Saison cyclonique 2009

[paix 0]

Un autre avion arrive au contact de 94L :

Product: Air Force Tropical RECCO Message (URNT11 KNHC)

Transmitted: 1st day of the month at 17:19Z

Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 305)

Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)

Mission Number: 1

Observation Number: 03

Mandatory Data...

Observation Time: Tuesday, 17:15Z

Radar Capability: Yes

Aircraft Altitude: Below 10,000 meters

Coordinates: 17.9N 58.6W (View map)

Location: 221 miles (355 km) to the ENE (76°) from Saint John's, Antigua and Barbuda.

Turbulence: None

Conditions Along Flight Route: In the clear

Pressure Altitude: 430 meters

Flight Level Wind: From 70° at 30 knots (From the ENE at ~ 34.5 mph)

- The above is a spot wind.

- Winds were obtained using doppler radar or inertial systems.

Flight Level Temperature: 23°C

Flight Level Dew Point: 10°C

Weather (within 30 nautical miles): Shower(s) (continuous or intermittent precipitation - from cumuliform clouds)

Mean Sea Level Pressure (MSLP): 1012 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 60° at 30 knots (From the ENE at ~ 34.5 mph)

La question : Existe-t-il un LLC, centre de bas niveau ? À suivre...

[ElNino27 0]

Erika s'est formé ... Peut-être un ouragan dans quelques jours. En tout cas, j'espère qu'il ne provoquera pas de marée noire.

[paix 0]

Le centre est exposé et est toujours mal défini, mais bon, il y a un LLC, quelque part par 17°N et 57°W.

L'avion refait une troisième boucle pour fixer le centre.

Modifié 1 septembre 2009 par paix

[paix 0]

Jimena a l'air de vouloir rester à l'écart de la péninsule pour l'instant, ce qui protège les habitants de la basse Californie, mais ce qui lui sauve sans doute aussi la vie puisqu'elle a l'air de rester ouragan de catégorie 3.

[ElNino27 0]

C'est vraiment un petit ouragan, je trouve ...

[paix 0]

Effectivement. Elle a légèrement diminuée, mais garde un plus grand diamètre de vents de force tempête tropicale de 330 kilomètres ce matin.

EP, 13, 2009090206, , BEST, 0, 234N, 1117W, 95, 965, HU, 34, NEQ, 120, 90, 60, 100, 1008, 180, 30, 0, 0, E, 0, , 0, 0, JIMENA, D,

EP, 13, 2009090206, , BEST, 0, 234N, 1117W, 95, 965, HU, 50, NEQ, 70, 50, 30, 50, 1008, 180, 30, 0, 0, E, 0, , 0, 0, JIMENA, D,

EP, 13, 2009090206, , BEST, 0, 234N, 1117W, 95, 965, HU, 64, NEQ, 45, 20, 15, 15, 1008, 180, 30, 0, 0, E, 0, , 0, 0, JIMENA, D,

Pour compléter, Jimena a eu un Integrated Kinetic Energy de 39 TJ au maximum hier,

Jimena change complètement de cap et devrait stagner au dessus de la Basse Californie finalement, donc moins de vents mais plus de pluies, donc un danger encore plus grand. Une grande partie de la Basse Californie est maintenant en alerte ou en vigilance.

000

WTPZ43 KNHC 020900

TCDEP3

HURRICANE JIMENA DISCUSSION NUMBER 19

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009

200 AM PDT WED SEP 02 2009

THE SATELLITE PRESENTATION OF JIMENA APPEARED TO BE DETERIORATING

SIGNIFICANTLY SEVERAL HOURS AGO...BUT RECENTLY A NEW CONVECTIVE

BAND HAS DEVELOPED THAT WRAPS AROUND THE WESTERN SIDE OF THE

CIRCULATION. RECENT TRMM PASSES AT 2340 UTC AND 0612 UTC SUGGEST

THAT A MID-LEVEL CENTER OF CIRCULATION WAS SHED OFF TOWARD THE

NORTHEAST BUT THAT THE LOW-LEVEL CLOUD PATTERN REMAINS LARGELY

SYMMETRIC. DVORAK T-NUMBERS HAVE CONTINUED TO DECREASE...AND AN

AVERAGE OF THE SUBJECTIVE AND OBJECTIVE TECHNIQUES YIELDS AN

INITIAL INTENSITY OF 90 KT.

