The area of disorganized showers and thunderstorms within the southwestern Caribbean Sea has now been designated as Invest 99L. Only a few of the models are seeing any type of organization so we will have to see if any other models fall in line but there are is only a few days before landfall will occur.
Tropical Storm Paula has been upgraded to Hurricane Paula as of the 5am advisory from the NHC. Hurricane Paula is forcast to strengthen to a possible category two hurricane, but this will for a very short time. Heat Oceanic content is very high right now and for the next few days but the atmosheric conditions will become less conducive for development as southwesterly upper level winds are forecast will begin to impact Hurricane Paula and a day or two later, dry air will be pushing southward and toward the center of circulation. Paula will is forecast to track to the NW then northward around the western periphery of a Mid-to Upper level ridge that is located over the northern Caribbean Sea. Model guidance is poor at best as there is no model consensus. The GFDL wants to make Paula a stronger system and head NE into Cuba and then into the Bahamas whereas the GFS, ECMWF, and HWRF want to keep Paula as a shallower and weaker system and keep Paula into the Western Caribbean and in some cases have landfall into Nicaragua. Since the forecast is for the upper level winds along with the drier air, the forecast is to follow the latter models BUT since the model guidance confidence is low, the GFDL guidance cannot be ruled out.
ADDENDUM: At 1:45pm EST the recon plane found winds of over 85knots or about 100MPH. Hurricane Paula is now a category 2 storm. Further strengthening for the next day or two is still forecast.
Below is the GFDL Model:
Below are the GFS, ECMWF, & HWRF Models:
Invest 98L has been upgraded to Tropical Storm Paula as of the 5PM advisory from the NHC. Recon earlier today found winds of 60 MPH, but that might be a little conservative. The forecast is for Tropical Storm Paula for additional strengthening and Paula is forecast to possibly become a hurricane within 24 hours according to the models SHIPS, and LGEM. Strengthening will only be possible for a few days, then slow weakening on days 4 or 5. For the next few days the track for Paula will be NW then N. The western edge of a ridge that extends across northern Caribbean is expected to weaken because of a deep-layered trough that will be moving eastward across the Southeastern US. After that forecast period most of the guidance is suggesting that the trough will move east and then leave Paula in an area of weak steering currents and Paula is expected to drift eastward for for a day or two then possibly drift southward. Model guidance after day 3 or 4 and confidence is quite low. Whether Paula will stay in the Western Caribbean and impact Nicaragua or head north and northeast unfortunately it is too difficult to forecast.
The system in the Western Caribbean has now been designated as Invest 98L. A few of the models want to take the system North and then turn NE over Cuba. The GFDL and HWRF want to let this system spin up into a tropical storm and hurricane. Although, at the time this cannot be discounted, most of the other models want to keep the system in the Caribbean. There is some cyclonic turning but convection has not been sustained over several hours. There is a very large area of dry air to the North, Northwest, and West of Invest 98L (as shown in the Water Vapor image below).
Hurricane Otto, still classified as a tropical cyclone with top winds of 85MPH will soon start the transition from tropical to extra tropical but gradually. Otto is between a large deep-layer trough of the coast of the US and a subtropical ridge over the Eastern Atlantic.
A couple waves in the atlantic (PGI48L, PGI49L) merged as Invest 97L. PGI49L was the dominant wave and eventually merged into one large system. There are two trains of thought on this system. One of the problems is that 97L is close to the ITCZ, but will probably gather some latitude soon. If not, then this system will be headed toward the Caribbean. So far, some of the models favor a WNW then NW track. The large trough off the East coast of the US will be headed NNE and this will weaken the ridge over the Mid-Atlantic and allow 97L to turn to the NW. The Euro and Canadian Model are forecasting that turn which will keep 97L away from the US coast. There might be a problem with those model runs as they were initialized with the two separate (PGI48L & PGI49L) systems. There is also a TUTT (Tropical Upper Tropospheric Trough) retrograding westward that is to the NW of 97L along with some dry air. If the TUTT doesn’t weaken, then this may keep 97L in check and continue the westward movement for a little longer. 97L is forecast possibly become TS Otto in a few days.
The problem is if the westward movement continues, this may allow 97L to slide under the ridge allowing the Northern Leeward Islands to be affected. This will also tend to keep the U.S. East Coast under the gun or possibly go through the Florida Straights and then a new trough pick up 97L anywhere from the Gulf States to Florida. Until the models can get a better grip on this system and have a more consensus between the models and since this is the peak of hurricane season, everyone should keep an eye on the tropics.
