Hurricane Daniel (05E) in CPAC

[WxGuy1]

What else does Daniel need to do before he becomes a category 5 hurricane? Colder cloud tops? Is that the only thing left?

Well, 156mph sustained winds helps, too . . .

Haha, that's real funny. The only problem is I'm trying to find out how Daniel will get those winds. It's just like saying that Daniel needs to become a CAT5 hurricane to be a CAT5 hurricane. Get it?

Since it's stabilized for a bit, the only real way to get more strengthening (enough to bring it up another 20kts) would be for the pressure to drop. Like all tropical cyclones, this is accomplished through more rigorous convection. If the eye constricts, allowing for more convection as close to the center as possible, and convection intensifies, it may be able to decrease its central pressure. Of course, 'wind' is caused by a pressure gradient, so if the storm 'shrinks' it would increase the dP/dr (pressure gradient). However, I think it's much more common for storms to expand with time, not contract. So, how do you get more intense convection? Largely by providing more favorable environmental parameters (e.g. through warmer SSTs and weaker shear). There are also a lot of organizational factors at play as well (which is why we don't see Cat 5 storms every time a disturbance is in warm SSTs and weak vertica lwind shear).

That said, now that Daniel is mature, well-organized, and intense, internal processes (including ERCs) can play a very significant role in future intensity changes.

The environment and storm organization really has to be near perfect for a storm to reach Cat 5 strength. It may help that it is already as strong as it is, but I think it would be very difficult for Daniel to intensify much more owing to the shallowness of warm water (as reflected in the TCHP -- http://www.aoml.noaa.gov/phod/dataphod1 ... 6201cp.jpg ). He may pop back up to 120kts, but I can't imagine he would go much further, especially given the rather limited time before environmental conditions deteriorate.

[cycloneye]

WTPZ45 KNHC 211440
TCDEP5
HURRICANE DANIEL DISCUSSION NUMBER 19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052006
800 AM PDT FRI JUL 21 2006

DANIEL REMAINS A VERY IMPRESSIVE HURRICANE IN INFRARED SATELLITE
IMAGERY. THE EYE HAS EXPANDED DURING THE LAST FEW HOURS AND IS NOW
ABOUT 30-35 NM IN DIAMETER. CURRENT INTENSITY ESTIMATES FROM ALL
AGENCIES REMAIN 115 KT AND THIS WILL BE THE INITIAL INTENSITY FOR
THIS ADVISORY. THE INTENSITY FORECAST ASSUMES THAT DANIEL WILL
SOON BEGIN A SLOW WEAKENING TREND. THE SHIPS MODEL DOES NOT
FORECAST AS MUCH NORTHEASTERLY SHEAR AS IN PREVIOUS FORECASTS AND
THE HURRICANE MAY BE SLOWER TO WEAKEN DURING THE NEXT COUPLE DAYS
THAN PREVIOUSLY THOUGHT. THEREAFTER... DANIEL WILL BE ENCOUNTERING
COOLER WATERS WHICH SHOULD ACCELERATE WEAKENING. THE OFFICIAL
FORECAST FOLLOWS THE SHIPS MODEL CLOSELY.

AS NOTED IN THE PREVIOUS DISCUSSION...DANIEL IS MOVING SLIGHTLY
FASTER AND WESTWARD THIS MORNING. HOWEVER...A LONGER 12-18 HOUR
AVERAGE MOTION IS ESTIMATED AT 285/10. MODEL GUIDANCE REMAINS
CLUSTERED ON A GENERAL WEST-NORTHWEST HEADING DURING THE NEXT 3
HOURS. LATER IN THE FORECAST PERIOD...THE DYNAMICAL MODELS WEAKEN
THE RIDGE IN RESPONSE TO A DIGGING TROUGH TO THE NORTHWEST OF THE
HURRICANE. THIS SHOULD SLOW THE CYCLONE AND TURN IT MORE
NORTHWESTWARD. THE NOGAPS IS MUCH FASTER THAN ALL THE OTHER
GUIDANCE. THE OFFICIAL FORECAST REMAINS VERY CLOSE TO THE PREVIOUS
ADVISORY AND THE MODEL CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 21/1500Z 13.4N 126.3W 115 KT
12HR VT 22/0000Z 13.7N 127.7W 110 KT
24HR VT 22/1200Z 14.2N 129.5W 100 KT
36HR VT 23/0000Z 14.6N 131.3W 85 KT
48HR VT 23/1200Z 15.1N 133.1W 75 KT
72HR VT 24/1200Z 16.0N 136.0W 60 KT
96HR VT 25/1200Z 17.5N 138.0W 45 KT
120HR VT 26/1200Z 19.0N 139.5W 35 KT

