Local

SLO County weather forecast for the week of Sept. 18

These parallel lines of Langmuir circulation were easily seen at Port San Luis last week. They resemble corresponding paths of dark and light lines on the ocean’s surface that linger up and down the coastline. The scientist who discovered this was Irving Langmuir, who was born in January 1881 in Brooklyn, N.Y. When the winds blow across a flat ocean, long sets of shallow parallel counter-rotating vortices form in the surface waters. These can also develop in lakes and even slow-flowing rivers.
These parallel lines of Langmuir circulation were easily seen at Port San Luis last week. They resemble corresponding paths of dark and light lines on the ocean’s surface that linger up and down the coastline. The scientist who discovered this was Irving Langmuir, who was born in January 1881 in Brooklyn, N.Y. When the winds blow across a flat ocean, long sets of shallow parallel counter-rotating vortices form in the surface waters. These can also develop in lakes and even slow-flowing rivers.

Here is this week’s weather forecast by PG&E meteorologist John Lindsey.

A ridge of high pressure over California will produce gentle to moderate (8- to 18-mph) Santa Lucia (northeasterly) winds during the morning hours and gale-force northwesterly winds along the coastline during the afternoon hours Monday into Wednesday.

These northeasterly (offshore) winds will keep the marine layer out to sea during the morning hours, and strong to gale-force afternoon northwesterly winds will keep most of the beaches mild and blustery. In other words, the weather will have an autumn feel with crisp morning minimums followed by pleasant afternoons. Overall, afternoon highs will range from the high 80s to low 90s in the North County and high 70s to low 80s in the coastal valleys, The beaches will remain in the 60s, except the southerly facing beaches of Cayucos, Avila Beach and Shell Beach, which will reach the 70s.

Moderate gale-force to fresh gale-force (32 to 46 mph) northwesterly winds are forecast along our coastline later Thursday, which will keep the skies mostly clear and the temperatures mild. Warmer weather should return by the weekend, but no significant heat is expected.

Surf report

A 3- to 5-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 11-second period) is forecast along our coastline through Monday.

A 975-millibar storm moved eastward and crossed the Aleutian Islands into the Gulf of Alaska on Saturday. Northwesterly swell from this storm reached 24 feet with a 14-second period Saturday morning. This northwesterly swell, combined with gale-force northwesterly winds along our coastline, will generate a 7- to 9-foot northwesterly (300-degree, deep-water) sea and swell (with a 5- to 17-second period) Tuesday and will remain at this height but with a gradually shorter period Wednesday into Thursday. This northwesterly sea and swell will decrease to 4 to 6 feet (with a 7- to 11-second period) Friday into next Sunday.

Seawater temperatures will range between 55 and 61 degrees through Monday, decreasing to 54 to 60 degrees Tuesday. Seawater temperatures will decrease to 52 and 56 degrees Wednesday into Friday.

▪  ▪  ▪ 

At PG&E, the safety of our customers and employees is our top priority. Buckling up is such a simple thing to do; it only takes two seconds, and no other single action has as much lifesaving potential. If more adults wore safety belts, their kids would, too. Besides, it’s the law.

John Lindsey’s Weekly Forecast is special to The Tribune. He is PG&E’s Diablo Canyon Power Plant marine meteorologist and media relations representative. Contact him at pgeweather@pge.com. Follow him on Twitter @PGE_John.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

MON

TUE

WED

THU

FRI

SAT

SUN

53 90

52 86

51 85

53 80

53 81

53 87

54 90

LOWS AND HIGHS, SLO AND COASTAL VALLEYS

MON

TUE

WED

THU

FRI

SAT

SUN

56 80

56 79

56 78

56 77

56 76

56 80

56 82

Related stories from San Luis Obispo Tribune

  Comments