Caribbean-On-Line's Caribbean Hurricane Blog



Hurricane Igor

EXTREMELY DANGEROUS IGOR INTENSIFIES AGAIN

Published on September 16, 2010 6:35 AM | Comments

Igor is a monster - there is a NOAA buoy report of 29 foot waves - and the buoy is far from the storm. This is still not looking good for Bermuda unfortunately:

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.



Igor a strong Category 4 Hurricane

Published on September 14, 2010 6:14 PM | Comments

24 hours ago the NHC reports had Igor weakening a bit - that didn't happen:

HURRICANE IGOR DISCUSSION NUMBER 27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
500 PM AST TUE SEP 14 2010

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. THE
INITIAL INTENSITY IS INCREASED TO 125 KT AND IS SUPPORTED BY
SATELLITE INTENSITY ESTIMATES OF T6.5/127 KT FROM SAB...3-HR
AVERAGE ODT VALUES OF T6.7/133 KT FROM TAFB...AND UW-CIMSS ADT
VALUES OF T6.5/127 KT.

THE INITIAL MOTION ESTIMATE IS 295/07...BASED ON A 12-HR AVERAGE OF
SMOOTHING OUT THE MANY TROCHOIDAL WOBBLES IN THE TRACK. IGOR MAY
BRIEFLY WOBBLE BACK TO THE WEST DURING THE NEXT SEVERAL HOURS...BUT
THE GENERAL MOTION OVER THE NEXT 24 HOURS SHOULD BE TOWARD THE
WEST-NORTHWEST...FOLLOWED BY A TURN TO THE NORTHWEST AFTER THAT
THROUGH 72 HOURS. A SERIES OF SHORTWAVE TROUGHS MOVING QUICKLY IN
THE MID-LATITUDE WESTERLIES ACROSS THE NORTHERN U.S. AND THE NORTH
ATLANTIC IS FORECAST TO GRADUALLY WEAKEN THE SUBTROPICAL RIDGE
BETWEEN 60W-70W LONGITUDE ABOUT EVERY 24-36 HOURS. AS A RESULT...
IGOR IS EXPECTED TO TURN NORTHWARD IN 96-120 HOURS AS DEEP-LAYER
SOUTHERLY FLOW TO THE EAST OF IGOR STRENGTHENS BETWEEN IT AND A
STRONG SUBTROPICAL HIGH FORECAST OT BE NEAR 30N/40W BY THAT TIME.
THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND
IS CLOSE TO THE MIDDLE OF THE TIGHTLY CLUSTERED MODEL GUIDANCE. BY
120 HOURS...IGOR IS EXPECTED TO BE A VERY LARGE HURRICANE AND BE
CLOSE ENOUGH TO BERMUDA TO BRING ADVERSE WEATHER CONDITIONS TO THAT
ISLAND.

IGOR IS FORECAST TO REMAIN IN AN ENVIRONMENT OF LIGHT VERTICAL WIND
SHEAR...WARM SEA-SURFACE TEMPERATURES OF NEAR 29C...AND MAINTAIN A
VERY FAVORABLE OUTFLOW PATTERN THROUGH THE FORECAST PERIOD. AS A
RESULT...THERE MAY BE SOME ADDITIONAL STRENGTHENING DURING THE NEXT
12-24 HOURS...ESPECIALLY LATER TONIGHT DURING THE CONVECTIVE
MAXIMUM PERIOD. HOWEVER...OWING TO THE LARGE SIZE OF IGOR...ITS
STRONG CATEGORY 4 INTENSITY...AND ITS RELATIVELY SLOW FORWARD
MOTION OF LESS THAN 10 KT...SOME COLD UPWELLING MAY OCCUR BENEATH
THE CORE OF THE HURRICANE AND CAUSE SOME WEAKENING OF THE CYCLONE
DESPITE THE AFOREMENTIONED FAVORABLE CONDITIONS. EYEWALL
REPLACEMENT CYCLES ARE ALSO A DISTINCT POSSIBILITY. REGARDLESS...
IGOR IS STILL EXPECTED TO REMAIN A MAJOR HURRICANE THROUGH THE
FORECAST PERIOD. THE OFFICIAL INTENSITY FORECAST IS A LITTLE HIGHER
THAN THE PREVIOUS ADVISORY AND IS SIMILAR TO A BLEND OF THE
SHIPS-LGEM INTENSITY MODELS THROUGH 72 HOURS. IT APPEARS AS THOUGH
THE SHIPS GUIDANCE AT FOUR AND FIVE DAYS MAY BE ADVERSELY AFFECTED
BY THE REPRESENTATION OF THE WARM CORE OF THE HURRICANE IN THE GFS
MODEL. IN ADDITION...ALL THE GLOBAL MODELS FORECAST A VERY
FAVORABLE OUTFLOW PATTERN THROUGH DAY FIVE...AND SO THE OFFICIAL
FORECAST IS HELD A LITTLE ABOVE THE GUIDANCE NEAR THE END OF THE
FORECAST PERIOD.




