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kold weather

Tropical Storm Danny

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Over the past 12hrs despite pretty heavy shear 92L has been able to develop a closed LLC. Last night recon found high winds and thus the system has skipped the tropical depression stage and has gone right to Tropical Storm Danny.

Right now the NHC has this at 40kts, the lower level recon flight should give us a good measure of what strength this system is really at, could be stronger or even a little weaker, we shall see.

As for future strength, a ULL has dropped southwards overnight and has sheared the system even more. Right now deep convection is still bursting quite strongly on the eastern side of the system which is giving Danny a classic sheared profile. The models have constantly pushed this ULL out of the way and strengthen the system right from the word go however that is a somewhat optimistic outlook. Instead I suspect there will be little in the way of strengthening at least for the next 12hrs but it is only a matter of time. A lower end category-1 hurricane seems possible out of this IMO.

Finally track is something once again the models haven't got a good grip on. The NHC appear to have somewhat sided with the GFS suite a little more then the ECM/CMC combo, whilst the 0z UKMO was a good middle ground. The NHC offical track takes this northwards about 100 miles offshore however IMO this is a very close one to call. If I was to make a punt it'll probably just about hit the Outer Banks, continue NNE and strike the far NE USA on a NNE track, though as has been mentioned by the NHC it could be extra-tropical by that landfall.

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This is the latest from NHC "AFTER THE AIR FORCE HURRICANE HUNTER AIRCRAFT LEFT DANNY EARLIER

THIS AFTERNOON...VISIBLE SATELLITE IMAGERY SEEMED TO SUGGEST THAT A

NEW LOW-LEVEL CENTER WAS FORMING FARTHER TO THE NORTHEAST CLOSER TO

THE DEEP CONVECTION. THE OVERALL CIRCULATION REMAINS DISTORTED AND

LIKELY CONSISTS OF A BROAD CENTER WITH A SHARP SURFACE TROUGH

EXTENDING TO THE SOUTHWEST. NONETHELESS...A NOAA HURRICANE HUNTER

AIRCRAFT CONDUCTING A RESEARCH MISSION THIS EVENING DID RELAY SOME

RELIABLE SFMR DATA WHICH SUGGESTED THAT THE MAXIMUM WINDS ARE NEAR

45 KT WITHIN THE DEEP CONVECTION ABOUT 100 N MI TO THE NORTHEAST OF

THE CENTER. A DROPSONDE FROM THIS FLIGHT ALSO INDICATED THAT THE

MINIMUM PRESSURE HAS FALLEN TO NEAR 1006 MB."

It shows that Danny is a complicated little system, it also raises a few questions in my mind though.

Was the Low level cloud centre ever coupled with the higher level circulation ?

Why are the strongest winds 100 miles away ?, It kind of shows that the winds are not due to the Tropical centre....

Further to this a Low pressure of 1006mb shouldn't really be able to sustained 50 mph winds.

Regardless of all these NHC are far from certain on what his intensity is likely to be.

Here's the NHC discussion again

"ALL THE INTENSITY GUIDANCE CONTINUES TO STRENGTHEN DANNY...BUT IT IS

NOT CLEAR WHY THEY MAKE THE CYCLONE SO STRONG. THE UPPER-LEVEL

ENVIRONMENT IS EXPECTED TO BE FAVORABLE FOR STRENGTHENING OVER THE

NEXT 36-48 HOURS...BUT THEN THE VERTICAL SHEAR IS FORECAST TO

INCREASE TO 40 KT...AND MUCH MORE...ONCE DANNY ACCELERATES TO THE

NORTH AND NORTHEAST. THE SHIPS AND LGEM MODELS MYSTERIOUSLY SHOW

THE SYSTEM STRENGTHENING TO 70-75 KT ONCE THE SHEAR INCREASES.

SINCE THIS DOES NOT SEEM VERY REALISTIC...THE OFFICIAL FORECAST

LIMITS THE INTENSITY AT 65 KT."

So they don't think that 70-75Kts is very realistic and can't see why there would be this much strengthening, however the Latest GFDL takes it to a 100Kts CAT 3 within 60 hrs. HWRF takes it to 90Kts.

This looks to be the strangest tropical storm this year and we could get a Hurricane with the highest pressure ever recorded. GFDL takes it to Hurricane strength at around the 1000mb mark.

post-6326-12513527714359_thumb.png

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Latest update from the NHC 15 mins ago.

"DATA FROM NOAA BUOY 41047 AND THE AIR FORCE RECONNAISSANCE AIRCRAFT

HAVE BEEN CRITICAL IN LOCATING THE BROAD AND ELONGATED CIRCULATION

OF DANNY THIS MORNING...WHICH APPEARS TO HAVE MADE ANOTHER

NORTHWARD REFORMATION. THE AIR FORCE PLANE FOUND 55 KT WINDS AT 850

MB AND DROPSONDE AND RELIABLE SFMR WINDS OF ABOUT 45 KT. AN EARLIER

NOAA HURRICANE HUNTER AIRCRAFT SHOWED 12000 FT WINDS OF 66 KT AND

RELIABLE SFMR VALUES OF 45-50 KT. THE NOAA SFMR DATA ALSO

REASONABLY FIT A 2254 UTC QUIKSCAT PASS WHICH HAD A FEW 50 KT WIND

BARBS. THEREFORE...THE ADVISORY INTENSITY IS SET TO 50 KT. IT

SHOULD BE NOTED THAT DANNY DOES NOT HAVE A TYPICAL TROPICAL CYCLONE

STRUCTURE AND HAS MOST OF THE STRONG WINDS LOCATED WELL NORTH AND

EAST OF THE CENTER."

