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Greetings from the Western Pacific Warm Pool 🐠
Premium update #9
Hi all! This week I’m writing to you from the Philippines, where my wife Kate and I have had the pleasure of vacationing.
Although it’s nearly 9,000 miles away, the weather here can be linked back to the Hudson Valley.
How can that be? Come take a dive with me into the Western Pacific Warm Pool! 🤿
The Western Pacific Warm Pool (WPWP) is home to the warmest sea water on Earth. It encompasses an area of the West Pacific where the ocean surface temperature exceeds 82˚F and is considered the “heat engine” of the globe.
It’s home to an abundance of coral reefs, tropical fish, tall cumulonimbus (thunderstorm) clouds, some of the world’s most intense cyclones (one initially delayed our travel!), delectable tropical fruits, and Kate and I over the last week…
The WPWP expands and contracts based on the phase of the El Niño Southern Oscillation. Right now, we’re in a moderate oceanic La Niña state, which means the WPWP covers a smaller geographical area of the West Pacific but extends deeper into the ocean. This is because of the tropical trade winds, which are stronger during La Niña. These winds blow east-to-west and cause extremely warm water to pile up in the western part of the Pacific. During El Niño, the opposite phase, the trade winds are weaker and allow the warm pool to expand eastward.
♨️ This warm water is a breeding ground for thunderstorm activity, or convection ⛈️
You’re probably more familiar with convection than you think. It happens on your stove top every time you boil a pot of water. The water near the burner heats up first, rises, and bubbles to the top since it’s less dense. Cooler water moves down to replace it, creating a convection loop current 🔃
In the atmosphere, the sun is the “burner”, heating up the ground from above, which, in turn, heats up the air. The warmer air near the ground then rises up and is replaced by cooler, denser air. The warm air, which contains (invisible) water vapor is buoyant and continues to rise upward. Eventually, the warm air is cooled by its surroundings. At this point, depending on the moisture content of the environment, the water vapor may release its heat and condense into a cloud.
Because this process can occur very efficiently in the tropics due to abundant sunshine and moisture, storm clouds can grow to some 50,000 feet tall.
🐉 I was gobsmacked by this “dragon cloud” that I spotted near the equator over West Papua while flying to the Philippines! It appeared to be at least as high as the plane’s cruising height of 40,000 feet but could have easily been taller ☁️
During La Niña, thunderstorm (convective) activity expands in the West Pacific, influenced by the characteristics of the warm pool.
This affects the Walker Circulation, which contains branches of rising and sinking air over the equatorial Pacific, induced by the contrast between the warm waters of the western Pacific and the cooler waters of the eastern Pacific.
Changes in the Walker Circulation then affect global weather patterns, including in the Hudson Valley.
In the Hudson Valley, La Niña Novembers have tended to run somewhat milder and drier than normal on average.
So far, November 2022 is going to script and should continue to do so for at least the first half of the month.
La Niña Decembers, on the other hand, have historically run slightly colder than average.
It continues to look like the 2nd half of November will represent a pivot point for the weather in the Hudson Valley, away from a milder pattern and toward one that is at least seasonably cool if not colder than normal at times 📉
🔴 So could the West Pacific Warm Pool be a harbinger of a cold pool over the Hudson Valley in a few weeks? 🔵
Time will tell, but the sun will soon set on the region’s unusually warm temperatures, so enjoy them while they’re still around 🌅