The Monsoon – Tropical Storm Hector – And Why Southern California Weather Is Beautiful & Boring

Good morning bloggers,

I will be leaving for Kauai, Hawaii tomorrow morning.  And, while I am there a potential hurricane will be heading west on a track that will most likely end up south of the Hawaiian Island chain.  Kauai is the farthest west island, and the mountains go just high enough, around 5,000 feet, that the orographic lifting (Mountain lifting) creates conditions for some of the wettest weather on earth.  The most precipitation in the United States and the world falls at Mt. Waialeale on Kauai in Hawaii. It rains an average of 460 inches a year on the tropical island mountain. The mountain peaks at just over 5,000 feet, which is just perfect for creating the conditions for these wet conditions. It is also perfect to create the conditions for too much rain, like what happened early this year, just a few months ago when 28″ of rain fell in less than 24 hours.  The post office on the north shore just opened this week, and now they have this threatening the island:


This map above shows the Hawaiian Island chain being threatened by a major hurricane within a week.  I will be on that farthest west island of Kauai, which is just north of the system as you can see here clearly.on our analysis there is about a 50% chance this system tracks south of the islands, and close to a 50% chance it tracks north of the islands.  Either way, it will be an interesting storm to watch and monitor, especially since I will be there.  Kauai is that farthest west island. The one where the volcanic eruptions have been ongoing is the farthest west and largest island.  Hawaii rarely takes direct hits from hurricanes.  In 1992, the same year that south Florida was devastated by CAT 5 Hurricane Andrew, Hurricane Iniki blasted the island that I am going to, Kauai with 140 mph winds, and the condo that I am staying out was pretty much destroyed.  Iniki stayed over the warmer waters, that are located south of Hawaii, and then turned north right into Kauai.  Hopefully Hector doesn’t quite do that.  Let’s monitor this closely as it becomes a hurricane and tracks west.

I am in Southern California right now in my home town of Los Angeles.  The summer monsoon has been producing some spotty showers and thunderstorms the past few days.  These thunderstorms are most likely over the mountains due to what is called orographic lifting, or rising air caused by the mountains.  The thunderstorms also form over the deserts, but rarely over the populated areas of Southern California near the coast. Why?  Look at these next two pictures I snapped:



In areas near the Atlantic coast and Gulf coast, the water is warm and the humidity is high. This supports unstable air and thunderstorms form much easier. In Southern California, the Alaskan current flows south down the west coast with cool water being transported in from cool northeast Pacific Ocean.  This creates a stable lower layer and prevents the conditions favorable for thunderstorms.  The stable stratus clouds can be seen in both of these pictures, with the monsoon moisture above. The bright white cirrus cloud is actually an indication of the monsoon moisture.  Due to the strength of the upper level high height area, the thunderstorms have been spotty and weak over the mountains and deserts this week.

Rainfall Forecast: Next 15 Days


Look at the rainfall forecast above closely.  And, notice how 2 to 4 inches of rain are forecast just southeast of San Diego.  This is and example of why it was always so frustrating for me as a young child growing up in LA.  Or, actually I didn’t know any better, and I thought the thunderstorms over the mountains with anvils occasionally spreading out over the coastal sky was exciting.  Once every few years, the monsoon would be strong enough to break through and produce rare coastal rain and thunderstorms, but that stable Pacific Ocean caused cooler lower layers often messed it all up.

Kansas City Weather:

It looks like there are a few light sprinkles or showers early this morning. These will fall apart, and then it will heat up into the 90s the next few days. The drought continues to worsen in our local area, while other areas just to our west have been getting adequate moisture.  The next decent chance of thunderstorms may arrive early next week. Jeff will get you updated over the weekend.  I will check back in from Hawaii in a few days.

Have a great day, and thank you for spending a few minutes of your day reading the Action Weather Blog featuring Weather 2020 and the cycling pattern. Go over to the Weather2020 blog and let’s share in this weather experience.


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