I am glad I wasn't being silly questioning this as a tropical storm, it does seem to be rather strange for a TS. NHC go on to say that most of the strengthening 3 days and beyond is down to extra tropical factors and NOT tropical factors.

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Well NHC have updated and still the centre is totally devoid of convection.(see piccie)

The mass of convection is clearly NOT related to the warm core of the system and for the life of me I can't see that this is a Tropical storm with a clearly coupled LLCC.

"THE CENTER IS STILL EXPOSED...THE CONVECTION HAS MORE OF A LINEAR

CHARACTER THAN THE CURVED BANDS CHARACTERISTIC OF A TROPICAL

CYCLONE...AND THE STRONGEST WINDS ARE STILL WELL REMOVED FROM THE

CENTER. "

However we still have Danny at 50Kts due to start the move to extra tropical in 48 hrs, with still a possibility of a hurricane, but I'll eat my hat if this becomes a hurricane without any convection near the Centre.

post-6326-12513859610013_thumb.jpg

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TS Danny does look very wierd. not sure what is going on with it, but agree with iceberg, it doesn't currently look like hurricane material, unless we get some serious organisation

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Danny is still going due west (at least the LLCC is), Dvorak has gone down to 2.0 which is below TS strength, however winds are still at maybe 45Kts.

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latest for Danny

...DANNY REMAINS DISORGANIZED...

A TROPICAL STORM WATCH IS IN EFFECT FOR THE NORTH CAROLINA COAST

FROM CAPE LOOKOUT NORTHWARD TO DUCK...INCLUDING THE PAMLICO AND

ALBEMARLE SOUNDS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM

CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 36

HOURS.

INTERESTS ELSEWHERE FROM THE CAROLINAS NORTHWARD TO NEW ENGLAND AND

THE CANADIAN MARITIMES SHOULD MONITOR THE PROGRESS OF DANNY.

ADDITIONAL WATCHES AND WARNINGS MAY BE REQUIRED FOR PORTIONS OF THIS

AREA ON FRIDAY.

DANNY REMAINS VERY DISORGANIZED IN ITS SATELLITE PRESENTATION.

LITTLE DEEP CONVECTION HAS BEEN NOTED NEAR THE ESTIMATED CENTER.

THERE ARE A FEW CLUSTERS OF DEEP CONVECTION OVER THE EASTERN AND

NORTHERN PORTIONS OF THE CIRCULATION...BUT THIS CONVECTION SHOWS

LITTLE OR NO EVIDENCE OF BANDING FEATURES. DROPSONDE DATA FROM THE

NOAA G-IV JET AIRCRAFT SUGGEST THAT THE CYCLONIC CIRCULATION OF

DANNY HAS LITTLE VERTICAL DEPTH. A NOAA P-3 HURRICANE HUNTER

AIRCRAFT...CONDUCTING A RESEARCH MISSION IN DANNY THIS EVENING...

INDICATES THAT THE STRONGEST WINDS CONTINUE TO BE DISPLACED WELL TO

THE NORTHEAST OF THE CENTER. PEAK WINDS REPORTED BY THE PLANE WERE

42 KT...SO THE INITIAL INTENSITY IS REDUCED TO 40 KT FOR THIS

ADVISORY. DANNY HAS BEEN EXPERIENCING STRONG WEST-SOUTHWESTERLY

SHEAR DUE TO AN UPPER-LEVEL TROUGH AND CYCLONIC SHEAR AXIS TO ITS

WEST. THERE IS STILL A WINDOW OF OPPORTUNITY FOR THE STORM TO

STRENGTHEN AS GLOBAL MODELS SHOW THE UPPER-LEVEL FLOW BECOMING MORE

ANTICYCLONIC...WITH SOME LESSENING OF THE SHEAR DURING THE NEXT 24

HOURS. THEREFORE THE OFFICIAL FORECAST SHOWS SOME STRENGTHENING

OVER THE NEXT DAY OR SO. HOWEVER BY 48 HOURS THE SHEAR OVER DANNY

IS EXPECTED TO BE 40 KT OR MORE SO ANY INTENSIFICATION OF THE

SYSTEM AS A TROPICAL CYCLONE SHOULD CEASE BY THAT TIME. IN

FACT...BY 48 HOURS...THE GLOBAL MODELS AND THE FSU CYCLONE PHASE

SPACE ANALYSES IMPLY THAT DANNY MAY HAVE ALREADY BECOME AN

EXTRATROPICAL CYCLONE.

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The LLCC is still going almost due west well out the way of the NHC path, however since it has virtually no convection attached to it, it' not really a problem (unless and it can't be ruled out it suddenly gets it's act together in which case North Carolina should watch out.!)

The obvious implications are that if there is no Danny, it can't possibly reach us. Expect lots of changes to the UK models as they totally fail to pick up on the lack of an LP system.

post-6326-12514643463927_thumb.png

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Recon have been in Danny and the strongest winds they've found at 39Kts at flight level(rain contaminated).

This would suggest he isn't even TS strength, but NHC will probably stay with 35Kts.

NHC have also suggested that it will stop issuing advisories on Danny this morning, as it is now almost totally extra-tropical.

Min pressure has stayed at 1007mb and considerable deepening of the system is needed to fulfil the model predictions over the next 24 hrs.

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I don't think Danny is over 100% just yet

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