SLO County weather: More heavy rain and a chance of thunderstorms
Much like last week, an unsettled weather pattern will continue through Monday with periods of rain and high sea and swell. This week will also be an excellent time to break out your coats and sweaters, as high temperatures will remain below the 60s.
On Sunday, an intense 537 decameter upper-level low-pressure will move southward over the Central Coast. This system will produce strong to gale-force (25 to 38 mph with gusts to 45 mph) southwesterly winds, rain showers, and a chance of thunderstorms with brief downpours and hail. Scattered convective rain showers and dropping snow levels will develop Sunday night and continue through Monday morning.
In fact, snow levels will drop to approximately 3,000 feet by Sunday night into Monday morning. Total rainfall amounts will range between 1 and 2 inches with up to 4 inches along the southerly-facing mountain slopes due to orographic enhancement.
Overnight lows will drop to the 30s in the inland valleys (Paso Robles) and low to mid-40s in the coastal valleys (San Luis Obispo), while daytime highs will range from the low to mid-50s throughout the Central Coast. Rain showers will end by Monday afternoon.
The skies will clear as Santa Lucia (northeasterly) winds develop and increase to moderate to fresh (13 to 24 mph) levels on Monday night and continue through Friday. However, variable mid to high-level clouds will continue to stream over the Central Coast.
A cold front will move through the Central Coast on Saturday with increasing southerly winds, mid to high-level clouds, and a chance of rain showers. A stormy weather pattern is expected over the Christmas holiday with gusty southerly winds, moderate to heavy rain, and low snow levels.
Surf report
Sunday’s 12- to 14-foot west-northwesterly (285-degree, deep-water) sea and swell (with a 7- to 14-second period) will remain at this level through Monday, decreasing to 6- to 8-feet (with an 8- to 12-second period) on Tuesday.
A 5- to 7-foot northwesterly (300-degree, deep-water) swell (with an 8- to 12-second period) will develop along our coastline on Wednesday through Friday.
A strong northerly flowing current combined with less upwelling, has brought a warmer body of seawater to the Central Coast. Seawater temperatures will range between 57 and 61 degrees through Friday.
This week’s temperatures
LOWS AND HIGHS, PASO ROBLES
SUN | MON | TUE | WED | THU | FRI | SAT | SUN |
39, 53 | 37, 52 | 33, 52 | 34, 54 | 37, 57 | 36, 56 | 39, 54 | 33, 56 |
LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS
SUN | MON | TUE | WED | THU | FRI | SAT | SUN |
47, 53 | 44, 54 | 42, 54 | 40, 55 | 44, 58 | 45, 59 | 49, 55 | 37, 58 |
John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on Twitter @PGE_John.