It started out as a usual Mother’s Day. My family and I headed out of Los Osos to San Luis Obispo and then out of nowhere, “Achoo!” My wife started sneezing and developed itchy eyes before we merged onto Highway 101.
Like so many others, she suffers from hay fever. The number of people affected is staggering — doctors estimate between 10 percent and 30 percent of the adult population has hay fever, with the numbers even higher in children.
The medical community will tell you hay fever (seasonal allergic rhinitis, or SAR, is the correct term because hay is not usually the problem) is frequently caused by pollen.
People who suffer from SAR have a particular gene that causes their immune systems to overreact to pollen, producing itchy eyes, sneezing, runny noses and other symptoms. SAR is usually worse in the spring or fall.
By contrast, someone with these symptoms year-round likely has perennial allergic rhinitis. Dr. Scott Robertson told me that PAR is quite common on the Central Coast, as we never really have a hard freeze that forces all plant life into a dormant state.
As is so often the case during spring along the Central Coast, on Mother’s Day the northwesterly winds were blowing off the Pacific Ocean toward San Luis Obispo and things in the air were stirring. To put the wind direction into perspective, the winds blow out of the northwest about 60 percent of the time on the south side of the Cuesta Grade on average.
These nearly pollen-free northwesterly (onshore) winds coming off the Pacific usually keep the pollen counts low at Montaña de Oro State Park, Los Osos, Morro Bay and other northwesterly facing beach communities. However, as these winds travel inland they pick up small, light, dry pollen grains from grasses, trees and weeds and invisibly spread them across the coastal valleys toward the interior. This condition increased the inland pollen count, and by the time we reached San Luis Obispo my wife was full-on sneezing.
On the other hand, when the winds shift out of the northeast (offshore) and blow from the land out to the ocean, they transport pollens from the grasses and tress in the inland valleys and mountains toward the sea.
At moments like this, even the beach communities will experience high pollen counts.
The year’s above-normal rainfall and warm and sunny weather during January and most of February produced a bumper crop of grasses, such as annual rye and wild oats.
“The ranchers and cows are very pleased with the amount of forage that the rains have produced, but unfortunately as the grasses dry and the wind blows, allergens spread and it can be quite uncomfortable,” said Sally Krenn, Pacific Gas and Electric Co. terrestrial biologist.
Last week’s May rains washed away a lot of the pollen from the atmosphere and provided temporary relief, but pollen counts are expected to increase again.
Dr. Robertson told me the best way to prevent allergies is to avoid the things you are allergic too, though he knows that is easier said than done.
Here are some tips he gave me:
Avoid allergic triggers.
Keep doors and windows closed on windy days.
Use air conditioning whenever possible.
Don’t hang laundry outside.
Wear a dust mask when doing yard work.
Limit early-morning outdoor activities.
Dr. Robertson went on to say, “If despite following all of these simple steps and you are still miserable a trip to the allergist may be in order.”
This week’s weather report
Batten down the hatches. A 1,030-millibar Eastern Pacific High will remain nearly stationary about 700 miles to the west of California while a 1,007-millibar thermal low develops over the desert southwest.
This condition will produce moderate gale- to fresh gale-force (32 mph to 46 mph) northwesterly winds along the coastline today through Monday.
These onshore winds will mark a slight cooling trend for today and tomorrow, with a few light showers likely across the northern and central Sierra each afternoon through Monday.
Today and tomorrow’s temperatures will range from the high 50s along the northwesterly (Los Osos and Morro Bay) facing beaches to the high 60s along the southwesterly (Avila Beach and Cayucos) facing beaches and coastal valleys (San Luis Obispo). The North County (Paso Robles) will range between the low and mid-70s.
A warming trend will develop on Tuesday along with the return of night and morning low clouds and fog.
A cold front will move in from the Pacific and produce rain as far south as Monterey Bay on Wednesday. However, The Central Coast will only see partly cloudy skies.
Warmer temperatures will most likely occur on Thursday with the North County reaching to low 90s by Friday.
Dry and mild weather will continue through the Memorial Day Weekend.
Surf and sea report
Moderate gale- to fresh gale-force (32 mph to 46 mph) northwesterly winds along our coastline will generate an 8- to 10-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 14-second period) today through Monday.
This northwesterly (300-degree deep-water) sea and swell will decrease to 6 to 8 feet (with a 7- to 14-second period) on Tuesday, further lowering to 4 to 6 feet Wednesday.
Another round of increasing northwesterly winds will generate a 6- to 8-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 11-second period) Thursday through Saturday.
Arriving from the Southern Hemisphere: Today’s 2- to 3-foot Southern Hemisphere (190-degree deep-water) swell (with a 13- to 15-second period) will gradually decrease today.
A 2- to 3-foot Southern Hemisphere (190-degree deep-water) swell (with a 16- to 18-second period) will arrive along our coastline Monday and Tuesday, decreasing 1 to 2 feet Wednesday.
Seawater temperature report: Increasing northwesterly winds will produce cooler seawater temperatures today through Monday. Seawater temperatures will range between 48 and 50 degrees through today, further lowering to 47 to 49 degrees Monday through Tuesday.
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John Lindsey, media relations representative for PG&E and local weather expert, has lived along the Central Coast for more than 25 years. To subscribe to his daily weather forecast or ask him a question, email him at firstname.lastname@example.org.