Tropical Storm Matthew

[Somerset Squall]

Invest 95L has become a 30kt tropical depression in the Caribbean. Interesting track forecast putting the Nicaragua and Honduras at risk, then the Yucatan. 15L is expected to become a hurricane fairly swiftly as the environment is very conducive for strengthening.

Image is from Unisys Weather.

[Paranoid]

Intresting (from a meteorological view point only) that Matthew as it will be then is forecast to remain a hurricane while stalling over the Yucutan. This is a cause for some concern as that area is mountainous and there could be a lot of rain from Matthew resulting in flooding and mudslides. The same thing happened with Mitch (whom Matthew replaced).

[Iceberg]

It's really difficult to try and find anything like an accurate track for Matthew.

ECM frankly losses the plot and doesn't really have even a closed circulation when NHC have him as a hurricane.

GFDL takes him into the Yucatan and then makes him go directly backwards back into the yucatan channel.(I've never seen a hurricane go into land and come out again at exactly the same angle).

GFS does something similar, but actually seems to create a new LLCC a few hundred miles to the east of the one that goes into the Yucatan.

All in All I wouldn't really trust any model until until maybe Friday night.

[Cookie]

This is going to be an interesting one, one way or another. I fear this could be the worst of the season, early days I know and at the moment all speculation.

[Somerset Squall]

Thanks for the images Cookie. They show that 15L has really got it's act together over the last few hours. The depression is beginning to look a little more symmetrical and you can clearly see where the centre of circulation is now. Will become a tropical storm sooner rather than later, if not tonight then early tomorrow. Looking quite concerning for the areas I mentioned in my first post.

[Cookie]

Now tropical storm Matthew

[summer blizzard]

The more northward movement the better as far as i am concerned, the warmest waters on the planet right now are between Jamaca and the Yucatan.

Certainly a major out of this one, if it hits land i doubt we will see a category 5.

[Iceberg]

Matthew *could* be going though some rather quick, maybe even rapid intensification, it has a solid CDO around the centre now with cloud tops of -80, microwave also shows the possibility of an eye like feaure, intensity on some Dvorak anlaysis has gone upto 55kts already.

Nice to see the NHC commenting on the track below, as mentioned above the models are really really strugglin with this which does not make life easy for those that live in this part of the world cosidering the danger Matthew posses. There is little chance now IMO that matthew will not be a hurricane before first landfall.....

THE OVERALL ORGANIZATION OF MATTHEW HAS CONTINUED TO GRADUALLY

IMPROVE THIS EVENING. A BURST OF DEEP CONVECTION HAS RECENTLY

DEVELOPED OVER THE CENTER AND SEVERAL BROKEN BANDS OF THUNDERSTORMS

ARE SEEN AROUND THE PERIPHERY OF THE CIRCULATION. THE LATEST

SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 45 AND 35

KT...RESPECTIVELY. BASED ON THESE ESTIMATES THE INITIAL INTENSITY

IS SET AT 40 KT.

THE INITIAL MOTION ESTIMATE IS 275/15. FOR THE NEXT 36-48 HOURS...

MATTHEW IS EXPECTED TO CONTINUE IN A WEST TO WEST-NORTHWEST

DIRECTION TO THE SOUTH OF A SUBTROPICAL RIDGE THAT EXTENDS FROM THE

ATLANTIC WESTWARD INTO THE SOUTHEASTERN UNITED STATES. THE TRACK

GUIDANCE IS IN GOOD AGREEMENT DURING THAT TIME AND THERE IS FAIRLY

HIGH CONFIDENCE IN THAT PART OF THE FORECAST. IN 2-3 DAYS...

THE WESTERN PORTION OF THE RIDGE IS EXPECTED TO WEAKEN AS A STRONG

MID-LATITUDE TROUGH MOVES INTO THE CENTRAL UNITED STATES. THIS

SHOULD RESULT IN A WEAKENING OF THE STEERING CURRENTS AND A

DECELERATION OF THE CYCLONE. THEREAFTER...THE MODEL SOLUTIONS

DIVERGE SIGNIFICANTLY...WITH SEVERAL OF THEM SHOWING RATHER

COMPLEX SCENARIOS. THE GFS...UKMET...AND ECMWF ALL MOVE MATTHEW

WELL INLAND OVER THE SOUTHERN PORTION OF THE YUCATAN PENINSULA IN

2-3 DAYS. AFTER THAT TIME...THE GFS AND ECMWF ACTUALLY WEAKEN

MATTHEW...THEN DEVELOP A SECOND CYCLONE OVER THE NORTHWEST

CARIBBEAN SEA. ON THE OTHER HAND...THE NOGAPS...GFDL....AND HWRF

KEEP MATTHEW AS THE PRIMARY SYSTEM AND SHOW IT TURNING NORTHWARD

ALONG THE CARIBBEAN COAST OF THE YUCATAN PENINSULA AT DAYS 4 AND 5.

