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Saison 2010 : Ouragans, cyclones, typhons, tempêtes et dépressions

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A mon avis, le NHC a estimé que le bazar était loin des terres, et que les chances de fort développement étaient petites. Ils ont peut-être estimé que le stade de TD était atteint, mais que cela n'allait pas faire long feu, d'où l'absence d'upgrade. Je crois que le mieux, ce serait de leur poser la question. Ils ont une lourde responsabilité, mais ils font aussi un métier difficile.

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Sans doute oui. C'est une bonne idée de leur écrire un mot doux. Je vais réessayer, d'autant qu'ils ne m'ont toujours pas répondu pour Felicia. Je vais leur envoyer du parfum avec l'email, en espérant que cela les amadouera, et qu'ils condescendront à répondre au pauvre mortel que je suis :lol2: :lol2:

Toujours au sujet de 92L, maintenant que le cisaillement a explosé cette brave bête, on voit nettement un reste de LLC, par 15°N et 52°O. Je suis en train de me demander si on ne pourrait pas aussi essayer de travailler a posteriori avec les cyclones tropicaux, en remontant des effets aux causes. J'avais déjà eu la même démarche avec Felicia, et là, face à 92L, j'ai toujours cette démarche, et cela vient de me titiller l'esprit. Si on admet que l'image satellite nous montre un centre de basse pression avec circulation cyclonique dans les basses couches, est-ce que cela suffit pour justifier que 92L a été une dépression il y a quelques heures ? Autrement dit, y-a-t il un lien de cause à effet univoque entre un LLC mis en pièce par le cisaillement de vent, et ce tourbillon caractéristique ? Ou bien ce genre de tourbillon peut-il se former spontanément dans le flux d'une onde tropicale, sans signer la postériorité d'un LLC ? Parce que, à ma connaissance, je n'ai jamais vu passer d'étude à sur ce genre de réflexion a posteriori.

Bref, je vais quand même essayer de recevoir une réponse du NHC.

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Pour la Dépression Tropicale 2E, elle a une circulation très large, et semble capable d'aspirer 92E (le gros tas nuageux informe au Sud Ouest de son centre dépressionnaire par 15°N et 105°O). Elle a peu progresser en terme d'organisation, mais reste très près des côtes. Par chance, le cisaillement du vent et la terre protège les côtes mexicaines, mais le NHC s'attend quand même à ce qu'ils se prennent une rincée mémorable.

HAZARDS AFFECTING LAND

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

RAINFALL...THE DEPRESSION IS EXPECTED TO PRODUCE TOTAL RAIN

ACCUMULATIONS OF 4 TO 8 INCHES ALONG THE COAST OF OAXACA...WITH

POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 12 INCHES. THESE COULD PRODUCE

LIFE-THREATENING FLASH FLOODS AND MUDSLIDES.

000

WTPZ42 KNHC 162036

TCDEP2

TROPICAL DEPRESSION TWO-E DISCUSSION NUMBER 2

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022010

200 PM PDT WED JUN 16 2010

VISIBLE SATELLITE IMAGERY SHOWS THAT THE DEPRESSION HAS CHANGED

LITTLE IN ORGANIZATION SINCE THIS MORNING. THE LOW-LEVEL CENTER

IS NEAR THE NORTHEASTERN EDGE OF A PULSATING MASS OF DEEP

CONVECTION. SATELLITE CLASSIFICATIONS REMAIN UNCHANGED AND A

RECENT ASCAT PASS SUPPORTS MAINTAINING THE 25-KT INITIAL INTENSITY.

IT APPEARS THAT THE DEPRESSION HAS BEEN MOVING SLOWLY NORTHWESTWARD

OR 310/3 OVER THE PAST 6-12 HOURS. THE TRACK FORECAST REMAINS

HIGHLY UNCERTAIN AS THE GUIDANCE MODELS ARE IN POOR AGREEMENT. THE

MODELS SHOW VARYING SCENARIOS DEPENDING ON HOW THE SYSTEM INTERACTS

WITH THE LOW PRESSURE AREA TO THE WEST AND A TROPICAL WAVE TO THE

EAST. THE UKMET MODEL...WHICH MAINTAINS THE DEPRESSION AS A

SEPARATE SYSTEM...TAKES THE CYCLONE GENERALLY WESTWARD WHILE A

MID-LEVEL RIDGE BUILDS OVER THE GULF OF MEXICO AND NORTHERN MEXICO.

THE OFFICIAL FORECAST FOLLOWS THIS REASONING AND IS CLOSE TO THE

PREVIOUS NHC FORECAST TRACK. IT SHOULD BE NOTED THAT ANY DEVIATION

OF THE CENTER TO THE NORTH OF THE FORECAST TRACK WOULD BRING THE

CENTER ONSHORE IN SOUTHERN MEXICO.

THE SHIPS GUIDANCE SUGGESTS THAT THE DEPRESSION WILL BE IN A LOW

SHEAR ENVIRONMENT DURING THE NEXT SEVERAL DAYS. HOWEVER...THE

CURRENT SATELLITE APPEARANCE OF THE DEPRESSION SUGGESTS THAT THE

NORTHEASTERLY SHEAR MIGHT NOT BE SO FAVORABLE. AS A RESULT...THE

INTENSITY FORECAST WILL REMAIN A LITTLE BELOW THIS GUIDANCE...

ESPECIALLY BEYOND 36 HOURS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 16/2100Z 15.0N 95.8W 25 KT

12HR VT 17/0600Z 15.1N 96.7W 30 KT

24HR VT 17/1800Z 15.3N 97.6W 35 KT

36HR VT 18/0600Z 15.5N 98.6W 40 KT

48HR VT 18/1800Z 15.7N 99.6W 45 KT

72HR VT 19/1800Z 16.0N 101.5W 45 KT

96HR VT 20/1800Z 16.3N 104.0W 50 KT

120HR VT 21/1800Z 16.5N 107.0W 50 KT

$$

FORECASTER BROWN/KIMBERLAIN

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Curieusement, c'est 92E qui est en train de prendre l'ascendant. Il a une tête de dépression tropicale je pense, et un upgrade est possible. par contre, la dépression tropicale 2 a franchement une sale tête. Je ne suis même pas sûr qu'il reste un LLC.

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Le premier 100% du NHC de l'histoire. :whistling:

ZCZC MIATWOEP ALL

TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

500 AM PDT THU JUN 17 2010

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL

DEPRESSION TWO-E LOCATED ABOUT 65 MILES SOUTHEAST OF PUNTO MALDONADO

MEXICO.

1. AN AREA OF LOW PRESSURE LOCATED ABOUT 300 MILES SOUTH OF MANZANILLO

MEXICO CONTINUES TO BECOME BETTER ORGANIZED. IF CURRENT

DEVELOPMENT TRENDS CONTINUE...TROPICAL CYCLONE ADVISORIES WILL BE

INITIATED LATER THIS MORNING. THERE IS A HIGH CHANCE...NEAR 100

PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE

NEXT 48 HOURS AS IT MOVES LITTLE.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

PUBLIC ADVISORIES ON TROPICAL DEPRESSION TWO-E ARE ISSUED UNDER WMO

HEADER WTPZ32 KNHC AND UNDER AWIPS HEADER MIATCPEP3.

FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTPZ22 KNHC AND

UNDER AWIPS HEADER MIATCMEP2.

$$

FORECASTER BLAKE

NNNN

92E est donc bien en train de devenir une dépression tropicale. Il ne lui manque plus qu'un soupçon de persistance, et le NHC a donc temporisé. Cependant, il n'y a plus grand'chose qui s'oppose à la formation de la troisième dépression du pacifique Est.

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Pour 92E, un T-number de 2.0 vient d'être estimé. En clair, 92E est une dépression tropicale avec 25 ou 30 nœuds de vents. Il n'y a plus qu'a attendre le NHC, pour savoir à quel intensité ils l'estiment.

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Dans l'Atlantique, ex-92L reste une onde vigoureuse, mais prise par un cisaillement de vent zonal à 50 nœuds environ. Cela est d'ailleurs bien visible même sans animation, avec cette traînée de nuages vers l'Est. Il semble qu'il puisse exister une nouvelle fenêtre pour un développement d'ici quelques jours. Rien n'est certain, mais c'est un combattant, et le cisaillement du vent pourrait se décaler vers le Nord pour laisser un espace suffisant à son redéveloppement. Aucun modèle n'envisage cette possibilité cependant pour l'instant.

