Major Hurricane Danielle

[Iceberg]

An Interesting view on the phase analysis of Danielle as it makes its way upto 40N.

http://moe.met.fsu.edu/cyclonephase/gfs/fcst/archive/10082506/2.html

To many pictures to really show but the link is from the lates 06Z run from GFS.

Main points for me are the deep warm core charecteristics even at T180 when it's zooming eastwards across the Atlantic towards us.

Winds are also still just in the CAT 4 Region with a very large Cat 1 wind area.

Extra-Tropical transistion also does not seem to have taken place at T180.

Once the GFS goes into lower res mode it tends to give up what to do with this and loses it in an existing LP very quickly, this is NOT realistic IMO.

[Iceberg]

Danielle is starting to look quite good again, outflow is much better in all quadrants except the SW which is still under shear. She has a much better convective CDO than yesterday with inflow, particularly from the north.

I can't access Microwave imagery at work, but it looks like an eye is clearly forming within the heavy convection around the LLCC, so a further intensity upgrade from NHC is likely to probably 80kts, outside chance of Danielle becoming a CAT 2.

[Iceberg]

Latest from NHC, they are not as keen as me on the look of Danielle atm, but Dvorak ranges are incredibly large at 90kts to 65kts.

The important thing is that Recon have said that they will start flights on Friday for Danielle and will fly at 12 hrly intervals, so we will by then at last have a real sample ( personally I think she will be a major my then ).

"DANIELLE HAS A LARGE CENTRAL DENSE OVERCAST THIS MORNING WITH

CLOUD TOPS TO -80C. HOWEVER...RECENT MICROWAVE IMAGERY SHOWS THAT

THE CONVECTION IS ORGANIZED IN BANDS EAST OF THE CENTER WITH NO

EVIDENCE OF AN EYEWALL. UPPER-LEVEL WESTERLY WINDS ASSOCIATED WITH

A TROUGH TO THE NORTHWEST OF THE HURRICANE ARE CAUSING 15-20 KT OF

WESTERLY VERTICAL SHEAR...AND THIS HAS LIKELY AFFECTED THE

CONVECTIVE STRUCTURE. SATELLITE INTENSITY ESTIMATES REMAIN 90 KT

FROM TAFB AND 65 KT FROM SAB. BASED ON THIS...THE INITIAL

INTENSITY REMAINS 75 KT...AND THIS MIGHT BE A LITTLE GENEROUS. THE

CIRRUS OUTFLOW IS FAIR IN THE EASTERN SEMICIRCLE AND RESTRICTED

ELSEWHERE."

[The PIT]

Ah the Fat Lady Miss Shear is trying to warm up again is she. She's damn persistent isn't she.

[Cookie]

shear is causing a lot of issues

[Iceberg]

Danielle is doing OK again, latst dvorak put her between 80 and 90 kts so they might well go for 80kts just shy of CAT 2.

She is definately getting sheared but it's only slowing development down rather than stopping it atm.

[Somerset Squall]

An eye looks to be emerging again, Danielle definitely strengthening:

[Paranoid]

Still no change in strength. Most of energy is probably going into her reorganising her structure.

On another note, interesting that Wetterzentrale shows Danielle on the last of their charts somewhere in the mid Atlantic. From the looks of it Danielle appears to have only just begun to undergo extratropical transistion.

http://www.wetterzentrale.de/pics/Rtavn2161.html

[Cookie]

[The PIT]

Yes this system is certainly causing GFS ECM some problems and this will FI is going to within T96 until Danielle is zapped by Fat lady Shear or it actually manages to lose the fat lady and gets a move on.

[Iceberg]

Danielle is actually doing quite well atm, a solid if rather ragged eye is now evident and cleared, importantly is a large eye so plenty of scope for intensification before any problem ERC's occur.

Intensity has been raised to 90kts so getting close to a Major Hurricane CAT 3, and the latest NHC foecast conservatively IMO goes for strengthening to just shy of a CAT 4 !.

