Major Hurricane Igor

[Iceberg]

Igor has started a turn North of west, we need to wait a little longer to see if this is just a jog or a path change.

Bermudians can't be happy with this though.

[Iceberg]

How long until (if ever) Igor comes into range of Recon?

Sorry I meant to answer this yesterday. The latest from NHC is below, so Thursday evening atm.

IGOR AT 16/1800Z NEAR 23.5N 58.5W.

[Thundery wintry showers]

Just out of interest, is Igor the feature that is progged by GFS and ECMWF to enter the Atlantic Ocean and retain much of its intensity as it approaches the mid latitudes?

http://www.netweather.tv/gfsimages/gfs.20100914/06/168/h500slp.png

I am thinking of that monster low off the east coast of the USA. If this comes to fruition Igor really will be exceptional- very rarely do we see a tropical cyclones approach the mid latitudes and lose little of its intensity.

[johnholmes]

Just out of interest, is Igor the feature that is progged by GFS and ECMWF to enter the Atlantic Ocean and retain much of its intensity as it approaches the mid latitudes?

http://www.netweathe...168/h500slp.png

I am thinking of that monster low off the east coast of the USA. If this comes to fruition Igor really will be exceptional- very rarely do we see a tropical cyclones approach the mid latitudes and lose little of its intensity.

In my view it is one and the same, and no its not that unusual Ian for storms, ex hurricanes to arrive into the Atlantic that intense. Indeed there are well documented instances of them decaying somewhat and regenerating into major Atlantic storms once they meet up with the predominant north Atlantic westerlies and polar jet.

[Cookie]

Shows how their has to be perfect conditions for cat 5

[Iceberg]

Igor is strengthening again IMO back upto a strong CAT 4 somewhere between 120-130kts.

Interesting ECM tonight as it takes him nearly to the US west coast.

[Iceberg]

NHC have confirmed that Igor is strengthening, now back upto 125kts (so up 10kts).

[Paranoid]

Pressure is back down to what it was at Igor's peak too (933mb)

[Chris D]

It is interesting what the NHC say in their Discussion:

"CLOUD TOPS SURROUNDING THE EYE HAVE COOLED CONSIDERABLY DURING THE

AFTERNOON AND THE EYE HAS ALSO WARMED AND BECOME MORE DISTINCT IN

BOTH VISIBLE AND INFRARED SATELLITE IMAGERY. SEVERAL DISTINCT

VORTICES INSIDE THE EYE WERE ALSO NOTED...SIMILAR TO WHAT HAS BEEN

SEEN WITH PAST HURRICANES THAT WERE NEAR CATEGORY 5 STRENGTH"

I think it will briefly be classified as a Cat 5 for a time early tomorrow morning.

Edited September 14, 2010 by chris93

[smich]

A magnificent hurricane. And as others have mentioned, not likely to cause too much damage (although if I were Bermudan, I'd be keeping a close eye on Igor's track...

Am I right in thinking there hasn't been an Eyewall Replacement Cycle yet? The eye has looked very stable - to my eyes - all day.

smich

[Paranoid]

Allegedly there was on last night/this morning, but the eye seemed totally stable so i dont know, maybe the secondary eyewall collapsed without ever replacing the first one.

[mrpsb]

Just read the 11pm forecast discussion and this made me smile:

THE OFFICIAL FORECAST MAINTAINS THIS INTENSITY FOR THE NEXT 12-24 HOURS. GRADUAL WEAKENING IS EXPECTED THEREAFTER WHEN IT IS LIKELY THAT INTERNAL DYNAMICS...WHICH ARE NOT WELL UNDERSTOOD...WILL INFLUENCE THE INTENSITY.

Igor doesn't want to play nice with their shiny new experimental ERC probability system.

Edited September 15, 2010 by mrpsb

[Iceberg]

The good news is that recon might begin today.

ADDITIONAL DAY OUTLOOK: BEGIN 12-HRLY FIXES OF

HURRICANE IGOR AT 17/1800Z NEAR 25.4N 61.7W.

The track beyond the next 3 days where it barely moves NW, is highly variable still.

We've also got the added complication that Igor and Julia might well be effecting each other come Friday....

[Iceberg]

Igor is in very real danger of pressing the self destruct button today, Bit surprising since he looked on the verge of a CAT 5 yesterday evening.

Dry air has started to erode the eye as NHC have metioned in their last advisory, IF Igor can't mix it out, then he will quickly go down to a CAT 3 or less.

This might all be related to his internal structure, due to the very strong inner eye wall that caused the RI to begin with, he hasn't managed an EWRC. This looks to be connected to a failure to create a secondary eye wall as well, if he could do this he would be able to withstand a dry air attack alot better than a fear he might now.

Anyway the above could be total rubbish as alot of it assumption and as NHC say internal dynamics of hurricanes are not well understood......

[Kain]

EW is seems to be now filling in after looking very ragged this morning...Could this be him finally going through a EWRC?

[Iceberg]

Looking at the latest Microwave, it does look as if the inner eye wall is maybe 70% collapsed now and that a very large secondary wall is maybe 80% complete.

