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

[paix 0]

Le NHC confirme et met effectivement un ouragan avant échouage. Le centre est un peu décalé à 86,1°O et 17,3°N, et l'organisation à la peine, mais une structuration sous le CDO donnera quelque chose de fantastique. On va attendre l'avion maintenant, et espérer quand même qu'Alex ne s'intensifie pas trop avant de toucher le Yucatán.

000

WTNT41 KNHC 261446

TCDAT1

TROPICAL STORM ALEX DISCUSSION NUMBER 4

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010

1000 AM CDT SAT JUN 26 2010

SATELLITE IMAGES SHOW THAT ALEX IS A LARGE CYCLONE WITH AN EXTENSIVE

AREA OF CLOUDINESS...NUMEROUS SQUALLS IN RAINBANDS...AND A WELL

ESTABLISHED UPPER-LEVEL OUTFLOW IN ALL QUADRANTS. HOWEVER... A

RECENT MICROWAVE IMAGE REVEAL THAT ALEX STILL HAS A POORLY

ORGANIZED INNER CORE. THE INITIAL INTENSITY OF 40 KNOTS IS BASED

ON 3.0 AND 2.5 DVORAK T-NUMBERS FROM TABF AND SAB

RESPECTIVELY...AND SURROUNDING SURFACE OBSERVATIONS. AN AIR FORCE

PLANE IS SCHEDULED TO INVESTIGATE ALEX LATER TODAY AND WILL PROVIDE

A BETTER ESTIMATE OF THE INTENSITY. ALTHOUGH ALEX IS EMBEDDED

WITHIN A FAVORABLE ENVIRONMENT FOR INTENSIFICATION...THE

STRENGTHENING WILL BE LIMITED BY THE EFFECT OF LAND PRIMARILY AS

THE CYCLONE CROSSES THE YUCATAN PENINSULA WITHIN 12 TO 24 HOURS.

ONCE IN THE GULF OF MEXICO...IN A COUPLE OF DAYS...THE CYCLONE

COULD GAIN SOME STRENGTH AND ALEX IS FORECAST TO BECOME BECOME A

HURRICANE BY THE END OF THE FORECAST PERIOD. THE OFFICIAL INTENSITY

FORECAST IS A BLEND OF BOTH THE LGEM AND DECAY SHIPS MODELS.

SINCE WE DO NOT HAVE A RELIABLE CENTER LOCATION...THE INITIAL MOTION

CONTINUES TO BE UNCERTAIN. THE BEST ESTIMATE IS 290 DEGREES AT 9

KNOTS. ALEX IS CURRENTLY LOCATED ON THE SOUTH SIDE OF A SUBTROPICAL

RIDGE EXTENDING WESTWARD FROM THE BAHAMAS ACROSS THE GULF OF

MEXICO. THIS RIDGE WILL KEEP ALEX MOVING ON THE SAME GENERAL

WEST-NORTHWEST TRACK FOR THE NEXT 24 TO 48 HOURS. THEREAFTER...THE

RIDGE IS FORECAST TO WEAKEN AND ALEX SHOULD DECREASE ITS FORWARD

SPEED. HOWEVER...MOST OF THE GLOBAL MODELS SHOW THAT THE RIDGE WILL

BE STRONG ENOUGH TO KEEP THE CYCLONE ON A GENERAL WEST-NORTHWEST

TRACK OVER THE SOUTHERN PORTION OF THE GULF OF MEXICO. IN

FACT...THE GFDL/HWRF PAIR WHICH PREVIOUSLY MOVED ALEX ON A MORE

NORTHERLY COMPONENT ACROSS THE GULF HAVE SHIFTED SOUTHWARD AND ARE

NOW SHOWING A MORE WESTERWARD TRACK LIKE MOST OF THE GLOBAL MODELS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/1500Z 17.3N 86.1W 40 KT

12HR VT 27/0000Z 17.7N 87.5W 50 KT

24HR VT 27/1200Z 19.0N 89.1W 30 KT...INLAND

36HR VT 28/0000Z 20.5N 91.0W 30 KT...OVER WATER

48HR VT 28/1200Z 22.0N 92.5W 40 KT

72HR VT 29/1200Z 23.0N 94.0W 55 KT

96HR VT 30/1200Z 23.5N 96.0W 65 KT

120HR VT 01/1200Z 24.0N 98.5W 25 KT...INLAND

$$

FORECASTER AVILA

Une petite image : Alex a les fesses posé sur des températures de l'eau de 29/30° Celsius...

La réserve d'énergie directement sous lui est cependant quelque peu limité par manque de profondeur de l'isotherme 26°. La côte n'est pas loin, et ce sera sans doute le facteur qui limitera le plus son intensification, comme souligné par le NHC.

Modifié 26 juin 2010 par paix

[ElNino27 0]

http://www.lesoir.be/actualite/monde/2010-...oire-778525.php

Modifié 26 juin 2010 par ElNino27

[paix 0]

Alex s'est bien restructuré, mais il est trop tard. Il est déjà en train de se manger le Belize.

L'avion a trouvé une pression estimé de 998 hPa (il fera sans doute un deuxième tour pour une dropsonde), avec un 925 hPa à 669 mètres. Il a aussi trouvé des rafales de vents à 60 nœuds au sol et 40 nœuds en soutenu.

Magnifique CDO n'empêche. Un jour de plus au dessus de l'Océan... Un jour...

