Major Hurricane Danielle

[Iceberg]

Quick last comment from me, as I want to be up early to catch the neat eye of a CAT 3 ....

It's not just the size of the CDO which is important in making Danielle note worthy. It's also that we have 7 days or so plus various EWRC's to really spread out the Hurricane wind envelope, this will be the size of Rita/Katrina by the time it starts to go ex-tropical.

[Rob]

Expected to become Cat 3 mid week, Major Hurricane Status, also got Invest 96L following up the rear, could we have 2 storms on our hands?

[Somerset Squall]

Wouldn't be surprised Rob, 96L looks really well organised already, especially for being so close to the African coast.

I agree that Danielle appears to be rapidly intensifying- could have quite a nice storm to look at by tomorrow!

[Gray-Wolf]

So ,number 2 of the season! I'd agree that the depression to the rear looks promising but the models seem to have it act as a secondary around Danielle? Maybe D will make the break NW before it's (the forming storm) organised and so it can live out an independent life?

[Cookie]

[Iceberg]

Given the below 75Kts seems about right,as NHC mentioned the eye has formed but has not yet cleared, looking at the loops I can find the below image where it did clear a bit.

So given this the eye seems to be smallish and tight, supporting probably a 75Kt storm in this condition, when it clears and becomes better defined we will probably get to CAT2.

Danielle still has plenty of time 5+ Day for any strenghening so plenty of time yet.

The biggest problem for Danielle seems to be the wall of dry air in front of it, there is yet the chance it will will take a gasp of this still and start choking, as long as it can maintian a good inflow and outflow though it should cope.

Latest from NHC

DANIELLE HAS STRENGTHENED SOME MORE THIS EVENING. A 2148 UTC SSMIS

OVERPASS SHOWED THE PRESENCE OF AN EYE WITH LITTLE OR NO VERTICAL

TILT...BUT THIS FEATURE HAS NOT YET BECOME APPARENT ON

GEOSTATIONARY SATELLITE IMAGES. THE CLOUD PATTERN IS MORE

SYMMETRIC THAN IT WAS EARLIER AND CONSISTS OF A CENTRAL DENSE

OVERCAST AND SPIRAL BANDS WITH CLOUD TOPS AS COLD AS -80 C. DVORAK

CLASSIFICATIONS FROM TAFB AND SAB ARE 4.5/77 KT AND 4.0/65

KT...RESPECTIVELY AND OBJECTIVE SATELLITE ESTIMATES FROM CIMSS AT

THE UNIVERSITY OF WISCONSIN ARE NEAR 4.5/77 KT. THE INITIAL

INTENSITY FOLLOWS THE HIGHER ESTIMATES AND IS SET AT 75 KT FOR THIS

ADVISORY.

Also below the CIMSS Dvorak analysis they mentioned.

UW - CIMSS

ADVANCED DVORAK TECHNIQUE

ADT-Version 8.1.1

Tropical Cyclone Intensity Algorithm

----- Current Analysis -----

Date : 24 AUG 2010 Time : 034500 UTC

Lat : 15:39:22 N Lon : 43:23:17 W

CI# /Pressure/ Vmax

4.3 / 984.4mb/ 72.2kt

Final T# Adj T# Raw T#

4.3 4.3 4.0

Latitude bias adjustment to MSLP : +2.2mb

Center Temp : -72.0C Cloud Region Temp : -66.6C

Scene Type : UNIFORM CDO CLOUD REGION w/ MW EYE

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC

Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : MW ON

Weakening Flag : OFF

Rapid Dissipation Flag : OFF

****************************************************

[peterf]

iv'e been following this thread with interest.if this system does fish as some have mentioned,whats the odds on it affecting the UK?

[Coast]

Tropical Storm Danielle is now nearing hurricane intensity in the Atlantic Ocean. The National hurricane Center upgraded the storm to a hurricane, which is the second hurricane in the Atlantic this season. The storm is still very far out at sea as of late Monday Afternoon, but is moving west northwest at a speed of 17 MPH. It is carrying a top sustained wind of 75 miles per hour, making the storm a category one hurricane.