NEEDLESS TO SAY...THERE IS A MUCH HIGHER DEGREE OF UNCERTAINTY IN

THE 4 AND 5 DAY FORECASTS THAN NORMAL. FOR NOW THE OFFICIAL

FORECAST HAS BEEN ADJUSTED CLOSER TO THE MULTI-MODEL

CONSENSUS...TVCN...AND IS WEST OF THE PREVIOUS FORECAST BEYOND 72

HOURS.

[AderynCoch]

At least the ensembles are being a bit more helpful, aiming Matthew more towards the Gulf coast of Florida (anywhere from the Panhandle down to the Florida Strait, the latter including western Cuba along the way). Yesterday they really were all over the place. Development over the western Gulf is not being favoured at this time: I can only assume this is due to excessive weakening over land, as the shear forecast looks low.

In the short term, the track has moved slightly south and it doesn't look as though Matthew will escape interaction with Honduras (though even this can't be ruled out yet). There will be time to strengthen before then however as moderate wind shear relaxes over the next couple of days. Then things really sit on tenterhooks...

[AderynCoch]

Matthew now approaching landfall near the Honduras/Nicaragua border at 50mph. Tropical storm force winds are already ashore.

The track has shifted south again and the NHC are now going for dissipation over land, though they still admit great uncertainty past 48 hours:

000

WTNT45 KNHC 241457

TCDAT5

TROPICAL STORM MATTHEW DISCUSSION NUMBER 5

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152010

1100 AM EDT FRI SEP 24 2010

AN AIR FORCE PLANE INVESTIGATING MATTHEW THIS MORNING FOUND THAT THE

TROPICAL CYCLONE HAS NOT BECOME ANY STRONGER. EASTERLY SHEAR HAS

KEPT THE LOW-LEVEL CENTER NEAR THE NORTHEAST EDGE OF A ROUND BLOB

OF VERY DEEP CONVECTION AS INDICATED BY THE AIR FORCE PLANE AND

MICROWAVE DATA. SATELLITE INTENSITY ESTIMATES SUPPORT AN INITIAL

INTENSITY OF 45 KNOTS...BUT DATA FROM THE RECONNAISSANCE PLANE SO

FAR SUGGEST THAT THIS ESTIMATE COULD BE GENEROUS. MATTHEW ONLY HAS

12 HOURS OR LESS TO STRENGTHEN BEFORE LANDFALL...AND GIVEN THAT THE

ENVIRONMENT IS ONLY MARGINALLY FAVORABLE FOR INTENSIFICATION DUE TO

SHEAR...THE OFFICIAL FORECAST NO LONGER FORECAST MATTHEW TO BECOME

A HURRICANE.

THE CYCLONE HAS INCREASED ITS FORWARD SPEED AND THE BEST ESTIMATE OF

THE INITIAL MOTION IS TOWARD THE WEST OR 275 DEGREES AT 17 KNOTS.

MATTHEW IS EMBEDDED WITHIN A STRONG DEEP EASTERLY FLOW AND THERE IS

HIGH CONFIDENCE IN THE FORECAST THAT THE CYCLONE WILL CONTINUE

WESTWARD OVER CENTRAL AMERICA FOR THE NEXT DAY OR TWO. BEYOND TWO

DAYS...MODELS SHOW DIFFERENT SCENARIOS AND THE FORECAST BECOMES

HIGHLY UNCERTAIN. THE MOST LIKELY SCENARIO IS THAT THE MID-LEVEL

CENTER CONTINUES WESTWARD AND DISSIPATES...WHILE THE LOW-LEVEL

CIRCULATION WEAKENS AND BECOMES PART OF A NEARLY STATIONARY BROAD

AREA OF LOW PRESSURE OVER CENTRAL AMERICA. SUCH A WEATHER PATTERN

WOULD LIKELY PRODUCE DANGEROUS TORRENTIAL RAINS IN CENTRAL AMERICA

OVER THE NEXT FEW DAYS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 24/1500Z 14.4N 82.2W 45 KT

12HR VT 25/0000Z 14.6N 84.2W 35 KT...INLAND

24HR VT 25/1200Z 15.4N 86.5W 30 KT...INLAND

36HR VT 26/0000Z 16.0N 89.0W 30 KT...INLAND

48HR VT 26/1200Z 17.0N 90.0W 25 KT...INLAND

72HR VT 27/1200Z 18.0N 90.5W 20 KT...POST-TROP/REMNT LOW

96HR VT 28/1200Z 18.5N 90.5W 20 KT...POST-TROP/REMNT LOW

120HR VT 29/1200Z 18.5N 90.5W 20 KT...POST-TROP/REMNT LOW

$$

FORECASTER AVILA

It just goes to show what a fine line these storms tread. Dissipation or not though, the risk of flooding and mudslides is a very serious one.

