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Remnants of Emily Part II: 295 Miles SSE Of Cape Hatteras, NC


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I believe the cone is the average forecast error at that time frame, or some variant thereof, and doesn't reflect uncertainty of the particular storm in question at all.

The cone is made by 2/3 probability circles.

"The entire track of the tropical cyclone can be expected to remain within the cone roughly 60-70% of the time."

Statistically speaking, there is ~33% chance that any given Atlantic storm will track outside of the cone. This assumes all the storms are uniform and does not take into account the forecast uncertainty, as you stated.

http://www.nhc.noaa.gov/aboutcone.shtml

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No doubt. The cone should be way bigger, IMO, than it is now. If you asked me to draw a path right now, I would draw my center path line on the western edge of their cone, with my cone of uncertainty all the way to Pensacola

I just hope they make some serious adjustments at 5 PM... it's pretty clear that Emily is not just suddenly going to turn NW into the island and continue on said path.

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I believe the cone is the average forecast error at that time frame, or some variant thereof, and doesn't reflect uncertainty of the particular storm in question at all.

I think you are correct. But then that begs the question, how useful is a fixed cone based on a running error radius at different lead times? Do all forecast tracks have the same uncertainty? Hell no. In this case, I believe if you wanted to communicate the degree of uncertainty with Emily, you best believe the cone size should be bigger than your typical cone.

post-84-0-74340200-1312399338.png

pg 30 in the pdf below:

http://www.nhc.noaa.gov/verification/pdfs/Verification_2010.pdf

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I think you are correct. But then that begs the question, how useful is a fixed cone based on a running error radius at different lead times? Do all forecast tracks have the same uncertainty? Hell no. In this case, I believe if you wanted to communicate the degree of uncertainty with Emily, you best believe the cone size should be bigger than your typical cone.

or you could chalk it up to the 1/3rd of the time a storm goes outside of the cone

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or you could chalk it up to the 1/3rd of the time a storm goes outside of the cone

Actually, I agree with gibbs here. We're getting good enough now to use a Bayesian approach to the cone, rather than just a fixed non-conditional probability. There is work going on at CIRA right now on just this problem.

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I wonder how much the landmasses of Haiti and Cuba will alter the track of a naked Emily vs a weak, but somewhat covectively active TS?

I've been thinking this same thing.... mostly with respect to Haiti. I don't think it'll be very easy for it to miss Cuba too much, but I think it IS possible for Emily to parallel the Tiburon peninsula until it moves away from it.

With respect to naked swirl vs. convectively active... I believe you have to have a certain amount of convection before there is any sort of difference, and right now, I'm not sure she is there yet (the LLC is still very shallow it seems)

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Actually, I agree with gibbs here. We're getting good enough now to use a Bayesian approach to the cone, rather than just a fixed non-conditional probability. There is work going on at CIRA right now on just this problem.

But what happens when the next three shifts are Avila, Stewart, Berg? A Bayesian cone may be good for conveying uncertainty and more scientifically justified, but quantifying uncertainty is really tricky. I would also worry that varying the size of the cone could decrease public confidence in official forecasts, etc. I'm sure I'm on the wrong side of what will eventually happen if CIRA is working on it, but it sounds awfully difficult to me.

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track wise, if it survives, i think you smoke nhc on your first call

Yeah, but for slightly the wrong reasons, obviously, due to her being about 12 hrs behind my timing.....but, from this point on, I'd still keep my original track, just with some timing tweaks, and a reduction in intensity for tonight's 00z benchmark.

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But what happens when the next three shifts are Avila, Stewart, Berg? A Bayesian cone may be good for conveying uncertainty and more scientifically justified, but quantifying uncertainty is really tricky. I would also worry that varying the size of the cone could decrease public confidence in official forecasts, etc. I'm sure I'm on the wrong side of what will eventually happen if CIRA is working on it, but it sounds awfully difficult to me.

The research is based on the spread of the operational model guidance, rather than on anything subjective. I don't know enough about social science to comment on public impact of varying the cone.

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The research is based on the spread of the operational model guidance, rather than on anything subjective. I don't know enough about social science to comment on public impact of varying the cone.

Doesn't the BMO do something like that currently?

