textproduct: Sacramento

KEY MESSAGES

- Isolated showers today with additional chances for isolated mountain showers/thunderstorms on Saturday.

- Elevated fire weather conditions Sunday-Monday due to increased North winds across portions of the Valley.

- Cooler temperatures and breezy onshore flow expected Tuesday onward.

DISCUSSION

A trough from the Gulf of Alaska will move through the area today-Saturday, bringing isolated light showers and mountain thunderstorm chances. A few showers will move over the Valley today, although the majority of precipitation will be over the mountains. Forecast precipitation amounts are generally less than 0.10", however, amounts 0.20" to 0.40" are forecast over the northern Sierra and southern Cascades. There is a 10% chance for isolated thunderstorms along the Sierra crest today, but the highest likelihood for any thunderstorms development will be on Saturday where there is a 15 to 20% chance over the southern Cascades and eastern Shasta County. Additionally, enhanced onshore winds are expected through the Delta and Valley through Saturday introducing cooler temperatures and higher humidities throughout the area.

As the trough exits into the Great Basin area, north winds increase on Sunday through the western portions of the Sacramento Valley & Delta. This will result in renewed fire weather conditions Sunday into Monday. Strongest winds are expected Sunday morning. Since the strongest winds are forecast during the morning hours, they will not coincide with the lowest relative humidities. That being said, winds will still remain gusty through the afternoon hours when relative humidities will be in the teens to mid 20s. Monday sees significantly weaker winds and therefore also lower fire weather concerns.

Latest deterministic EC and GFS depicts a lobe of energy phasing out of the exiting trough on Sunday, which may introduce additional mountain shower and thunderstorm chances north of I-80. The overall environment will be dry which may negate any shower development, however, the feature will be closely monitored for any significant changes and/or additional fire weather concerns.

Moving further into the week, another cooling trend is expected Tuesday and beyond, resulting in below normal temperatures across interior NorCal and periods of breezy onshore flow in the forecast.

AVIATION

General VFR conditions are expected over the next 24 hours. South to southwest wind gusts 15-25 kts through 15Z Saturday in Sacramento, and 20-35 kts through the forecast period for the Delta and over the Sierra Crest. The remainder of the Sacramento Valley will have gusts 15-25 kts through 06Z Saturday, with more northerly wind gusts picking back up in the northern Sacramento Valley around 23z Saturday. 10-15% chance isolated thunderstorms in the Sierra/southern Cascades through 03z Saturday bringing local MVFR/IFR conditions.

STO WATCHES/WARNINGS/ADVISORIES

None.