Friday, September 12, 2008

Hurricane Ike: September 12 Update A

If you are in Galveston, evacuate now - your Emergency Managers, the NWS
and the NHC are looking out for your safety. The NWS issued an
unprecedentedly strong statement last night, saying:
"All neighbourhoods and possibly entire coastal communities will be
inundated during the period of the peak storm tide" and "Persons not
heeding evacuation orders in single family one- or two-storey homes will
face certain death."

This was issued because apparently some residents are not evacuating.
They are expecting a very large storm surge.

A technical note about storm surge before I get to Ike. I've heard that
some news media are reporting a '6 to 7 foot storm surge' already in
Galveston. This number is not the storm surge, but it is the water
level, which is the tide (which is taken into consideration in the
normal, predicted water level) PLUS the storm surge. Unfortunately,
Galveston is, at the moment, facing a fairly high tide as well, so the
normal water level is about 2 ft above mean sea level anyway. The
normal, predicted tides will subside in about 12 hours to close to 0 ft.
Technically, the storm surge at the moment is about 4 to 5 feet above
normal. End of technical note.

Ike is currently centered somewhere around 26.9N, 92.2W and is moving
WNW at 13 mph. Galveston is about 230 miles NE of the storm. The
forecast is for him to turn to the NW later today. At this speed, he
will get to the coast in about 17-18 hours, so in the early hours of
tomorrow morning. The bad side of the storm (for Galveston) is the north
side because winds will continue to push water up against the coast. The
best scenario at this point is that he takes a slightly more northward
turn and pass north of Galveston. However, within 24 hours of landfall
the NHC and computer models are usually pretty good, and they are all
heading to or just south of Galveston.

He has intensified slightly, and now has winds of 105 mph, even though
his central pressure is a bit higher at 956 mb. This makes him a cat 2
still (range: 96 - 110 mph), but is very close to a cat 3.
Interestingly, the strongest winds are not near the eye at all - they
are approx. 60 miles from the center. Convection has improved quite a
bit in the central parts of the storm, but is still ragged around the
edges and he is still experiencing some wind shear from the north.

A short historical note: Galveston is notorious for having had the
deadliest natural disaster in US history. On Sept. 8, 1900 a cat 4 storm
(that's the estimate anyway) made landfall in Galveston. About 8,000
people perished. This disaster was the impetus for improving Galveston's
defenses against the sea (by building a sea wall for example), and is
the basis for Erik Larson's book: "Isaac's Storm" - should you wish to
read more about that disaster. End of historical note.

More later,

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These remarks are just what I think/see regarding tropical storms - not
the opinion of any organization I represent. If you are making an
evacuation decision, please heed your local emergency management and the
National Hurricane Center's official forecast and the National Weather
Service announcements. This is not an official forecast. If I "run away,
run away" (Monty Python), I'll let you know.

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