THE 0612 UTC TRMM OVERPASS INDICATED THAT THE LOW-LEVEL CENTER HAS

MOVED A LITTLE TO THE WEST OF THE PREVIOUS FORECAST TRACK...AND THE

INITIAL MOTION IS ESTIMATED AT 340/11. THE MODEL GUIDANCE IS IN

GOOD AGREEMENT FOR THE NEXT 24 HOURS AND SHOWS THE CENTER OF JIMENA

MOVING NORTH-NORTHWESTWARD VERY NEAR CABO SAN LAZARO. ONLY THE

UKMET IS AN OUTLIER BY SHOWING A MORE SUDDEN NORTHWARD TURN INLAND.

BEYOND 24 HOURS OR SO...THE NORTHWARD MOTION OF JIMENA IS EXPECTED

TO BE IMPEDED BY A MID-LEVEL ANTICYCLONE LOCATED OVER THE

SOUTHWESTERN UNITED STATES. CONSEQUENTLY...THE MODEL ENVELOPE

SHOWS JIMENA SLOWING DOWN CONSIDERABLY BY 36-48 HOURS FOLLOWED BY A

SLOW WESTWARD DRIFT AT DAYS 3 AND 4. THE NEW OFFICIAL FORECAST IS

SLOWED DOWN AND SHIFTED SOUTHWEST FROM THE PREVIOUS TRACK AND NOW

INDICATES A SLOW WESTWARD TURN BEYOND 48 HOURS.

SEA SURFACE TEMPERATURES CONTINUE TO DECREASE AS JIMENA MOVES

NORTH-NORTHWESTWARD PARALLEL TO THE BAJA COAST...AND THE

THERMOCLINE ALONG THAT PART OF THE COAST IS VERY SHALLOW DUE TO

NORMAL COASTAL UPWELLING. COMBINED WITH POSSIBLE LAND

INTERACTION...THIS IS EXPECTED TO CAUSE JIMENA TO CONTINUE TO

WEAKEN OVER THE NEXT 24 HOURS. HOWEVER...THE OFFICIAL FORECAST

STILL SHOWS JIMENA MOVING INLAND AS A HURRICANE. ONCE

INLAND...WESTERLY UPPER-LEVEL WINDS ARE EXPECTED TO STRENGTHEN

CONSIDERABLY...AND JIMENA SHOULD SPIN DOWN TO A TROPICAL DEPRESSION

BY 48 HOURS AND A REMNANT LOW BY 72 HOURS. THE NEW FORECAST SHOWS

DISSIPATION BY DAY 5 SINCE MOST OF THE GLOBAL MODEL FIELDS LOSE THE

SURFACE CIRCULATION BY THEN.

INTERESTS IN THE HURRICANE WARNING AREA ARE ADVISED THAT STRONG

WINDS WILL PRECEDE THE ARRIVAL OF THE CENTER BY SEVERAL HOURS...SO

PREPARATIONS NEED TO BE COMPLETED VERY SOON. REMEMBER NOT TO FOCUS

ON THE EXACT FORECAST TRACK SINCE DANGEROUS IMPACTS EXTEND SOME

DISTANCE FROM THE CENTER. THE FORECAST TRACK OF JIMENA IS ALMOST

PARALLEL TO THE COAST OF BAJA CALIFORNIA...AND SMALL DEVIATIONS

LEFT OR RIGHT OF THE TRACK COULD RESULT IN LARGE ERRORS IN BOTH THE

LOCATION AND TIMING OF LANDFALL.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/0900Z 23.9N 111.9W 90 KT

12HR VT 02/1800Z 25.3N 112.5W 80 KT

24HR VT 03/0600Z 26.6N 113.0W 65 KT...ON THE BAJA COAST

36HR VT 03/1800Z 27.4N 113.5W 45 KT...INLAND

48HR VT 04/0600Z 27.7N 113.9W 30 KT...INLAND

72HR VT 05/0600Z 27.7N 114.5W 25 KT...REMNANT LOW INLAND

96HR VT 06/0600Z 27.5N 115.0W 20 KT...REMNANT LOW

120HR VT 07/0600Z...DISSIPATED

$$

FORECASTER BERG/PASCH

L'œil est maintenant pratiquement bouché, indiquant un fort affaiblissement de Jimena.

Pour Erika, l'avion n'arrive toujours pas à déterminer où se situe le LLC...