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Et voici la troisième dépression tropicale du Pacifique EST. Poussé logiquement à 30 nœuds sur la base du Dvorak T 2.0, elle n'aura cependant pas l'occasion de s'intensifier beaucoup.

000

WTPZ43 KNHC 171451

TCDEP3

TROPICAL DEPRESSION THREE-E DISCUSSION NUMBER 1

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP032010

800 AM PDT THU JUN 17 2010

SATELLITE IMAGES INDICATE THAT CONVECTION HAS FINALLY BECOME

PERSISTENT AND ORGANIZED AROUND THE AREA OF LOW PRESSURE SOUTH OF

MANZANILLO THAT THE NHC HAS BEEN MONITORING FOR SEVERAL DAYS. A

1215 UTC SSMI MICROWAVE IMAGE SHOWS THAT THE CENTER IS ON THE

NORTHEASTERN SIDE OF A BALL OF CONVECTION. DVORAK CLASSIFICATIONS

FROM TAFB/SAB ARE 2.0...30 KT...AND THIS WILL BE THE INITIAL

INTENSITY. THE DEPRESSION HAS A NARROW WINDOW OF OPPORTUNITY TO

STRENGTHEN OVER THE NEXT DAY OR SO BEFORE INCREASING EASTERLY

SHEAR...COOLER SSTS AND DRIER AIR IMPINGE ON THE SYSTEM. THE NHC

FORECAST IS CLOSE TO THE INTENSITY CONSENSUS.

THE INITIAL MOTION HAS BEEN HARD TO DETERMINE...BUT THE DEPRESSION

APPEARS TO BE MOVING SLOWLY TO THE NORTHEAST. MIDDLE-LEVEL RIDGING

OVER MEXICO SHOULD STRENGTHEN DURING THE NEXT COUPLE OF DAYS...WHICH

WOULD STEER THE DEPRESSION GENERALLY TOWARD THE WEST-NORTHWEST AT

AN INCREASING FORWARD SPEED. ONE COMPLICATING FACTOR IS THAT THE

MODELS HAVE CONSISTENTLY MOVED THE PRECURSOR LOW FROM THE

DEPRESSION MUCH TOO QUICKLY TO THE WEST...PROBABLY BECAUSE IT HAS

BEEN ENTANGLED IN LOW-LEVEL SOUTHWESTERLY WINDS ASSOCIATED

WITH THE INTERTROPICAL CONVERGENCE ZONE. ALTHOUGH THE DEPRESSION IS

BECOMING A LITTLE MORE SEPARATED FROM THAT FEATURE...THE OFFICIAL

FORECAST WILL STAY ON THE SLOWER SIDE OF THE GUIDANCE...NOT TOO FAR

FROM THE ECMWF MODEL.

FORECAST POSITIONS AND MAX WINDS

INITIAL 17/1500Z 15.3N 105.3W 30 KT

12HR VT 18/0000Z 15.4N 105.2W 35 KT

24HR VT 18/1200Z 15.6N 105.5W 35 KT

36HR VT 19/0000Z 15.7N 106.3W 35 KT

48HR VT 19/1200Z 15.9N 107.5W 30 KT

72HR VT 20/1200Z 16.5N 110.0W 25 KT

96HR VT 21/1200Z 16.5N 112.5W 20 KT...POST-TROP/REMNT LOW

120HR VT 22/1200Z 16.5N 115.0W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER BLAKE

Par contre, pour sa voisine c'est la fin.

000

WTPZ42 KNHC 171438

TCDEP2

TROPICAL DEPRESSION TWO-E DISCUSSION NUMBER 5

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022010

800 AM PDT THU JUN 17 2010

CONVENTIONAL AND MICROWAVE SATELLITE DATA INDICATE THAT THE

CIRCULATION OF THE DEPRESSION HAS DISSIPATED. THE GOVERNMENT OF

MEXICO HAS DISCONTINUED ALL TROPICAL STORM WATCHES AND WARNINGS

AND THIS WILL BE THE LAST NHC ADVISORY ON THIS SYSTEM.

REMNANT MOISTURE FROM THE SYSTEM ALONG WITH THE MONSOON-LIKE

LOW-LEVEL SOUTHWESTERLY FLOW SOUTH OF MEXICO COULD PRODUCE LOCALLY

HEAVY RAINFALL ALONG PORTIONS OF THE SOUTHERN COAST OF MEXICO OVER

THE NEXT COUPLE OF DAYS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 17/1500Z 15.8N 98.6W 25 KT

12HR VT 18/0000Z...DISSIPATED

$$

FORECASTER BROWN

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Le NHC rallume la vigilance pour 92L. Il y a une proba de 0% (après l'autre extrême de 100%), mais on pourra noter le "should", qui montre l'absence de certitude et qui justifie la réactivation de la vigilance. À noter que certain modèles montrent aussi son développement dans le Golfe du Mexique (GFS dans sa der' réactu pour ne pas le citer :lol: ).

ZCZC MIATWOAT ALL

TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

200 PM EDT THU JUN 17 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. A STRONG TROPICAL WAVE APPROACHING THE LEEWARD ISLANDS IS PRODUCING

DISORGANIZED SHOWERS AND THUNDERSTORMS AS IT MOVES TO THE

WEST-NORTHWEST AT ABOUT 15 MPH. ALTHOUGH STRONG UPPER-LEVEL WINDS

SHOULD PREVENT TROPICAL CYCLONE FORMATION...LOCALLY HEAVY RAIN AND

GUSTY WINDS ARE POSSIBLE IN THE LEEWARD ISLANDS AND PUERTO RICO

OVER THE NEXT DAY OR TWO. THERE IS A LOW CHANCE...NEAR 0

PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE

NEXT 48 HOURS.

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$

FORECASTER BLAKE

NNNN

Le plus impressionnant est son organisation et la vigueur de sa convection malgré les 40 nœuds de cisaillement, sans doute du aux températures de l'océan très élevées dans le coin et la bonne divergence d'altitude, paradoxalement soutenue par le jet stream qui le cisaille mais aide aussi à ventiler. Cela peut sembler démentiel, mais on distingue même une ébauche de rotation à l'Ouest de la balle de convection, par 16/17° N et 59/60° Ouest. Cependant, il faut raison garder, et on ne peut quand même pas parler de LLC. Et le NHC parle de structure désorganisé rapport au cisaillement de vent qui maintiendra l'onde ouverte.

201006172015goes13xvis1.jpg

Dans le Pacifique Est, voici Blas, ex-92E, ex-TD2 :

000

WTPZ43 KNHC 172031

TCDEP3

TROPICAL STORM BLAS DISCUSSION NUMBER 2

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP032010

200 PM PDT THU JUN 17 2010

BANDING FEATURES HAVE BECOME BETTER DEFINED IN THE WESTERN

SEMICIRCLE OF BLAS THIS AFTERNOON WHILE CONVECTION NEAR THE CENTER

HAS REMAINED NEARLY STEADY. THE SHIP MAERSK SHAHRAN REPORTED

TROPICAL-STORM-FORCE WINDS AND A PRESSURE OF 1002 MB AS IT MOVED

NEAR THE CENTER OF BLAS EARLIER TODAY. THESE DATA...ALONG WITH

INCREASING DVORAK T-NUMBERS FROM ALL AGENCIES...SUPPORT AN INITIAL

INTENSITY OF 40 KT FOR THIS ADVISORY. WATER VAPOR IMAGES SHOW

STRONGER EASTERLY WINDS ALOFT TO THE EAST OF BLAS...WHICH SHOULD

CAUSE VERTICAL WIND SHEAR TO INCREASE IN A DAY OR SO. AROUND THAT

TIME...THE TROPICAL CYCLONE WILL BE MOVING DEEPER INTO AN AREA OF

STRATOCUMULUS CLOUDS AND...PRESUMABLY...A MORE STABLE ENVIRONMENT.

THESE FACTORS SHOULD LIMIT FURTHER STRENGTHENING OF BLAS. THE

INTENSITY FORECAST IS CLOSE TO THE LGEM AND INTENSITY CONSENSUS

MODELS...AND IS A LITTLE HIGHER THAN BEFORE.