HURRICANE IGOR DISCUSSION NUMBER 25

Published on September 14, 2010 8:37 AM | Comments

HURRICANE IGOR DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
500 AM AST TUE SEP 14 2010

ENHANCED INFRARED SATELLITE IMAGES SHOW THAT THE CLOUD TOPS
SURROUNDING THE EYE OF THE HURRICANE HAVE WARMED A LITTLE...AND
DVORAK DATA T-NUMBERS FROM BOTH TAFB AND SAB HAVE DECREASED. THE
ADVISORY INTENSITY IS SET AT 115 KT WHICH IS A BLEND OF THE DVORAK
CURRENT INTENSITY AND T-NUMBERS. THIS IS ALSO CLOSE TO THE LATEST
OBJECTIVE DVORAK INTENSITY ESTIMATES FROM UW-CIMSS. AS STATED
EARLIER...FLUCTUATIONS IN STRENGTH DUE TO INNER CORE EVOLUTION ARE
PROBABLE OVER THE NEXT COUPLE OF DAYS. HOWEVER...THE LARGE-SCALE
ATMOSPHERIC AND OCEANIC ENVIRONMENT IS LIKELY TO REMAIN QUITE
CONDUCIVE FOR THE MAINTENANCE OF A MAJOR HURRICANE FOR THE NEXT 48
TO 72 HOURS. THEREFORE AT LEAST SLIGHT RESTRENGTHENING IS A
DISTINCT POSSIBILITY. THE OFFICIAL FORECAST IS CONSISTENT WITH
THIS REASONING AND IS CLOSE TO THE LATEST INTENSITY MODEL CONSENSUS
THROUGH DAY 3 AND IS QUITE SIMILAR TO THE STATISTICAL-DYNAMICAL
LGEM MODEL AT DAYS 4 AND 5.

SATELLITE FIXES OF THE WELL-DEFINED EYE OF IGOR INDICATE THAT THE
MUCH-AWAITED TURN TOWARD THE WEST-NORTHWEST HAS OCCURRED...AND THE
INITIAL MOTION IS ESTIMATED TO BE 285/7. VERY LITTLE CHANGE HAS
BEEN MADE TO THE NHC FORECAST TRACK ON THIS PACKAGE. WATER VAPOR
IMAGES AND GLOBAL MODEL INITIALIZATIONS SHOW A BROAD TROUGH JUST
EAST OF THE EASTERN U.S. SEABOARD. THE DYNAMICAL MODELS SHOW A
SERIES OF SHORT WAVE TROUGHS PASSING THROUGH THIS FEATURE DURING
THE NEXT SEVERAL DAYS. THE RESULTING WEAKNESS IN THE SUBTROPICAL
RIDGE SHOULD CAUSE THE HURRICANE TO GRADUALLY TURN TOWARD THE
NORTHWEST AND NORTH-NORTHWEST DURING THE FORECAST PERIOD. THE
OFFICIAL FORECAST TRACK IS VERY CLOSE TO A CONSENSUS OF THE
DYNAMICAL MODELS EXCLUDING THE U.K. MET. OFFICE TRACK...WHICH IS
LOOKING MORE AND MORE LIKE A WESTERN OUTLIER.

INTERESTS IN BERMUDA SHOULD NOT FOCUS ON THE 5-DAY POINT...SINCE
TRACK ERRORS COULD EASILY BE A FEW HUNDRED MILES AT THAT FORECAST
INTERVAL. IT IS STILL TOO EARLY TO SAY WITH CERTAINTY WHETHER IGOR
WILL HAVE A SIGNIFICANT IMPACT ON THAT ISLAND.



Igor & Julia

Published on September 14, 2010 8:33 AM | Comments

The track can always change - but - it is not looking promising at the moment for Bermuda. Let's hope that Igor gets steered one way or another away from this island. We also now have Hurricane Julia tracking behind Igor. The NHC is pretty confident that both of these storms will take a northern track, and Julia at the moment looks to not to be a threat to land anywhere.



Tropical Storm Igor 5 Day Path

Published on September 11, 2010 12:42 PM | Comments



TROPICAL STORM IGOR DISCUSSION NUMBER 13

Published on September 11, 2010 12:39 PM | Comments

TROPICAL STORM IGOR DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
1100 AM AST SAT SEP 11 2010

ALTHOUGH THE CONVECTIVE CLOUD TOPS HAVE WARMED...VISIBLE SATELLITE
IMAGES SHOW A BANDING EYE PRESENTATION WITH IGOR. WHILE THE
WEAKENING OF THE CONVECTION HAS LED TO A DECREASE IN DVORAK
T-NUMBERS...IT IS PREMATURE TO LOWER THE INTENSITY AND 60 KT WILL BE
KEPT FOR THIS ADVISORY.

