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Quakes, Storms, Heat, and Smoke

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WEATHER DISCUSSION

Well to say that today has been interesting (weather-wise) is an understatement. Starting early this morning, we have seen many things change with the weather, plus an earthquake in California to top it all off.

First, we’ll talk about the earthquake that happened near the San Francisco Bay Area. While not a weather issue, meteorologists still like to keep tabs on geological natural disasters, purely because of scientific value. The quake was a registered 6.0 magnitude shock that occurred 8 miles north of San Pablo Bay, and 5 miles SSW of Napa, CA. It happened at 3:20 a.m. Since the initial shock, there have been numerous small aftershocks, and 6 of which were 2.5+ in magnitude. This was the larges earthquake in the Bay Area since 1989. According to the latest survey put out by the USGS:

  • Within the next 7-day:
  1. At least 15-20 more weak aftershocks are expected in the area (3.0-5.0 in magnitude)
  2. Of those 15-20, there is a 36% chance that one or more could be a strong aftershock (5.0+ in magnitude)
  3. The possibility of a stronger earthquake than the original (above 6.0) is at about 5-10%

It is not common to get a stronger quake than the original, but the chance is always there.

Now, on to thunderstorms that rolled through the Klamath Basin today. Lake county started seeing cumulonimbus in the early afternoon with very little rain making it to the ground. Very low surface humidity has been evaporating the rain. However, there was enough moisture in the atmosphere to kick off some lightning. Mostly negative strikes. Which is good news. Negative strikes are the type of lightning that originates from the negatively charged base of the thunderstorm where rain is abundant and falling. Positive strikes, are less common and are what we know as “dry lightning.” The cirrus or “anvil” that stretches from the base of the thunderstorm is positively charged, and when there is enough of a negatively charged spot on the ground below, a positive strike will occur. This is what causes dry lightning. As of 7:30 p.m. Sunday there was only one recorded positive strike near Hart Lake in Lake County. Storms were weak as there was very little instability and moisture associated with them. They will likely fizzle out in the next few hours.

On to the Heat. A thermal trough sat over the coast Saturday and allowed for a very pronounced Chetco event which brought Brookings to a high of 90 degrees. Even other coastal cities were much warmer than average. This trough moved inland Sunday and brought more heat to the inland locations. Brookings was cooler by an average of 25 degrees Sunday because of the onshore flow and the wind shift. Tomorrow, another thermal trough is expected to sit over the coast and the Chetco will once again heat up Brookings. The forecast high for Brookings is 85 on Monday, but could once again exceed that. Temperatures will rise significantly on Tuesday for inland locations, as that is when the thermal trough will move inland again. Expect a 5-10 degree jump from highs on Monday to Tuesday for inland locations. We will stay in the upper 90′s in the west side for at least a few days. A low pressure trough will usher in cooler air next weekend and allow for another cool down into the 80′s for Medford.

Smoke is now the issue in Northern California. Winds Saturday were mainly out of the north and northeast. This pushed the smoke from the fires in Western Siskiyou County south. Today, a rapid shift in the winds back to the northwest and west, allowed for air quality in Central Siskiyou to plummet within a few hours. AQI levels in Yreka, Fort Jones, and Etna went from the good category to the unhealthy category very quickly. Smoke is expected to shift south again Monday as the trough moves inland. So levels will temporarily get better Monday. However, Tuesday starts the NW winds again and therefore smoke will enter Central Siskiyou County again. Stay indoors whenever possible, and purchase an air purifier for your home if you have not already done so.  The fire complexes causing the smoke are only up to 36% contained. So air quality will be suffering for a while.

Thanks for logging on and have a great week!

Meteorologist Seth Phillips

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Photos Submitted Today:

Herb Kennedy: “Cloud Fish”

cloud fish

Darcy Hayford: “Smoke in Lake Shastina”

smoke