Hurricane Wilma - Cat. 5

[f5]

From the 5 a.m. NHC advisory:

COASTAL STORM SURGE FLOODING OF 7-11 FEET ABOVE NORMAL TIDE
LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE
EXPECTED NEAR AND TO THE NORTH OF WHERE THE CENTER MAKES LANDFALL ON
THE YUCATAN PENINSULA.

Question...if this has been a Cat 5 storm, now a 4, I'm wondering why the surge there is only 7-11 feet. Is that the expected surge for a storm of this category in that area due to topography? I am concerned about surge on the FL coast, particularly after observing Katrina/Rita, which is why I'm watching this carefully. I've heard very divergent opinions from pro mets on what we could expect here.

Yucatan doesn't have a shallow ramp for storm surge like the northern Gulf Coast has

[inotherwords]

From the 5 a.m. NHC advisory:

COASTAL STORM SURGE FLOODING OF 7-11 FEET ABOVE NORMAL TIDE
LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE
EXPECTED NEAR AND TO THE NORTH OF WHERE THE CENTER MAKES LANDFALL ON
THE YUCATAN PENINSULA.

Question...if this has been a Cat 5 storm, now a 4, I'm wondering why the surge there is only 7-11 feet. Is that the expected surge for a storm of this category in that area due to topography? I am concerned about surge on the FL coast, particularly after observing Katrina/Rita, which is why I'm watching this carefully. I've heard very divergent opinions from pro mets on what we could expect here.

Yucatan doesn't have a shallow ramp for storm surge like the northern Gulf Coast has

Thanks. How does w FL coastal ramp compare with MS/LA's?

[infonut]

I have a question. It's late and I am tired, but, why on all the recon obs you are supposed to multiply by .9 etc for surface winds, but they leave the flight wind speeds when they give the advisories. People comment about the unusual difference in pressure vs wind speed, but it's not out of line if you convert it down. Am I missing something? I thought I have seen people say you go by "surface" winds.

example: 4AM Advisory lists 150 mph winds and 929 mb, which puts the pressure high for the wind speeds, but if it was converted down from the ob of 130kt to 135 mph (.9 factor) wich would correspond with a 929 mb pressure.

oh well, it's late, and I am tired....mentally and physically.

The advisories give the estimated sustained winds at the surface. For example, the 5am ET advisory states "Maximum sustained winds...150
mph."

The .9 factor is a rule-of-thumb. Depending on the flight level sometimes a .8 factor is used.

There is an imperfect relationship between the surface pressure and winds. The Saffir Simpson scale gives the relationship between pressure and max wind speed at the surface but again, it is only a rule-of-thumb.
http://en.wikipedia.org/wiki/Saffir-Sim ... cane_Scale

thats the way I understood it. But the recon showed 130 kt (150 mph) flight level, and the advisory shows 150 mph surface.

[StrongWind]

Katrina was 927 mb CAT 3 in mississippi.i guess its due to her enormous size

Katrina was weakening though, this hurricane isnt weakening right now (pressure dropped to 929 on last vortex). I think Cancun might get totally devastated....if the NHC track verifies Cancun will experience hurricane force winde from not till early Monday Morning....thats 3 fulls days of 75 mph+ and probably a day of major hurricane conditions.

Does anyone know what the top few longest periods of time any place has been subjected to hurricane force winds are?

[ColinDelia]

I have a question. It's late and I am tired, but, why on all the recon obs you are supposed to multiply by .9 etc for surface winds, but they leave the flight wind speeds when they give the advisories. People comment about the unusual difference in pressure vs wind speed, but it's not out of line if you convert it down. Am I missing something? I thought I have seen people say you go by "surface" winds.

example: 4AM Advisory lists 150 mph winds and 929 mb, which puts the pressure high for the wind speeds, but if it was converted down from the ob of 130kt to 135 mph (.9 factor) wich would correspond with a 929 mb pressure.

oh well, it's late, and I am tired....mentally and physically.

The advisories give the estimated sustained winds at the surface. For example, the 5am ET advisory states "Maximum sustained winds...150
mph."

The .9 factor is a rule-of-thumb. Depending on the flight level sometimes a .8 factor is used.

There is an imperfect relationship between the surface pressure and winds. The Saffir Simpson scale gives the relationship between pressure and max wind speed at the surface but again, it is only a rule-of-thumb.
http://en.wikipedia.org/wiki/Saffir-Sim ... cane_Scale

thats the way I understood it. But the recon showed 130 kt (150 mph) flight level, and the advisory shows 150 mph surface.

They assumed that the recon did not sample the highest winds. From the 5 am discussion: "The maximum flight level winds at 700 mb are
130 knots. This does not justify an initial intensity of 130 knots
but it is assumed that somewhere within the eyewall these winds are
occurring and have not been sampled by the aircraft yet."

[StrongWind]

Latest satellite shows a wobble back to the NW with a v. healthy looking lady.

[Tertius]

Katrina was 927 mb CAT 3 in mississippi.i guess its due to her enormous size

Katrina was weakening though, this hurricane isnt weakening right now (pressure dropped to 929 on last vortex). I think Cancun might get totally devastated....if the NHC track verifies Cancun will experience hurricane force winde from not till early Monday Morning....thats 3 fulls days of 75 mph+ and probably a day of major hurricane conditions.

