Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
480 FXUS65 KREV 042144 AFDREV Area Forecast Discussion National Weather Service Reno NV 244 PM PDT Thu Jul 4 2024 .SYNOPSIS... * A long duration heatwave is expected that will result in a moderate to major HeatRisk lasting through at least the middle of next week. * Dry conditions continue into next week with chances of showers and storms remaining below 5% through the weekend. * Breezy afternoon winds may produce elevated to locally critical fire weather conditions on Sunday. && .DISCUSSION... The latest RAP upper air analysis shows the CWA being underneath the eastern portion of a large high pressure ridge this afternoon. Current surface observations and satellite imagery report dry conditions as well light and variable winds across most of the region underneath sunny skies. Southern Mono County however does have some high clouds forming as an exception to the previous statement. Going through the rest of the day and through the weekend, forecast guidance projects the ridge slowly moving eastward where it continues to control the upper air pattern over the western CONUS. Models then show the axis of this ridge passing over the CWA on Tuesday afternoon along with a weak upper air low moving off the coast of the Baja Peninsula. On Wednesday, model guidance projects the CWA to be underneath the western portion of the ridge as the ridge`s advance continues with the aforementioned upper air low moving northward over the CA coast. What this upper air pattern translates to down at the surface is that temperatures are expected to continue to rise to above normal values going into the weekend and into the beginning of next week. It does not look that until the later half of next week that this heat will break and it could be a slow decline at that. While dry conditions are mostly expected to prevail, the main hazard for the upcoming days will be the above normal temperatures and heat. While the region expects to top off in the 80s and 90s for high temperatures today, some areas of western NV including the Reno- Tahoe International airport see around a 70% chance of hitting the century mark today. The NBM probabilities of 100F or greater then increase to between 70-90% with the coverage starting to expand a bit on Friday. By Saturday, these NBM probabilities cover a good portion of the western NV portion of the CWA along with portions of northeastern CA while the upper limit raises to around 95%. As this looks to remain this way going through next week along with the expected moderate to high HeatRisk in the region, the Excessive Heat Warning for western NV and the Heat Advisory for the CA portion of the CWA continues for Saturday through Wednesday. Please see the heat products for more detailed information on these upcoming heat hazards. It is recommended to take precautions during this time such as limiting outdoor activity, taking breaks in a cool area, staying hydrated, and checking in on neighbors and relatives that may be more susceptible to heat related illness. For more heat safety tips, please visit weather.gov/safety/heat. Near record to record high temperatures and warmest low temperatures are also possible for this weekend and going into next week. While models show the CWA staying dry through the weekend, they do show single probabilities of precipitation returning next week which are still pretty low. There may be a chance that they increase when the ridge starts to depart in the latter half of next week. But for right now, the precipitation chances look to be rather low. Will continue to monitor to see if these chances do increase in future model runs or if there is a chance for some dry lightning that may cause a fire weather concern. Also with the ongoing CA wildfires, will be monitoring for potential smoke in the area though for now there may be some slightly hazy skies in some locations for a bit. -078 && .AVIATION... VFR conditions continue at all REV TAF sites through the remainder of the holiday and going into tomorrow. Models show clear skies over the region with the exception of a few clouds over western NV tonight during the overnight hours. Typical afternoon breezes are also in the forecast across the region with KMMH possibly seeing gusts up to around 20 kts between 20Z-03Z. Well above normal temperatures through the weekend and into next week still look to result in density altitude concerns across the whole area. -078 && .FIRE WEATHER... No major changes from the previous fire weather forecast package with well above normal temperatures, low daytime relative humidity values, and dry conditions prevailing for the rest of the week and into next week. However, winds look to a limiting factor as they are generally light and unsupportive of critical weather at least through the remainder of this week. Beyond this week, models are hinting at some gusts near or above 30 mph starting on Sunday within the Sierra and Sierra Front areas. So, will continue to monitor these conditions over the next few days as this could lead to periods of elevated to locally critical fire weather conditions for those localized areas. There are also some very slight chances for showers and thunderstorms starting on Sunday afternoon. However, these chances remain at or below 5%. -078 && .CLIMATE... Record High and Warm Low Temperatures for July 6th-9th at Reno-Tahoe International Airport (KRNO) ------------------------------------------------------- DateRecord High Record Warm Low ------ ----------- --------------- July 6101F 71F July 7102F 68F July 8104F 71F July 9104F 69F && .REV Watches/Warnings/Advisories... NV...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday NVZ002. Excessive Heat Warning from 10 AM Saturday to 10 AM PDT Wednesday NVZ001-003>005. CA...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday CAZ070>073. && $$