000

WTNT41 KNHC 020859

TCDAT1

TROPICAL STORM ERIKA DISCUSSION NUMBER 3

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009

500 AM AST WED SEP 02 2009

AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT HAS BEEN SEARCHING

FOR THE CENTER OF THE TROPICAL STORM OVER THE PAST FEW HOURS. THE

CIRCULATION HAS BECOME QUITE DISORGANIZED...BUT IT APPEARS THAT THE

CENTER HAS REFORMED TO THE SOUTHWEST OF THE PREVIOUSLY ESTIMATED

TRACK. HOWEVER THE FLIGHT-LEVEL WINDS SUGGEST THAT THERE MAY BE

MULTIPLE CENTERS...SO THE ADVISORY POSITION IS HIGHLY UNCERTAIN AND

PROBABLY REPRESENTS A MEAN CENTER...OR THE LOCATION OF THE

LOW-LEVEL VORTICITY MAXIMUM. THE INITIAL MOTION...270/4...IS OF

COURSE ALSO HIGHLY UNCERTAIN. TO MAINTAIN SOME CONTINUITY FROM THE

PREVIOUS FORECAST AND FOLLOWING THE TRACK GUIDANCE...A WEST-

NORTHWESTWARD TRACK IS PREDICTED TO RESUME. ERIKA SHOULD BE

STEERED BY THE FLOW TO THE SOUTH OF A WEAK SUBTROPICAL RIDGE FOR A

COUPLE OF DAYS. LATER IN THE FORECAST PERIOD...DYNAMICAL GUIDANCE

SHOWS A MORE NORTHWESTWARD MOTION FOR A STRONGER CYCLONE...E.G. THE

GFDL AND HWRF...AND A CONTINUED WEST-NORTHWESTWARD MOTION FOR A

WEAKER SYSTEM...E.G. THE GFS. THIS IS A LOW-CONFIDENCE TRACK

FORECAST.

DATA FROM THE AIRCRAFT INDICATE THAT ERIKA HAS WEAKENED A LITTLE...

WHICH IS NOT SURPRISING CONSIDERING THE DISORGANIZED APPEARANCE OF

THE SYSTEM ON SATELLITE IMAGES. MODERATE WESTERLY SHEAR HAS BEEN

DISRUPTING THE CYCLONE BUT THE SHEAR IS NOT EXPECTED TO BE STRONG

ENOUGH TO PREVENT SOME STRENGTHENING DURING THE NEXT DAY OR SO.

THEREAFTER...AN UPPER-TROPOSPHERIC TROUGH FARTHER TO THE WEST IS

LIKELY TO IMPART INCREASING SOUTHWESTERLY SHEAR ON ERIKA...WHICH

SHOULD INDUCE WEAKENING. THE NHC INTENSITY FORECAST IS VERY

SIMILAR TO THE PREVIOUS OFFICIAL FORECASTS...BUT BELOW THE

CONSENSUS OF THE NUMERICAL INTENSITY GUIDANCE. IT SHOULD BE NOTED

THAT SOME OF THESE NUMERICAL MODELS...SUCH AS THE HWRF AND GFDL...

HAVE SHOWN A HIGH BIAS FOR A COUPLE OF THIS YEAR'S ATLANTIC

TROPICAL CYCLONES.

GIVEN THE SOUTHWARD SHIFT IN THE TRACK...A TROPICAL STORM WARNING

HAS BEEN ISSUED FOR THE NORTHERN LEEWARD ISLANDS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/0900Z 17.0N 59.0W 45 KT

12HR VT 02/1800Z 17.3N 60.1W 50 KT

24HR VT 03/0600Z 17.8N 61.5W 55 KT

36HR VT 03/1800Z 18.4N 62.9W 55 KT

48HR VT 04/0600Z 19.0N 64.3W 55 KT

72HR VT 05/0600Z 20.3N 66.9W 50 KT

96HR VT 06/0600Z 22.0N 69.5W 45 KT

120HR VT 07/0600Z 24.0N 72.0W 45 KT

$$

FORECASTER PASCH

Modifié 2 septembre 2009 par paix

[ElNino27 0]

Erika est toujours faible et désorganisée, mais sa trajectoire est de plus en plus vers l'Ouest. Il ne faudrait pas qu'elle gagne en intensité, sinon les Floridiens ou autres pourraient avoir du souci à se faire ...