BLAS HAS TURNED TOWARD THE NORTHWEST AND IS NOW MOVING AT ABOUT

320/3. GLOBAL MODELS ARE IN GOOD AGREEMENT WITH MID-TROPOSPHERIC

RIDGING BUILDING OVER MEXICO...WHICH SHOULD FORCE THE TROPICAL

CYCLONE TO MOVE MORE TO THE WEST-NORTHWEST AND WEST WITH TIME AND

INCREASE ITS FORWARD SPEED. TRACK GUIDANCE IS IN MUCH BETTER

AGREEMENT THAN EARLIER WITH THIS SCENARIO...AND THE NHC FORECAST IS

CLOSE TO...BUT SLOWER THAN...THE VARIABLE CONSENSUS MODEL TVCN.

WIND RADII AND 12 FOOT SEAS INFORMATION HAVE BEEN ADJUSTED BASED ON

REPORTS FROM THE AFOREMENTIONED SHIP.

FORECAST POSITIONS AND MAX WINDS

INITIAL 17/2100Z 15.2N 105.8W 40 KT

12HR VT 18/0600Z 15.4N 106.3W 45 KT

24HR VT 18/1800Z 15.6N 107.1W 45 KT

36HR VT 19/0600Z 15.8N 107.7W 40 KT

48HR VT 19/1800Z 16.2N 108.8W 40 KT

72HR VT 20/1800Z 16.7N 112.0W 35 KT

96HR VT 21/1800Z 16.7N 115.0W 25 KT

120HR VT 22/1800Z 16.5N 119.0W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER BLAKE

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P.S. : QuickScat, tu nous manque :crying:

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Et 92L est toujours aussi...comment dire.. hallucinant ?

Il soutient toujours une profonde convection face au cisaillement de vent, et les Antilles vont se prendre une bonne douche.

post-3513-1276853203_thumb.png

Des petites images qui en disent long ...

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Le NHC reste pourtant assez peu optimiste :

ZCZC MIATWOAT ALL

TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

200 AM EDT FRI JUN 18 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. A STRONG TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LESSER

ANTILLES TODAY ACCOMPANIED BY A LARGE AREA OF THUNDERSTORMS. THERE

ARE NO SIGNS OF A SURFACE CIRCULATION AND UPPER-LEVEL WINDS ARE

FORECAST TO REMAIN UNFAVORABLE FOR DEVELOPMENT. THERE IS A LOW

CHANCE...20 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE

DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY

RAINS AND GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE LESSER

ANTILLES THE VIRGIN ISLANDS...AND PUERTO RICO OVER THE NEXT DAY OR

TWO.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

FORECASTER AVILA

NNNN

...TROPICAL WAVES...

A TROUGH OF LOW PRESSURE IS APPROACHING THE LESSER ANTILLES

NORTH OF 13N. LOW-LEVEL CYCLONIC FLOW REMAINS CONCENTRATED NEAR

A 1011 MB LOW NEAR 17N60W. SEVERAL DAYS AGO THIS SYSTEM HAD A

HIGHER CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE...BUT DUE TO

STRONG UPPER LEVEL WINDS THERE IS CURRENTLY A LOW PROBABILITY OF

DEVELOPMENT. HOWEVER...THIS SYSTEM CONTINUES TO BE EMBEDDED IN A

LARGE AREA OF ENHANCED DEEP LAYER MOISTURE SUPPORTING WIDESPREAD

SHOWER ACTIVITY. NUMEROUS STRONG CONVECTION IS NEAR THE LOW

CENTER FROM 14N-18N BETWEEN 56W-61W WITH SCATTERED

MODERATE/ISOLATED STRONG CONVECTION EXPANDING NORTH TO 22N

BETWEEN 52W-61W. AS THIS SYSTEM MOVES WESTWARD...LOCALLY HEAVY

RAINFALL IS POSSIBLE OVER THE LEEWARD ISLANDS NORTH OF 13N...THE

VIRGIN ISLANDS...AND PUERTO RICO.

[...]

CARIBBEAN SEA...

AN UPPER LEVEL TROUGH CONTINUES TO COVER THE WRN HALF OF THE

CARIBBEAN. UPPER LEVEL DIFFLUENCE AROUND THE BASE OF THE TROUGH

IS ENHANCING SHOWERS/THUNDERSTORMS ACROSS THE FAR SW CARIBBEAN S

OF 14N W OF 74W AFFECTING THE COASTAL WATERS OF PANAMA...COSTA

RICA...AND NICARAGUA. THE REMAINDER OF THE WRN CARIBBEAN IS

EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF DRY

AIR ALOFT. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM OFF

THE COAST OF NORTHERN COLOMBIA AND WESTERN VENEZUELA NEAR A

TROPICAL WAVE ALONG 73W SOUTH OF 14N. SEE TROPICAL WAVE SECTION

ABOVE FOR MORE DETAILS REGARDING THIS WAVE. A FAIRLY STRONG

SURFACE TROUGH WILL IMPACT THE LEEWARD ISLANDS NORTH OF 13N OVER

THE NEXT 6 HOURS. MORE DETAILS ON THIS FEATURE CAN BE FOUND IN

THE TROPICAL WAVE SECTION.

http://forecast.weather.gov/product.php?si...&glossary=1

THE ACTIVE TROPICAL WAVE AND ASSOCIATED WEAK SURFACE LOW LOCATED

JUST EAST OF THE LEEWARD ISLANDS LATE THIS THURSDAY EVENING...

WILL ENTER THE NORTHEAST CARIBBEAN OVERNIGHT...THEN MOVE WEST

NORTHWEST ACROSS THE LOCAL AREA FRIDAY THROUGH SATURDAY...WITH

WEATHER LINGERING INTO OR THROUGH SUNDAY. SHOWERS AND

THUNDERSTORMS CONTINUE TO INTENSIFY WITH THIS SYSTEM...WITH

CONVECTIVE CLOUD TOP TEMPERATURES AS LOW AS -83C. SHEAR IS

EXPECTED TO CONTINUE TO SLOWLY RELAX DURING THE NEXT 24 TO 36

HOURS...BUT LOW LEVEL CIRCULATION REMAINS JUST WEST OF THE DEEPEST

CONVECTION. AS PREVIOUS SHIFTS HAVE MENTIONED...THE LIKELIHOOD IS

FOR A CONTINUATION OF DEEP CONVECTION TO SPREAD WEST NORTHWEST

TOWARD THE LOCAL AREA OVERNIGHT AND THEN GRADUALLY ACROSS THE

LOCAL ISLANDS FRIDAY AND FRIDAY NIGHT AND CONTINUING INTO

SATURDAY. ALTHOUGH IT IS PROBABLE THAT HEAVY RAINFALL AND SOME

FLOODING WILL OCCUR OVER PARTS OF THE LOCAL ISLANDS...WITH THE

SYSTEM SLOWING DOWN A BIT AND THE DEEPEST SURGE OF MOISTURE

EXPECTED ONCE THE SURFACE LOW/WAVE AXIS GET CLOSE TO/PASS BY THE

LOCAL ISLANDS...OPTED TO HOLD OFF ON FLASH FLOOD WATCH FOR SIX

MORE HOURS AND ALLOW MIDNIGHT SHIFT TO ISSUE...AS NECESSARY.

Des sommets à -83° ...

Et on est mi-juin...

On va se marrer en Août/Septembre/Octobre :whistling:

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Je n'ai pas beaucoup causé de Blas. Il se portait à merveille cette nuit, mais a faibli depuis. Il a partiellement embarqué dans sa circulation les restes de la 2è dépression tropicale.

000

WTPZ43 KNHC 180833

TCDEP3

TROPICAL STORM BLAS DISCUSSION NUMBER 4

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP032010

200 AM PDT FRI JUN 18 2010

THE CLOUD PATTERN HAS DETERIORATED DURING THE PAST FEW HOURS AND

MICROWAVE DATA SHOW THAT THE CENTER IS STILL WELL REMOVED TO THE

NORTHEAST OF THE LIMITED CONVECTION. SINCE DVORAK T-NUMBERS HAVE

DECREASED...THE INITIAL INTENSITY HAS BEEN ADJUSTED DOWN TO 35

KNOTS. IN FACT...A RECENT ASCT PASS SHOWS MAXIMUM WINDS OF ONLY 30

KNOTS. THE OFFICIAL FORECAST CALLS FOR NO CHANGE IN STRENGTH

DURING THE NEXT 2 DAYS AND A GRADUAL WEAKENING THEREAFTER. BLAS

COULD WEAKEN FASTER THAN INDICATED SINCE IT SEEMS THAT STABLE AIR

IS ALREADY AFFECTING THE CIRCULATION...AND THE CYCLONE IS NEAR

COOLER WATERS. NONE OF THE LATEST GUIDANCE SHOWS INTENSIFICATION.

