Los meteorólogos del CNH se hacen eco de lo que yo destacaba: ese nuevo borbotón convectivo formado en el oeste del LLCC y que lo cubrió parcialmente. También destacan esa cizalladura del este de 20 KT que mostraban los mapas de CIMSS:

000
WTNT41 KNHC 091431
TCDAT1
TROPICAL STORM IGOR DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
1100 AM AST THU SEP 09 2010

DEEP CONVECTION FORMED NEAR THE LOW-LEVEL CENTER OF IGOR AROUND 1030
UTC...AND HAS EXPANDED SINCE THAT TIME. HOWEVER...THIS CONVECTION
REMAINS WEST OF THE CENTER DUE TO ABOUT 20 KT OF EASTERLY SHEAR
...AS SHOWN BY UW-CIMSS ANALYSES. ALTHOUGH AN ASCAT PASS AROUND
0000 UTC ONLY SHOWED MAXIMUM WINDS OF 25-30 KT...THE WINDS ARE
ASSUMED TO BE A LITTLE STRONGER NOW DUE TO THE INCREASE IN
CONVECTION. THEREFORE...IGOR WILL REMAIN A TROPICAL STORM WITH AN
INITIAL WIND SPEED ESTIMATE OF 35 KT. THE SHIPS MODEL SHOWS THE
EASTERLY SHEAR DECREASING OVER THE NEXT FEW DAYS. THIS...COMBINED
WITH WARM WATERS AND A RELATIVELY MOIST ATMOSPHERE SHOULD ALLOW FOR
STEADY INTENSIFICATION. THE STATISTICAL AND DYNAMICAL INTENSITY
MODELS BRING IGOR TO HURRICANE STRENGTH IN ABOUT 3 DAYS AND SHOW
ADDITIONAL STRENGTHENING THEREAFTER. THE NHC OFFICIAL FORECAST IS
SIMILAR TO THE PREVIOUS ONE AND IS IN CLOSEST AGREEMENT WITH THE
STATISTICAL GUIDANCE.

IGOR HAS BEEN GENERALLY MOVING NORTH-NORTHWESTWARD DURING THE LAST
SEVERAL HOURS...AND THE 6-HOUR INITIAL MOTION ESTIMATE IS 330/5.
HOWEVER...THE LAST FEW FEW VISIBLE IMAGES SUGGEST A SLIGHTLY FASTER
NORTHWESTWARD MOTION. NOW THAT IGOR APPEARS TO HAVE ABSORBED THE
WEAK LOW THAT HAD BEEN IN ITS VICINITY...A LOW- TO MID-LEVEL RIDGE
NORTH AND NORTHEAST OF IGOR SHOULD STEER THE CYCLONE WESTWARD OR
WEST-NORTHWESTWARD WITH A GRADUAL INCREASE IN FORWARD SPEED.  BY
THE END OF THE PERIOD...THE GLOBAL MODELS SHOW IGOR NEARING A
CENTRAL ATLANTIC TROUGH WHICH SHOULD CAUSE A NORTHWESTWARD TURN.
THE OFFICIAL FORECAST IS ADJUSTED TO THE NORTH IN THE SHORT-TERM
DUE TO THE INITIAL POSITION AND MOTION...AND IS A LITTLE SLOWER AT
THE END OF THE FORECAST PERIOD AS SUGGESTED BY THE GUIDANCE SUITE.


FORECAST POSITIONS AND MAX WINDS

INITIAL      09/1500Z 14.7N  24.8W    35 KT
 12HR VT     10/0000Z 15.0N  26.3W    35 KT
 24HR VT     10/1200Z 15.8N  29.0W    40 KT
 36HR VT     11/0000Z 16.4N  32.0W    50 KT
 48HR VT     11/1200Z 16.7N  35.0W    60 KT
 72HR VT     12/1200Z 17.3N  40.4W    70 KT
 96HR VT     13/1200Z 18.5N  44.5W    80 KT
120HR VT     14/1200Z 20.0N  48.5W    85 KT

$$
FORECASTER CANGIALOSI/BRENNAN

Acaba de salir el aviso intermedio 5A sobre IGOR, y no aporta novedades... La verdad es que pocos cambios ha sufrido esta tarde la tormenta tropical... En resumen:

...IGOR MOVING ERRATICALLY...

