/Warnings/Advisories... NV...Red Flag Warning from 2 PM this afternoon to 11 PM PDT this evening NVZ420-423-429. Lake Wind Advisory from 2 PM this afternoon to 11 PM PDT this evening NVZ001-003-004. CA...None. && $$