BLAS IS MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 4 KNOTS

EMBEDDED WITHIN WEAK STEERING CURRENTS. MOST OF THE GLOBAL MODELS

BUILD A RIDGE TO THE NORTH OF THE CYCLONE...A PATTERN WHICH FAVORS A

WEST-NORTHWEST TO WEST MOTION WITH A SLIGHT INCREASE IN FORWARD

SPEED. BECAUSE BLAS IS EXPECTED TO WEAKEN...IT MOST LIKELY BE

STEERED WESTWARD BY THE LOW LEVEL FLOW.

FORECAST POSITIONS AND MAX WINDS

INITIAL 18/0900Z 15.8N 106.7W 35 KT

12HR VT 18/1800Z 16.0N 107.2W 35 KT

24HR VT 19/0600Z 16.3N 108.0W 35 KT

36HR VT 19/1800Z 16.7N 109.5W 35 KT

48HR VT 20/0600Z 17.0N 111.0W 35 KT

72HR VT 21/0600Z 17.0N 114.0W 30 KT

96HR VT 22/0600Z 17.0N 117.0W 25 KT

120HR VT 23/0600Z 16.5N 120.5W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER AVILA

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Une belle image ce soir je trouve. Le cisaillement de vent est matérialisé par une bande nuageuse d'altitude du Yucatan à la Jamaïque, qui circule avec le Jet Stream d'Ouest en Est, alors qu'au sol les alizés au Sud de l'anticyclonique subtropicale sont de l'est. L'anticyclone étire une dorsale en direction du Golfe du Mexique, avec cette espace dégagé de nuage de l'Atlantique au Golfe. Cependant, cela ne ne suffit pas à stabiliser la masse d'air. Avec le réchauffement diurne, des tas de cumulonimbus se sont développés isolément dans la masse d'air sur l'ensemble de la Floride. Les vents d'altitudes, sur le flanc de la dorsale qui s'établit sur l'ensemble de la colonne d'air, ventile les cirrus vers l'Ouest. Au nord de l'anticyclone, s'étirant sur le 35°N, un front froid délimite les tropique des latitudes moyennes. Dans cette affaire, 92L, porté par les alizés, arrive dans le mur du cisaillement. La probabilité est assez mince, mais si l'onde survit, elle pourrait se développer dans le GOM. Sur le Honduras, une activité convective c'est aussi développée avec une onde tropicale assez faible. Les sommets de nuages sont soufflées eux aussi par le Jet Stream vers l'Est.

Pendant ce temps, 94E, au Sud du Mexique, qui a récupéré une partie de 93E, se développe et a déjà une bonne tête. Il est cependant encore sous l'influence de l'équateur météo et est un peu cisaillé.

post-3513-1276902498_thumb.jpg

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Dans le Pacifique, Blas a continué de se renforcer. Il a maintenu un CDO avec des températures au sommets de l'ordre de -85°, avec un CDO très bien organisé. Il n'a cependant pas de bande convective, et garde une présentation quelque peu amorphe comme dirait le NHC. Il souffre d'un cisaillement de vent du Nord Est, ce qui déplace la convection par rapport au centre, et il frotte contre l'anticyclone sur son flanc Nord Ouest, interdisant toute structure en bandes convectives. Le centre n'a sans doute pas beaucoup bougé, et semble être situé par 17°N et 109°O d'après un dernier passage ASCAT. Ce même passage ASCAT semble d'ailleurs montrer que les vents ne sont peut être pas aussi soutenu.

Il a reçu un T-number 3.5 à 6Z, estimation que n'a pas suivi le NHC. Actuellement, au vu de la présentation satellite et du passage de l'ASCAT, je pense qu'il continue à soutenir des vents à 45 nœuds.

000

WTPZ43 KNHC 190845

TCDEP3

TROPICAL STORM BLAS DISCUSSION NUMBER 8

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP032010

200 AM PDT SAT JUN 19 2010

INFRARED SATELLITE IMAGERY INDICATES THAT BLAS HAS MAINTAINED A

LARGE AREA OF COLD CONVECTIVE TOPS DURING THE PAST SEVERAL HOURS.

HOWEVER...THE CONVECTIVE PATTERN...WITH A SHARP EASTERN EDGE...

APPEARS SOMEWHAT AMORPHOUS AND RESEMBLES THAT OF A SHEARED TROPICAL

CYCLONE. A 0451 UTC TRMM PASS CONFIRMS THAT BLAS CONTINUES TO SUFFER

FROM THE EFFECTS OF NORTHEASTERLY SHEAR...WITH THE LOW-LEVEL CENTER

STILL ON THE NORTHEASTERN EDGE OF THE DEEPEST CONVECTIVE CLOUDS.

GIVEN THAT THERE HAS BEEN NO FURTHER INCREASE IN ORGANIZATION AND

THE TAFB DVORAK INTENSITY ESTIMATE REMAINS AT 3.0/45 KT...THE

INITIAL INTENSITY IS UNCHANGED AT 45 KT.

CONVENTIONAL AND MICROWAVE SATELLITE CENTER FIXES YIELD AN INITIAL

MOTION ESTIMATE OF 285/6. GLOBAL MODELS SHOW A STRONG DEEP LAYER

RIDGE EXTENDING WEST-SOUTHWESTWARD FROM THE SOUTH CENTRAL UNITED

STATES INTO THE TROPICAL EAST PACIFIC WHICH SHOULD STEER BLAS ON A

GENERAL WESTWARD TO WEST-NORTHWESTWARD COURSE THROUGH 36-48

HOURS...WITH A MINOR INCREASE IN FORWARD SPEED. THEREAFTER...BLAS

IS EXPECTED TO BECOME A SHALLOW SYSTEM AND TURN WEST-SOUTHWESTWARD

IN THE LOW-LEVEL FLOW. THE NEW TRACK FORECAST REPRESENTS A BLEND

OF THE PREVIOUS OFFICIAL TRACK AND THE MULTI-MODEL TVCN CONSENSUS.

THE SHIPS MODEL AND UW-CIMSS VERTICAL WIND SHEAR ANALYSES CONTINUE

TO ANALYZE MODERATE NORTHEASTERLY SHEAR OVER THE CYCLONE. HOWEVER...

THE SHIPS MODEL STILL INDICATES A REDUCTION IN THE VERTICAL SHEAR

OVER THE NEXT COUPLE OF DAYS...POSSIBLY A RESULT OF BLAS MOVING OUT

OF THE MONSOONAL ENVIRONMENT IN WHICH IT HAS BEEN EMBEDDED AND INTO

ONE WITH A DEEP LAYER OF EASTERLIES. HOWEVER...BEYOND 24 HOURS BLAS

IS EXPECTED TO REACH COOLER WATER AND ENCOUNTER A MORE STABLE

ATMOSPHERE...THE COMBINATION OF WHICH SHOULD LEAD TO WEAKENING. THE

OFFICIAL INTENSITY FORECAST REPRESENTS AN UPDATE OF THE PREVIOUS

ONE...WITH THE FORECAST CLOSELY FOLLOWING THE LGEM INTENSITY

GUIDANCE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/0900Z 16.4N 109.1W 45 KT

12HR VT 19/1800Z 16.7N 110.4W 45 KT

24HR VT 20/0600Z 16.9N 112.1W 40 KT

36HR VT 20/1800Z 17.0N 114.0W 40 KT

48HR VT 21/0600Z 17.1N 115.9W 35 KT

72HR VT 22/0600Z 16.9N 119.5W 30 KT

96HR VT 23/0600Z 16.5N 123.0W 25 KT...POST-TROP/REMNT LOW

120HR VT 24/0600Z 16.0N 126.5W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER KIMBERLAIN

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Et dans le Pacifique Est voici 94E (et non 94L comme je disait tantôt par erreur :lol2: :lol2: ) qui devient la quatrième dépression tropicale.

000

WTPZ44 KNHC 191240

TCDEP4

TROPICAL DEPRESSION FOUR-E SPECIAL DISCUSSION NUMBER 1

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

530 AM PDT SAT JUN 19 2010

INFRARED SATELLITE IMAGERY INDICATES DEEP CONVECTION HAS DEVELOPED

AROUND A LARGE BUT WELL-DEFINED LOW- TO MID-LEVEL CIRCULATION NOTED

IN A 19/0805Z AMSR-E MICROWAVE OVERPASS. ALTHOUGH SATELLITE

INTENSITY ESTIMATES AT 06Z WERE ONLY T1.0/25 KT FROM BOTH TAFB AND

SAB...THE IMPROVED CONVECTIVE ORGANIZATION SINCE THAT TIME SUGGESTS

THAT THIS SYSTEM HAS BECOME A TROPICAL DEPRESSION AT A SLIGHTLY

HIGHER INITIAL INTENSITY THAN THE RECENT SATELLITE ESTIMATES.