However there is still alot of dry air around and the size of the new EW will make it very difficult to deal with it.

IF Igor can achieve this I will be very impressed. It will be interesting to watch.

[Cookie]

Its old but great vapour image from last night

more recent image and very impressive Hurricane still

[Paranoid]

Latest advisory is in. The NHC have kept Igor at Cat 4 (just) but he's forecast to weaken slightly to a Cat 3.

000

WTNT31 KNHC 151437

TCPAT1

BULLETIN

HURRICANE IGOR ADVISORY NUMBER 30

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010

1100 AM AST WED SEP 15 2010

...IGOR WEAKENS A LITTLE FURTHER...STILL A LARGE AND POWERFUL

HURRICANE...

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

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

LOCATION...19.8N 55.0W

ABOUT 540 MI...870 KM ENE OF THE NORTHERN LEEWARD ISLANDS

ABOUT 1055 MI...1700 KM SE OF BERMUDA

MAXIMUM SUSTAINED WINDS...135 MPH...215 KM/HR

PRESENT MOVEMENT...WNW OR 300 DEGREES AT 8 MPH...13 KM/HR

MINIMUM CENTRAL PRESSURE...942 MB...27.82 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 IGOR WAS LOCATED

NEAR LATITUDE 19.8 NORTH...LONGITUDE 55.0 WEST. IGOR IS MOVING

TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/HR. A GENERAL MOTION

TOWARD THE NORTHWEST WITH SOME INCREASE IN FORWARD SPEED IS

EXPECTED OVER THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 135 MPH...215

KM/HR...WITH HIGHER GUSTS. IGOR IS A CATEGORY FOUR HURRICANE ON

THE SAFFIR-SIMPSON HURRICANE WIND SCALE. SOME FLUCTUATIONS IN

STRENGTH ARE POSSIBLE DURING THE NEXT OR TWO...BUT IGOR IS EXPECTED

TO REMAIN A DANGEROUS HURRICANE.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM

THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 225

MILES...360 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 942 MB...27.82 INCHES.

HAZARDS AFFECTING LAND

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

SURF...LARGE SWELLS GENERATED BY IGOR WILL AFFECT THE LEEWARD

ISLANDS...PUERTO RICO AND THE VIRGIN ISLANDS TODAY AND THURSDAY.

THE SWELLS ARE EXPECTED TO REACH PORTIONS OF THE BAHAMAS TONIGHT

AND THURSDAY AND CONTINUE THROUGH THE WEEKEND. SWELLS ASSOCIATED

WITH IGOR WILL ALSO REACH THE EAST COAST OF THE UNITED STATES

THURSDAY AND FRIDAY AND CONTINUE OVER THE WEEKEND. THESE SWELLS ARE

LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.

PLEASE CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE FOR

ADDITIONAL INFORMATION.

NEXT ADVISORY

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

NEXT COMPLETE ADVISORY...500 PM AST.

$$

FORECASTER KIMBERLAIN

[Iceberg]

Latest top bit of the discussion, mentioning the EWRC, outer and inner eyes etc, in the last couple of hours they can see evidence that the inner wall is gaining a bit more strength, this might happened as the outer wall is so big, Igor does seem to be mixing out the dry air though and might be avoiding the self destruct button

THE CLOUD PATTERN ASSOCIATED WITH IGOR WAS DETERIORATING DURING THE

PAST SEVERAL HOURS...WITH CLOUD TOP TEMPERATURES WARMING AND A DRY

SLOT EVIDENT NORTHWEST OF THE CENTER. SEVERAL MICROWAVE OVERPASSES

ALSO INDICATED A FURTHER EROSION OF THE INNER EYEWALL AND THE

FORMATION OF AN OUTER EYEWALL AT ABOUT 60-70 NMI RADIUS. SINCE

ABOUT 1300 UTC...THERE APPEARS TO BE SOME EVIDENCE OF A RE-

ORGANIZATION OF THE INNER CORE. DVORAK T-NUMBERS AT 1200 UTC ARE

5.5 AND 6.0 FROM SAB AND TAFB...RESPECTIVELY.

[Paranoid]

Both Igor and Julia seem to have lost their eyes on the visible sat loops. In Igor's case i assume the first eyewall is being replaced at the moment?

[Kain]

000

WTNT41 KNHC 160855

TCDAT1

HURRICANE IGOR DISCUSSION NUMBER 33

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010

500 AM AST THU SEP 16 2010

MICROWAVE AND INFRARED SATELLITE IMAGERY SUGGEST THAT THE EYEWALL

REPLACEMENT WITH IGOR IS COMPLETE. THE NEW EYEWALL APPEARS TO BE

CONSOLIDATING AT A RADIUS OF ABOUT 30-35 N MI AND IS PRODUCING

RATHER DEEP CONVECTION...SUGGESTING THE INTENSITY IS INCREASING

AGAIN. A BLEND OF THE SATELLITE ESTIMATES GIVES AN INITIAL

INTENSITY OF 125 KT.