The center said that we can expect the storm to strengthen as it gets closer to land, before tapering off. The storm could potentially reach the level of a category 3 by Wednesday, but there is a chance that the it will then taper off into a category 2.

A category three storm carries sustained wind levels of 111 MPH and are capable of creating a lot of damage wherever they make windfall. The storm is heading in the general direction of Bermuda, but it could take several days before Danielle approaches any land. Forecasting any landfall so far out has been unreliable, and the National Hurricane Center is waiting to make any sort of prediction on when that could potentially happen.

news.spreadit.org/hurricane-danielle

[Iceberg]

Danielle has furthre intensified and is now a CAT 2 at 85Kts, NHC are also forecasting her to become a CAT 3 in 24 hrs.

ALTHOUGH THE CLOUD PATTERN ASSOCIATED WITH DANIELLE IS NOT AS WELL

ORGANIZED AS IT WAS SEVERAL HOURS AGO...LATEST DVORAK SATELLITE

INTENSITY ESTIMATES FROM SAB AND TAFB ARE AT 77 AND 90 KT...

RESPECTIVELY. THE CONVECTIVE ORGANIZATION OF THE CYCLONE HAS BEEN

PULSATING FOR REASONS THAT ARE NOT WELL UNDERSTOOD...BUT THE

OVERALL TREND IS INDICATIVE OF A GENERAL INTENSIFICATION. UPPER-

LEVEL OUTFLOW IS WELL ESTABLISHED OVER THE EASTERN SEMICIRCLE BUT

IS LESS DEFINED TO THE WEST. BASED UPON THE HIGHER SATELLITE

INTENSITY ESTIMATES...THE ADVISORY INTENSITY IS INCREASED TO 85 KT.

AN EYE FEATURE THAT FORMED EARLIER IS NO LONGER EVIDENT...BUT A 0434

UTC AMSR-E OVERPASS WAS HELPFUL IN LOCATING THE CENTER. THAT

OVERPASS AND OTHER RECENT FIXES YIELD AN INITIAL MOTION SLIGHTLY TO

THE LEFT OF THE PREVIOUS ESTIMATE...280/17. DANIELLE IS EXPECTED

TO MOVE ON A GENERAL WEST-NORTHWESTWARD COURSE FOR THE NEXT 12

HOURS OR SO BUT IS FORECAST TO GRADUALLY TURN MORE TOWARD THE

NORTHWEST WHEN IT BEGINS TO ENCOUNTER A WEAKNESS IN THE SUBTROPICAL

RIDGE APPARENT IN WATER VAPOR IMAGERY BETWEEN 45-50W. DYNAMICAL

MODEL GUIDANCE SHOWS THE BREAK IN THE RIDGE BECOMING MORE

PRONOUNCED BY 48 HOURS WHEN A STRONGER MID-LATITUDE TROUGH

AMPLIFIES OVER THE CENTRAL ATLANTIC. THE EVOLUTION OF THESE

FEATURES SHOULD CAUSE DANIELLE TO DECELERATE AND TURN NORTH-

NORTHWESTWARD LATER IN THE FORECAST PERIOD. THE OFFICIAL NHC TRACK

FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE AND LIES

CLOSE TO THE MULTI-MODEL CONSENSUS.

Re Danielle and the UK the latest ECM still has Danielle effecting our part of the Atlantic after the re-curve.

Whether it effects us will depend on the strength of the ridge over the UK, however the models have really over played the ridge persistance over the UK between days 5-7 so I would not be surprised to see if downgraded as it draws near.

Realistically anywhere between England and Greenland could be hit by Danielle in some form or another ex-tropical.

ECM is still keen to keep a wedge of TS winds the size of France though in the below and some 80-110mph 850 winds.

[peterf]

Danielle has furthre intensified and is now a CAT 2 at 85Kts, NHC are also forecasting her to become a CAT 3 in 24 hrs.

ALTHOUGH THE CLOUD PATTERN ASSOCIATED WITH DANIELLE IS NOT AS WELL

ORGANIZED AS IT WAS SEVERAL HOURS AGO...LATEST DVORAK SATELLITE

INTENSITY ESTIMATES FROM SAB AND TAFB ARE AT 77 AND 90 KT...

