Tuesday, August 30, 2016

Hawaii in the Gunsights

Picturesque Hawaiian waterfalls could be roaring soon
Two powerful hurricanes have developed over the tropical eastern Pacific and are headed westward toward Hawaii.  Hurricane Madeline is currently (1200 UTC 30 Aug) a category 4 hurricane and will be the first to approach the islands on Wednesday and Thursday.  It is the westernmost hurricane in the image below.  Hurricane Lester is farther upstream (east) and a potential player for the Labor Day Weekend.

Based on analyses from the National Weather Service Central Pacific Hurricane Center, about 22 tropical storms and hurricanes have passed within 200 miles of Hawaii since 1950 and 10 have passed within 75 miles.

Source: NWS/CPHC
Model guidance presently shows a wide range of tracks for Madeline as she approaches Hawaii.  The GFS ensemble has a few bringing it directly over the Big Island, but others push her further south.  

Source: NCAR/RAL
A look at a multi model suite shows a couple of tracks that pass between the Big Island and Maui, but others going to the south.  

The official track cone, which represents the area that is likely to include the probable track of the tropical cyclone center, extends from the center of the Big Island southward.

Madeline is expected to weaken some as it approaches Hawaii, but will still be a dangerous storm with hurricane-force winds possible on the Big Island on Wednesday (depending on track and intensity), heavy rain on the Big Island and possibly other Hawaiian Islands Wednesday through Friday, and dangerous surf.  Official graphics and forecasts are available here.

As a mountain meteorologist, I'm interested in seeing how precipitation is affected by the interaction of the system with the topography of the Big Island.  I plan to keep an eye on this over the next couple of days.


  1. Those historical track plots look outdated. Iselle and Darby hit Hawaii last year, 2 of only 5 tropical storms or hurricanes to have made landfall since 1949. Jeff Masters has a nice discussion on it here including the possible role of the Fujiwara Effect in this situation: https://www.wunderground.com/blog/JeffMasters/td-9-organizing-in-the-gulf-of-mexico-td-8-headed-towards-north-carol.

    1. I should have mentioned also that Iselle last year dropped up to 15 inches on the windward side of the big island, massively aided by upslope flow and Madeline looks to be taking a similar track.

    2. Adam,

      Thanks for that clarification as it is a good point. Other graphics on the site include data through 2013, but it's unclear if those plots go through that year.