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The research is based on the spread of the operational model guidance, rather than on anything subjective. I don't know enough about social science to comment on public impact of varying the cone.

This is part of what I want to go in to... uncertainty would have to be discussed with the public in an easy to understand way. Having a few "levels" of uncertainty would be good... and ensuring that the uncertainty (perhaps with the forecasters going by strict guidelines) would help too. It's not too often that the models go from being all over the place to being clustered and unchanging... usually that is a gradual process... and that would help with the public as well. If there is a sudden change, it would have to be explained simply and appropriately.

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This is part of what I want to go in to... uncertainty would have to be discussed with the public in an easy to understand way. Having a few "levels" of uncertainty would be good... and ensuring that the uncertainty (perhaps with the forecasters going by strict guidelines) would help too. It's not too often that the models go from being all over the place to being clustered and unchanging... usually that is a gradual process... and that would help with the public as well. If there is a sudden change, it would have to be explained simply and appropriately.

the public already doesnt understand what 40% chance means or the difference between watch and warning. i think most people can live with the cone as it is.

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Yup. That was a quick pulse. You can almost see a cold pocket that reached the surface right at the center of the swirl... the last thing Emily needs.

Round 2.... fight!

Also, it seems that Emily is slowing down.... trying to turn right?

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Emily just seems to want to the left...

Product: Air Force Vortex Message (URNT12 KNHC)

Transmitted: 3rd day of the month at 20:17Z

Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 306)

Storm Number & Year: 05L in 2011

Storm Name: Emily (flight in the North Atlantic basin)

Mission Number: 8 seeall.png

Observation Number: 08

A. Time of Center Fix: 3rd day of the month at 19:53:40Z

B. Center Fix Coordinates: 16°49'N 70°29'W (16.8167N 70.4833W) viewmap.png

B. Center Fix Location: 121 miles (195 km) to the SSW (199°) from Santo Domingo, Dominican Republic.

C. Minimum Height at Standard Level: 1,461m (4,793ft) at 850mb

D & E. Estimated (by SFMR or visually) Maximum Surface Wind: Not Available

F. Maximum Flight Level Wind Inbound: From 360° at 20kts (From the N at ~ 23.0mph)

G. Location of Maximum Flight Level Wind Inbound: 24 nautical miles (28 statute miles) to the WSW (239°) of center fix

H. Minimum Sea Level Pressure: 1003mb (29.62 inHg)

I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 1,524m (5,000ft)

J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21°C (70°F) at a pressure alt. of 1,527m (5,010ft)

K. Dewpoint Temp (collected at same location as temp inside eye): 8°C (46°F)

K. Sea Surface Temp (collected at same location as temp inside eye): Not Available

L. Eye Character: Not Available

M. Eye Shape: Not Available

N. Fix Determined By: Penetration, Wind, Pressure and Temperature

N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 850mb

O. Navigation Fix Accuracy: 0.02 nautical miles

O. Meteorological Accuracy: 1 nautical mile

Remarks Section:

Maximum Flight Level Wind: 41kts (~ 47.2mph) in the northeast quadrant at 17:51:20Z

Maximum Flight Level Wind Outbound: 31kts (~ 35.7mph) in the north quadrant at 20:08:00Z

Maximum Flight Level Temp: 21°C (70°F) which was observed 6 nautical miles to the SSW (207°) from the flight level center

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I would kind of like to watch a recently-exposed naked swirl (especially from a stronger system) as it passed overhead. Watching the tiny popcorn cumulus quickly swirl around the center with nothing obstructing the view would be kinda cool.

Reminds me of somewhat of Charley's passage over Wilmington a few years ago. All the convection was on the front (north) side...then the eye moved overhead with its calm winds. I could see the dark, towering eye wall curving around my northern horizon but my southern horizon was clear. ...

Confused, I wondered where the back side of the hurricane was; or even if there was going to be a back side....until wham! The back side (right rear quadrant) hit with significantly more ferocity than the front side, yet it was with a mostly sunny sky! Everyone was caught off guard...and man was it abrupt! Before I could dash the hundred feet back to my apt., I was hit in the foot by a piece of siding blown off the building, lol. Those back sides can be sneaky devils!

sun.gif

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