THE INITIAL MOTION ESTIMATE IS 255/05 BASED ON MICROWAVE SATELLITE

POSITION ESTIMATES OVER THE PAST 12 HOURS. MOST OF THE NHC MODEL

GUIDANCE MOVES THE CYCLONE IN A WEST-SOUTHWEST TO WESTWARD

DIRECTION THROUGHOUT THE FORECAST PERIOD AS A MASSIVE MID-LEVEL

RIDGE TO THE NORTH BUILDS WEST-SOUTHWESTWARD FROM THE U.S. SOUTHERN

PLAINS ACROSS NORTHERN MEXICO AND INTO THE EASTERN PACIFIC WEST OF

THE BAJA PENINSULA. THE OFFICIAL FORECAST TRACK IS SIMILAR TO BUT

SLIGHTLY SOUTH OF THE CONSENSUS MODEL...TVCN...OUT OF RESPECT FOR

THE MORE LOWER LATITUDE AND SLOWER ECMWF FORECAST TRACK. AS A

RESULT OF THE WESTWARD TRACK AWAY FROM MEXICO...COASTAL TROPICAL

CYCLONE WATCHES OR WARNINGS ARE NOT ANTICIPATED AT THIS TIME.

THE RECENT AMSR-E OVERPASS REVEALED A CLOSED EYE-LIKE FEATURE IN THE

LOW-LEVELS WITH A NEARLY CLOSED MID-LEVEL CIRCULATION NOTED IN THE

89-GHZ CHANNEL. BASED ON THIS IMPROVED VERTICAL STRUCTURE...AT

LEAST STEADY INTENSIFICATION WOULD APPEAR TO BE IN ORDER FOR THE

NEXT 72 HOURS OR SO...WITH THE POSSIBILITY OF RAPID INTENSIFICATION

OCCURRING DURING THIS SAME TIME PERIOD. THE OFFICIAL INTENSITY

FORECAST IS HIGHER THAN THE SHIPS MODEL AND CLOSER TO THE HWRF AND

GFDL...WHICH MAKE THE SYSTEM A HURRICANE WITHIN 48 HOURS. THE

SHIPS FORECAST IS BASED ON THE MUCH FASTER MEDIUM BAM MODEL TRACK

WHICH BRINGS THIS CYCLONE OVER COLDER WATER AND INTO STRONG

VERTICAL SHEAR CONDITIONS MUCH SOONER THAN THE OFFICIAL FORECAST

TRACK INDICATES.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/1230Z 12.8N 97.0W 30 KT

12HR VT 19/1800Z 12.6N 97.8W 35 KT

24HR VT 20/0600Z 12.5N 99.2W 40 KT

36HR VT 20/1800Z 12.5N 100.7W 50 KT

48HR VT 21/0600Z 12.5N 102.0W 60 KT

72HR VT 22/0600Z 12.5N 104.0W 65 KT

96HR VT 23/0600Z 12.5N 106.0W 65 KT

120HR VT 24/0600Z 13.0N 108.5W 65 KT

$$

FORECASTER STEWART/BRENNAN

Sur l'image, on a effectivement une structure ressemblant à un œil, mais ce n'est évidemment pas un œil. La TD 4 semble partir vers une organisation en une bande convective qui s'enroule autour du centre, laissant le LLC (le centre de bas niveau ) dégagé sans qu'il n'y ai d'œil à proprement parler. Je suis un peu surpris que le NHC n'ai pas attendu les images visibles qui devraient bientôt arriver, mais tous les autres indicateurs convergent dans le même sens (sauf l'ASCAT ... QuickScat tu nous manque :( )

post-3513-1276953958_thumb.jpg

Et la température de brillance à 85GHz qui a du grandement poussé le NHC à l'upgrade :

201006191145f15x85hw94e.jpg

P.S. Pour Blas, le Best Track le pousse quand même à 55 nœuds sur base du T-number 3.5 cité auparavant :

EP, 03, 2010061912, , BEST, 0, 165N, 1094W, 55, 992, TS

J'ai quand même un doute sur cette estimation.

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Et la première image visible, qui confirme le bazar. Le centre est par 13°N et 97°O, c'est le petit point noir au cœur de la masse nuageuse :

post-3513-1276955552_thumb.jpg

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Le NHC suit quand même et monte Blas à 55 nœuds. Je trouve cela quand même un peu dommage que le NHC ne se base que sur le Dvorak T-number 3.5. Au vu de sa présentation, je ne lui aurais pas donné plus de 50 nœuds. M'enfin, on va pas pinailler pour 5 nœuds. La convection de Blas a un peu faibli, et le CDO reste nettement cisaillé.

Au nord, on pourra noter la présence de l'anticyclone qui "écrase" la convection.

post-3513-1276964637_thumb.jpgpost-3513-1276964630_thumb.jpg

000

WTPZ43 KNHC 191437

TCDEP3

TROPICAL STORM BLAS DISCUSSION NUMBER 9

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP032010

800 AM PDT SAT JUN 19 2010

EARLY MORNING VISIBLE SATELLITE IMAGERY SUGGESTS THAT THE CENTER OF

BLAS IS LOCATED JUST TO THE EAST-NORTHEAST OF THE DEEPEST

CONVECTION. THIS IS CONSISTENT WITH THE MORE EASTERLY SHEAR

ANALYZED OVER THE CYCLONE BY UW-CIMSS. WITH THE CENTER EMBEDDED

CLOSER TO THE CONVECTION...DVORAK INTENSITY ESTIMATES HAVE

INCREASED TO 55 KT FROM TAFB AND SAB...AND THAT IS THE INITIAL

INTENSITY FOR THIS ADVISORY.

WITH A LACK OF MICROWAVE IMAGERY OVER THE PAST SEVERAL HOURS THE

INITIAL MOTION ESTIMATE IS A RATHER UNCERTAIN 280/06. WHILE THE

INITIAL POSITION IS A LITTLE SOUTH OF THE PREVIOUS FORECAST...THE

OVERALL TRACK FORECAST REASONING REMAINS UNCHANGED. BLAS WILL

CONTINUE MOVING GENERALLY WESTWARD TO THE SOUTH OF A DEEP-LAYER

RIDGE OVER THE EASTERN PACIFIC FOR THE NEXT COUPLE OF DAYS WITH A

SLIGHT INCREASE IN FORWARD SPEED. BY 72 HOURS AND BEYOND...A MOTION

SOUTH OF DUE WEST IS EXPECTED AS THE WEAKENING CYCLONE IS

INCREASINGLY STEERED BY THE LOW-LEVEL FLOW. THE NEW TRACK FORECAST

IS ADJUSTED SOUTHWARD FROM THE PREVIOUS PACKAGE DUE TO THE MORE

SOUTHERLY INITIAL POSITION...BUT LIES CLOSE TO THE MIDDLE OF THE

GUIDANCE ENVELOPE.

THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD TO ACCOUNT FOR THE

OBSERVED INTENSITY TRENDS...AND SHOWS A PEAK AT 12 HOURS IN

AGREEMENT WITH THE SHIPS...LGEM...HWRF...AND GFDL. WHILE NONE OF

THE GUIDANCE SHOWS BLAS REACHING HURRICANE INTENSITY...THERE IS

ABOUT A 30 PERCENT CHANCE THAT BLAS COULD BECOME A HURRICANE IN THE

NEXT 24 HOURS ACCORDING TO PROBABILISTIC GUIDANCE BASED ON

PREVIOUS NHC FORECAST ERRORS. SLOW WEAKENING IS FORECAST TO BEGIN

BY 24 HOURS AS BLAS MOVES OVER COOLER WATERS AND INTO A LESS

FAVORABLE THERMODYNAMIC ENVIRONMENT. THE OFFICIAL FORECAST IS CLOSE

TO THE LGEM GUIDANCE AND IS A LITTLE HIGHER THAN THE PREVIOUS

PACKAGE. BLAS SHOULD BECOME A REMNANT LOW IN 4 OR 5 DAYS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/1500Z 16.3N 109.7W 55 KT

12HR VT 20/0000Z 16.5N 111.0W 60 KT

24HR VT 20/1200Z 16.7N 112.8W 55 KT

36HR VT 21/0000Z 16.9N 114.8W 50 KT

48HR VT 21/1200Z 17.0N 116.8W 45 KT

72HR VT 22/1200Z 16.5N 120.5W 35 KT

96HR VT 23/1200Z 16.0N 124.5W 25 KT

120HR VT 24/1200Z 15.5N 128.0W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER BRENNAN

Part contre, au Sud, on trouve Celia, ex TD 3. La bande convective s'est affirmée et couvre le LLC maintenant. Une évolution vers le stade d'ouragan reste probable.

post-3513-1276964643_thumb.jpg

avnl6.jpg

000

WTPZ44 KNHC 191439

TCDEP4

TROPICAL STORM CELIA DISCUSSION NUMBER 2

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

800 AM PDT SAT JUN 19 2010

CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATE THE DEPRESSION

HAS CONTINUED TO BECOME MUCH BETTER ORGANIZED THIS MORNING. A

19/1145Z SSMI OVERPASS REVEALED A SIMILAR LOW- AND MID-LEVEL

EYE-LIKE FEATURE NOTED IN AN EARLIER AMSR-E OVERPASS...AND SHIP

WKDY LOCATED ABOUT 40 NMI EAST OF THE CENTER AT 12Z REPORTED A

SOUTH-SOUTHEAST WIND OF 24 KT AND A PRESSURE OF 1007.5 MB...WHICH

SUGGESTS THAT THE CENTRAL PRESSURE IS NEAR OR BELOW 1005 MB.

SATELLITE INTENSITY ESTIMATES AT 12Z FROM TAFB AND SAB WERE T1.5

AND T2.0...RESPECTIVELY...BUT SINCE THEN CONVECTION HAS WRAPPED

MORE THAN HALF WAY AROUND THE CENTER YIELDING A DATA T-NUMBER OF

T2.5/35 KT. BASED ON THE ABOVE INFORMATION...THE DEPRESSION HAS

BEEN UPGRADED TO TROPICAL STORM CELIA.

THE INITIAL MOTION ESTIMATE IS 245/04 BASED ON MICROWAVE SATELLITE

POSITION ESTIMATES OVER THE PAST 06 HOURS. THE PREVIOUS TREND OF

CELIA MOVING IN A WEST-SOUTHWESTWARD DIRECTION FOR THE NEXT 24

HOURS OR SO...AND THEN TURNING WESTWARD...IS MAINTAINED BY ALL OF

THE MODEL GUIDANCE AS A BROAD MID-LEVEL RIDGE TO THE NORTH OF THE

CYCLONE IS FORECAST TO BUILD WEST-SOUTHWESTWARD FROM THE SOUTHERN

UNITED STATES ACROSS NORTHERN MEXICO AND INTO THE EASTERN PACIFIC

WEST OF THE BAJA PENINSULA. THE OFFICIAL FORECAST TRACK IS SIMILAR

TO BUT SLIGHTLY SOUTH OF THE PREVIOUS TRACK AND THE CONSENSUS

MODEL...TVCN. DUE TO CELIA'S WESTWARD TRACK AWAY FROM MEXICO...

COASTAL TROPICAL CYCLONE WATCHES OR WARNINGS ARE NOT ANTICIPATED AT

THIS TIME.

AS A RESULT OF THE IMPRESSIVE VERTICAL STRUCTURE OF CELIA NOTED IN

MICROWAVE IMAGERY...STEADY INTENSIFICATION IS FORECAST FOR THE NEXT

12 HOURS UNTIL DEEP CONVECTION DEVELOPS IN THE DRY SLOT IN THE

EASTERN QUADRANT...WITH A PERIOD OF RAPID INTENSIFICATION FORECAST

AFTER THAT BASED ON THE LOW VERTICAL SHEAR CONDITIONS OF LESS THAN

5 KT FORECAST BY THE SHIPS INTENSITY MODEL. BY 72 HOURS...

SOUTHEASTERLY VERTICAL WIND SHEAR OF 20-25 KT IS FORECAST TO

DEVELOP ACROSS CELIA...WHICH MAY HALT THE INTENSIFICATION PROCESS.

HOWEVER...SINCE THE CYCLONE IS FORECAST TO BE OVER NEAR-30C SSTS...

LITTLE OR NO WEAKENING IS ANTICIPATED AT THIS TIME.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/1500Z 12.5N 97.1W 35 KT

12HR VT 20/0000Z 12.4N 98.3W 40 KT

24HR VT 20/1200Z 12.3N 99.7W 55 KT

36HR VT 21/0000Z 12.3N 101.1W 70 KT

48HR VT 21/1200Z 12.3N 102.3W 75 KT

72HR VT 22/1200Z 12.3N 104.3W 75 KT

96HR VT 23/1200Z 12.5N 106.5W 70 KT

120HR VT 24/1200Z 13.0N 109.0W 70 KT

$$

FORECASTER STEWART/BRENNAN

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Celia est entrain de nous faire une intensification rapide :blink:

Là, on s'accroche, c'est parti pour quelques jours de douce folie. Le dernier avis du NHC :

000

WTPZ44 KNHC 192035

TCDEP4

TROPICAL STORM CELIA DISCUSSION NUMBER 3

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

200 PM PDT SAT JUN 19 2010

CELIA'S APPEARANCE IN SATELLITE IMAGERY HAS CONTINUED TO IMPROVE

TODAY AS SEVERAL CURVED CONVECTIVE BANDS HAVE FORMED AND WRAPPED

AROUND THE LOW-LEVEL CIRCULATION CENTER. UPPER-LEVEL OUTFLOW HAS

ALSO IMPROVED IN ALL QUADRANTS EXCEPT TO THE EAST. THE INITIAL

INTENSITY OF 40 KT IS BASED ON A BLEND OF A SATELLITE INTENSITY

ESTIMATE OF T2.5/35 KT FROM BOTH TAFB AND SAB...ADT ESTIMATES OF

T2.9/43 KT FROM UW-CIMSS...AND A 3-HR AVERAGE OBJECTIVE ESTIMATE OF

T3.0/45 KT FROM NHC. HOWEVER...THE INITIAL INTENSITY COULD BE A

LITTLE LOW GIVEN CURRENT ORGANIZATIONAL TRENDS.

THE INITIAL MOTION ESTIMATE IS 265/06. THERE IS NO CHANGE TO

PREVIOUS FORECAST TRACK REASONING. ALL OF THE MODELS MAINTAIN A

STRONG MID-LEVEL RIDGE TO THE NORTH OF CELIA THROUGH 96 HOURS...AND

THEN ERODE THE WESTERN PERIPHERY OF THE RIDGE AFTER THAT TIME AS AN

UPPER-LEVEL TROUGH DIGS SOUTHWARD OFF THE WEST COAST OF THE U.S.

AND BAJA CALIFORNIA. THIS SCENARIO SHOULD ALLOW FOR CELIA TO

GRADUALLY GAIN LATITUDE BETWEEN 96-120 HOURS. THE GFS AND NOGAPS

MODELS DID NOT INITIALIZE CELIA VERY WELL AT 12Z...AND AS A RESULT

MUCH LESS WEIGHT WAS PLACED ON THOSE MODELS WHICH TAKE A MUCH WEAKER

CYCLONE SOUTHWESTWARD THROUGHOUT THE PERIOD. THE OFFICIAL TRACK

FORECAST IS CLOSE TO A BLEND OF THE UKMET...ECMWF...CANADIAN...

GFDL...AND HWRF MODELS.

CELIA IS SHOWING SIGNS OF POTENTIAL RAPID INTENSIFICATION BASED ON

THE INCREASE IN CONVECTIVE BANDING AND THE RECENT DEVELOPMENT OF A

SMALL CDO FEATURE. THE SHIPS INTENSITY MODEL SHARPLY INCREASES THE

VERTICAL SHEAR TO 20-25 KT THE NEXT 24 HOURS...BUT THIS APPEARS TO

BE DUE IN PART TO THE GFS MODEL'S POOR 12Z INITIALIZATION. THE

OTHER MODELS ONLY INDICATE 10-15 KT 200-MB WINDS ALONG CELIA'S

FORECAST TRACK AND THE LATEST UW-CIMSS SHEAR ANALYSIS SHOWS 5 KT OR

LESS OF VERTICAL SHEAR...COMPARED TO THE SHIPS-GFS ANALYSIS OF

10-15 KT. GIVEN THE WEAK SHEAR AND CURRENT TRENDS...RAPID

INTENSIFICATION IS FORECAST FOR THE NEXT 24 HOURS OR SO...WITH A

LEVELING OFF BETWEEN 24-72 HOURS AS EASTERLY SHEAR IS EXPECTED TO

INCREASE. BY DAYS 4 AND 5...THE SHEAR IS EXPECTED TO RELAX AGAIN...