La relocalistaion du centre (17°11'N et 87°21'W) fait que la bouée dont je parlais tantôt n'a plus guère d'utilité.

Maintenant, la grande question est de savoir comment il se portera après son passage à travers la péninsule.

Une webcam au Belize :

http://www.wunderground.com/webcams/CCWeatherGuy/1/show.html

http://www.wunderground.com/webcams/Callum/1/show.html

Les palmiers souffrent....

Et le radar :

http://www.hydromet.gov.bz/Latest_Radar_Image.htm

Modifié 26 juin 2010 par paix

[ElNino27 0]

Il n'a pas une direction plein Ouest pour l'instant, ce qui le ferait dissiper sur le Mexique ...

[paix 0]

Oh la vache

Product: Air Force Vortex Message (URNT12 KNHC)

Transmitted: 26th day of the month at 19:19Z

Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 302)

Storm Number & Year: 01L in 2010

Storm Name: Alex (flight in the North Atlantic basin)

Mission Number: 3

Observation Number: 09

A. Time of Center Fix: 26th day of the month at 19:08:30Z

B. Center Fix Coordinates: 17°19'N 87°28'W (17.3167N 87.4667W)

B. Center Fix Location: 49 miles (79 km) to the ESE (105°) from Belize City, Belize.

C. Minimum Height at Standard Level: 655m (2,149ft) at 925mb

D. Estimated (by SFMR or visually) Maximum Surface Wind: 56kts (~ 64.4mph)

E. Location of the Estimated Maximum Surface Wind: 29 nautical miles (33 statute miles) to the S (182°) of center fix

F. Maximum Flight Level Wind Inbound: From 237° at 52kts (From the WSW at ~ 59.8mph)

G. Location of Maximum Flight Level Wind Inbound: 26 nautical miles (30 statute miles) to the S (181°) of center fix

H. Minimum Sea Level Pressure: 996mb (29.41 inHg) - Extrapolated

I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 19°C (66°F) at a pressure alt. of 755m (2,477ft)

J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 764m (2,507ft)

K. Dewpoint Temp (collected at same location as temp inside eye): 22°C (72°F)

K. Sea Surface Temp (collected at same location as temp inside eye): Not Available

L. Eye Character: Not Available

M. Eye Shape: Not Available

N. Fix Determined By: Penetration, Wind, Pressure and Temperature

N. Fix Level: 925mb (If this vortex is from mid 1990's or earlier 925mb might be incorrect. See note.)

O. Navigation Fix Accuracy: 0.02 nautical miles

O. Meteorological Accuracy: 4 nautical miles

Remarks Section:

Maximum Flight Level Wind: 52kts (~ 59.8mph) in the south quadrant at 18:59:50Z

Sea Level Pressure Extrapolation From: 925mb

Special Notes:

- If this vortex is from approximately the mid 1990's or earlier, the "fix level" is properly decoded as "Other". Meaning, the level is not 1500ft, 850mb, 700mb, 500mb, 400mb, 300mb, or 200mb, but might not necessarily be 925mb. In vortex messages since approximately the mid 1990's, the number "9" in the vortex for this section explicitly decodes as 925mb and "NA" means "Other".

996 hPa et 55 nœuds ....

Et il vient de reprendre apparemment une trajectoire Ouest. La localisation du centre par l'avion peut cependant être aussi en cause.

Modifié 26 juin 2010 par paix

[ElNino27 0]

Sacrée convection explosive sur le centre. Ca va dracher au Belize !

[paix 0]

L'avis du NHC. Rien de surprenant, c'est plus une mise à jour en fonction des données de l'avion. Ce qui m'a surtout titiller est le "little stonger". Vu qu'Alex vient de prendre 15 nœuds et perdre 7 hPa en 3 heures, cela fait un peu euphémisme .

000

WTNT41 KNHC 262033

TCDAT1

TROPICAL STORM ALEX DISCUSSION NUMBER 5

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010

400 PM CDT SAT JUN 26 2010

AN AIR FORCE PLANE REACHED ALEX AND FOUND THAT THE CYCLONE WAS A

LITTLE STRONGER...WITH A MINIMUM PRESSURE OF 996 MB AND

FLIGHT-LEVEL WINDS OF 59 KNOTS ON THE SOUTH SIDE. THERE WERE

SEVERAL SFMR VALUES AROUND 55 KNOTS...AND THIS IS THE VALUE USED

FOR THE INITIAL INTENSITY. THIS INTENSITY IS ALSO IN AGREEMENT WITH

THE LATEST T-NUMBERS WHICH REACHED 3.0 AND 3.5 ON THE DVORAK SCALE.

THERE IS LITTLE ROOM FOR ALEX TO INTENSIFY MUCH MORE SINCE A

PORTION OF THE CIRCULATION IS ALREADY OVER LAND. ALEX IS EXPECTED

TO WEAKEN OVER THE YUCATAN PENINSULA...BUT ONCE IN THE GULF OF

MEXICO IT SHOULD BEGIN TO RE-STRENGTHEN. ALEX HAS A COUPLE OF DAYS

OVER WATER AND IN A FAVORABLE ENVIRONMENT BEFORE IT REACHES THE

MEXICAN COAST IN AROUND 96 HOURS.

