At the beginning of January, Twitchell Reservoir was nearly empty; as of Saturday, it increased to 61 percent of capacity. Lake Lopez spilled for the first time in 25 years on Thursday. Whale Rock Reservoir and Salinas Reservoir continue to spill. Up north, San Antonio Reservoir was at 60 percent, and Lake Nacimiento reported 91 percent of capacity with water still being released for flood control.

The wet pattern filling many of our lakes and reservoirs will continue this week. In the meantime, a classic spring Central Coast weather pattern with afternoon gale-force northwesterly winds and mostly clear skies will continue through Monday morning.

An area of high pressure (1,035 millibars) over the Great Basin will produce moderate to fresh (13 to 24 mph with gusts to 40 mph) Santa Lucia (northeasterly) winds during the night and morning, shifting and increasing out of the northwest to strong to gale-force (25 to 38 mph) levels during the afternoon through Monday morning. This condition will give primarily clear skies, with morning temperatures dropping to the high-30s in the coastal valleys (San Luis Obispo) and the low-30s in the inland valleys (Paso Robles); consequently, frost is expected to develop Sunday night into Monday morning, especially in the wind-sheltered valleys.

Depending on where you live, you may wake up to the whirly sound of wind machines used for frost protection. Daytime highs will reach the low to mid-60s through the Central Coast.

Monday afternoon and night will be a transitional period with decreasing winds but increasing mid to high-level clouds during the afternoon and night.

A storm will rapidly intensify to 980 millibars off the coast of far Northern California, making it the third atmospheric bomb cyclone (when the atmospheric pressure drops at least 24 millibars in 24 hours) of the rainfall season.

The associated cold front will move through the Central Coast on Tuesday with fresh to strong (19 to 31mph with gusts to 45 mph) southerly winds and rain. This cold front will be followed by an upper-level trough that will continue to produce rain showers into Wednesday. Plenty of cold air aloft combined with the longer days of spring will create atmospheric instability and, in turn, a chance of thunderstorms. Thunderstorms can produce microbursts, heavy rain, hail, and lightning. Remember, when thunder roars, go indoors. Total rainfall amounts are expected to range between 1 and 2 inches.

Increasing northwesterly winds and clearing skies are forecast on Thursday into Friday. The next chance of rain is expected on April 6 and 7.

Seawater temperatures will range between 53 and 55 degrees through Friday.

Surf report

A 7- to 9-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 14-second period) is expected along our coastline on Sunday, decreasing to 3- to 5-feet on Monday.

Increasing southerly winds along the California coastline will generate 5- to 7-foot southerly (180-degree, shallow-water) seas (with a 3- to 7-second period) on Tuesday, followed by a 7- to 9-foot northwesterly (290-degree, deep-water) swell (with an 8- to 12-second period) on Wednesday.

A 6- to 8-foot northwesterly (300-degree, deep-water) sea and swell (with a 5- to 11-second period) is expected along our coastline on Thursday, decreasing to 2- to 4-feet on Friday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

John Lindsey’s is a longtime meteorologist who lives in Los Osos. Email him at JohnLindseyLosOsos@gmail.com.