RESPECTIVELY. THE CONVECTIVE ORGANIZATION OF THE CYCLONE HAS BEEN

PULSATING FOR REASONS THAT ARE NOT WELL UNDERSTOOD...BUT THE

OVERALL TREND IS INDICATIVE OF A GENERAL INTENSIFICATION. UPPER-

LEVEL OUTFLOW IS WELL ESTABLISHED OVER THE EASTERN SEMICIRCLE BUT

IS LESS DEFINED TO THE WEST. BASED UPON THE HIGHER SATELLITE

INTENSITY ESTIMATES...THE ADVISORY INTENSITY IS INCREASED TO 85 KT.

AN EYE FEATURE THAT FORMED EARLIER IS NO LONGER EVIDENT...BUT A 0434

UTC AMSR-E OVERPASS WAS HELPFUL IN LOCATING THE CENTER. THAT

OVERPASS AND OTHER RECENT FIXES YIELD AN INITIAL MOTION SLIGHTLY TO

THE LEFT OF THE PREVIOUS ESTIMATE...280/17. DANIELLE IS EXPECTED

TO MOVE ON A GENERAL WEST-NORTHWESTWARD COURSE FOR THE NEXT 12

HOURS OR SO BUT IS FORECAST TO GRADUALLY TURN MORE TOWARD THE

NORTHWEST WHEN IT BEGINS TO ENCOUNTER A WEAKNESS IN THE SUBTROPICAL

RIDGE APPARENT IN WATER VAPOR IMAGERY BETWEEN 45-50W. DYNAMICAL

MODEL GUIDANCE SHOWS THE BREAK IN THE RIDGE BECOMING MORE

PRONOUNCED BY 48 HOURS WHEN A STRONGER MID-LATITUDE TROUGH

AMPLIFIES OVER THE CENTRAL ATLANTIC. THE EVOLUTION OF THESE

FEATURES SHOULD CAUSE DANIELLE TO DECELERATE AND TURN NORTH-

NORTHWESTWARD LATER IN THE FORECAST PERIOD. THE OFFICIAL NHC TRACK

FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE AND LIES

CLOSE TO THE MULTI-MODEL CONSENSUS.

Re Danielle and the UK the latest ECM still has Danielle effecting our part of the Atlantic after the re-curve.

Whether it effects us will depend on the strength of the ridge over the UK, however the models have really over played the ridge persistance over the UK between days 5-7 so I would not be surprised to see if downgraded as it draws near.

Realistically anywhere between England and Greenland could be hit by Danielle in some form or another ex-tropical.

ECM is still keen to keep a wedge of TS winds the size of France though in the below and some 80-110mph 850 winds.

thanks for that iceberg

[philglossop]

Looking very likely that Earl is going form behind Danielle as well.

Although a fish spinner- oh the ironic point that it could hit the UK as a remant low!

[Gray-Wolf]

I'm wondering if D might paste New York as a remnant. The L.P. (mid Atlantic) that gets trapped behind the H.P. that is set to form over us is key (IMHO). As for 96L? I think we'll need to wait and see as the mods are not looking to have it develop but I think it has too?

[AderynCoch]

Well if anything fish-spinners are more likely to affect us as they usually require less mid-latitude curvature to reach here. It will certainly be interesting to see where Danielle ends up and how much she manages to strengthen before heading north.

[Iceberg]

Danielle has weakened due to the dry air being digested from the NW.

Dvorak estimates are probably in the 65Kt to 75Kt range, so back down to CAT 1 IMO.

There is no reason why this isn't just a temporary set back and she still has plenty of time to intensify.

The dry air could be due to over expansion yesterday. Danielle has no recognisable eye anymore.

GFS 06Z has both Danielle and 96L effecting the UK.

[summer blizzard]

ECWMF has Danielle becoming a strong low south of Greenland, GFS has both Danielle and Earl hitting us directly.

http://www.ssd.noaa.gov/goes/flt/t1/rb-l.jpg

Hurricane Danniele looks a little ragged at the moment, so i can't see it being category 3 until at least the 9pm update tonight, if not tommorow, however interaction with 96L has ceased so there should be no more easterly shear, all stumbling blocks now lie to the west.