THE CENTER WAS VERY DIFFICULT TO LOCATE EARLIER TODAY BUT NOW THAT

THE STORM IS BETTER ORGANIZED AND THE HURRICANE HUNTER PLANE

PROVIDED A GOOD FIX...THE INITIAL MOTION IS MORE RELIABLE AND IT IS

ESTIMATED AT 280 DEGREES AT 10 KNOTS. A STRONG SUBTROPICAL RIDGE

EXTENDING FROM THE BAHAMAS ACROSS THE GULF OF MEXICO IS EXPECTED TO

TO KEEP ALEX ON A GENERAL WEST-TO WEST-NORTHWEST TRACK OVER THE

SOUTHERN GULF OF MEXICO THROUGH THE FORECAST PERIOD. A DECREASE IN

FORWARD SPEED IS ANTICIPATED WHILE ALEX IS LOCATED IN THE SOUTHERN

GULF OF MEXICO AS THE STEERING CURRENTS WEAKEN A LITTLE BIT. THE

CONFIDENCE IN THE FORECAST IS HIGH BECAUSE MOST OF THE DYNAMICAL

MODELS ARE IN GOOD AGREEMENT AND HAVE SHIFTED FARTHER SOUTH JOINING

THE RELIABLE ECMWF.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/2100Z 17.3N 87.8W 55 KT

12HR VT 27/0600Z 17.7N 89.2W 30 KT...INLAND

24HR VT 27/1800Z 19.0N 91.0W 30 KT...INLAND

36HR VT 28/0600Z 20.0N 92.5W 45 KT...OVER WATER

48HR VT 28/1800Z 20.5N 93.5W 55 KT

72HR VT 29/1800Z 21.5N 95.5W 65 KT

96HR VT 30/1800Z 22.0N 98.0W 65 KT...INLAND

120HR VT 01/1800Z 22.0N 101.0W 20 KT...INLAND

$$

FORECASTER AVILA

Je pense qu'Alex pourra survivre en partie grâce à sa circulation gigantesque. Il tire sa subsistance de l'ensemble de la portion Ouest des Caraïbes et même du Pacifique. À ce sujet, une p'tite photo. Les deux bandes convectives s'affaiblissent au dessus des terres, mais elle couvrent un territoire immense, de 20° de longitude et 15° de latitude. Même en Floride, il parle d'Alex. De ce que j'ai compris, il ne font pas le lien directement, mais Alex a poussé au dessus de la Floride une masse d'air tropicale chaude et humide. Le flux est associé à la périphérie de la bande convective Est. Ce n'est pas forcément évident, mais la bande de cumulus sur le 25° Nord et qui affecte les Keys est la limite extrème de l'influence d'Alex. Sans commentaire...

.DISCUSSION...

.CURRENTLY...

KBYX DETECTS WIDELY SEPARATED SHOWERS THROUGHOUT THE FORECAST AREA.

SKIES OVER THE ISLAND CHAIN ARE PARTLY CLOUDY. WINDS OVER LAND ARE

EAST TO SOUTHEAST NEAR 15 MPH. C-MAN WINDS...ON AVERAGE...ARE EAST

TO SOUTHEAST NEAR 15 KNOTS. TEMPERATURES ARE NEAR 90 DEGREES.

.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...

AN ATLANTIC RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS NORTH CENTRAL

FLORIDA TONIGHT THROUGH MONDAY NIGHT. MEANWHILE...TROPICAL STORM

ALEX WILL APPROACH THE YUCATAN PENINSULA TONIGHT. TROPICAL STORM

ALEX SHOULD CROSS THE YUCATAN PENINSULA SUNDAY...BEFORE ENTERING THE

SOUTHWEST GULF OF MEXICO SUNDAY NIGHT INTO MONDAY. TROPICAL STORM

ALEX WILL WEAKEN TO A TROPICAL DEPRESSION AS IT CROSSES THE YUCATAN

PENINSULA SUNDAY...THEN RESTRENGTHEN INTO A TROPICAL STORM LATE

SUNDAY NIGHT OR MONDAY MORNING. DEEP...FRESH SOUTHEASTERLY FLOW

COUPLED WITH ABOVE NORMAL ATMOSPHERIC MOISTURE SHOULD INCREASE

SHOWER COVERAGE TONIGHT DURING A BRIEF NOCTURNAL WIND SURGE. AS A

RESULT...POPS TONIGHT WILL BE KEPT ABOVE ALL NUMERICAL MODEL

STATISTICS. THE BEST CHANCE OF RAINFALL SUNDAY WILL OCCUR DURING THE

MORNING HOURS. ANOTHER SOUTHEASTERLY WIND SURGE IS EXPECTED SUNDAY

NIGHT. ONCE AGAIN...THIS SHOULD RESULT IN AN INCREASE IN SHOWER

COVERAGE DUE TO ABOVE NORMAL ATMOSPHERIC MOISTURE IN PLACE COUPLED

WITH DEEP SOUTHEASTERLY FLOW. POPS SUNDAY NIGHT WILL BE KEPT ABOVE

ALL NUMERICAL MODEL OUTPUT STATISTICS. THE BEST CHANCE OF RAINFALL

MONDAY WILL OCCUR DURING THE MORNING HOURS. A WIND SURGE IS LESS

LIKELY MONDAY NIGHT...BUT FORECAST CONFIDENCE FOR MONDAY NIGHT IS

LOW DUE TO VARYING NUMERICAL MODEL SCENARIOS. THE GFS NUMERICAL

MODEL GUIDANCE VEERS WINDS A BIT MONDAY NIGHT AND ADVECTS

ABUNDANT...TROPICAL MOISTURE NORTHWARD FROM THE CARRIBEAN. ON THE

OTHER HAND...THE EUROPEAN NUMERICAL GUIDANCE KEEPS THE ABUNDANT...