[paix 0]

Dans l'immédiat, je m'inquiète surtout pour les Petites Antilles. Au début, elle devait passer au Nord et juste effleurer les îles les plus au Nord, mais maintenant qu'elle tire tout droit, et qu'en plus son centre n'est toujours pas défini clairement, des îles comme la Guadeloupe ou même Sainte Lucie pourrait se faire étriller alors qu'il n'y a pas encore de vigilance ou d'alerte émise. Après, effectivement, elle aura tout loisir de frapper les USA si elle reste aussi au Sud. On verra ce qu'en dit le NHC à 1500 UTC

[paix 0]

Et Jimena a touché terre, sans doute en tant que catégorie 2, il y a une ou deux heures. Lever de Soleil sur l'échouage :

[ElNino27 0]

Marrant ... Jimena était censée pénétrer la péninsule et passer ensuite dans le Golfe, mais maintenant le NHC la fait ressortir dans le Pacifique. Elle ne pourrait pas se régénérer si elle fait ca ?

[ElNino27 0]

A propos d'Erika, on pourrait se demander si elle va survivre. Il y a peu d'organisation dans le centre, mais un très bon outflow dans le Sud. Et pour ce qui est de la trajectoire, a fortiori rien de certain s'il est difficile de positionner le centre, mais cette image devrait nous éclairer :

Soit vers l'ONO et la Floride, soit vers le Nord à partir de 65W. Si elle franchit cette longitude sans apparence de virage vers le Nord, la Floride pourrait commencer à se préparer.

[paix 0]

Pour Jimena, je me suis loupé, il reste en fait un œil, qui vient seulement de toucher terre, le petit point bleu contre la ligne blanche de la côte, fermé par un mur jaune orange :

Elle n'a donc pas encore touché terre.

On ne sait toujours pas où se situe Erika, la trajectoire prédite est donc hautement incertaine, et les modèles rament. Tant que le centre de Erika ne sera pas sûr, rien ne sera sûr. Elle est retombé à 1500 UTC à 35 noeuds, le seuil de la tempête tropicale. L'alerte à la tempête tropicale a été étendu au Sud à la Guadeloupe, alors qu'Erika est pratiquement sur eux...

000

WTNT41 KNHC 021447

TCDAT1

TROPICAL STORM ERIKA DISCUSSION NUMBER 4

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009

1100 AM AST WED SEP 02 2009

VISIBLE SATELLITE IMAGES AND AIR FORCE RESERVE HURRICANE HUNTER

DATA SHOW THAT ERIKA IS A POORLY ORGANIZED SYSTEM. THERE ARE

MULTIPLE SWIRLS APPARENT ON THE SATELLITE IMAGERY ROTATING IN THE

LARGER CIRCULATION ENVELOPE WITH A MEAN CENTER TO THE WEST OF THE

DEEP CONVECTION. THE SFMR EARLIER REPORTED WINDS OF ABOUT 35

KT...WHICH IS IN GOOD AGREEMENT WITH SATELLITE INTENSITY

ESTIMATES...SO THAT VALUE WILL BE USED AS THE INITIAL INTENSITY.

VERTICAL WIND SHEAR HAS INCREASED EARLIER THAN EXPECTED...WITH CIMSS

DIAGNOSING ABOUT 15-20 KT OF SHEAR. AT FIRST GLANCE...THE SHEAR DOES

NOT APPEAR TO BE TOO STRONG OVER THE SYSTEM WITH SOUTH OR

SOUTHEASTERLY WINDS REPORTED AT 200 MB OVER THE NORTHERN LEEWARD

ISLANDS. HOWEVER...UPPER-AIR DATA FROM GUADELOUPE AND ST. MAARTEN

SUGGEST THAT THE SHEAR IS PRIMARILY COMING FROM SOUTHWESTERLY WINDS

BETWEEN 300 MB-250 MB...AND THIS IS APPARENTLY UNDERCUTTING THE

OUTFLOW LAYERS AT 200 MB AND ABOVE. MOST OF THE GLOBAL MODELS DO

NOT SHOW MUCH RELAXATION OF THIS SHEAR...AND ACTUALLY SHOW IT

INCREASING SIGNIFICANTLY IN A COUPLE OF DAYS. DESPITE ALL THIS

SHEAR...ALL RELIABLE GUIDANCE RESTRENGTHENS THIS SYSTEM TO NEAR

HURRICANE STRENGTH IN A FEW DAYS. THIS REINTENSIFICATION

DOES NOT SEEM VERY LIKELY AND THE NHC FORECAST IS MUCH LOWER THAN

THE GUIDANCE. GIVEN THE POSSIBLE SHEAR DURING THE FORECAST

PERIOD...IT WOULD NOT BE SURPRISING IF ERIKA DISSIPATED.