Madre mía... Creo que se le va la pinza al europeo profundizando a los ciclones ¿eh? Por cierto, han rebajado a IGOR a depresión tropical. Me lo veía venir. Muy explosivo en sus inicios, pero con las condiciones ambientales un poco sosas todavía. Veo normal lo que ha pasado. De todos modos, pronto ha de recuperar vigor. A lo sumo, 48 horas... Adjunto el boletín de discusión nº6 del CNH:

000
WTNT41 KNHC 092038
TCDAT1
TROPICAL DEPRESSION IGOR DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
500 PM AST THU SEP 09 2010

THE DEEP CONVECTION THAT WAS LOCATED NEAR THE CENTER EARLIER TODAY
HAS ERODED AND NOW TAKES THE SHAPE OF A CURVED BAND OVER
THE WESTERN SEMICIRCLE...SITUATED ABOUT 90 N MI WEST OF THE CENTER.
THIS ASYMMETRIC CONVECTIVE PATTERN IS DUE TO ABOUT 20-25 KT OF
EASTERLY SHEAR. SINCE THE CONVECTION IS WELL REMOVED FROM THE
CENTER AND BECAUSE EARLIER ASCAT DATA DID NOT SHOW WINDS OF
TROPICAL STORM FORCE...IGOR IS BEING DOWNGRADED TO A TROPICAL
DEPRESSION AT THIS TIME. ALTHOUGH IGOR HAS WEAKENED TODAY...
INTENSIFICATION IS STILL EXPECTED DURING THE FORECAST PERIOD. THE
SHIPS MODEL SHOWS THE SHEAR DECREASING SIGNIFICANTLY DURING THE
NEXT COUPLE OF DAYS.  THIS...IN COMBINATION WITH A RELATIVELY WARM
OCEAN AND MOIST ATMOSPHERE SHOULD ALLOW IGOR TO STRENGTHEN.
HOWEVER...THE CYCLONE WILL BE PASSING THROUGH AN AREA OF SLIGHTLY
COOLER SSTS IN A COUPLE DAYS...SO THE NEW OFFICIAL FORECAST SHOWS A
MORE GRADUAL STRENGTHENING THAN THE PREVIOUS ONE...BUT STILL MAKES
IGOR A HURRICANE IN 3 DAYS.

THE LOW-LEVEL CENTER HAS BEEN RACING NORTHWESTWARD DURING
THE LAST FEW HOURS...AND IS NOW LOCATED NORTH OF THE
PREVIOUS FORECAST TRACK. HOWEVER...A WEST-NORTHWESTWARD MOTION IS
EXPECTED TO BEGIN SOON AND PERSIST FOR THE NEXT FEW DAYS AS A LOW-
TO MID-LEVEL RIDGE LOCATED NORTH AND NORTHEAST OF IGOR BECOMES
THE PRIMARY STEERING MECHANISM. THE GLOBAL MODELS SHOW IGOR
APPROACHING A LARGE BUT RATHER FLAT TROUGH IN 4 TO 5 DAYS...WHICH
SHOULD CAUSE THE CYCLONE TO TURN NORTHWESTWARD WITH A DECREASE IN
FORWARD SPEED. THE NEW NHC TRACK FORECAST IS ADJUSTED TO THE NORTH
IN THE SHORT-TERM BUT IS OTHERWISE SIMILAR TO THE PREVIOUS ONE.

FORECAST POSITIONS AND MAX WINDS

INITIAL      09/2100Z 16.0N  26.4W    30 KT
 12HR VT     10/0600Z 16.7N  27.9W    30 KT
 24HR VT     10/1800Z 17.3N  30.8W    35 KT
 36HR VT     11/0600Z 17.5N  33.9W    45 KT
 48HR VT     11/1800Z 17.8N  36.8W    55 KT
 72HR VT     12/1800Z 18.4N  41.9W    65 KT
 96HR VT     13/1800Z 19.5N  46.0W    75 KT
120HR VT     14/1800Z 21.0N  49.0W    85 KT

$$
FORECASTER CANGIALOSI/BRENNAN

Es curioso, no tiene tan mala pinta....