TROPICAL MOISTURE SOUTH OF THE FLORIDA KEYS MONDAY NIGHT. THE GFS

NUMERICAL MODEL GUIDANCE LOOKS FLAWED TO ME DUE TO HIGHLY UNLIKELY

CYCLOGENESIS IN THE NORTHERN GULF OF MEXICO.

.LONG TERM (TUESDAY THROUGH SATURDAY)...

THE TUESDAY AND TUESDAY NIGHT PORTION OF THE FORECAST WILL BE BASED

ON THE AFOREMENTIONED EUROPEAN NUMERICAL MODEL SOLUTION OF KEEPING

THE ABUNDANT TROPICAL MOISTURE SOUTH OF THE FLORIDA KEYS. NO LARGE

SCALE LIFTING MECHANISMS SHOULD IMPACT THE FORECAST AREA WEDNESDAY

THROUGH SATURDAY.

Pour les pays d'Amérique Central, même sans vigilance à la tempête, c'est la douche. En El Salvador, les précipitations ne sont pas exceptionnelles, mais cela descend bien, alors qu'ils sont du côté Pacifique de l'Amérique Centrale...

[ElNino27 0]

[paix 0]

Je ne sais pas trop quoi espérer pour Alex. Si il meurt au dessus du Mexique sans pouvoir rejoindre le Golfe, les mexicains vont souffrir. Alex pourra soutenir des pluies diluviennes pendant des jours. Si il rejoint le Golfe, il va pourvoir devenir ouragan et menacer sérieusement le Nord du Mexique et/ou le Texas. Si il part vers le Nord, il va aggraver la marrée noire. Si il suit la trajectoire prévu par le NHC et longe la côte mexicaine dans le Golfe, il nous refera un scénario à la Mitch 98. Et espérer qu'Alex ne puisse s'intensifier dès qu'il rejoindra le Golfe n'est pas réaliste.

La situation n'est pas non plus désespérée, mais le Mexique va avoir fort à faire avec Alex.

Modifié 26 juin 2010 par paix

[paix 0]

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

The first named storm of the Atlantic hurricane season of 2010 is here. Tropical Storm Alex formed last might from an African tropical wave that plowed through the Caribbean this week. Alex's formation location is a typical one for June tropical storms, and the formation date of June 25 is also a fairly typical date for the first storm of the season to form (we average about one June named storm every two years in the Atlantic.) Heavy rainfall will ramp up through the day in Honduras, Belize, and Mexico's Yucatan Peninsula, as Alex continues to intensify, and flooding from these heavy rains will be the main concern from Alex today and Sunday. Satellite loops show that Alex's heavy thunderstorm are growing in intensity and areal coverage at a respectable pace. There is an upper-level high pressure system a few hundred miles west of Alex, and the clockwise flow air around this high is bringing upper-level winds out of the northwest of about 10 knots over the storm, contributing to the 10 knots of wind shear observed in this morning's wind shear analysis from the University of Wisconsin's CIMSS group. Sea Surface Temperatures are very warm, 29 - 30°C, and dry air is not a problem for Alex. We currently don't have a Hurricane Hunter aircraft in the storm, so we will have to wait until 2pm this afternoon to get an updated estimate of Alex's surface winds. The latest satellite estimates of Alex's winds at 8am EDT put the storm's strongest winds at 40 mph.

Figure 1. Satellite image of the tropics at 9am EDT Saturday 6/26/10. Image credit: GOES Science Project.

Forecast for Alex

As I discussed in last night's post, an examination of the nineteen tropical cyclones that have formed in the Western Caribbean and hit the Yucatan Peninsula over the past twenty years reveals that 8 went on to make a second Gulf Coast landfall in Mexico, 5 hit the U.S. Gulf Coast, and 6 died after hitting the Yucatan. The ones that died all took a more southerly path across the Yucatan, spending more time over land than Alex will. Alex is large enough and moving far enough north across the Yucatan that passage over the peninsula will not kill it. So, will Alex follow the path climatology says is more likely, and make a second landfall along the Mexican Gulf Coast?

Figure 2. Forecast swath of tropical storm force winds (34 - 63 knots, green colors) and hurricane force winds (yellow and orange colors) as predicted by this morning's 2am EDT run of the HWRF model. Image credit: Morris Bender, NOAA GFDL team.

The key question remains how Alex will react to the trough of low pressure expected to swing down over the Eastern U.S. on Monday. Some of yesterday's model runs predicted that this trough would be strong enough to pull Alex northwards through the oil slick region into the northern Gulf of Mexico coast. However, the models that were predicting this (the GFS, GFDL, and HWRF models) are all backing off on that prediction. It now appears likely that Alex will cross the Yucatan, emerge into the Gulf of Mexico, then slow down as the trough to its north weakens the steering currents in the Gulf of Mexico on Monday. By Tuesday, the influence of the trough will wane, high pressure will build in, and Alex will resume a west-northwest, or possibly a due west or west-southwest motion, towards the Texas/Mexico border region. Based on the current trends in the models, Alex's tropical storm force winds are likely to stay well south of the oil slick region (Figure 2.) I put the odds of Alex bringing tropical storm-force winds to the oil slick region at 10%. The most significant impact Alex will likely have on the oil slick region is to bring 2 - 4 foot swells that may wash oil over some of the containment booms. These swells will reach the oil slick region on Tuesday and Wednesday.

