Category: Weather

2017 Will Be One of Those Harvests You Never Forget

Posted on by LHP

Saturday evening we attended a “Release Dinner” for one of our favorite wineries up in Napa. That’s where they roll out the vintage they’ll sell in the upcoming year (in this case, the 2014 vintage), sip some samples of the vintage, and maybe some past vintages, enjoy some food, and hobknob with the owner and the winemaker and the staff and other fans of the winery. They are fun events.

Midway through the evening each of the principals stood up and said a few words. The winemaker, Ricardo Herrera, was third or fourth up, and he said, in his quiet, shy way, that he told his staff and his colleagues that 2017 would be “one of those harvests you never forget.” He was referencing the difficulties they had with the weather, which was warm all summer and featured late rain, and a delicate balancing act. The grapes hadn’t ripened fully due to the odd weather, but the unusually high heat they experienced in September presented the possibility that the fruit might not fully ripen before it was shriveled by the sun. So it was wait and risk a severely reduced yield or harvest early and try to work with under ripe fruit. They decided to wait and risk it, but hedged with some extra irrigation. (They are loathe to do that because they prefer that the vines drive their roots down to find their own water rather than rely on irrigation.) There was a lot of discussion among winemakers and vineyard managers about which course was correct, and not everyone decided to wait. We’ll have to see how the wine turns out to know if Ricardo guessed right. He said he thought we would be rewarded.

Of course when he spoke, Ricardo could not have known about the wildfires that were to sprout a night later, the unforgettable unwinding of the deal he had struck with nature.

Why has the Summer Been So Gloomy?

Posted on by LHP

My explanation of Southern California’s June Gloom didn’t shed much sunlight on why it has become the June-July-August Gloom. Last week the National Weather Service released a brief statement explaining why: cooler than usual waters in the Pacific Ocean and a persistent “upper level trough” in the atmosphere above the coastline. That upper level trough — or low pressure system — has helped keep the air cool. Together, our cooler water and cooler air have prompted the formation of the clouds and fog that creep inland overnight. This combo has also kept monsoonal moisture at bay. So while the American Southwest is enjoying afternoon thunderstorms, Southern California’s mountains and deserts have not.

All that was supposed to have changed this weekend. Temps were up inland and slightly higher here at the beach. And this morning’s bright sunrise, among a handful of fogless dawns this summer, promised a scorcher. But by noon today dense fog had tumbled in from the harbor. If you listen, you can hear the ships’ fog horns booming in the distance, heralding the end of the heatwave that wasn’t.

Now I Know: Southern California’s June Gloom

Posted on by LHP

June Gloom is the phrase many Southern Californians use to describe the generally overcast skies that hang over the region in late spring and early summer. The gloom is deepest just after dawn and heaviest near the beaches. But by midday — earlier over points inland — the clouds burn off and the basin’s familiar over-saturated sunlight washes over all. Well, the sunlight washes over all except those of us who live within a mile of the shoreline, where the overcast may linger deep into the afternoon.

The gloom and overcast are a result of the marine layer, which is a kind of temperature inversion layer. Normally, higher air temperatures are found near the ground and cooler temperatures are found aloft. An inversion layer sees this relationship turned upside down: cooler temperatures are found near the surface and warmer temperatures lie above. One effect of an inversion layer is a “capping” of normal convection currents — the rising and falling of air due to thermals — which traps dust and other particles under the inversion layer. LA’s famously bad air quality is partly a result of this meteorological quirk.

Our local inversion layer is generated by the especially chilly waters of the Pacific Ocean. The California Current carries frigid sea water south from the Gulf of Alaska to the tip of Baja. The sea water cools the air above, creating a temperature inversion. If there is enough moisture in the air, and the cooling effect is strong enough, then clouds and fog are generated within the marine layer. Depth of the marine layer is affected by the movement of much larger weather systems in the atmosphere above. High pressure systems squish the marine layer so that only coastal areas lie under the gloom. Low pressure systems allow the marine layer to expand upward and outward; fog along the shore rises and pushes inland.

It’s just after 2:00 pm PDT here in Long Beach, CA, and the sun is just beginning to burn through the clouds above. June Gloom has stretched all the way through July. But when the alternative is thunderstorms and sweltering heat, I don’t think many of the locals mind.