Según se desprende del último boletín de discusión del CNH, que acaba de salir hace pocos minutos, IGOR podría seguir débil, pero cogiendo aire para comenzar a dar pasos firmes hacia una intensificación, ya que el ciclón sigue estando cizallado, pero con una circulación más definida. Además, podría escapar de esa cizalladura y comenzar a moverse hacia el oeste, iniciando ese proceso de intensificación:

000
WTNT41 KNHC 100833
TCDAT1
TROPICAL DEPRESSION IGOR DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
500 AM AST FRI SEP 10 2010

IGOR IS STILL STRONGLY SHEARED WITH THE CENTER LOCATED TO THE EAST
OF A STRONG AND CIRCULAR CONVECTIVE MASS AS OBSERVED IN BOTH
MICROWAVE DATA AND CONVENTIONAL IR IMAGERY. AS WE SPEAK...FIRST
METEOSAT VISIBLE IMAGE CONFIRMED THAT THE CENTER IS EXPOSED BUT
BETTER DEFINED. INITIAL INTENSITY IS KEPT AT 30 KNOTS BUT IT WILL
NOT TAKE MUCH FOR IGOR TO REGAIN TROPICAL STORM STATUS AND IN
FACT...THIS IS EXPECTED TO OCCUR LATER TODAY. THE CYCLONE IS
ESCAPING FROM THE MONSOON-TYPE LOW-LEVEL SOUTHWESTERLY FLOW AND IS
BECOMING EMBEDDED IN THE TRADE WINDS. THIS WOULD RESULT IN LESS
SHEAR AND WILL LEAD TO INTENSIFICATION...AS INDICATED IN THE
OFFICIAL FORECAST. GLOBAL MODELS FORECAST IGOR TO BE A LARGE
HURRICANE OVER THE CENTRAL TROPICAL ATLANTIC BY THE END OF THE
FORECAST PERIOD AND BEYOND.

THE INITIAL MOTION IS UNCERTAIN SINCE IT WAS DIFFICULT TO FOLLOW
VARIOUS LOW-LEVEL CENTERS THAT WERE ROTATING AROUND A LARGER GYRE
DURING THE PAST 12 HOURS OR SO. THE BEST ESTIMATE IS 280 DEGREES AT
11 TO 12 KNOTS. THE SUBTROPICAL RIDGE IS FORECAST TO BUILD WESTWARD
AND THIS PATTERN SHOULD STEER IGOR WESTWARD WITH AN INCREASE IN
FORWARD SPEED DURING THE NEXT 3 TO 4 DAYS. BY THE END OF THE
FORECAST PERIOD...IGOR SHOULD BE ON THE SOUTHWESTERN EDGE OF THE
RIDGE AND SHOULD BEGIN TO GAIN MORE LATITUDE. TRACK GUIDANCE
OVERALL IS FAIRLY CONSISTENT IN TAKING IGOR WESTWARD. HOWEVER...A
COUPLE OF MODELS FORECAST A STRONGER SUBTROPICAL RIDGE TO THE NORTH
OF THE CYCLONE...RESULTING IN A MORE PRONOUNCED WESTWARD TRACK. THE
OFFICIAL FORECAST IS HEAVILY BIASED TOWARD THE GFS AND THE ECMWF
MODELS WHICH FORECAST A MODERATE BUT A MORE REALISTIC SUBTROPICAL
RIDGE TO THE NORTH.


FORECAST POSITIONS AND MAX WINDS

INITIAL      10/0900Z 16.0N  29.3W    30 KT
 12HR VT     10/1800Z 16.0N  31.1W    35 KT
 24HR VT     11/0600Z 16.3N  34.2W    40 KT
 36HR VT     11/1800Z 16.5N  37.5W    45 KT
 48HR VT     12/0600Z 16.8N  40.2W    55 KT
 72HR VT     13/0600Z 17.0N  45.0W    65 KT
 96HR VT     14/0600Z 18.0N  49.5W    80 KT
120HR VT     15/0600Z 19.5N  53.5W    90 KT

$$
FORECASTER AVILA

Y a tenor de las últimas imágenes satelitales, creo que no tardará mucho en recuperar el estatus de tormenta tropical. Yo diría que en el siguiente aviso completo ya lo será, si no antes...