A 24-HOUR MOTION IS ABOUT 275/9. A WEST-NORTHWESTWARD TRACK IS

PREDICTED TO RESUME AS THE STORM MOVES TO THE SOUTH OF A WEAK

SUBTROPICAL RIDGE FOR A COUPLE OF DAYS. THIS RIDGE IS FORECAST TO

WEAKEN SOMEWHAT IN A FEW DAYS...AND A NORTHWESTWARD MOTION IS

POSSIBLE BY THE END OF THE FORECAST. THE OFFICIAL FORECAST HAS BEEN

SHIFTED LEFT OF THE PREVIOUS ONE AND IS LEFT OF THE DYNAMICAL

CONSENSUS DUE TO THE ANTICIPATION OF ERIKA REMAINING WEAK. IT

SHOULD BE EMPHASIZED THAT...OVERALL...THIS IS A LOW-CONFIDENCE

TRACK FORECAST.

TROPICAL STORM WATCHES COULD BE REQUIRED FOR THE U.S. AND BRITISH

VIRGIN ISLANDS AS WELL AS PUERTO RICO LATER TODAY.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/1500Z 16.5N 60.4W 35 KT

12HR VT 03/0000Z 16.9N 61.5W 35 KT

24HR VT 03/1200Z 17.4N 62.8W 40 KT

36HR VT 04/0000Z 18.0N 64.2W 45 KT

48HR VT 04/1200Z 18.6N 65.5W 40 KT

72HR VT 05/1200Z 20.0N 68.5W 35 KT

96HR VT 06/1200Z 21.5N 71.5W 30 KT

120HR VT 07/1200Z 23.5N 73.5W 30 KT

$$

FORECASTER BLAKE/FRANKLIN

Le centre est estimé être par 16°5N et 60°4W, c'est à dire au Nord Ouest de la masse convective principale, dans le même carré que la Guadeloupe. Elle reste très désorganisé, et a nettement faibli depuis ce matin. L'outflow au Sud Est reste bon, mais est moins prononcé que tantôt.

Modifié 2 septembre 2009 par paix

[paix 0]

Marrant ... Jimena était censée pénétrer la péninsule et passer ensuite dans le Golfe, mais maintenant le NHC la fait ressortir dans le Pacifique. Elle ne pourrait pas se régénérer si elle fait ca ?

Et non...

JIMENA SHOULD CONTINUE TO WEAKEN DUE TO LAND INTERACTION...THE

COLDER SEA SURFACE TEMPERATURES WEST OF BAJA CALIFORNIA...AND

INCREASING WESTERLY VERTICAL WIND SHEAR. THE CYCLONE IS FORECAST

IS WEAKEN TO A TROPICAL STORM IN ABOUT 24 HOURS...TO A TROPICAL

DEPRESSION IN ABOUT 48 HR...AND TO A REMNANT LOW IN ABOUT 72 HR.

EVEN IF THE CENTER EMERGES OVER THE WARM WATERS OF THE GULF OF

CALIFORNIA...THE FORECAST SHEAR SHOULD PREVENT ANY

RE-INTENSIFICATION.

[ElNino27 0]

GIVEN THE POSSIBLE SHEAR DURING THE FORECAST

PERIOD...IT WOULD NOT BE SURPRISING IF ERIKA DISSIPATED.

Effectivement ... Et les Américains pourraient continuer à respirer. Cela étant dit, je pense que certaines régions voudraient bien quelques pluies tropicales au vu de la sécheresse dans le Sud.