AN EYE HAS BECOME APPARENT ON INFRARED SATELLITE IMAGERY OVER THE

PAST FEW HOURS...ALTHOUGH THE COLDEST CONVECTIVE TOPS AROUND THE EYE

HAVE BEEN FLUCTUATING IN COVERAGE. BASED ON A DVORAK ESTIMATE OF

5.0 FROM TAFB...THE INITIAL INTENSITY IS RAISED TO 90 KT FOR THIS

ADVISORY. UPPER-LEVEL OUTFLOW APPEARS EXCELLENT EXCEPT TO THE

SOUTHWEST...AS THE HURRICANE IS CURRENTLY EXPERIENCING

SOUTHWESTERLY SHEAR OF AROUND 10 KT ACCORDING TO ANALYSES FROM

UW-CIMSS AND THE SHIPS MODEL. THE SHEAR IS EXPECTED TO REMAIN LOW

FOR THE NEXT 2 TO 3 DAYS...AND THIS SHOULD ALLOW DANIELLE TO

INTENSIFY TO MAJOR HURRICANE STATUS IN THE NEXT DAY OR SO. AFTER

72 HOURS...INCREASING SHEAR DUE TO INTERACTION WITH A MID-LATITUDE

TROUGH ALONG WITH COOLER WATERS SHOULD RESULT IN WEAKENING. THE

INTENSITY FORECAST HAS BEEN NUDGED UPWARD AND IS NOW A LITTLE

HIGHER THAN THE SHIPS AND LGEM THROUGH 24 HOURS AND IS CLOSE TO

THOSE MODELS BEYOND THAT TIME.

Edited August 26, 2010 by Iceberg

[Iceberg]

A few piccies showing track and her current state, the eye is clearly visible on Microwave and even daylight imagery.

The wrap around the of the deep convection is almost finished, just the SE to do now, then I've got a feeling that some RI might well happen, maybe later this afteroon or this evening.

Also Danielle due to the strengthening/weakening cycles of the past few days, has quite an expanded wind field as seen in the AMRSE shot.

[Paranoid]

Danielle's appearence has improved greatly over the past few hours and a distinct eye is now clearly visible on the satellite loops, although there has been little change in strength. I second Iceberg's thoughts on some rapid intensification occuring now that the structure has sorted itself out.

[Iceberg]

Agree Paranoid, we still have to wait until tomorrow for some recon really to see what she really is (only 24 hrs to go).

Latest NHC discussion below, which I kind of agree with, Danielle has taken a bit of time to get the eye sorted out, but considering the size of the eye this isn't really a surprise.

The 90Kts might be right personally I would say 95kt and that it's just on the verge of a CAT 3.

We nolonger need microwave to see the eye as its very nicely formed on visual, as we go though this evening I would expect more and more convection within the CDO and the eye to become better defined (not that it's too bad at the moment ! ).

It's only a short jump now to a 120kt CAT 4 Storm IMO, the hard work of the shear, the dry air, getting the eye sorted etc has been done.

DANIELLE HAS GONE THROUGH ANOTHER ROUND OF CHANGES IN ITS CONVECTIVE

STRUCTURE. THE EYE THAT WAS APPARENT FROM 05-07Z DISAPPEARED AT

ABOUT 10Z...ACCOMPANIED BY AN OVERALL DECREASE IN ORGANIZATION.

SINCE THEN...THE EYE HAS RE-APPEARED...EMBEDDED IN A RAGGED CENTRAL

DENSE OVERCAST. SATELLITE INTENSITY ESTIMATES ARE 90 KT FROM TAFB

AND SAB...SO THAT REMAINS THE INITIAL INTENSITY. HOWEVER...THIS MAY

BE SMOOTHING THROUGH SOME SHORT-TERM FLUCTUATIONS.