Continued intensification of Alex is likely today, up until landfall. It is a good thing the storm waited until last night to get organized; had it formed a day earlier, it could have easily been a hurricane in the Western Caribbean today. Once Alex emerges back into the Gulf of Mexico on Monday, it will likely take the storm at least 24 hours to get re-organized, particularly since the total ocean heat content is low for the 100-mile-wide stretch of water on the west side of the Yucatan Peninsula. Once Alex moves more than 100 miles from the Yucatan, total heat content of the ocean increases substantially, and Alex will have the opportunity to intensify significantly. Steering currents will be weak in the Gulf next week, and it appears that Alex will have time to intensify into a hurricane before making its second landfall along the South Texas/northern Mexico coast. Wind shear is expected to be light, and dry air not a significant impediment. Most of the models are calling for landfall on Wednesday, but I wouldn't be surprised to see this delayed until Thursday. I give Alex a 60% chance of becoming a hurricane in the Gulf of Mexico next week.

Elsewhere in the tropics

A tropical wave (Invest 94L) is a few hundred miles northeast of the northernmost Lesser Antilles Islands. This wave is producing a modest amount of heavy thunderstorm activity, and is passing beneath a trough of low pressure that is generating 30 - 40 knots of wind shear, and is not a threat to develop today. However, by Monday, the storm will be in a region of much lower wind shear, and NHC is giving the storm a 10% chance of developing into a tropical depression by Monday morning. None of the models currently develop 94L, but Bermuda should keep and eye on this system, as it will pass very close to the island on Tuesday.

[ElNino27 0]

Alex devrait passer une quinzaine d'heures sur le Yucatan. Après, cela pourrait durer 2 jours, peut-être 3 ou encore plus. Remember Humberto qui est passé en cat2 tout près des côtes.

[paix 0]

En cat1, Humberto.. Mais oui, remember...

La fin de Celia :

000

WTPZ44 KNHC 262054

TCDEP4

HURRICANE CELIA DISCUSSION NUMBER 31...CORRECTED

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042010

200 PM PDT SAT JUN 26 2010

CORRECTED FOR POST-TROPICAL STATUS AT 48 AND 72 HOURS

WHAT LITTLE ASSOCIATED DEEP CONVECTION REMAINS THIS AFTERNOON...IS

CONFINED TO THE WEST QUADRANT OF THE CYCLONE. DVORAK CURRENT

SATELLITE INTENSITY ESTIMATES ARE 70 KT FROM BOTH TAFB AND SAB..AND

A 1730 UTC ADVANCED OBJECTIVE DVORAK TECHNIQUE ESTIMATE WAS 67

KT. THEREFORE...THE INITIAL INTENSITY IS LOWERED TO 70 KT.

CONTINUED RAPID WEAKENING IS EXPECTED...AND THE TROPICAL CYCLONE

SHOULD DECAY TO A REMNANT LOW IN 2 DAYS....AND WITH DISSIPATION IN 4

DAYS...OR POSSIBLY SOONER.

THE INITIAL MOTION IS 285/7. CELIA IS FORECAST TO MOVE TOWARD THE

WEST-NORTHWEST DURING THE NEXT 36 HOURS WITHIN THE

EAST-SOUTHEASTERLY STEERING FLOW OF A RIDGE TO THE NORTH.

THROUGH THE REMAINING PERIOD...CELIA IS EXPECTED TO SLOW IN FORWARD

SPEED IN RESPONSE TO AN APPROACHING MID TO UPPER-LEVEL TROUGH FROM

THE NORTHWEST. THE NHC FORECAST FOLLOWS THE PREVIOUS NHC

FORECAST AND IS BASED ON THE DYNAMICAL MULTI-MODEL BLEND.

FORECAST POSITIONS AND MAX WINDS

INITIAL 26/2100Z 15.7N 122.2W 70 KT

12HR VT 27/0600Z 15.9N 123.1W 55 KT

24HR VT 27/1800Z 16.0N 124.1W 40 KT

36HR VT 28/0600Z 16.0N 124.6W 30 KT

48HR VT 28/1800Z 16.0N 125.1W 25 KT...POST-TROP/REMNT LOW

72HR VT 29/1800Z 16.0N 126.0W 20 KT...POST-TROP/REMNT LOW

96HR VT 30/1800Z...DISSIPATED

$$

FORECASTER ROBERTS/AVILA

[paix 0]

Je crois qu'Alex a une ébauche d'œil, mais cela est très tenu et ne fait pas de lui un ouragan. Il doit s'être encore un peu renforcé, 60 noeuds de vent sans doute, mais il n'ira plus loin maintenant. It's too late.

[ElNino27 0]

Ah il me semblait que Humberto avait tout juste atteint la cat2

[paix 0]

C'est comme moi, j'étais sûr que le Belize cause espagnol, et en fait la langue officiel est l'anglais...

Ales a bien une structure d'œil qui se maintient. Bon, cela ne fait pas de lui un ouragan, et le frottement avec les terres a sans doute aidé. Mais il n'empêche, le cœur du système est remarquablement organisé.

[paix 0]

Oh my God ! Je plains ceux qui sont en dessous. Alex semble ne pas souffrir de son passage au dessus des terres, et il prend même une trajectoire Ouest Nord Ouest, direction le golfe....

