2026 C and E Pacific tropical activity

[vortex95]

On 9/9/2026 at 10:01 PM, GaWx said:

Thanks for that info.

 It seems that this has been a really bad year for Hawaii! When was the last season as bad as this? And the season is far from over!

-H Lala: extreme rainfall and very strong winds to H force in some cases

-TS Moke: additional heavy rains along with gusty winds only a week after Lala thus hampering recovery efforts

-H Lowell: lots of damage from sustained TS force/gusts to H force W islands, significant storm surge, and very high waves 

No season prior has had two very close passes to any of the islands w/ both at hurricane-strength. 

All areas "pay the piper" sooner or later when it comes to hurricanes.  HI now, FL 2004 and other years, New England 1938-1960, the GA coast in the 1890s (3 hurr landfalls, 2 in one season!), etc.

Why is Hawaii generally not favorable for TCs most of time?  Gt this write-up some years ago.  Very strong El Nino disrupts the typical flow/circulation regime, and makes it more favorable.

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A TC approaching the Hawaiian Islands will often get sheared due to strong upper southwesterlies putting too much stress on the vertical structure of a TC moving westward in the slower but more dense trade flow over only marginally warm water.

The shape and size of the NPAC basin means that, particularly in
summer w/ the shorter wavelengths of the upper westerlies, there is usually room for more than one ridge or one trough in the middle and higher latitude flow.  The Gulf of AK therefore often becomes home to a strong vertical high pressure cell, while troughing may prevail farther to the W near the coast of Asia and Japan.  The rounded shape of the Gulf of AK fits well w/ the shape of the high w/ the high usually centered close to 45N latitude.  A strong high at that latitude over the oceans can be considered a type of blocking high of great vertical extent.

A strong blocking high tends to induce a cutoff low centered 15 deg S of the high center, which would place the low at 30N.  This low pressure circulation in the weaker flow of summer is often not easy to detect in the surface flow except for a slight cyclonic shear w/ the easterlies increasing going northward and a slight curvature in the isobars along w/ increased clouds and showers.

The longitude of these pressure features w/ the high at 45N and the low at 30N is usually near 160W.  Thus, by extension, over the
Hawaiian Islands still farther to the S and SE at 20N between 155W and 160W, this area experiences during this very common flow pattern of summer and fall a broad band of southwesterlies aloft, which is detrimental to TCs.