WHICH MAY ALLOW FOR SOME ADDITIONAL STRENGTHENING.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/2100Z 12.4N 98.0W 40 KT

12HR VT 20/0600Z 12.3N 99.0W 55 KT

24HR VT 20/1800Z 12.2N 100.4W 70 KT

36HR VT 21/0600Z 12.2N 101.7W 75 KT

48HR VT 21/1800Z 12.2N 103.0W 75 KT

72HR VT 22/1800Z 12.3N 105.3W 75 KT

96HR VT 23/1800Z 12.5N 107.5W 80 KT

120HR VT 24/1800Z 13.0N 110.5W 90 KT

$$

FORECASTER STEWART/BRENNAN

La configuration a effectivement évolué sans traîner, avec formation d'un CDO. Et, dans les heures qui viennent de s'écouler, formation d'un œil par 12°5 de latitude Nord et 98° de longitude Ouest...

Sur l'image de la température de brillance, on voit nettement la structure œil et mur de l'œil. Au Nord et à l'Est, le mur reste quelque peu faible. Par contre, la circulation périphérique est bien développé, avec trois bandes convective.

201006191807trmmxtmi85v.jpg

L'image satellite IR montre un CDO un peu chaud, avec des sommets de nuages à -70°/-75° Celsius. Cependant, l'organisation ne souffre aucune critique, avec un œil gris ennoyé dans un mur blanc. la qualité de la circulation périphérique se retrouve là aussi :

post-3513-1276982549_thumb.jpg

Et enfin, l'image visible, avec cette petite dépression, signe du creusement de l'œil :

post-3513-1276982618_thumb.jpg

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Quelle déchéance !

post-3513-1276988946_thumb.jpg

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Mwouais ... Le NHC négocie en général assez mal les rapides intensifications à long terme. C'est mieux de revenir dans 3 jours pour y voir un peu plus clair. Le cisaillement, c'est une belle saloperie à prévoir, passez-moi l'expression.

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Je vous fait un post à la sauvage, because manque de temps... :whistling:

La situation est très intéressante et mériterait une analyse détaillée, mais bref.

El Nino a raison, la prévision d'intensification rapide est très délicate. Et si hier soir, Celia semblait sur ce chemin, ce fut plutôt un échec. Cependant, elle continue à se renforcer, et une intensifaction (sans le rapide ... :D ) est quand même en cours. Pour l'ionstant, Celia est toujours TS, et le NHC a bien eu raison, l'oeil ne s'est pas encore suffisament établi pour un ouragan :

000

WTPZ44 KNHC 200916

TCDEP4

TROPICAL STORM CELIA DISCUSSION NUMBER 5...CORRECTED

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

200 AM PDT SUN JUN 20 2010

CORRECT INITIAL INTENSITY FROM 60 KT TO 55 KT

ENHANCED SATELLITE IMAGERY INDICATES THAT CELIA HAS CHANGED LITTLE

IN ORGANIZATION DURING THE PAST SEVERAL HOURS. ALTHOUGH THE MAIN

CONVECTIVE MASS HAS CONSOLIDATED FURTHER...CLOUD TOP TEMPERATURES

HAVE NOT COOLED. UPPER-LEVEL APPEARS WELL-ESTABLISHED OVER THE

WESTERN SEMICIRCLE BUT IS RESTRICTED TO THE EAST. WITH NO

IMPROVEMENT NOTED IN THE SATELLITE SIGNATURE AND A TAFB DVORAK

INTENSITY ESTIMATE OF 3.5/55 KT...THE INITIAL INTENSITY IS

UNCHANGED AT 55 KT.

CONVENTIONAL SATELLITE FIXES INDICATE THAT CELIA MAY HAVE BEGUN

MOVING ON A SLIGHTLY MORE WESTERLY COURSE...WITH AN INITIAL MOTION

ESTIMATE OF 265/8. HOWEVER...WITH NO RECENT MICROWAVE PASSES OVER

CELIA THE INITIAL MOTION ESTIMATE IS UNCERTAIN. DYNAMICAL MODEL

GUIDANCE INDICATES THAT A MIDDLE- TO UPPER-LEVEL RIDGE NORTH OF

CELIA SHOULD STEER THE CYCLONE ON A WESTWARD COURSE THROUGH ABOUT 72

HOURS. THEREAFTER...THE AMPLIFICATION OF A LONGWAVE TROUGH ALONG

THE UNITED STATES WEST COAST SHOULD RESULT IN AN EROSION OF THE

WESTERN PERIPHERY OF THE AFOREMENTIONED RIDGE AND CELIA SHOULD

RESPOND BY MOVING WEST-NORTHWESTWARD BEYOND 96 HOURS. THE OFFICIAL

FORECAST TRACK IS CLOSE TO THAT OF THE PREVIOUS ADVISORY...THOUGH A

BIT FASTER AFTER 72 HOURS IN AGREEMENT WITH THE MULTI-MODEL TVCN

CONSENSUS.

THE RAPID INTENSIFICATION THAT TOOK PLACE EARLIER HAS SLOWED...

POSSIBLY AS A RESULT OF MODERATE EAST-SOUTHEASTERLY VERTICAL WIND

SHEAR DIAGNOSED IN THE SHIPS MODEL AND UW-CIMSS ANALYSES. THE

VERTICAL WIND SHEAR DOES NOT APPEAR TO BE ENOUGH...HOWEVER...TO

PREVENT FURTHER GRADUAL INTENSIFICATION THROUGH THE NEXT 24-48

HOURS...ESPECIALLY IN THE FACE OF OTHER FAVORABLE FACTORS. THE GFS

MODEL SHOWS THE SHEAR DECREASING AFTER ABOUT 24-36 HOURS...AND THE

SHIPS MODEL RESPONDS BY MAKING CELIA A MAJOR HURRICANE AT 60

HOURS...EARLIER THAN 6 HOURS AGO. HOWEVER...THE GFDL...HWRF...AND

GFDN CALL FOR NO APPRECIABLE INTENSIFICATION...WITH ONLY THE GFDL

FORECASTING IT TO BE A HURRICANE AT 120 HOURS. THE NEW INTENSITY

FORECAST MAINTAINS THE REASONING OF THE PREVIOUS FORECAST...

INDICATING A HIGHER INTENSITY IN BEST OVERALL AGREEMENT WITH THE

SHIPS MODEL. IT SHOULD BE NOTED THAT...IF THE SHEAR DECREASES

FASTER THAN FORECAST...CELIA COULD BECOME SIGNIFICANTLY STRONGER

THAN CURRENTLY FORECAST AND SOONER.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/0900Z 12.0N 99.4W 55 KT

12HR VT 20/1800Z 11.8N 100.4W 65 KT

24HR VT 21/0600Z 11.7N 101.7W 75 KT

36HR VT 21/1800Z 11.8N 102.8W 80 KT

48HR VT 22/0600Z 11.8N 104.0W 85 KT

72HR VT 23/0600Z 12.0N 106.7W 95 KT

96HR VT 24/0600Z 13.0N 110.0W 100 KT

120HR VT 25/0600Z 14.0N 113.5W 100 KT

$$

FORECASTER KIMBERLAIN

Oeil et mur sur la t de brillance à 85 Ghz

201006200358trmmxtmi85v.jpg

Structure qui ne se retrouve pas sur l'IR, mais bonne convection et gros CDO :

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Ben visiblement, le NHC ne lâche pas le bout, et annonce le premier "major" de la saison. Après tout, pourquoi pas ?

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Il y a toujours une ébauche d'œil pour Celia, mais sans plus. Il est par 12°5N et 100°O à peu près. Visible sur le visible, il est moins discernable sur l'IR. C'est le petit point noir dans la masse blanche (faut trouver...).

Sur la température de brillance à 85GHz, la configuration reste identique. l'image est un peu plus ancienne, et l'œil est un chouïa plus à l'Est, mais le mur reste toujours aussi faible au Nord et à l'Est.

