SLO County forecast for week of April 20: Clouds give way to breezy, warmer spring weather

After a weekend of mostly cloudy skies, morning drizzle and below-normal seasonal temperatures, the gale-force northwesterly (onshore) winds of spring will return along the Central Coast.

Spring is a transition season in terms of weather conditions: not quite summer and not quite winter. You may have stormy weather one day followed by record-breaking heat the next. However, spring along the Central Coast usually means constant northwesterly winds.

Strong to gale-force (25 to 38 mph) afternoon northwesterly winds along the coastline and temperatures rising back to above normal are forecast Monday afternoon through Friday. Afternoon highs will remain in the mid-60s along the coast due to persistent onshore flow but will climb back into the low to mid-70s across coastal valleys and the upper 70s to low 80s in the inland valleys.

The long-range models indicate that dry weather pattern will continue through the following week.

Monday’s surf report

Strong to gale-force (25 to 38 mph) northwesterly winds along the California coastline will generate 5- to 7-foot northwesterly (300-degree, deep-water) sea and swell (with a 5- to 15-second period) along our coastline starting Monday afternoon and continuing through Wednesday. This northwesterly sea and swell will further build to 6 to 8 feet (with a 7- to 14-second period) on Thursday through Friday.

Seawater temperatures

As the northwesterly winds blow along the coastline, the friction of the wind causes the ocean surface water to move. The apparent Coriolis force turns the surface water to the right, or offshore, causing upwelling along the shoreline as cold subsurface water ascends to the surface along the beaches.

At times like these, seawater temperatures can plummet to a bone-chilling 48 degrees. Seawater temperatures will drop to 50 and 53 degrees by the end of the week.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

During the COVID-19 outbreak, PG&E is alerting customers to be aware of potential scam phone calls or emails threatening to shut off power if a payment is not made. Please remember, PG&E has voluntarily implemented a moratorium on service disconnections for non-payment.