L'image parle d'elle même

L'option entrevue par GFS est non suivi par le NHC ou Jeff Masters précédemment reprend de l'intérêt.

Modifié 27 juin 2010 par paix

[paix 0]

La discussion du NHC qui résume bien tout ceci :

000

WTNT41 KNHC 270857

TCDAT1

TROPICAL STORM ALEX DISCUSSION NUMBER 7

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010

400 AM CDT SUN JUN 27 2010

RATHER THAN BECOMING DISORGANIZED AFTER MOVING INLAND...RADAR AND

SATELLITE DATA INDICATE THAT ALEX HAS ACTUALLY BECOME MUCH BETTER

DEFINED. AN EYE FEATURE HAS BEEN NOTED IN BELIZE RADAR DATA AND

SATELLITE IMAGERY INDICATES THAT CLOUD TOPS HAVE COOLED

SIGNIFICANTLY WITH A NEARLY CLOSED RING OF -80C AND COLDER TOPS

ENCIRCLING THE RADAR CENTER. THE UPPER-LEVEL OUTFLOW PATTERN

REMAINS IMPRESSIVE AND ADDITIONAL CONVECTIVE BANDING FEATURES HAVE

DEVELOPED IN ALL QUADRANTS. THE RADAR AND SATELLITE DEPICTIONS OF

ALEX LOOKS MORE LIKE A HURRICANE THAN A LOW-END TROPICAL STORM.

THE MOTION ESTIMATE IS 300/10. THE SHORT TERM MOTION IS THE ONLY

THING STRAIGHT-FORWARD ABOUT THE FORECAST TRACK. ALL OF THE MODELS

AGREE ON AN UPPER-LEVEL LOW CURRENTLY JUST EAST OF HUDSON BAY

CANADA TO DIG SOUTHWARD AND CARVE OUT A DEEP TROUGH OVER MUCH OF

THE EASTERN U.S. DURING THE NEXT 5 DAYS. AS THE TROUGH AMPLIFIES

...THE SUBTROPICAL RIDGE CURRENTLY SITUATED ACROSS FLORIDA AND THE

NORTHERN GULF OF MEXICO ERODES IN THE 36-72 HOUR TIME FRAME LEAVING

A LARGE WEAKNESS IN THE RIDGE OVER THE CENTRAL AND WESTERN GULF.

THIS WEAK FLOW PATTERN IS EXPECTED TO CAUSE ALEX TO SLOW DOWN AND

ALLOW THE CYCLONE TO GAIN SOME LATITUDE. AFTER THAT...HOWEVER...THE

MODELS DIVERGE SIGNIFICANTLY WITH THE GFS AND CANADIAN MODELS

TAKING ALEX NORTHWARD THROUGH THE WEAKNESS IN THE RIDGE TO THE

TEXAS-LOUISIANA BORDER AREA...WHEREAS THE ECMWF...NOGAPS...GFDL...

HWRF...UKMET...AND GFS-PARALLEL MODELS MOVE ALEX WESTWARD INTO

NORTHEASTERN MEXICO. THE MAIN DIFFERENCE IN THE MODELS IS HOW THEY

HANDLE THE MID-LATITUDE TROUGH-RIDGE PATTERN. THE GFS AND CANADIAN

MODELS ARE MORE PROGRESSIVE AND LESS AMPLIFIED WITH THE FLOW

PATTERN ACROSS THE NORTHERN U.S. DURING THE FORECAST PERIOD...

WHEREAS THE OTHER MODELS PRODUCE A STRONGER...MORE HIGHLY AMPLIFIED

...AND SLOWER PATTERN. THE CURRENT PROGRESSIVE 5-WAVE NORTHERN

HEMISPHERIC FLOW PATTERN WOULD TEND TO FAVOR THE THE GFS-CANADIAN

SOLUTION...BUT AT LEAST ONE MORE MODEL CYCLE WILL BE REQUIRED TO

CONFIRM THAT TREND. THE OFFICIAL FORECAST TRACK IS TO THE RIGHT OF

AND SLOWER THAN THE PREVIOUS ADVISORY...AND IS SIMILAR TO THE

CONSENSUS MODEL...TVCN. NOTE...IF THE RECENT NORTHWARD SHIFT IN THE

MODELS CONTINUES...THEN ALEX COULD REMAIN OVER WATER FOR THE NEXT 5

DAYS RESULTING IN A VERY POWERFUL HURRICANE.

BASED ON THE MUCH IMPROVED STRUCTURE OF ALEX WHILE IT IS HAS BEEN

OVER LAND...THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD FROM

THE PREVIOUS ADVISORY. WITH VERTICAL SHEAR FORECAST TO BE 5 KT OR

LESS DURING MOST OF THE FORECAST PERIOD AND SSTS OF 28C AND WARMER

EXPECTED ALONG THE TRACK...THERE IS AT LEAST A MODERATE LIKELIHOOD

THAT ALEX COULD BECOME A MAJOR HURRICANE. THE OFFICIAL INTENSITY

FORECAST IS NEARLY IDENTICAL TO THE SHIPS AND DECAY-SHIPS INTENSITY

MODELS...AND HIGHER THAN BOTH THE GFDL AND HWRF MODELS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/0900Z 18.3N 89.4W 35 KT

