textproduct: Reno

KEY MESSAGES

* Warming trend with light winds and valley inversions today through Saturday.

* Weekend storm brings more gusty ridgetop winds with light valley rain and mountain snow showers and increased thunder potential.

* A brief warm up Tuesday may give way to another potential storm lurking for the middle of next week.

DISCUSSION

Who ordered spring? Afternoon highs will reach 10-15 degrees above normal by the end of the week, meaning the upper 60s and 50s for valleys and high elevations, respectively. Odds to hit 70 or higher in Reno Saturday have fluctuated a bit since yesterday afternoon, but currently sit at a 60% chance. Light winds will continue for most locations today and tomorrow, with the exception of ridgetops. Light valley inversions will also set up, including the chance (20%) for patchy freezing fog for Sierra valleys.

A pattern shift has its sights for the weekend, with light rain showers moving into the Tahoe Basin and northward by mid Saturday afternoon. This is associated with a low pressure system off the coast of north-central California. A couple things to note for Saturday; snow levels will sit around 9000-9750 ft so precip that falls will mainly be rain, except for the highest peaks. The orientation of this low, seen with the 500 hPa heights, has a negative tilt to it, which increases forcing and instability. Combined with the warmer than normal temperatures, the chances for isolated thunderstorms for NE CA has increased to 15-20%. As such, parts of NE CA are in an area of 'general thunder' from the Storm Prediction Center Saturday. Thunderstorms may also develop around the Tahoe Basin; keep in mind that lightning can strike up to 10 miles away from a storm system. Recreating this weekend? Keep an eye and ear to the skies!

Shower chances renew by the afternoon hours both Sunday and Monday, though confidence remains low on just when we could see showers setting up due to the nature of the low level system. Snow levels do drop, though, by Sunday afternoon to 7500-8500 ft (locally higher as you move southward) and below 7250 ft by Monday afternoon. There are also some isolated thunderstorm chances both afternoons. Additional hydrology impacts are also possible with this weekend. Please see the hydrology section below for more details.

A brief drying pattern sets up by Tuesday of next week, with another system possibly dropping in as early as Thursday of next week. Stay tuned for more details as we get closer!

-Giralte

AVIATION

VFR conditions will prevail through at least Friday with light winds. The only exception will be at KTRK where patchy FZFG is possible each morning. Saturday, increasing turbulence is likely due to increased ridgetop winds. -SHRA may impact KTRK and KTVL Saturday by 21Z, though timing and confidence is low at this time.

-Giralte

HYDROLOGY

The Middle Fork of the Feather near Portola continues to rise towards minor flood stage this afternoon. The river is expected to crest below flood stage later today or tonight, but minor flooding can not be ruled out. Most other rivers and streams have crested but very high flows are persisting.

Snowmelt yesterday was very rapid for this time of year despite limited rain. Large extents of the snowpack have been primed by the previous rain, warm temperatures along with high winds and humidity. All but the coldest and deepest SNOTEL locations reported significant melt yesterday. Most of these sites recorded record snow water equivalent (SWE) losses yesterday for the February 25th date.

Snowmelt is expected to continue with warm temperatures through the weekend, and additional rises are possible with warm afternoon temperatures and even modest amounts of rain. Currently no new flooding is forecast, but conditions are primed for rapid streamflow response and flood risk if significant rain returns before significant cooling and or drying.

Updated river forecasts are available at www.cnrfc.noaa.gov.

-TB

REV Watches/Warnings/Advisories

NV...None. CA...None.