[paix 0]

L'avis toujours aussi intéressant de JeffMasters :

http://www.wunderground.com/blog/JeffMasters/show.html

The tropical wave we were calling Invest 94 finally decided to stop dawdling and become Tropical Storm Erika yesterday. However, Erika seems intent upon keeping us guessing about its intentions, as the storm's future track and intensity remain highly uncertain. After a modest burst of intensification to a 60 mph tropical storm last night, Erika has become quite disorganized this morning. The Hurricane Hunters found multiple swirling centers inside Erika early this morning, and the main center took a jump to the southwest to relocate itself under a batch of intense thunderstorms. The exact location and path of Erika remain uncertain at this point, and it is possible the storm will have another center relocation later today. Wind shear analyses from the University of Wisconsin diagnose a moderate 10 - 15 knots of shear over Erika, a decrease from yesterday. SSTs are warm, 29°C. Why, then, is Erika so disorganized? The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone. Upper air data from Guadeloupe and Saint Martin from last night show a complicated shear pattern in Erika's region, with 30 knot winds out of the south to southwest at 200 mb height, nearly calm winds between 300 - 500 mb, and northeasterly winds of 10 - 20 knots from the surface to 500 mb. Some extremely dry air with humidities near 10% was present in a thin layer near 600 mb on the Guadeloupe sounding, so dry air from the Saharan Air Layer is probably being injected by a northeasterly jet of wind into the core of Erika. The shear of 30 knots at the top of the storm is ripping away the heat and moisture Erika's thunderstorms are lifting there, and the result of the shear and dry air is a very disorganized tropical storm.

Erika is embedded in a weak steering current pattern, and the future track of the storm will depend greatly upon how strong the storm gets over the next few days. A stronger Erika will extend higher into the atmosphere and be steered more to the northwest by upper-level winds. A weaker Erika will be steered more by the low-level winds, which will keep the storm on a more westerly track. Given the complicated nature of the wind shear pattern in the region, it is difficult to forecast how strong Erika will get. Virtually anything can happen over the next five days, from dissipation (as forecast by the ECMWF model) to intensification to a Category 3 hurricane (as forecast by the HWRF model). Large-scale wind shear is expected to increase to 20 - 25 knots between 3 - 4 days from now, so Erika will have to deal with an increasing amount of adversity. The storm is a long-term threat to the Bahamas and U.S. East Coast, particularly if the storm stays weak over the next three days. Potential landfall solutions from the models range from Florida on Tuesday (GFS model) to North Carolina on Wednesday (Canadian model).

[Ephraïm 0]

35 nœuds, 1008 mb.

[Ephraïm 0]

Les spaghettis et la trajectoire.

[Ephraïm 0]

Jimena continue sa route. Beaucoup de warnings en cours. 973 mb et 85 nœuds.

Pas de cyclones ni de systèmes dans le Pacifique central.

Modifié 2 septembre 2009 par Ephraïm

[ElNino27 0]

Les spaghettis et la trajectoire.

Il y a quand même 3 modèles qui la font passer par PR et Hispanola, et non des moindres ! Mais si ca devait être le cas, elle aurait encore moins de chances de survivre !

[Ephraïm 0]

Météo France Antilles-Guyane

[paix 0]

Quel bazar !

MF donne le centre par 60°N et 16°O. Je l'ai repris sur l'image visible, et je l'ai un peu déplacé vers le Nord Ouest car il a bougé depuis l'émission de la carte par MF.

Le NHC donne Erika par 16°4 N et 61°7 O.

Il existe toujours le même faux centre dont parlé JeffMasters, qui vient de passer la Guadeloupe.

Il existe un autre LLC en formation au Nord, peut-être prendra-t-il l'ascendant bientôt.

En fait, tout ces centres sont un axe Sud Ouest Nord Est qui représente simplement l'ancienne axe de l'onde.

Et je me suis permis de souligner moi même une zone que je trouve suspecte au Sud Est de la Guadeloupe. Je vous donne aussi la version non barbouillé de l'image visible. Il y a tellement de centre qu'on ne si retrouve plus...

000

WTNT41 KNHC 022045

TCDAT1

TROPICAL STORM ERIKA DISCUSSION NUMBER 5

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062009

500 PM AST WED SEP 02 2009

SATELLITE IMAGES SHOW THAT THE CIRCULATION OF ERIKA IS ELONGATED

FROM SOUTHWEST TO NORTHEAST...IN AGREEMENT WITH SURFACE OBSERVATIONS

FROM THE LESSER ANTILLES AND REPORTS FROM AN AIR FORCE HURRICANE

HUNTER AIRCRAFT. THE SWIRL SOUTHWEST OF GUADELOUPE APPEARS TO BE

PART OF THIS ELONGATED CIRCULATION...BUT IS NOT THE MEAN CENTER OF

THE OVERALL CYCLONIC ENVELOPE. AIRCRAFT DATA ALSO INDICATE THAT

ERIKA IS STILL A TROPICAL STORM. PEAK FLIGHT LEVEL WINDS WERE 44

KT AND SFMR DATA WERE BETWEEN 35-40 KT. HOWEVER THE STRONGEST

WINDS WERE NEAR A LARGE THUNDERSTORM COMPLEX WELL SOUTHEAST OF THE

CENTER AND NOT DIRECTLY ASSOCIATED WITH THE STORM CIRCULATION. THE

INITIAL INTENSITY WILL BE HELD AT 35 KT FOR THIS ADVISORY.