[Iceberg]

What the hell as Danielle done, she's in terrible shape now, the LLCC is nearly exposed. Currently this is barely a hurricane.

Longer term the expectations are still pretty much the same, but Danielle is doing her best to nolonger be a hurricane.

[Cookie]

really looking ragged now and exposed

[Paranoid]

Still a Hurricane but has weakened significantly.

000

WTNT31 KNHC 241442

TCPAT1

BULLETIN

HURRICANE DANIELLE ADVISORY NUMBER 12

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010

1100 AM AST TUE AUG 24 2010

...DANIELLE UNEXPECTEDLY WEAKENS...BUT FORECAST TO REGAIN

STRENGTH...

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION

-----------------------------------------------

LOCATION...16.6N 46.5W

ABOUT 985 MI...1585 KM E OF THE LESSER ANTILLES

MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/HR

PRESENT MOVEMENT...WNW OR 290 DEGREES AT 20 MPH...32 KM/HR

MINIMUM CENTRAL PRESSURE...985 MB...29.09 INCHES

WATCHES AND WARNINGS

--------------------

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

AT 1100 AM AST...1500 UTC...THE CENTER OF HURRICANE DANIELLE WAS

LOCATED NEAR LATITUDE 16.6 NORTH...LONGITUDE 46.5 WEST. DANIELLE IS

MOVING TOWARD THE WEST-NORTHWEST NEAR 20 MPH...32 KM/HR. A TURN

TOWARD THE NORTHWEST WITH A DECREASE IN FORWARD SPEED IS EXPECTED

DURING THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 80 MPH...130

KM/HR...WITH HIGHER GUSTS. DANIELLE IS NOW A CATEGORY ONE

HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. ALTHOUGH

DANIELLE HAS WEAKENED...RE-STRENGTHENING IS POSSIBLE DURING THE

NEXT 48 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES...45 KM...FROM

THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140

MILES...220 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 985 MB...29.09 INCHES.

HAZARDS AFFECTING LAND

----------------------

NONE.

NEXT ADVISORY

-------------

NEXT COMPLETE ADVISORY...500 PM AST.

$$

FORECASTER BERG

[Iceberg]

Yep as per below, still a hurricane just (A CAT 1 now), although I too think that 70kts is very kind.

She has really struggled with the dry air.

THE PERIOD OF RAPID INTENSIFICATION HAS ENDED WITH A THUD. THE

LOW-LEVEL CENTER OF DANIELLE HAS BECOME EXPOSED BETWEEN A RAGGED

CENTRAL DENSE OVERCAST TO ITS EAST...AND A BROKEN CONVECTIVE BAND

TO ITS WEST. ALL ALONG...MICROWAVE IMAGERY SINCE ABOUT 0300 UTC

SHOWED A DRY SLOT WRAPPING AROUND THE WESTERN AND SOUTHERN SIDE OF

THE CIRCULATION...AND AS A RESULT THE EYEWALL BECAME ERODED. DATA

T-NUMBERS HAVE FALLEN QUICKLY AND ARE NOW AS LOW AS T3.9 FROM THE

HURRICANE INTENSITY ESTIMATE...AN EXPERIMENTAL FORM OF THE UW-CIMSS

ADT. THE INITIAL INTENSITY IS LOWERED TO 70 KT AT THIS TIME...

WHICH COULD STILL BE GENEROUS. SHIPS GUIDANCE SHOWS WESTERLY TO

SOUTHWESTERLY SHEAR INCREASING TO BETWEEN 15 AND 20 KT OVER THE

NEXT 24 HOURS OR SO...AND IT IS UNCLEAR HOW WELL DANIELLE WILL BE

ABLE TO MIX OUT THE DRY AIR. ONLY SLOW STRENGTHENING IS INDICATED

IN THE OFFICIAL FORECAST...AND THE INTENSITY AT DAYS 4 AND 5 IS

HELD JUST BELOW MAJOR HURRICANE STRENGTH TO MAINTAIN SOME SORT OF

CONTINUITY...BUT THIS IS NOW ABOVE MANY OF THE INTENSITY MODELS.