ALTHOUGH EASTERLY SHEAR REMAINS PRESENT...IT HAS DECREASED SINCE
YESTERDAY AND IS FORECAST TO FURTHER DIMINISH DURING THE NEXT DAY
OR SO. AROUND THAT TIME...THE CYCLONE IS FORECAST TO MOVE OVER
WATERS WARMER THAN 28C. THESE CONDITIONS SHOULD PROMOTE GRADUAL
STRENGTHENING IN THE SHORT-TERM...WITH THE POTENTIAL FOR A MORE
SIGNIFICANT INTENSIFICATION IN A COUPLE OF DAYS. INTERESTINGLY...
WHILE THE STATISTICAL MODELS MAKE IGOR A CATEGORY 4 HURRICANE...THE
GFDL AND HWRF MODELS SHOW SOME WEAKENING WITH IGOR BEFORE
RESTRENGTHENING THE CYCLONE IN A FEW DAYS. AT THIS POINT...I AM
INCLINED TO LEAN ON THE STATISTICAL MODELS AT THE END OF THE
PERIOD GIVEN THE FORECAST UPPER-LEVEL WIND PATTERN...AND HAVE RAISED
THE WINDS FOR THAT TIME.

MICROWAVE AND VISIBLE IMAGES SUGGEST THE SYSTEM HAS SLOWED A BIT AND
IS MOVING 275/17. THE GLOBAL MODELS ARE IN GOOD AGREEMENT ON A
WESTWARD TRACK OF IGOR FOR THE NEXT FEW DAYS AS RIDGING REMAINS
ENTRENCHED TO THE NORTH. IN ABOUT 3 DAYS...THE WESTERN PART OF THE
RIDGE WEAKENS DUE TO A LARGE MID-LATITUDE TROUGH. THIS PATTERN
SHOULD ALLOW IGOR TO GAIN A BIT MORE LATITUDE AND SLOW DOWN. WHILE
THE MODELS ARE IN GENERAL AGREEMENT WITH THIS SCENARIO...THERE ARE
SOME LARGE SPEED DIFFERENCES...AS THE ECMWF IS SIGNIFICANTLY SLOWER
THAN MOST OF THE OTHER GUIDANCE. THE NHC FORECAST IS CLOSE TO THE
PREVIOUS ONE...ON THE SOUTHERN AND WESTERN SIDES OF THE GUIDANCE
ENVELOPE...ATTEMPTING TO ACCOUNT FOR THE MODEL TENDENCIES OF BEING
TOO SLOW AND POLEWARD WITH LOW-LATITUDE SYSTEMS.



Tropical Storm Igor...

Published on September 8, 2010 12:25 PM | Comments

Is in the house. It is very far off, but it is expected to become a major hurricane. Best case scenario at the moment is that is stays north of the Caribbean. We'll be posting more soon as it becomes available:


TROPICAL STORM IGOR DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010
1100 AM AST WED SEP 08 2010

THE LOW OVER THE FAR EASTERN TROPICAL ATLANTIC OCEAN HAS BECOME
BETTER DEFINED AND DEEP CONVECTION NEAR THE CENTER HAS PERSISTED
LONG ENOUGH FOR THIS SYSTEM TO BE CONSIDERED A TROPICAL CYCLONE. A
1042 UTC ASCAT PASS SHOWED WINDS OF 35 KT...AND THE INITIAL
INTENSITY WILL BE SET TO THAT VALUE. EASTERLY SHEAR IS PRESENT
OVER IGOR...BUT IS FORECAST TO LIGHTEN IN A DAY OR SO. ALL
RELIABLE MODELS SHOW INTENSIFICATION INTO A HURRICANE IN THE NEXT
SEVERAL DAYS. BECAUSE OF THE SHEAR...THE NHC INTENSITY FORECAST
WILL ONLY SHOW RELATIVELY SLOW STRENGTHENING...BELOW THE GUIDANCE
INITIALLY...BUT THE FORECAST ENDS UP CLOSE TO THE CONSENSUS AT DAY
5. IF THE UPPER ANTICYCLONE PATTERN SEEN IN MOST OF THE GLOBAL
MODELS VERIFY...THE OFFICIAL FORECAST COULD BE CONSERVATIVE IN THE
LATTER PART OF THE FORECAST PERIOD.

THE INITIAL MOTION IS 265/7. A MID-LEVEL RIDGE OVER THE EASTERN
ATLANTIC OCEAN IS FORECAST TO STRENGTHEN OVER THE NEXT FEW
DAYS...WHICH SHOULD CAUSE A WESTWARD MOTION AT AN INCREASING
FORWARD SPEED. AT THE END OF THE PERIOD...A TROUGH OVER THE
CENTRAL ATLANTIC COULD WEAKEN THE RIDGE...FORCING THE STORM TO MOVE
MORE TO THE WEST-NORTHWEST. THE MODEL GUIDANCE IS IN RELATIVELY
GOOD AGREEMENT ON THIS SCENARIO...ALTHOUGH THERE IS SOME SHORT-TERM
UNCERTAINTY ON HOW IGOR WILL INTERACT WITH THE LARGE CONVECTIVE
SYSTEM TO THE NORTHEAST OF THE STORM. THE NHC FORECAST IS NEAR OR
SLIGHTLY SOUTH OF THE MODEL CONSENSUS.