Thursday, June 23, 2011

Strong Pacific Storm could eventually impact the United States

In the next day or two, a very strong system will emerge from the West Pacific with central pressure forecast below 980 millibars. This surface analysis above projects the low about 42 hours out from the time of posting. The reason why I made this post is because, should this system remain as strong as it is forecast to be and make landfall in the US, it could spell out catastrophe in the way of severe weather or flooding concerns.

This image is the forecast for 84 hours away. We see the strong low pressure up by Alaska moving East Northeast towards Alaska. There is also a weaker low moving southeast that may eventually make landfall on the US as well. Right off the bat, we can determine that these systems are being pulled along by the jet stream, which appears to be nose diving towards the West Coast of the US after brushing Alaska as seen in the above picture.
24 hours later, the low off the West Coast of the US has intensified within the jet stream. More importantly is the low moving closer to Alaska. It remains at a very strong strength.
This whole jet stream pattern will be supported by a strong ridge in the atmosphere, as defined by the negative region in blue below the strong low in red.
Another 24 hours later, this ridge begins to weaken and collapse the jet stream pattern. The strong low has weakened slightly and how begins to move southward as the ridge weakens towards the United States. As the ridge weakens, the low just off the coast of the US will weigh down on the jet stream and get pumped into Canada. At the same time, the second low in Alaska may also be propelled into Canada unless some pattern sets up north of Alaska that forces the low more southward than anticipated and into possibly the Central Plains.
One day later, the ridge has nearly totally weakened, and the jet stream is now trying to thrust northward. This creates a dilemma for the low in Alaska. With the second low now in California and no longer weighing down on the jet stream, that loss of pressure also encourages the jet stream to shoot into Canada instead of stay in the pattern that would direct the low in Alaska towards the West Coast. The low moving south from Alaska i also weakening.
Finally, yet another 24 hours later, the low seems to still have a good amount of strength to force the jet stream south once again, which could lead to the possibility of this low also moving down to the US.

We will be watching this system closely over the next several days.

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