12HR VT 27/1800Z 19.1N 90.6W 30 KT...INLAND

24HR VT 28/0600Z 20.2N 91.9W 40 KT...OVER WATER

36HR VT 28/1800Z 20.9N 92.8W 55 KT

48HR VT 29/0600Z 21.5N 93.6W 65 KT

72HR VT 30/0600Z 22.6N 95.5W 75 KT

96HR VT 01/0600Z 23.2N 97.4W 85 KT

120HR VT 02/0600Z 23.5N 99.7W 30 KT...INLAND

$$

FORECASTER STEWART

[ElNino27 0]

Le gaillard est repassé en TD, mais sa structure est encore excellente, et dans quelques heures il va repasser sur la BOC. Le NHC prévoit du 75 noeuds, encore un peu plus que l'estimation précédente, ce qui est classique. A ce rythme, il ne faudrait pas s'étonner qu'il passe en cat2. La trajectoire a aussi été ajustée vers le Sud. Vu la taille du truc, ses bandes pourraient affecter Mexico.

[ElNino27 0]

Une image qui dit tout : la circulation de haute altitude s'étend jusqu'à l'Est de Cuba. A l'Ouest, c'est différent vu la présence de Daby.

Quand Alexa va repasser au-dessus de l'eau dans 3-4h, cela risque d'exploser !

[paix 0]

C'est là ou on voit la puissance de l'inflow d'Alex. El Salvador, toujours, et localement plus de 200 mm en 48 heures, alors qu'Alex ne leur ai jamais passé dessus....

D'un point de vue plus génrale, les lames d'eau sont tous aussi sympathique en Belize et Mexico.

On attendra la sortie d'Alex, mais les lames d'eau devrait être supérieur à 200 millimètres de manière généralisé, ce qui est quand même beaucoup.

L'avis de Jeff Masters :

Tropical Depression Alex has held together fairly well during its passage over Mexico's Yucatan Peninsula, and stands poised to re-intensify back into a tropical storm once it emerges from the coast tonight. Alex brought heavy rains to northern Honduras, Mexico's Yucatan Peninsula, and Belize over the weekend. It was not a good beach day in Cozumel yesterday, as 9.25" of rain fell. Cancun received 2.05" over the weekend, and Belize City received 4.57". Satellite loops show that Alex's heavy thunderstorms are mostly gone near the center, though there are some impressive bands of precipitation well away from the center. There is an upper-level high pressure system a few hundred miles west of Alex, and the clockwise flow air around this high is bringing upper-level winds out of the northwest of about 5 knots over the storm, contributing to the 5 knots of wind shear observed in this afternoon's wind shear analysis from the University of Wisconsin's CIMSS group. Sea Surface Temperatures are very warm, 29 - 30°C, and dry air is currently not a problem for Alex.

Figure 1. Afternoon satellite image of Alex.

Forecast for Alex: which model should you trust?

While the track forecast for Alex today through Monday is fairly well-assured, the longer range forecast has become highly uncertain. An increasing number of our reliable models are now indicating Alex may take a more northerly track beginning on Tuesday, with possible landfall on the Texas coast near Galveston on Friday (according to the 8am run of the GFS model) or into western Louisiana on Wednesday (the 8am run of the Canadian model.) The key question remains how Alex will react to the trough of low pressure expected to swing down over the Eastern U.S. on Monday and Tuesday. Most of the models were predicting that the trough would not be strong enough to swing Alex to the north, and several of them continue to predict this. The 8am run of the NOGAPS model, for example, takes Alex into the Gulf coast of Mexico 150 miles south of Texas, on Wednesday. The GFDL and HWRF models split the difference, with the GFDL predicting a Thursday landfall in southern Texas near Brownsville, and the HWRF predicting a Thursday landfall near Corpus Christi. So which model should you trust? Last year, the best performing models at the 3 - 4 days period were the GFS and the Canadian, and these are the models that are currently calling for the more northerly track towards the upper Texas coast and Louisiana. Residents of those areas should review their hurricane preparedness plans and anticipate the Alex could make landfall as early as Wednesday in their vicinity.

Re-intensification of Alex is likely once the center of Alex moves offshore, though this will initially be slow due to the current disorganized state of the storm and the relatively low total ocean heat content in the 100-mile-wide stretch of water on the west side of the Yucatan Peninsula. Once Alex moves more than 100 miles from the Yucatan, total heat content of the ocean increases substantially, and Alex will have the opportunity to intensify significantly. A longer time spent over water will give Alex more of a chance to strengthen, and it is possible Alex could intensify into a major hurricane if landfall is delayed until Thursday or Friday. However, Alex's intensification may be limited the farther north it gets, as water vapor satellite images show plenty of dry air over Texas that might interfere with development. Wind shear might also be an issue for Alex if it pushes far enough north, and a slow-moving storm tends to pull up cold water from the depths, limiting intensification. In short, Alex has the potential to intensify into a major hurricane, but there are plenty of roadblocks that make this only a 10% probability in my estimation.

Et une image. Alex a finalement faibli après des heures d'une lutte invraisemblable.

[ElNino27 0]

L'énorme zone de pluies sur le Panama et même la Colombie !!!

Je vous quitte, je crois qu'il commence à pleuvoir des cordes sur Lima ...

[paix 0]

C'est une onde tropicale prise dans l'équateur météo. Il n'est pas prévu qu'elle se développe (cisaillement de vent totalement destructeur), et quand bien même elle le ferrait, je pense que ce serait plus dans la Pacifique que l'Atlantique.

Le dernier avis du NHC. Alex a retrouvé l'eau liquide ...