[The PIT]

Over and out again seems to be the likely story again.

[Paranoid]

The last few frames of the sat loop seem to show some of the convection re-asserting itself over the centre, but still lacking in convection on the western side of Danielle.

[Cookie]

Edited August 24, 2010 by cookie

[Iceberg]

Well it's nolonger Hurricane Danielle but is now tropical storm Danielle again as NHC degrade her again.

However as NHC say this is due to be temporary and have her back to a hurricane again tomorrow.

I agree with Paranoid above I Think convection is starting to go get better again, the LLCC is still slightly exposed but convection is slowly getting it's act together again.

As NHC say we don't really know what caused the decline today, but a fair assumption is probably some westerly shear and some dry air.

The GFDL is really the pick of the bunch as it takes her to a CAT 5, probably unrealistic but a strong hurricane is still a very good possibility.

WITH JUST A LITTLE BIT OF UNEXPECTED WESTERLY SHEAR...DANIELLE HAS

UNRAVELED DURING THE DAY. THE LOW-LEVEL CENTER HAS OCCASIONALLY

BEEN EXPOSED TO THE WEST OF A DISORGANIZED CLUSTER OF DEEP

CONVECTION...AND THE DVORAK ESTIMATES HAVE DECREASED ACCORDINGLY.

FINAL-T AND CI ESTIMATES FROM THE UW-CIMSS ADT ARE NOW NEAR

T3.5/4.5 AND SUPPORT DOWNGRADING DANIELLE TO A 60-KT TROPICAL

STORM. WITHOUT SUFFICIENT OBSERVATIONAL DATA IN THE CYCLONE

ENVIRONMENT...OPERATIONALLY WE CAN NOT SPECULATE WITH CERTAINTY WHY

DANIELLE WEAKENED TODAY.

ENVIRONMENTAL CONDITIONS SUPPORT DANIELLE RE-INTENSIFYING INTO A

HURRICANE SOON...AND THAT IS REFLECTED IN THE OFFICIAL FORECAST.

THE INTENSITY GUIDANCE...EXCEPT FOR THE GFDL WHICH SHOWS DANIELLE

BECOMING AN INTENSE HURRICANE IN ABOUT 4 DAYS...INDICATES GRADUAL

STRENGTHENING DURING THE FORECAST PERIOD. THE NEW OFFICIAL

FORECAST IS HIGHER THAN THE STATISTICAL MODELS...WHICH ARE STRONGLY

AFFECTED BY PERSISTENCE...BUT IT REMAINS MUCH LOWER THAN THE GFDL

AT THIS TIME.

Edited August 24, 2010 by Iceberg

[summer blizzard]

Looks like it is starting to look a little better now however it has been downgraded to a Tropical Storm.

[Iceberg]

Well Danielle was back upto Hurricane first thing this morning and has been upgraded again to 75kts so a solid CAT 1.

Danielle is in pretty good shape and finally managed to get convection back fully over the LLCC last night.

This morning as confirmed by the NHC we have better banding, an eye feature developing and even better outflow, although inflow is suffering IMO.

Dry air could still be a problem today particularly when the weakening diurnal effect is having it's most impact.

Shear is also still effecting Danielle although nowhere near as much as the freaky shear of yesterday.

GFS and ECM both bring Danielle into our neck of the woods longer term but are slowing down so we are looing at the weekend of the 4/5th now, ECM keeps the big ridge over the UK, GFS does not, but NHC do not like the ECM solution for Danielle's track and describe it as an outlier.

Intensification is very tricky to forecast, Danielle could easily and quickly go upto a CAT 3, if it doesn't gulp dry air or can overcome shear to get the eye sorted out, or it could equally struggle as a CAT 1 for the next 2 or 3 days.

GFDL yet again takes her to a strong CAT 4, but other models really struggle. The NHC forecast seems to be an average of the tropical models, but the realistic range is quite large.

Another interesting day to see what on earth Danielle will do !.