201006201450f18x91hw04e.jpg

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Modifié par paix

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Il n'y a pas grand chose d'autre à dire, et je n'ai pas envie de commenter. Simplement, c'est la première fois depuis 2001 qu'un ouragan se forme avant un typhon, et Celia est le premier ouragan/typhon de l'Hémisphère Nord en 2010.

000

WTPZ44 KNHC 202038

TCDEP4

HURRICANE CELIA DISCUSSION NUMBER 7

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

200 PM PDT SUN JUN 20 2010

SATELLITE IMAGERY INDICATES THAT CELIA HAS INTENSIFIED. A SSMIS

PASS FROM 1450 UTC SHOWED THE DEVELOPMENT OF A PARTIAL EYEWALL AND

AN EYE HAS BEEN INTERMITTENTLY SEEN IN VISIBLE IMAGERY. ALSO...

MICROWAVE IMAGERY SUGGESTS THAT THE LOW-LEVEL AND MID-LEVEL CENTERS

HAVE BECOME MORE VERTICALLY ALIGNED SINCE THIS MORNING. BASED ON

THESE TRENDS AND A DVORAK CI NUMBER OF 4.0 FROM TAFB...THE INITIAL

INTENSITY IS SET AT 65 KT FOR THIS ADVISORY.

THE SHIPS MODEL INDICATES THAT THE EASTERLY SHEAR CURRENT THAT HAS

BEEN AFFECTING CELIA WILL GRADUALLY DECREASE OVER THE NEXT 24

HOURS. THIS SHOULD ALLOW CELIA TO TAKE ADVANTAGE OF THE OTHERWISE

FAVORABLE CONDITIONS FOR INTENSIFICATION OVER THE NEXT COUPLE OF

DAYS. THE OFFICIAL INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD AND

IS IN CLOSE AGREEMENT WITH THE SHIPS MODEL. A BROAD PEAK IN

INTENSITY IS INDICATED LATER IN THE PERIOD...FOLLOWED BY SOME

WEAKENING BY DAY 5 AS CELIA IS FORECAST TO MOVE INTO AN AREA OF

COOLER WATERS AROUND THAT TIME. IT IS WORTH NOTING THAT THE SHIPS

RAPID INTENSIFICATION INDEX SHOWS ABOUT A 30 PERCENT CHANCE OF 25

KT OF INTENSIFICATION IN THE NEXT 24 HOURS...BUT ONLY A 2 PERCENT

CHANCE OF 30 KT OR MORE IN THAT PERIOD.

THE CENTER OF CELIA MOVED A LITTLE TO THE SOUTH OF THE PREVIOUS

FORECAST TRACK OVER THE PAST FEW HOURS...BUT THE LONG TERM INITIAL

MOTION ESTIMATE REMAINS 260/6. THE TRACK FORECAST REASONING

REMAINS UNCHANGED...AS CELIA WILL BE STEERED GENERALLY WESTWARD FOR

THE NEXT 2 OR 3 DAYS BY A DEEP-LAYER RIDGE NORTH OF THE CYCLONE.

BEYOND THAT TIME...THE GLOBAL MODELS SUGGEST THAT A MID- TO

UPPER-LEVEL TROUGH WILL AMPLIFY OFF THE U.S. WEST COAST BY THE END

OF THE PERIOD. THIS SHOULD ALLOW CELIA TO TURN MORE WEST-

NORTHWESTWARD AS THE SUBTROPICAL RIDGE WEAKENS. THE NEW TRACK

FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE BUT WAS

SHIFTED SOUTHWARD TO ACCOUNT FOR THE MORE SOUTHERLY INITIAL

POSITION OF THE CYCLONE. THE OFFICIAL FORECAST IS CLOSE TO THE

CONSENSUS OF THE DYNAMICAL MODELS EXCLUDING THE GFS...WHICH AGAIN

APPEARS TO BE A SOUTHERLY OUTLIER.

THE 34-KT WIND RADII IN THE NORTHEASTERN QUADRANT WERE EXPANDED

BASED ON AN ASCAT PASS FROM 1640 UTC.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/2100Z 11.6N 100.3W 65 KT

12HR VT 21/0600Z 11.4N 101.3W 75 KT

24HR VT 21/1800Z 11.4N 102.5W 85 KT

36HR VT 22/0600Z 11.5N 103.7W 90 KT

48HR VT 22/1800Z 11.6N 105.1W 100 KT

72HR VT 23/1800Z 12.3N 108.5W 100 KT

96HR VT 24/1800Z 13.5N 112.5W 100 KT

120HR VT 25/1800Z 15.0N 116.0W 90 KT

$$

FORECASTER BRENNAN

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Rectification, Celia est la deuxième. J'allais oublié Phet.... :whistling:

Et maintenant, je vais essayer de dormir.

Modifié par paix

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Le Pacifique, l'après-midi du 22 juin. Le tourbillon par 18°N et 120°O est le reste de Blas venu s'encastrer sous l'anticyclone, en le bousculant au passage. Celia est toujours un ouragan, mais l'œil est étiré et elliptique (ragged and elliptical eye).

000

WTPZ44 KNHC 221441

TCDEP4

HURRICANE CELIA DISCUSSION NUMBER 14

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

800 AM PDT TUE JUN 22 2010

EARLY MORNING VISIBLE SATELLITE IMAGES SHOW AN IMPRESSIVE CDO THAT

HAS BECOME MORE CIRCULAR SINCE YESTERDAY. HOWEVER...THERE IS STILL

NO EVIDENCE OF AN EYE IN GEOSTATIONARY IMAGERY. RECENT MICROWAVE

IMAGES REVEAL AN EYE THAT IS STILL A LITTLE TILTED FROM NORTHEAST

TO SOUTHWEST. DVORAK CURRENT INTENSITY NUMBERS REMAIN T5.0 AND

T4.5 FROM TAFB AND SAB RESPECTIVELY...SO THE INTENSITY IS

MAINTAINED AT 90 KT FOR THIS ADVISORY.

THE UPPER-LEVEL OUTFLOW HAS BECOME A LITTLE MORE SYMMETRIC THIS

MORNING...SUGGESTING THAT THE EASTERLY SHEAR MAY BE ABATING. THE

SHIPS MODEL CONTINUES TO PREDICT THAT THE SHEAR WILL DECREASE TO

BELOW 10 KT WITHIN 24 HOURS. THE OFFICIAL FORECAST FOLLOWS THIS

REASONING AND PREDICTS CELIA TO BECOME A MAJOR HURRICANE WITHIN

24 HOURS. THE OFFICIAL FORECAST IS A LITTLE ABOVE THE SHIPS/LGEM

GUIDANCE...BUT IS VIRTUALLY UNCHANGED FROM THE PREVIOUS ADVISORY.

IN 3-4 DAYS...CELIA IS EXPECTED TO MOVE OVER COOLER WATERS THAT

ARE LIKELY TO INITIATE WEAKENING.

CELIA CONTINUES MOVING WESTWARD OR 270 DEGREES AT 7 KT. THE GLOBAL

MODELS MAINTAIN A DEEP-LAYER RIDGE FROM NORTHERN MEXICO WESTWARD

OVER THE EASTERN PACIFIC. THE RIDGE IS FORECAST TO WEAKEN IN A FEW

DAYS...WHICH SHOULD ALLOW THE HURRICANE TO TURN TOWARD THE

WEST-NORTHWEST. THE NHC TRACK FORECAST IS CLOSE TO THE PREVIOUS

ADVISORY...BUT IS A LITTLE SLOWER AND TO THE RIGHT OF THE TVCN

CONSENSUS. THIS IS OUT OF RESPECT FOR THE ECMWF...WHICH WEAKENS

THE RIDGE MORE THAN THE REMAINDER OF THE GUIDANCE AND THEREFORE

SHOWS A SLOWER MOTION OF CELIA LATER IN THE FORECAST PERIOD.

FORECAST POSITIONS AND MAX WINDS

INITIAL 22/1500Z 11.6N 105.3W 90 KT

12HR VT 23/0000Z 11.7N 106.7W 100 KT

24HR VT 23/1200Z 11.8N 108.6W 105 KT

36HR VT 24/0000Z 12.1N 110.7W 105 KT

48HR VT 24/1200Z 12.5N 113.0W 100 KT

72HR VT 25/1200Z 13.7N 117.0W 90 KT

96HR VT 26/1200Z 15.0N 120.5W 75 KT

120HR VT 27/1200Z 16.0N 123.5W 55 KT

$$

FORECASTER BROWN

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