[summer blizzard]

http://www.ssd.noaa.gov/goes/flt/t1/rb-l.jpg

It made landfall just over an hour ago, and was strengthening in my opinion.

GFS still insistant on another centre forming north of Honduras then heading for western Cuba and the Florida Panhandle.

[summer blizzard]

It is very interesting but what appears to happen is Tropical Storm Mathew dissapates over land, however in 72-96 hours, the upper level moisture backs east between over the sea between Honduras and Belize and then forms a system (Nicole) which moves north strengthening. GFS has a Florida Panhandle hit as a category 2 hurricane.

[Paranoid]

Matthew appears to have strengthened while over land. After weakening to 45mph, the winds have increased again to 50mph. The convection Matthew has is also very impressive so he seems to be managing the passage across Honduras well (probably due to the proximity of warm water from the Carribean). How he'll fare over Mexico when its circulation is totally over land is a different matter.

[mountain shadow]

Matthew appears to have strengthened while over land. After weakening to 45mph, the winds have increased again to 50mph. The convection Matthew has is also very impressive so he seems to be managing the passage across Honduras well (probably due to the proximity of warm water from the Carribean). How he'll fare over Mexico when its circulation is totally over land is a different matter.

Is it possible Tropical Systems can develop over tropical rainforest?, drawing energy from the moisture in the canopy?

[summer blizzard]

Is it possible Tropical Systems can develop over tropical rainforest?, drawing energy from the moisture in the canopy?

Not in the sence that it would strengthen because of that, however systems can strengthen over land if a lack of moisture is the only bad thing, but shear, confluence, divergance are all good, though within 24 hours they do weaken rapidly.

[Paranoid]

It has happened before though, although only with weaker storms i think (below hurricane strength). It happened with TS Fay in 2008, that made landfall in Florida and reached its peak intensity while over land and managed to form an eye briefly, but if any intensification does happen, it is very shortlived.

[Cookie]

From Jeff masters

http://www.wunderground.com/blog/JeffMa ... rynum=1633

Forecast for the rest of the tropics

Most of the models continue to predict that by Wednesday, the remnants of Matthew, and/or a piece of a tropical disturbance over the Eastern Pacific off the coast of Guatemala, will evolve into a huge and very wet low pressure system that will start spinning over Central America and the Western Caribbean. NHC has been referring to this expected storm as a "monsoon low", and these sorts of storms are very dangerous for Central America and the Western Caribbean, even if they do not develop into a tropical storm. In October 2007, a similar monsoon low I dubbed "the sleeping giant" spent a week spinning over the region, dumping very heavy rains over all of Central America and the countries bordering the Western Caribbean. Rains from this system triggered flooding that killed 45 people in Haiti, damaged thousands of homes in Cuba, and caused havoc in Guatemala, El Salvador, Belize, Mexico, Jamaica, the Cayman Islands, and the Bahamas. A similar type of storm is likely to develop on Wednesday and Thursday, and most of Central America and the nations surrounding the Western Caribbean can expect to see dangerous flooding rains develop this week in association with this giant low. Most of the models also predict that this big low will eventually develop into a tropical storm or hurricane that would be drawn northwards over Cuba late in the week, and threaten the Bahamas, Florida, or the U.S. Gulf of Mexico coast. This is an exceptionally difficult system to forecast correctly, and the models have been coming up with some pretty unusual solutions as to what might happen. We'll just have to wait and see what unfolds over the next few days.

[Cookie]

Hundreds of people are believed to have been killed as they slept after a massive landslide buried 300 homes a remote area of southwestern Mexico.

Heavy rains in the mountainous Oaxaca state are believed to have triggered the landslide near Santa Maria Tlahuitoltepec, a town of around 9,000 people.

Governor Ulises Ruiz told Televisa that 500 or 600 people may have been killed, injured or buried alive in the landslide.

Read more: http://www.dailymail.co.uk/news/worldnews/article-1315930/Landslide-Mexican-town-buries-hundreds-people-alive-slept-beds.html?ito=feeds-newsxml#ixzz10rBswS9M

very sad, remenats of Matthew