000

WTNT41 KNHC 272035

TCDAT1

TROPICAL DEPRESSION ALEX DISCUSSION NUMBER 9

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012010

400 PM CDT SUN JUN 27 2010

SATELLITE IMAGES SHOW THAT ALEX CONTINUES TO HAVE A LARGE AND

WELL-DEFINED CIRCULATION WITH PLENTY OF BANDING FEATURES. NEAR THE

CENTER...HOWEVER...CONVECTION HAS DECREASED...PROBABLY DUE TO THE

INFLUENCE OF LAND. THE MEXICAN NAVY SURFACE STATION AT ISLA PEREZ

RECENTLY REPORTED 30 KT WINDS...SO THE INITIAL WIND SPEED IS KEPT

AT 30 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS

SCHEDULED TO INVESTIGATE ALEX THIS EVENING AFTER THE CENTER MOVES

OFFSHORE.

THE INITIAL MOTION OF ALEX IS A LITTLE SLOWER...WITH A 12-HR AVERAGE

YIELDING AN ESTIMATE OF 300/8. THE PIVOTAL QUESTION FOR THE

LONG-TERM FORECAST TRACK OF THE TROPICAL CYCLONE APPEARS TO HINGE

ON THE STRENGTH OF MID-LEVEL RIDGING OVER THE NORTHERN GULF COAST.

THE MODELS THAT SHOW A WEAKER RIDGE...SUCH AS THE CMC/GFS/HWRF...

ALLOW THE TROPICAL CYCLONE TO TURN TOWARD THE NORTH-NORTHWEST AND

NORTH AND APPROACH THE NORTHWESTERN GULF COAST IN SEVERAL DAYS.

OTHER MODELS...SUCH AS THE ECMWF/UKMET/NOGAPS...HAVE A STRONGER

RIDGE AND KEEP ALEX MOVING TO THE NORTHWEST OR WEST-NORTHWEST INTO

MEXICO. OVERALL THE MODEL GUIDANCE HAS SHIFTED SLIGHTLY TO THE

NORTH...AND THE OFFICIAL FORECAST IS A LITTLE TO THE RIGHT OF THE

PREVIOUS ONE. SINCE THERE IS CONSIDERABLE MODEL SPREAD...THIS TRACK

FORECAST IS THOUGHT TO BE OF BELOW-AVERAGE CONFIDENCE.

WHILE THERE IS A LARGE DISAGREEMENT ON THE TRACK OF ALEX...THE

GLOBAL MODELS ARE IN MUCH BETTER AGREEMENT WITH THE LARGE-SCALE

ENVIRONMENT. THESE MODELS SHOW AN UPPER-RIDGE AXIS SITTING VERY

NEAR THE TROPICAL CYCLONE FOR THE NEXT SEVERAL DAYS...IN A

FAVORABLE POSITION FOR INTENSIFICATION. COMBINED WITH THE WARM

WATERS OF THE GULF OF MEXICO...STRENGTHENING IS LIKELY...ESPECIALLY

AFTER ALEX MOVES FARTHER AWAY FROM THE YUCATAN PENINSULA. GIVEN THE

OVERALL ENVIRONMENTAL CONDITIONS...IT IS SURPRISING THAT THE

GFDL/HWRF DO NOT SHOW MORE INTENSIFICATION...LEAVING THE SYSTEM AS

A TROPICAL STORM FOR MANY DAYS. THE STATISTICAL GUIDANCE SEEMS MORE

REASONABLE AND THE NHC FORECAST IS CLOSE TO THE SHIPS MODEL...AND

IS NOT TOO DISSIMILAR FROM THE PREVIOUS FORECAST.

FORECAST POSITIONS AND MAX WINDS

INITIAL 27/2100Z 19.2N 90.9W 30 KT

12HR VT 28/0600Z 19.9N 91.8W 35 KT

24HR VT 28/1800Z 20.6N 92.6W 45 KT

36HR VT 29/0600Z 21.5N 93.3W 55 KT

48HR VT 29/1800Z 22.3N 94.2W 65 KT

72HR VT 30/1800Z 23.2N 96.3W 80 KT

96HR VT 01/1800Z 24.0N 98.5W 55 KT...INLAND

120HR VT 02/1800Z 24.5N 100.5W 20 KT...DISSIPATING INLAND

$$

FORECASTER BLAKE

P.S. : la prochaine bouée proche de la trajectoire :

http://www.ndbc.noaa.gov/station_page.php?station=42055

Modifié 27 juin 2010 par paix

[paix 0]

Détail amusant, storm2k en est à 123 pages sur Alex

Quand la saison entrera dans sa période la plus active, ils font faire sauter le forum

http://www.storm2k.org/phpbb2/viewtopic.ph...59&t=108276

[ElNino27 0]

Au premier cat5, cela va être terrible. Je ne sais plus pour quel système, mais une onde tropicale avait été pendant plusieurs jours au bord du stade de TD, et les forumeurs avaient beaucoup discuté sur le bazar. Puis finalement, la TD s'était formée, elle était remontée sur la Floride, avait fait du surplace sur la côte Est, puis était repartie vers l'Ouest. Je ne me rappelle plus de la quantité de pages, mais je pense qu'on était arrivé à 800.

Storm2k, ce n'est plus un forum, c'est une salle de chat, mais c'est super de les avoir : on a plein d'infos.

[ElNino27 0]

Alex repart déjà de plus belle ...