Random Chaos
Weather Analyst
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Loc: Maryland
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From 5pm discussion:
MORE SO THAN WITH MOST STORMS...THE WINDS WITH IRENE INCREASE
SHARPLY WITH HEIGHT ABOVE THE SURFACE. AS IRENE MOVES THROUGH
AREAS WITH HIGH-RISE STRUCTURES...THESE STRUCTURES WILL EXPERIENCE
WINDS SIGNIFICANTLY STRONGER THAN INDICATED BY THE ADVISORY
INTENSITY. WINDS AT THE 30-STORY LEVEL WILL LIKELY BE 20 PERCENT
HIGHER THAN AT THE SURFACE...AND WINDS 80-100 STORIES UP COULD BE
ABOUT 30 PERCENT HIGHER THAN AT THE SURFACE.
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MikeC
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And from just now
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danielw
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Loc: Hattiesburg,MS (31.3N 89.3W)
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I'm estimating that at a 1 foot rise per hour. Or more.
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cieldumort
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Loc: Austin, Tx
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1 Ft every couple of minutes of storm surge currently (live stream, time sensitive)
(LINK)
Edit: Hurricanetrack has estimated a total of six feet over two hours
Edited by cieldumort (Sat Aug 27 2011 07:12 PM)
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Random Chaos
Weather Analyst
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Loc: Maryland
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Currently they are near Nags Head. Exact location: http://www.hurricanetrack.com/map/
Chesapeake Bay near Sandy Point State Park (just north of Annapolis):
Edited by Random Chaos (Sat Aug 27 2011 07:36 PM)
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WeatherNut
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Loc: Atlanta, GA
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That 950 pressure reading has me concerned. I dont recall a Cat1 ever having a pressure reading that low. Is it possible that baroclinic influences have started to act on Irene? Also, wont a low pressure increase the surge?
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Born into Cleo (64)...been stuck on em ever since
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danielw
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I would think the low pressure would increase the surge. It has in other storms.
Using deltaP of 1013 minus mcp (current) 950 mb = 63/ 4= a possible surge height of 15.75 feet
(Formula has not been peer reviewed. But has been checked against many hurricanes from Category 1 up.
Formula was within a +/- 1 foot margin for Katina's high Water Marks~danielw)
This doesn't mean Irene will produce a 15.75 foot surge. It suggest Irene is capable of generating a surge to that limit.
Note: I have attached a jpeg of a spreadsheet that I developed a few years ago for calculating or estimating Storm Parameters, called HurriSheet. Some of the formulas are used by Meterologists the others are simple variations of their formulas. A+B=C/ D type formulas.~danielw
Edited by danielw (Sat Aug 27 2011 08:21 PM)
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cieldumort
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Quote:
That 950 pressure reading has me concerned. I dont recall a Cat1 ever having a pressure reading that low. Is it possible that baroclinic influences have started to act on Irene? Also, wont a low pressure increase the surge?
While baroclinic influences have been underway, these are not the only, even primary, reason for Irene's relatively very low pressure. Recall that Ike as a Cat 2 also had very low pressure (also about 950mb, in fact). Extra large and powerful hurricanes do not always end up concentrating their force within the core, and such has been the case with Irene, in many ways much as it had been with Ike.
This lower pressure is helping result in higher-than-usual surge for the given Saffir-Simpson category. It is important to note that the Saffir-Simpson scale is a wind scale, only. The has dropped suggesting any relation to surge, pressure, anything else, other than wind. However, if one wants to relate the current overall intensity of Irene to the old SS scale, 950mb would have lined up with Category 3.
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