ERIKA HAS A DIFFICULT ROAD AHEAD WITH INCREASING SHEAR LIKELY AS THE

STORM NEARS THE GREATER ANTILLES. WHILE SOME INTENSIFICATION CAN

NOT BE RULED OUT IN THE NEXT DAY OR SO...ALL OF THE GLOBAL MODELS

SHOW A VERY HOSTILE ENVIRONMENT WITH 20-30 KT SOUTHWESTERLY WINDS

AT 250 MB OVER ERIKA. THESE WINDS ARE FORECAST TO CONTINUE...OR

INCREASE...AS THE STORM MOVES NEAR HISPANIOLA. ALTHOUGH MOST OF THE

INTENSITY GUIDANCE STILL SHOWS RESTRENGTHENING OF ERIKA...THE

GUIDANCE HAS COME DOWN QUITE A BIT FROM THIS MORNING. THE NHC

FORECAST IS LOWER THAN THE PREVIOUS ONE...AND SHOWS DISSIPATION OF

THE TROPICAL CYCLONE BY 5 DAYS. ONE ALTERNATIVE SOLUTION IS THAT

INTERACTION WITH HISPANIOLA CAUSES AN EVEN FASTER DEMISE OF ERIKA.

THE LONG-TERM MOTION OF THIS SYSTEM IS ABOUT 275/9. DURING THE

NEXT SEVERAL DAYS...THE STORM SHOULD BE STEERED TO THE WEST OR

WEST-NORTHWEST PRIMARILY BY A RIDGE OVER THE WESTERN ATLANTIC. THE

GLOBAL MODELS HAVE SHIFTED SOUTHWARD WITH THE TRACK FORECAST SINCE

THIS MORNING...PERHAPS DUE TO THE WEAKER INITIAL STATE OF ERIKA.

THE NHC FORECAST IS SHIFTED SOUTHWARD AS WELL...REMAINING WEST OF

THE MODEL CONSENSUS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/2100Z 16.4N 61.7W 35 KT

12HR VT 03/0600Z 16.8N 62.9W 35 KT

24HR VT 03/1800Z 17.4N 64.6W 35 KT

36HR VT 04/0600Z 18.0N 66.4W 30 KT...INLAND

48HR VT 04/1800Z 18.7N 67.9W 30 KT

72HR VT 05/1800Z 20.0N 70.5W 25 KT

96HR VT 06/1800Z 21.5N 73.5W 20 KT...REMNANT LOW

120HR VT 07/1800Z...DISSIPATED

$$

FORECASTER BLAKE/FRANKLIN

Que pensez de tout ceci ? Actuellement, la pression n'est toujours pas tombée. Habituellement, la formation d'une circulation cyclonique tropicale fermée s'accompagne d'un creusement. Il n'existe pas un, mais des centres. Même si aucun centre n'exerce son pouvoir coercitif et que c'est franchement l'anarchie, on a quand même une rotation cyclonique avec des vents de tempête tropicale, donc Erika est bien dans la place.

Ce qui est curieux, la convection est particulièrement intense, avec des sommets de nuages à 70° environ, alors que la convergence dans les basses couches laisse franchement à désirer.

Le cisaillement de vent reste présent. Il a empêché la fermeture de l'ancienne axe à 225°, et il est responsable du déplacement de la convection vers l'Est d'Erika.

Modifié 3 septembre 2009 par paix

[Ephraïm 0]

Le point sur Erika. 35 nœuds, 1008 mb.

[Ephraïm 0]

Une onde tropicale "vigoureuse" est au large des côtes africaines et au sud-sud-est des Îles du Cap-Vert.

[Ephraïm 0]

Dans le Pacifique est, Jimena est à présent une tempête tropicale. 997 mb et 50 nœuds.

[paix 0]

Le point sur Erika. 35 nœuds, 1008 mb.

Et le lever de Soleil sur Erika.

Elle a vraiment une curieuse tête.