THE INITIAL MOTION IS 320/13. IN THE FIRST 48 HR OF THE FORECAST

PERIOD...DANIELLE SHOULD BE STEERED GENERALLY NORTHWESTWARD BY A

LOW/MID-LEVEL RIDGE PASSING TO THE NORTH AND NORTHEAST OF THE

HURRICANE. AFTER THAT TIME...A LARGE MID/UPPER-LEVEL TROUGH MOVING

THROUGH THE NORTHEASTERN UNITED STATES AND THE CANADIAN MARITIMES

IS EXPECTED TO CAUSE DANIELLE TO TURN TOWARD THE NORTH AND THE

NORTHEAST. THE GUIDANCE HAS MADE A MAJOR EASTWARD SHIFT SINCE THE

PREVIOUS ADVISORY...AND IT IS NOW IN GOOD AGREEMENT ON RECURVATURE

INTO THE WESTERLIES WITH AN INCREASE IN FORWARD SPEED AFTER 72 HR.

THE NEW FORECAST TRACK WILL ALSO BE SHIFTED EASTWARD DURING THIS

PERIOD...BUT NOT AS MUCH AS THE GUIDANCE HAS SHIFTED. THE NEW

FORECAST TRACK IS DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE FOR THE

FIRST 48 HR...AND IS ALONG THE LEFT EDGE OF THE GUIDANCE ENVELOPE

FROM 72-120 HR. ADDITIONAL EASTWARD ADJUSTMENTS OF THE FORECAST

TRACK MAY BE NECESSARY THIS AFTERNOON IF THE CURRENT TRENDS IN THE

GUIDANCE CONTINUE.

Sorry forgot to include the flight details.

I. ATLANTIC REQUIREMENTS

1. HURRICANE DANIELLE

FLIGHT ONE -- TEAL 70

A. 27/1800Z

B. AFXXX 0106A DANIELLE

C. 27/1330Z

D. 27.2N 59.7W

E. 27/1545Z TO 27/1900Z

F. SFC TO 15,000 FT

FLIGHT TWO -- TEAL 71

A. 28/0600Z

B. AFXXX 0206A DANIELLE

C. 28/0115Z

D. 28.5N 60.5W

E. 28/0345Z TO 28/0700Z

F. SFC TO 15,000 FT

2. SUCCEEDING DAY OUTLOOK: POSSIBLE FIX ON DANIELLE

AT 28/1800Z NEAR 30.7N 61.0W

3. ADDITIONAL DAY OUTLOOK: POSSIBLE FIX OF TROPICAL STORM

EARL AT 29/1800Z NEAR 17.5N 54.5W

[Iceberg]

The eye continues to get neater, with a good solid even CDO around it so intensification is certaintly happening, certainly a CAT 3.

Should be some good pictures from modis and aqua

[The PIT]

Ah good Mrs Shear has been sent off to the dressing room. So as long as nothing unexpected happens all eyes on how it crosses the Atlantic. At the moment still programmed to be a fish spinner by the GFS and ECM.

[Cookie]

breathtaking

[Iceberg]

There have been a few signs of further intensification of Danielle in the last few hrs, cloud tops have cooled a little to the NW and convection is deeper, also we can see that there are a few meso storms in the eye wall, which is an indication of great instability and strong intensification. On the negative side, it's possible that the eye wall might still be open.

Dvorak numbers should be out again soon.

Interesting GFDL for Danielle which shows a sub-tropical Hurricane 5 mph shy of CAT 3 not far from our shores, it all depends on how the Jet interacts and the ridge over us holds out.

[Iceberg]

A neat little app that has plotted the hurricane models on google earth for Danielle and Earl.

I'll post it in both threads as it will be interesting to see how they change over the next few days.

The re-curve northwards is due to take place to the left of the UK, however one of the GFS hurricanes ensembles APx takes in directly over the UK and others take it quite close to us.

