ATL: Ex-Hurricane DANIELLE - Discussion

[supercane]

is it possible she is going through erc? And if so, once she is through with that, won't she probably intensify again?

From latest discussion:

THE VISIBLE AND INFRARED SATELLITE PRESENTATIONS AND A SERIES OF
MICROWAVE IMAGES FROM THE NRL TROPICAL CYCLONE WEBSITE INDICATE
CONTINUED WEAKENING OF THE INNER EYEWALL STRUCTURE OF
DANIELLE...PARTICULARLY OVER THE WESTERN PORTION. THE OUTER
CONCENTRIC RING LOCATED ABOUT 60 NMI FROM THE CENTER OF THE
CYCLONE...HOWEVER...IS WELL DEFINED AND SYMMETRIC...AND APPEARS TO
BE CLOSE TO COMPLETING AN EYEWALL REPLACEMENT CYCLE.
CONSEQUENTLY...THERE MAY BE A SMALL WINDOW OF OPPORTUNITY FOR
STRENGTHENING DURING THE NEXT 12-18 HOURS BEFORE THE NORTHEASTERLY
SHEAR INCREASES SIGNIFICANTLY AND THE SYSTEM BEGINS ITS TRACK OVER
COOLER WATER. IT IS WORTH NOTING...HOWEVER...THAT THE SHIPS MODEL
PROBABILITY OF RAPID INTENSIFICATION DURING THE NEXT 24 HOURS HAS
DECREASED FROM 14 TO 4 PERCENT...SUGGESTING A SMALL CHANCE OF THIS
SCENARIO COMING TO FRUITION.

[artist]

thanks for the reply Luis and cheezy!

[KWT]

Very interesting supercane, I'm not sure it'll be able to totally complete its EWRC, I've tended to find systems that try to undergo EWRC whislt travelling over increasingly cooling water tend to struggle to complete it till they are in waters that are barely supportive for tropical features where Extra-tropical factors start to play a role.

Still if it does complete its EWRC there is a small period for strengthening as the NHC state.

[HURAKAN]

latest microwave

[KWT]

Looks like the EWRC is very nearly done now, just a bit of the inner eyewall left so look like it should complete the EWRC though the western part of the eyewall is still slightly open. A pretty large eye now as well!

[supercane]

Latest ASCAT pass:

[KWT]

Haha for once I don't think we really need Ascat for this one, pretty obvious where the center is for Danielle

[cycloneye]

18z Best Track

AL, 06, 2010082818, , BEST, 0, 296N, 602W, 90, 970, HU

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 010.invest

Down to 90kts.

[CrazyC83]

970mb seems too conservative for the pressure though given trends from Recon flights. I would estimate it to be around 956mb, although 90 kt is reasonable.

[Weather Watcher]

Look at danielle's real eye!

http://www.wunderground.com/tropical/tr ... ml#a_topad

[CrazyC83]

What is supposed to kick Danielle back to the north at the end? Wouldn't it just go around the edge of the ridge and eventually towards the Azores?

[CrazyC83]

Looking at the Recon for Earl and past trends, it seems background pressures are much lower than the Dvorak standard relationships that the NHC used on the advisory. If the winds are indeed 90 kt, the pressure should be closer to 955, not 970.

[supercane]

Latest microwave image. ERC complete, but as predicted cooler sea-surface temps did not allow for reintensification. In fact, the eyewall not closed on microwave:

[supercane]

Looking at the Recon for Earl and past trends, it seems background pressures are much lower than the Dvorak standard relationships that the NHC used on the advisory. If the winds are indeed 90 kt, the pressure should be closer to 955, not 970.

Huh? Dvorak actually did pretty well for this system. At its peak intensity of 115 kt, the minimum central pressure was 942mb. Looking at the Dvorak table, you get:

Code: Select all

  CI        MWS         MWS         MSLP           MSLP          Saffir-Simpson   
Number    (Knots)      (MPH)     (Atlantic)    (NW Pacific)         Category     
 1         25 KTS      29 MPH                                     (Approximate)
 1.5       25 KTS      29 MPH     
 2         30 KTS      35 MPH      1009 mb        1000 mb
 2.5       35 KTS      40 MPH      1005 mb         997 mb
 3         45 KTS      52 MPH      1000 mb         991 mb
 3.5       55 KTS      63 MPH       994 mb         984 mb
 4         65 KTS      75 MPH       987 mb         976 mb        1  (64-83 KTS)
 4.5       77 KTS      89 MPH       979 mb         966 mb        1  (64-83 KTS); 2  (84-96 KTS)
 5         90 KTS     104 MPH       970 mb         954 mb        2  (84-96 KTS); 3  (97-113 KTS)
 5.5      102 KTS     117 MPH       960 mb         941 mb        3  (97-113 KTS)
 6        115 KTS     132 MPH       948 mb         927 mb        4  (114-135 KTS)
 6.5      127 KTS     146 MPH       935 mb         914 mb        4  (114-135 KTS)
 7        140 KTS     161 MPH       921 mb         898 mb        5  (136+  KTS)
 7.5      155 KTS     178 MPH       906 mb         879 mb        5  (136+  KTS)
 8        170 KTS     196 MPH       890 mb         858 mb        5  (136+  KTS)

which was astonishingly good. In the second flight last night, Danielle was weaker and minimal pressure was 950 mb. Given the worsening satellite appearance, I have no reason to believe that its pressure would still be near last night's level, and the Dvorak interpolation is as good as anything else.

[CrazyC83]

Looking at the Recon for Earl and past trends, it seems background pressures are much lower than the Dvorak standard relationships that the NHC used on the advisory. If the winds are indeed 90 kt, the pressure should be closer to 955, not 970.

Huh? Dvorak actually did pretty well for this system. At its peak intensity of 115 kt, the minimum central pressure was 942mb. Looking at the Dvorak table, you get:

Code: Select all

  CI        MWS         MWS         MSLP           MSLP          Saffir-Simpson   
Number    (Knots)      (MPH)     (Atlantic)    (NW Pacific)         Category     
 1         25 KTS      29 MPH                                     (Approximate)
 1.5       25 KTS      29 MPH     
 2         30 KTS      35 MPH      1009 mb        1000 mb
 2.5       35 KTS      40 MPH      1005 mb         997 mb
 3         45 KTS      52 MPH      1000 mb         991 mb
 3.5       55 KTS      63 MPH       994 mb         984 mb
 4         65 KTS      75 MPH       987 mb         976 mb        1  (64-83 KTS)
 4.5       77 KTS      89 MPH       979 mb         966 mb        1  (64-83 KTS); 2  (84-96 KTS)
 5         90 KTS     104 MPH       970 mb         954 mb        2  (84-96 KTS); 3  (97-113 KTS)
 5.5      102 KTS     117 MPH       960 mb         941 mb        3  (97-113 KTS)
 6        115 KTS     132 MPH       948 mb         927 mb        4  (114-135 KTS)
 6.5      127 KTS     146 MPH       935 mb         914 mb        4  (114-135 KTS)
 7        140 KTS     161 MPH       921 mb         898 mb        5  (136+  KTS)
 7.5      155 KTS     178 MPH       906 mb         879 mb        5  (136+  KTS)
 8        170 KTS     196 MPH       890 mb         858 mb        5  (136+  KTS)

which was astonishingly good. In the second flight last night, Danielle was weaker and minimal pressure was 950 mb. Given the worsening satellite appearance, I have no reason to believe that its pressure would still be near last night's level, and the Dvorak interpolation is as good as anything else.

Aircraft data never supported 115 kt though, they left it there for continuity sake. The highest FL winds were 119 kt (107 kt the surface) and the SFMR only measured around 102 kt. The peak intensity was probably 105-110 kt.

[O Town]

You can see the inner eye wall collapse just like it would during
EWRC but there wont another strong eye wall again, I wouldn't think,
as it is getting into some cooler waters and about be sucked up with
that front. Nice animated microwave tho.

[supercane]

Latest microwave unchanged:

[Blown Away]

Thanks Danielle, you were a very pretty hurricane and thanks for missing Bermuda, but it's time for you to go so please exit in a hurry stage NE!

[WeatherGuesser]

Story on Danielle's effect on the east coast and related rescues:

http://www.breitbart.com/article.php?id ... _article=1

[Blown Away]

So looking back is Danielle moving out faster than the models predicted? Might give us an idea on what may happen with Earl and future Fiona?