(ABOVE) The latest from 5-Day Forecast Track from The National Weather Service
Hawaii County Civil Defense message (Aug. 6, 2014 – noon)
HILO, Hawaii – The Big Island of Hawaii is now under a Hurricane Warning, as Iselle appears to be picking up some strength.
At 11 a.m. HST, the National Weather Service said some weakening is forecast during the next 48 hours. However, Iselle may still be a hurricane as it passes near the Big Island.
“Although hurricane Iselle had previously shown signs of weakening,” said Hawaii County Civil Defense in an audio alert issued at noon, (above) “current assessment show the system is maintaining hurricane force conditions.”
The new warning was enough to force the state’s top politicians to rethink the annual Democratic Grand Rally traditionally held the evening before the primary election in Hilo.
In the interest of the safety, health and welfare of the people of Hawai‘i Island, I am calling upon the Democratic Party of Hawai‘i to cancel its Grand Rally scheduled for Friday, August 8 in Hilo. I do not do so lightly; I understand fully the history and tradition of this event. However, my primary responsibility is to ensure that residents stay safe.”Gov. Neil Abercrombie in a media release
Here is the latest from the National Weather Service:
Iselle has not weakened over the past six hours… And in fact appears to have strengthened a bit. Air Force hurricane hunters recently found maximum flight level winds of 85 kt… Which suggests about 77 kt when adjusted to the surface… And the sfmr found maximum surface winds of 72 knots. This data suggests raising the advisory intensity to 80 kt. The wind radii have been adjusted somewhat to better match what was found by reconnaisance… But may still be a bit generous. Iselle is in an environment of marginal sea surface temperatures of 26c… But the wind shear over the system is currently weak. A clearly defined eye feature has redeveloped in the infrared and visible imagery over the past 12 hours.
The global models and the ships guidance both show the shear remaining relatively weak through the next 24 hours… Though the sea surface temperatures will remain marginal. Since there appears to be less of a window for Iselle to weaken significantly before reaching the islands… We are upgrading the tropical storm warning for the Big Island to a hurricane warning. The forecast track and wind radii also necessitate issuing a tropical storm warning for Maui County. It is important to note that regardless of whether Iselle reaches the Big Island as a tropical storm or minimal hurricane… The impacts will still be very similar.
Although the sea surface temperatures increase along the forecast track beyond 36 hours… Northerly wind shear is expected to increase significantly over iselle as an upper level trough digs rapidly just to the northwest of hawaii. This should result in more rapid weakening in the longer term.
The forecast track philosophy has not changed. Iselle will continue to gradually gain latitude to the south of a relatively weak subtropical ridge several hundred miles north of the hawaiian islands. This forecast is essentially a continuation of the previous track forecast. National Weather Service discussion at 11 a.m. HST