What's the GFDL Seeing?

[MWatkins]

Er…could somebody check my math?

Here’s what I have, and it’s not adding up.

At 12Z (8AM this morning) the center of Emily was located at 11.0N 50.5W
At 18Z (2PM this afternoon) the center of Emily was located at 11.1N 51.9W

Ignoring the northerly component for a moment…that’s 1.4 degrees of longitude in 6 hours.

There are 24 hours in a day…so…

24/6 = 4 * 1.4 = 5.6 degrees * 60 minutes = 336 nautical miles in one day

336/24 hours = 14 knots.

The 12Z track guidance is tightly clustered around a location near (the NHC forecast for 0Z) : 11.4N 53.8W at 0Z this evening.

Saving some time that’s a forward rate of about 17 knots, rounded up. For Emily to make that verification point it will have to move at an average rate of 19 knots in the next six hours.

Either my math is bad, or Emily isn’t moving that fast, or Emily is accelerating.

The reason I have taken this long walk around a small house…perhaps…is that the GFDL model right now is the only model that isn’t rapidly zooming Emily off to the west, and the average pace in that model form 12Z more closely matches the math above. Perhaps the model is on to something. Or perhaps…there was a typo in the public advisory. Or…perhaps…the center is on the back side of the convective envelope and isn’t moving quite as fast as indicated.

Anyway…I realize I am reading FAR too much into 6 hours of motion…but all of this is an attempt to sniff out what the GFDL is up to.

MW

[clfenwi]

Plugging the points into the NHC's distance calculator and dividing the calculated distance by six yields 13.8 knots, so that part of your math is on.

[cycloneye]

The center is a tad on the back of convection.

[x-y-no]

Don't see anything wrong with your math, Mike.

Don't know the answer to your question, either.

Jan

[Brent]

Isn't the public advisory forward speed the 6-hour average motion???

[wxwonder12]

Sorry, but what does ll that mean???

[cycloneye]

12/1745 UTC 11.1N 52.0W T3.0/3.0 EMILY -- Atlantic Ocean


Mike look at where the SSD Dvorak sat estimates puts it.

[Fego]

MWatkins: you are something jeje. I read your post twice, then I understood. but let me tell you that was like trying to solve a mystery... umm playing CLUE against you can't be an easy task.. jejeje.
More seriously, which model project a weak Emily, because right now she looks kind of ill.
http://www.intellicast.com/Local/USNati ... e&pid=none

[Trader Ron]

11AM Emily was at 51.3 W. 2 PM 51.9 W. That's 40 miles. 40 divided by 3 hrs = 13 mph, if my math is correct.

[Sanibel]

Slow movement could mean the steering ridge isn't that strong. A lift towards the WNW is more likely in that case like GFDL is showing.

GFDL cranks a 135mph storm just off the west tip of Haiti, but then curiously brings it down a notch in improving SST's south of Cuba where Dennis went 150mph?

[clfenwi]

12/1745 UTC 11.1N 52.0W T3.0/3.0 EMILY -- Atlantic Ocean


Mike look at where the SSD Dvorak sat estimates puts it.

That adds 1 knot to the six hour average; approximately 15 knots/17 mph.

[jkt21787]

Slow movement could mean the steering ridge isn't that strong. A lift towards the WNW is more likely in that case like GFDL is showing.

GFDL cranks a 135mph storm just off the west tip of Haiti, but then curiously brings it down a notch in improving SST's south of Cuba where Dennis went 150mph?

GFDL intensity forecasts should be taken with a grain of salt. Every storm is a major to it.

Its track, I'm not sure. Some good theories here though.

[Sanibel]

I know. It verifies every now and then with the bombers.

I look at GFDL only and estimate its flaws. Sometimes that is more precise than getting confused by multiple models...

[clfenwi]

Worth noting that while the ECMWF model runs Emily a little bit slower than NOGAPS and UKMET (and maybe a bit further north than NOGAPS in the early to mid-term) it still ends up with the NOGAPS solution of a Yucatan Peninsula hit