A LARGE-SCALE ENVIRONMENT OF LIGHT SHEAR AND WARM WATER IS FAVORABLE

FOR THE MAINTENANCE OF AN EXTREMELY DANGEROUS HURRICANE FOR THE

NEXT FEW DAYS. THE EXACT INTENSITY OF IGOR WILL BE PRIMARILY

DICTATED BY EYEWALL CYCLES...WHICH ARE WELL BEYOND OUR FORECAST

ABILITIES. THE MAJORITY OF THE MODEL GUIDANCE INDICATES THAT SLOW

WEAKENING IS THE MOST LIKELY SOLUTION...AND THE NHC FORECAST REFLECT

THIS. HOWEVER...IT IS MORE IMPORTANT TO RECOGNIZE THAT ALL OF THE

GUIDANCE...AND THE NHC FORECAST...KEEPS IGOR AS A LARGE AND

DANGEROUS HURRICANE FOR THE NEXT SEVERAL DAYS.

THE INITIAL MOTION IS AN UNSTEADY 300/6. IGOR IS EXPECTED TO MOVE

SLOWLY AROUND THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE OVER THE

CENTRAL ATLANTIC. WEAK TROUGHING ALONG ABOUT 70W SHOULD RECURVE

THE CYCLONE IN 3 OR 4 DAYS. THE MAIN DIFFERENCE IN THE MODELS IS

HOW QUICKLY IGOR ACCELERATES TO THE NORTHEAST IN THE MID-LATITUDES.

SINCE THE TROUGHING OVER THE WESTERN ATLANTIC IS RATHER FLAT...

THERE HAS BEEN A TREND IN THE MODELS TO SHOW WEAKER FLOW NEAR

IGOR...AND CONSEQUENTLY DELAY THE INCREASE IN FORWARD SPEED. THE

OFFICIAL FORECAST IS A BIT SLOWER THAN THE PREVIOUS ONE...

ESPECIALLY AT THE END OF THE PERIOD. WITH REGARDS TO HOW CLOSE

IGOR COMES TO BERMUDA...THE ECMWF IS NOW THE MOST EASTERN MODEL

AFTER BEING THE WESTERNMOST YESTERDAY. THIS APPEARS TO BE DUE TO

THAT MODEL SHOWING A SLIGHTLY WEAKER RIDGE TODAY...WHICH ALLOWS

IGOR TO GAIN A LITTLE MORE LATITUDE EARLY ON AND EVENTUALLY PASS A

LITTLE FARTHER EAST OF BERMUDA. HOWEVER...ALL OF THE GUIDANCE IS

WELL CLUSTERED ON A TRACK CLOSE TO THAT ISLAND...AND LITTLE CHANGE

HAS BEEN MADE TO THE OFFICIAL TRACK NEAR BERMUDA. SINCE THIS IS

SUCH A LARGE HURRICANE...SIGNIFICANT IMPACTS ARE EXPECTED ON

BERMUDA...BUT IT IS TOO EARLY TO TELL HOW CLOSE THE CORE OF THE

HURRICANE...AND THE STRONGEST WINDS...WILL COME TO THAT ISLAND.

SO FAR...NOAA BUOY 41044 HAS REPORTED A PEAK 1-MINUTE WIND OF 45

KT...GUSTING TO 56 KT...ALONG WITH A MINIMUM PRESSURE OF 995

MB...AND A SIGNIFICANT WAVE HEIGHT OF 29 FT. HOWEVER...THE WORST

IS YET TO COME FOR THAT STATION...AS IGOR WILL MOVE VERY CLOSE TO

THE BUOY TONIGHT.

FORECAST POSITIONS AND MAX WINDS

INITIAL 16/0900Z 20.5N 56.8W 125 KT

12HR VT 16/1800Z 21.1N 57.8W 125 KT

24HR VT 17/0600Z 22.0N 59.4W 125 KT

36HR VT 17/1800Z 23.2N 61.1W 120 KT

48HR VT 18/0600Z 24.7N 62.7W 120 KT

72HR VT 19/0600Z 28.0N 65.0W 110 KT

96HR VT 20/0600Z 32.5N 64.5W 95 KT

120HR VT 21/0600Z 37.5N 59.0W 80 KT

$$

FORECASTER BLAKE

[Iceberg]

Igor seems to have a very large eye with a good cold cloud top circulation.

Against my judgements he seems to be managing to mix out the dry air that was their yesterday and do an EWRC. This maybe down to his very slow speed atm.

TS winds are being recorded as far away as 280 miles and tbh I don't fancy Bermuda's chances if it clears out this large eye and we could well yet see a CAT 5 and sub 900 pressure.

[Iceberg]

Here's the new eye as it's starting to form. Still quite ragged without a clear dry slot, so it's not visible on visual Sat yet.

Intensification should start again when the eye gets more pronounced and clears out.

[Iceberg]

Recon due to take off in the next hr.

2. HURRICANE IGOR

FLIGHT ONE -- TEAL 70

A. 16/1800Z

B. AFXXX 0111A IGOR

C. 16/1430Z

D. 21.4N 57.6W

E. 16/1600Z TO 16/1900Z

F. SFC TO 15,000 FT

[Iceberg]

Recon should be in Igor in the next 1 hr.