Marine Weather and Tide Forecast for Lucerne, CA

DISCUSSION

Today
Mostly sunny skies across interior NorCal at the time of this writing. Temperatures climbing into the 80s across Valley locations, with continued heating expected to top off in the upper 90s/triple-digits. Moderate HeatRisk with areas of Major HeatRisk remain the headline for today, as high pressure continues to keep air stagnant across the region. The Heat Advisory will run through 10 PM tonight, then our upper level pattern will begin to breakdown as we move closer to the weekend.

Friday
Upper level pattern begins to break down as a PacNW trough and weak closed low form offshore. While high temperatures will still be above normal Friday, the Delta Breeze and onshore flow will return to the area later that evening, ushering in relief from the summer-like temperatures in the evening. Wind gusts in the Delta are forecast to reach 35 to 45 mph at times Friday night into early Saturday morning, when the height gradient is expected to be strongest. Similar gusts are expected across Coast Range gaps and along the Sierra Crest Friday into Saturday.

...Saturday-Monday...
Gusty winds will continue through most of Saturday and we will see our first day of more fall-like high temperatures across interior NorCal. Highs are expected to be in the mid to upper 70s, low 80s in the northern San Joaquin Valley. Synoptic pattern will see a PacNW trough phase with a weak offshore low, and some moisture associated with the remnants of Hurricane Rachel. Recent ensemble runs are continuing to keep the bulk of tropical moisture south of our warning area. Some moisture advection will nose into portions of the Sierra Nevada, mainly on Sunday and Monday. Right now, best chances of seeing 0.50" of rain remains above roughly 3000 feet and south of I-80. With the path of the trough and an eventual low pressure developing/closing off, isolated t-storms will be possible in the higher elevations Sunday and Monday as well. While the NBM keeps probabilities at or below 15%, location of the aforementioned low will provide the lift, cold air/instability aloft to produce t-storms if enough moisture advects.

Sunday into Monday will continue to see the low dig further south into NorCal, which will create a north to south pressure gradient in the Valley. Little to no precip expected in the Valley, but periods of breezy to gusty north winds will develop; strongest Sunday afternoon as the low treks across our area. Wind gusts are forecast to be around 30 to 40 mph in the northern Sacramento Valley along and west of the I-5 corridor and adjacent foothills.
We will keep the potential for elevated fire weather conditions based on the north wind gusts, but daytime humidity values on Sunday and Monday will likely help keep the Valley out of critical conditions.

Still high level of uncertainty regarding exact impacts, but we can say for certain cooler temperatures, gusty winds, and light mountains showers with some rumbles of thunder are expected within this pattern change.

Tuesday and Beyond
By Tuesday, closed low begins to translate eastward, with sensible impacts of seasonable high temperatures and lingering mountain showers, mainly south of HWY-50. Ensembles suggest offshore ridging developing by Wednesday and Thursday, suggesting high temperatures will climb back into the low to mid 80s by the middle of the week.

AVIATION

VFR conditions continue across interior NorCal next 24 hours.
Surface wind gusts below 12 knots, gusts up to 15 to 20 knots in the higher elevations beginning 23z today through roughly 07z Friday.

STO WATCHES/WARNINGS/ADVISORIES
Heat Advisory until 10 PM PDT this evening for Butte County Below 1000 ft-C. San Joaquin County including Stockton-C. Solano County including Fairfield-C. Stanislaus County including Modesto-C. Yolo/NE Solano including Woodland-Central Colusa County Incl. I-5-Central Glenn Co & Interstate 5-Central Motherlode 1000-3000 ft-E. Diablo Range Above 1000 ft-Eastern Colusa County-Eastern Glenn County-N. Motherlode 1000-3000 ft-N.
Sac Valley in Tehama County-NE San Joaquin Valley Below 1000 ft- SW Solano County including Vallejo-Sac Metro/W. El Dorado/Amador County-Sacramento County Delta-San Joaquin County Delta-Shasta County Foothills 1000-3000 ft-Shasta Metro-Sierra (Tehama- Plumas) 1000-3000 ft-Southern Motherlode 1000-3000 ft- Sutter/Yuba counties below 1000 ft-Tracy Triangle Below 1000 ft- W Tehama Co Foothills 1000-3000 ft-W. Glenn/Colusa Foothills 1000-3000 ft-W. Shasta County 1000-3000 ft-W. Stanislaus County Above 1000 ft & I-5-W. Yolo County including Capay/I-505-Yolo / Solano County Hills.