Bueno, pues ya es oficial el regreso de IGOR a la potencia de tormenta tropical... A partir de ahora, cogerá carrerilla, aunque parece que se perderá en aguas abiertas sin impacto en tierra:

BEGIN
NHC_ATCF
invest_al112010.invest
FSTDA
R
U
040
010
0000
201009101252
NONE
NOTIFY=ATRP
END
      IGOR, AL, L, , , , , 11, 2010, TS, O, 2010090718, 9999999999, , , , , , WARNING, 1, AL112010
AL, 11, 2010090700,   , BEST,   0, 128N,  189W,  25, 1008, DB,   0,    ,    0,    0,    0,    0,
AL, 11, 2010090706,   , BEST,   0, 132N,  195W,  25, 1008, DB,   0,    ,    0,    0,    0,    0,
AL, 11, 2010090712,   , BEST,   0, 137N,  201W,  25, 1008, DB,   0,    ,    0,    0,    0,    0,
AL, 11, 2010090718,   , BEST,   0, 140N,  211W,  25, 1008, DB,   0,    ,    0,    0,    0,    0, 1010,  150,  60,   0,   0,   L,   0,    ,   0,   0,     INVEST, S,
AL, 11, 2010090800,   , BEST,   0, 140N,  219W,  25, 1007, DB,   0,    ,    0,    0,    0,    0, 1011,  150,  60,   0,   0,   L,   0,    ,   0,   0,     INVEST, S,
AL, 11, 2010090806,   , BEST,   0, 139N,  226W,  30, 1006, TD,   0,    ,    0,    0,    0,    0, 1010,  150,  50,   0,   0,   L,   0,    ,   0,   0,     INVEST, S,
AL, 11, 2010090812,   , BEST,   0, 138N,  233W,  40, 1005, TS,  34, NEQ,    0,   45,   45,   30, 1010,  180,  30,  45,   0,   L,   0,    ,   0,   0,       IGOR, S,
AL, 11, 2010090818,   , BEST,   0, 138N,  237W,  40, 1005, TS,  34, NEQ,    0,   45,   45,   30, 1010,  180,  30,  50,   0,   L,   0,    ,   0,   0,       IGOR, S,
AL, 11, 2010090900,   , BEST,   0, 138N,  242W,  35, 1005, TS,  34, NEQ,    0,   45,   45,   30, 1010,  125,  30,  50,   0,   L,   0,    ,   0,   0,       IGOR, S, 12, NEQ,   0,  45,  45,  30
AL, 11, 2010090906,   , BEST,   0, 138N,  243W,  35, 1006, TS,  34, NEQ,    0,   45,   45,   30, 1010,  125,  30,  45,   0,   L,   0,    ,   0,   0,       IGOR, S, 12, NEQ,   0,  45,  45,  30
AL, 11, 2010090912,   , BEST,   0, 142N,  245W,  35, 1006, TS,  34, NEQ,    0,    0,    0,   30, 1011,  160,  30,  45,   0,   L,   0,    ,   0,   0,       IGOR, S, 12, NEQ,  30,  60,  60,  60
AL, 11, 2010090918,   , BEST,   0, 149N,  263W,  35, 1004, TD,  34, NEQ,    0,    0,    0,   30, 1009,   90,  30,  45,   0,   L,   0,    ,   0,   0,       IGOR, S, 12, NEQ,  30,  60,  60,  60
AL, 11, 2010091000,   , BEST,   0, 153N,  274W,  30, 1004, TD,   0,    ,    0,    0,    0,    0, 1008,   90,  30,  40,   0,   L,   0,    ,   0,   0,       IGOR, S, 12, NEQ,  30,  45,  30,  30
AL, 11, 2010091006,   , BEST,   0, 159N,  287W,  30, 1004, TD,   0,    ,    0,    0,    0,    0, 1008,   90,  30,  40,   0,   L,   0,    ,   0,   0,       IGOR, S,
AL, 11, 2010091012,   , BEST,   0, 163N,  303W,  35, 1004, TS,  34, NEQ,    0,    0,   30,   30, 1012,  200,  30,   0,   0,   L,   0,    ,   0,   0,       IGOR, M,

Según el boletín de discusión nº9 del CNH, si IGOR no está explotando de forma más intensiva, es porque sigue habiendo cizalladura moderada afectando al ciclón, pero mejorando a cada minuto, cosa fácilmente comprobable en los mapas de CIMSS. Además, parece que hay varios centros de circulación ciclónica que están girando alrededor de un eje común. Es necesario que IGOR reconstruya un sólo centro de circulación y que la cizalladura se relaje de forma definitiva, de forma que el anticiclón encima suya se asiente y la máquina térmica quede bien ajustada. Entonces es cuando el ciclón va a pegar una explosión de las buenas...