Does anyone know what the top few longest periods of time any place has been subjected to hurricane force winds are?

No, but it has to be someplace affected by Mitch. He was a monster and stalled IIRC just off Honduras for a ridiculous length of time. Some people even thought Wilma would be a replay of Mitch but she has moved further north already and the predicted stall is looking less likely every hour.

[ColinDelia]

Katrina was 927 mb CAT 3 in mississippi.i guess its due to her enormous size

Katrina was weakening though, this hurricane isnt weakening right now (pressure dropped to 929 on last vortex). I think Cancun might get totally devastated....if the NHC track verifies Cancun will experience hurricane force winde from not till early Monday Morning....thats 3 fulls days of 75 mph+ and probably a day of major hurricane conditions.

Does anyone know what the top few longest periods of time any place has been subjected to hurricane force winds are?

No, but it has to be someplace affected by Mitch. He was a monster and stalled IIRC just off Honduras for a ridiculous length of time. Some people even thought Wilma would be a replay of Mitch but she has moved further north already and the predicted stall is looking less likely every hour.

I was thinking Mitch too.

[JamesFromMaine2]

Lets face it guys even the NHC is scratching their heads on this one. Its basically a watch and see thing now. Does she just skirt the coast??? Does she move inland into the Yucatan briefley and weaken a little??? or Does she sit over the Yucatan and the core of Wilma just falls apart and she is nothing but a tropical storm hitting Florida??? In my opinion if she continues to wobble more north like she is now she will stay offshore or make landfall on the northeast Yucatan and if she does make landfall unless she stalls she should get right back in the water and just lose a little strength. She seems to be stairstepping for sure but it sure has changed to more north than west so we shall see.

or does she stall over the water and just sit there and gain strength like the last run of the ukmet suggested!

hey James can u give me the link to the new ukmet run?

I don't have it but the NHC talked about it in the 5am discussion: "WILMA IS CURRENTLY MOVING TOWARD THE NORTH-NORTHWEST AT 5 KNOTS.
BECAUSE STEERING CURRENTS ARE FORECAST TO BE WEAK...TRACK MODELS
MOVE WILMA SLOWLY AND IN ALL DIRECTIONS DURING 24 TO 36 HOUR
PERIOD...MAKING THIS PORTION OF THE FORECAST HIGHLY UNCERTAIN.
NEVERTHERLESS...THIS PATTERN CALLS FOR LITTLE OR ERRATIC MOTION
OVER NORTHEASTERN YUCATAN OR THE ADJACENT WATERS UNTIL THE
WESTERLIES EXPAND SOUTHWARD AND CARRY WILMA TOWARD THE NORTHEAST
BEYOND 2 TO 3 DAYS. THIS SLOW MOTION SHOULD CONTINUE TO DELAY THE
RECURVATURE TOWARD FLORIDA PROLONGING THE AGONIZING WAIT. ON THE
OTHER HAND...IT GIVES TIME FOR THE HURRICANE TO WEAKEN DUE TO THE
EFFECTS OF LAND AND SHEAR. IN FACT...THE GFDL MODEL REFLECTS THE
SLOW MOTION AND HAS A WEAKENED WILMA JUST WEST OF HAVANA CUBA
BETWEEN DAYS 4 AND 5. HOWEVER...IF THE EYE REMAINS OFFSHORE EAST OF
YUCATAN LIKE SUGGESTED BY THE LAST RUN OF THE UK MODEL...WILMA
COULD BE STRONGER THAN INDICATED."

[Scorpion]

There is no way this is going to stall and bury itself in the Yucatan. Looks like part of the eye might go over at most. It will need a big jog west to directly impact Cozumel.

[Normandy]

There is no way this is going to stall and bury itself in the Yucatan. Looks like part of the eye might go over at most. It will need a big jog west to directly impact Cozumel.

Cozumel is getting slammed....they probably are geting major hurricane conditions as we speak...the eyewall is close.

[AZS]

[caneman]

There is no way this is going to stall and bury itself in the Yucatan. Looks like part of the eye might go over at most. It will need a big jog west to directly impact Cozumel.

Cozumel is getting slammed....they probably are geting major hurricane conditions as we speak...the eyewall is close.

I disagree with the stall. Looks like the system is already caught in the front and just a matter of time before she shoots NE. Perhaps 24 hours.

[Scorpion]

The center is highly unlikely to go over Cozumel. But they will get some of the worst winds still.

[Normandy]

The center is highly unlikely to go over Cozumel. But they will get some of the worst winds still.

That would be a good thing for them....at least they would get a calm break.

[AZS]

GFS :

24 hours




Over the Yucatan

[AZS]

GFS

48 Hours



Leaving the Yucatan

[Scorpion]

GFS is less on crack than before .

[jlauderdal]

There is no way this is going to stall and bury itself in the Yucatan. Looks like part of the eye might go over at most. It will need a big jog west to directly impact Cozumel.

Cozumel is getting slammed....they probably are geting major hurricane conditions as we speak...the eyewall is close.

I disagree with the stall. Looks like the system is already caught in the front and just a matter of time before she shoots NE. Perhaps 24 hours.

the current shortwave will not be enough to dig out the system and as it bypasses the system we get very weak if any motion then another sw comes through and helps the process and finally a third one later in the period should finally lift it out. a crobar might get it out now but not this shortwave.

[AZS]

GFS:

72 Hours




Moving into Florida