Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
508 FXUS65 KREV 150857 AFDREV Area Forecast Discussion National Weather Service Reno NV 157 AM PDT Wed May 15 2024 .SYNOPSIS... The weather will seem more like late June than mid-May leading up to the weekend as highs approach 90 degrees by Thursday for W.Nevada valleys. Temperatures will moderate by the weekend and into early next week as a trough approaches the western US. This will also increase late day breezes by Thursday and Friday, followed by a slight chance of showers and isolated storms over portions of the Sierra this weekend into next week. && .DISCUSSION... Unseasonable warmth along with drier conditions will be in place as upper level ridging builds across the western U.S. today. High temperatures will once again warm into the mid-80s across western Nevada this afternoon with mid-70s for Sierra valleys. Thursday is shaping up to be the warmest day of the week with highs nearing the 90 degree mark across western Nevada valleys. While not record breaking, this early season heat could yield some moderate heat risks for heat sensitive individuals. Light north breezes today will usher in a dry air airmass with near single digit RH this afternoon. Overnight lows will also be mild (10 degrees above avg.) along with RH recoveries of only 25-35% tonight across western Nevada. Heating on Thursday will aid in bring a return to our westerly zephyr winds with afternoon gusts around 25 mph. Temperatures will begin a slow cooling trend over the weekend as we will be sandwiched between a progressive trough across the PacNW and a closed low off the Baja Peninsula. The interaction between these two features may allow for enough instability and moisture to yield a return of afternoon showers and thunderstorms by Saturday but confidence is lower end at this time due to the phasing of these two lows. The current forecast keeps a slight chance (10-15%) for the eastern Sierra in Mono County Saturday and Sunday, then introduces slight chances across the Tahoe Basin by Monday afternoon. While the precipitation potential is less certain, confidence is higher in expecting a modest cooling trend to near season averages by early next week. Fuentes && .AVIATION... VFR conditions will prevail through Friday. Winds will be light and out of the N-NE today before shifting back out of the west on Thursday with gusts up to 20 knots. W-NW breezes will prevail into the weekend ahead an incoming trough which could yield additional afternoon showers and thunderstorms beginning Saturday. Fuentes && .HYDROLOGY... Unseasonably warm daytime temperatures and mild nights, combined with higher solar angles, longer days, and limited cloud cover, will continue to increase snowmelt rates this week. Even the higher elevation deeper snow areas will begin to melt in earnest. This rapid melt will lead to elevated flows with rivers and streams running cold and fast, most notably in areas draining significant terrain over ~7500 feet from Lake Tahoe south through Mono County. While these high and cold flows can be hazardous to recreationalists, flooding is very unlikely. Remember the highest flows are significantly lagged from the heat of the day and can often occur at night. More steady high flows will also continue along the Lower Humboldt, with additional rises likely in very late May or early June. Please use extra caution around local rivers and streams which will be running fast and cold. Bardsley && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$