000
WTNT41 KNHC 101455
TCDAT1
TROPICAL STORM IGOR DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
1100 AM AST FRI SEP 10 2010

IGOR REMAINS A SHEARED TROPICAL CYCLONE. DURING THE PAST FEW
HOURS...HOWEVER...THE SHEAR HAS BEGUN TO SHOW SIGNS OF ABATING AND
THE LOW-LEVEL CENTER IS NOW FARTHER INTO THE EASTERN PORTION OF THE
CENTRAL DEEP CONVECTION. THE UPGRADE TO STORM STATUS IS BASED ON A
SATELLITE INTENSITY ESTIMATE OF 35 KT FROM TAFB AND A 47-KT
UW-CIMSS 3-HR AVERAGE ADT.

THE INITIAL MOTION IS 280/14. THE INITIAL POSITION AND MOTION ARE
STILL SOMEWHAT UNCERTAIN DUE TO MULTIPLE CIRCULATIONS ROTATING
AROUND THE CENTER OF A LARGER CYCLONIC GYRE. HOWEVER...THE MOTION
IS EXPECTED TO BE BASICALLY WESTWARD FOR THE NEXT 96 HOURS OR SO
ALONG THE SOUTHERN PERIPHERY OF A STRONG SUBTROPICAL RIDGE LOCATED
TO THE NORTH OF THE CYCLONE. BY DAY 5...A SERIES OF WEAK SHORTWAVE
TROUGHS MOVING THROUGH THE BASE OF A BROAD LONGWAVE TROUGH FORECAST
TO BE OFF THE U.S. EAST COAST IS FORECAST BY ALL OF THE GLOBAL
MODELS TO CREATE A WEAKNESS IN THE RIDGE BETWEEN 50W-60W LONGITUDE.
THIS IS EXPECTED TO WEAKEN THE STEERING FLOW AND CAUSE IGOR TO SLOW
DOWN AND ALSO TURN WEST-NORTHWESTWARD. THE OFFICIAL FORECAST TRACK
IS SIMILAR TO THE PREVIOUS ADVISORY AND THE TVCN MODEL CONSENSUS. 

CURRENT SHEAR ANALYSES FROM SHIPS AND UW-CIMSS...ALONG WITH WATER
VAPOR WINDS...INDICATE THE VERTICAL SHEAR ACROSS IGOR HAS DECREASED
FROM 20 KT DOWN TO 10 KT DURING THE PAST 24 HOURS. THIS DECEASING
SHEAR TENDENCY IS EXPECTED TO CONTINUE THROUGHOUT THE FORECAST
PERIOD AS IGOR MOVES OVER GRADUALLY INCREASING SSTS...ESPECIALLY
AFTER 48 HOURS. THE RESULT SHOULD BE STEADY INTENSIFICATION WITH
IGOR POSSIBLY REACHING HURRICANE STATUS ON SUNDAY AND MAJOR
HURRICANE STATUS BY DAY 5...AS INDICATED BY THE SHIPS...GFDL...AND
HWRF MODELS. THE OFFICIAL INTENSITY FORECAST IS A LITTLE BELOW THE
GUIDANCE THROUGH 48 HOURS DUE TO UNCERTAINTY ABOUT WHEN IGOR WILL
DEVELOP A CONSOLIDATED CENTER OF CIRCULATION...BUT IS CLOSE TO THE
GUIDANCE THEREAFTER. 


FORECAST POSITIONS AND MAX WINDS

INITIAL      10/1500Z 16.4N  31.0W    35 KT
 12HR VT     11/0000Z 16.6N  33.2W    40 KT
 24HR VT     11/1200Z 16.8N  36.2W    45 KT
 36HR VT     12/0000Z 17.0N  39.2W    50 KT
 48HR VT     12/1200Z 17.1N  41.7W    60 KT
 72HR VT     13/1200Z 17.3N  46.2W    70 KT
 96HR VT     14/1200Z 18.2N  50.3W    85 KT
120HR VT     15/1200Z 19.5N  53.5W    95 KT

$$
FORECASTER STEWART

Buenísima esa imagen. A ver si finalmente el ECMWF no exageraba y vemos el primer cat.5 de la temporada...