$$
FORECASTER BROWN/AVILA




It has peaked in intensity.

[Epsilon_Fan]

he's looking as good as ever right now

[HurricaneHunter914]

That is the most beautiful annular hurricane (other than Isabel) that i've ever seen!!!!!

[Cyclenall]

I'm just going to flat out say it now, has the NHC lost it? I respect the NHC quite a lot but this is just madness. They kept Hurricane Daniel at 115 Knots even though he looks more powerful the ever before, has deeper convection around the eye, more annular then ever, and a perfect clear eye. Now, why on this green earth would it still be at 115 Knots? Goodness, it looks like a darn category 5 hurricane!!

Hurricane Daniel has indeed gone through a ERC and now, I love what I see. My guess at his strength is around 135 Knots but the NHC seems to think otherwise. His eye a larger, clear, and almost perfect with a very annular appearance. I going to say it, this is Isabel. I'm going to post a picture of Isabel and Daniel side by side and show why this could be a CAT5 as we speak. I'm thinking it's almost a CAT5, not one currently.

Looks like everything that I hoped had happened.

[benny]

n play a very significant role in future intensity changes.

The environment and storm organization really has to be near perfect for a storm to reach Cat 5 strength. It may help that it is already as strong as it is, but I think it would be very difficult for Daniel to intensify much more owing to the shallowness of warm water (as reflected in the TCHP -- http://www.aoml.noaa.gov/phod/dataphod1 ... 6201cp.jpg ). He may pop back up to 120kts, but I can't imagine he would go much further, especially given the rather limited time before environmental conditions deteriorate.

Heat potential in the Eastern Pacific is a very dangerous thing. Measurements indicate that the heat potential as measured by the depth of the 26C water is rather shallow. However experience has shown that the EPac has multiple TCs track across just about the same area repeatedly during the season with seemingly no effect. What's going on? Nick Shay has theorized that it is because that upper ocean layer is more stable than say the Gulf of Mexico water outside of the loop current. I believe it is due to the salinity gradients and density changes with the EPAC saltier than the GOM (I'm not an oceanographer though). The bottom line is that for a lower heat potential... a tropical cyclone can get stronger because it can't mix out the warmer water like in the GOM outside the loop current.

Bottom line... heat potential is not the same everywhere.. there are complicated ocean dynamics going on that make each ocean area different. 50 heat units in the GOM is not the same as 50 in the EPAC. For a given SST of about 27-27.5.. the maximum potential intensity of Daniel is about 135-140 kt....

[Cyclenall]

That is the most beautiful annular hurricane (other than Isabel) that i've ever seen!!!!!

I 2nd this. However, this looks almost the exact same as Isabel. I will check that out.

[benny]

I'm just going to flat out say it now, has the NHC lost it? I respect the NHC quite a lot but this is just madness. They kept Hurricane Daniel at 115 Knots even though he looks more powerful the ever before, has deeper convection around the eye, more annular then ever, and a perfect clear eye. Now, why on this green earth would it still be at 115 Knots? Goodness, it looks like a darn category 5 hurricane!!