[Iceberg]

Latest NHC below

SATELLITE IMAGERY THIS AFTERNOON INDICATES THAT DANIELLE HAS

DEVELOPED A WELL-DEFINED 20 NM WIDE EYE WITH CLOUD TOPS TO -75C IN

THE NORTHWESTERN EYEWALL. SATELLITE INTENSITY ESTIMATES AT 18Z WERE

90 KT FROM TAFB AND SAB...AND SINCE THAT TIME THE SATELLITE

APPEARANCE OF THE HURRICANE HAS IMPROVED. THUS...THE INITIAL

INTENSITY IS INCREASED TO 95 KT. THE CIRRUS IS FAIR TO GOOD IN ALL

DIRECTIONS EXCEPT TO THE SOUTH.

so upped to 95kts, which I think is still conservative going by how much better she is now.

Latest visual below before dark, the tell tale rippling near the eye of intensification and this could be anywhere from 90-110kts by morning.

[Cookie]

breathtaking

[Cookie]

UW - CIMSS

ADVANCED DVORAK TECHNIQUE

ADT-Version 8.1.1

Tropical Cyclone Intensity Algorithm

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

Date : 26 AUG 2010 Time : 211500 UTC

Lat : 25:10:40 N Lon : 56:52:41 W

CI# /Pressure/ Vmax

5.5 / 959.7mb/102.0kt

Final T# Adj T# Raw T#

5.5 5.7 5.7

Latitude bias adjustment to MSLP : -0.3mb

Estimated radius of max. wind based on IR : 24 km

Center Temp : +10.4C Cloud Region Temp : -61.4C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : ATLANTIC

Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT

Weakening Flag : OFF

Rapid Dissipation Flag : OFF

[londonsnow]

i see danielle has achieved cat 3. v impressive

[Iceberg]

NHC finally caught on that Danielle has been going through strong intensification (maybe a little harsh)

They are now saying she will hit CAT 4 in 24 hrs, however the secpial Dvorak rating they used of 6 does already support 115Kts sub 950 which would already make Danielle a CAT 4.

The current 105kts looks to be right though at the moment and with some recon finally today (later this afternoon evening) we will find out.

RECENT INFRARED IMAGERY HAS SHOWN THAT THE EYE OF DANIELLE HAS

CONTRACTED AND BECOME MORE DISTINCT...AND IS NOW EMBEDDED IN A RING

OF TOPS COLDER THAN -60C. A SPECIAL DVORAK CLASSIFICATION FROM TAFB

AT 0415 UTC YIELDED A DATA-T NUMBER OF 6.0/115 KT. BASED ON A

BLEND OF THIS ESTIMATE AND AND RECENT ADT ESTIMATES OF 5.5/102

KT...THE INITIAL INTENSITY IS INCREASED TO 105 KT. THE INTENSITY

FORECAST HAS BEEN ADJUSTED UPWARD THROUGH 48 HOURS...SHOWING A PEAK

OF 115 KT AT 24 AND 36 HOURS. BEYOND 48 HOURS...THE INTENSITY

FORECAST IS IDENTICAL TO THE PREVIOUS ADVISORY.

THE TRACK AND WIND RADII FORECASTS ARE UNCHANGED.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/0600Z 26.2N 58.1W 105 KT

12HR VT 27/1200Z 26.7N 59.0W 110 KT

24HR VT 28/0000Z 28.1N 60.4W 115 KT

36HR VT 28/1200Z 29.6N 60.9W 115 KT

48HR VT 29/0000Z 31.4N 60.3W 110 KT

72HR VT 30/0000Z 35.5N 56.5W 90 KT

96HR VT 31/0000Z 38.5N 50.5W 75 KT

120HR VT 01/0000Z 41.0N 42.0W 60 KT...POST-TROP/EXTRATROP

[Iceberg]

A quick look at imagery just released indicated that Danielle could have just started another bout in near RI, which is probably taking her to a CAT 4 now, a Top end CAT 4 , low end CAT 5 is possible given SST's and heat content over the next 36 hrs.

A classic powerful hurricane now with symetric CDO, stable sharp eye and the radar appearence of the CDO, outflow very good to the North but restricted a little to the SE.