Hurricane Daniel has indeed gone through a ERC and now, I love what I see. My guess at his strength is around 135 Knots but the NHC seems to think otherwise. His eye a larger, clear, and almost perfect with a very annular appearance. I going to say it, this is Isabel. I'm going to post a picture of Isabel and Daniel side by side and show why this could be a CAT5 as we speak. I'm thinking it's almost a CAT5, not one currently.

Looks like everything that I hoped had happened.

You can't just take one picture and say this is the intensity of the cycle (when it looks the best). You need some sort of longer average.. say 3 or 6 hours. Remember also that intensities are assigned about 30-60 min before the advisory goes out.. so the last picture NHC uses is about 1-1.5 hours beforehand... eg 14,20,2,8 UTC

That being said.. it does look nice and as strong as it ever did now.. and I would expect TPC to bump it up to at least 125-130 kt later today assuming no more ERC

[AnnularCane]

Whoa, look at Daniel! Is he gorgeous or what? OK, NOW I agree he is annular.

[cycloneye]

Whoa, look at Daniel! Is he gorgeous or what? OK, NOW I agree he is annular.

Yes he is an AnnularCane.

[Cyclenall]

Whoa, look at Daniel! Is he gorgeous or what? OK, NOW I agree he is annular.

I knew you would say that! How annular can you get?

This is now in my top 10 best looking tropical cyclones ever list.

You can't just take one picture and say this is the intensity of the cycle (when it looks the best). You need some sort of longer average.. say 3 or 6 hours. Remember also that intensities are assigned about 30-60 min before the advisory goes out.. so the last picture NHC uses is about 1-1.5 hours beforehand... eg 14,20,2,8 UTC

Hmm...that could be the reason because Daniel didn't look the best 1.5 hours ago. I just hope the NHC notices how amazing looking and powerful he is.

That being said.. it does look nice and as strong as it ever did now.. and I would expect TPC to bump it up to at least 125-130 kt later today assuming no more ERC

Let's hope so since I dislike tinted data!

[WmE]

WOW, what a nice looking hurricane!
Indeed, he looks stronger than that 115kt.

[curtadams]

This is now in my top 10 best looking tropical cyclones ever list.

You can't just take one picture and say this is the intensity of the cycle (when it looks the best). You need some sort of longer average.. say 3 or 6 hours. Remember also that intensities are assigned about 30-60 min before the advisory goes out.. so the last picture NHC uses is about 1-1.5 hours beforehand... eg 14,20,2,8 UTC

Hmm...that could be the reason because Daniel didn't look the best 1.5 hours ago. I just hope the NHC notices how amazing looking and powerful he is.

That being said.. it does look nice and as strong as it ever did now.. and I would expect TPC to bump it up to at least 125-130 kt later today assuming no more ERC

Let's hope so since I dislike tinted data!

The sat estimate have indeed bumped him up a notch. But they were pretty spot-on for Isabel (this kind of annular cane is exactly what they're designed for) and they've still got him as a mainline Cat 4.

[Cyclenall]

It's time to look in the eye to see if we see any "stars" swirling in there just like Isabel.

Looks like a near perfect tropical cyclone. Can someone start making loops and such for this historic hurricane?

[Matt-hurricanewatcher]

He is very Isabel like right now I would not be suprized if he was near cat5.

[RQSTR]

This is now in my top 10 best looking tropical cyclones ever list.

can you give your complete top 10 list? and yes, definitely, i really enjoy to follow daniel! it's good to see a wonderful cane without any victim!

[whereverwx]

Wow, that was a fast ERC, and just in time for the visible, too.

[Rainband]

Nice looking cane. The best kind. A fish.

[Derek Ortt]

Nick Shay gave a seminar at NHC last week and his results indicated that there is greater stratification on the EPAC, which reduces mixing between the surface and the cooler water beneath

[CrazyC83]

This is now in my top 10 best looking tropical cyclones ever list.

can you give your complete top 10 list? and yes, definitely, i really enjoy to follow daniel! it's good to see a wonderful cane without any victim!

My #1, by far, is Cyclone Monica at peak intensity (perfectly circular).