Tropical Depression Matthew has been downgraded to a remnant low. Although Matthew has been downgraded  and is just a low pressure system, Matthew along with a very large cyclonic gyre will continue to bring large amount of rain in Eastern Mexico and Central America.  The remains of Matthew is forecast to turn clockwise and either  be embedded into the gyre or dissipate. This monsoonal low is forecast to form somewhere in the western Caribbean and possibly head north to Jamaica, Cuba and Florida. With respect of the intensity if and when the new system forms is still unclear. Since the forecast is somewhat cloudy, all those in the Gulf States, Cuba, Jamaica, Florida, and the East coast of the U.S. need to keep and eye of this system. I will update this blog later today with some of the latest model runs.
ADDENDUM:
Below are three different model runs. Until forecasters can see where any storm may form – the model runs are just that – models. I have to discount the GFS run as it won’t to create two or three different tropical storms each running north over Cuba and then into south Florida but I am including it.
Pre-invest PGI48L is a new system in the Atlantic at roughly 12N – 34W. This is a system that has potential and may develop in in the next 3-5 days.
Tropical Storm Matthew which made landfall yesterday with 50mph winds has continued to trek W- WNW. As of the 2PM advisory, Matthew has been downgraded to a Tropical Depression. There is pretty much a consensus that Matthew will slow down and dissipate over Central America in the next two days. Copious amounts of rain has already made a bad situation worse in Honduras and it is expected to do the same in Belize, Guatemala and possibly Eastern Mexico. Although it is forecast for Matthew to dissipate, almost all the models are forecasting a new system to develop in the western Caribbean as the entire area is under the influence of a monsoonal low. If this forecast pans out, then there is the chance that the Gulf States, Florida, or the Eastern US may be impacted. These forecasts are very unpredictable at the moment as the fluid dynamics involved in the atmosphere are very complex. The few models below are for the next system (if any) and if named it would be Nicole.
Latest Satellite images of TD Matthew
Tropical Storm Lisa has been downgraded to a Tropical Depression. Although the deep convection has increased and has been better organized, and shear is still low – the dry air around Lisa is still a problem. Within 24-36 hours, Lisa should be in cooler SST’s along with an increase in shear. Lisa is forecast to continue the weakening trend and is forecast to be a post-tropical/remnant low in 120 hours.
ADDENDUM: as of the 5PM advisory from the NHC – Lisa has been upgraded to Tropical Storm Lisa.
A very bullish remnant low Julia has redeveloped but chances of it becoming anything tropical are very slim.
Invest 95L which will probably be Tropical Depression Fifteen as I speak as the first recon report is finding 39 MPH winds at flight level but you have to adjust for the surface winds which is roughly 32 MPH. A special Advisory from the NHC will be issued at 2:00PM. By later today or early tomorrow I am sure Tropical Depression Fifteen will be upgraded to Tropical Storm Matthew. Where this storm will have landfall is a big question mark. Some models still want it to make landfall closer to Honduras or Belize or will the other models want it make landfall somewhere further north in the Yucatan. To complicate things even more there is a possibility a new system might develop east of TD Fifteen and might be a part of the same gyre only to confuse the models even further. For the next 48 hours most do believe a W to WNW track is forecast for TD Fifteen. This a system that needs to be watched by all in the western Caribbean and all those in the Gulf states and especially Florida.
ADDENDUM: As of the 5PM advisory Tropical Depression Fifteen has been upgraded to Tropical Storm Matthew.
Hurricane Igor after battering Bermuda with category one hurricane winds has left and now is expected to pass by southeastern NewFoundland. Igor is expected to to become extratropical within 24 hours.
What was Tropical Depression Fourteen has been upgraded to Tropical Storm Lisa as of the 5:00am Advisory this morning by the NHC. Tropical Storm Lisa is headed directly north, but the motion now is in a weak steering current and in 24 hours Lisa will be begin to turn more NW due to a subtropical ridge from the north which will be building in. There is some disagreement within the models as to whether or not Lisa will be turned to the west because of the ridge amplifying or will there be a break in the ridge later on on the forecast period. The vertical shear will be very low for the next 48-72 hours so Lisa will have a chance to strengthen some but the mid level moisture envelope will be drying out and along with some cooler SST’s – strengthening will be limited.
PGI46L has now been designated as Invest 95L. For the next 24-36 hours, there is the possibility of some dry air wrapping into the system along with some northerly shear. This will limit some development. Beyond the forecast period, the environment will be conducive for development and most models want to keep 95L on a WNW path and eventually having landfall near Nicaragua but a possibility of of a more NW – to NNW and into Cuba/South Florida exists. Therefore, this system does need to be monitored carefully.
PGI47L which is just off the African coast will probably not be threat in any way and most models believe this sytem will dissipate.
Invest 91L has been upgraded to Tropical Storm status as of the 11AM Advisory. TS Igor came off Africa and was very healthy right from the beginning. Even before the upgrade, Igor had very good convection and the cyclonic turning was getting better each hour. At the present there is some easterly shear over Igor but shear will lift up and in a day or two the shear will be will then be light for a few days. This will allow intensification for days 2-4 and models are in agreement on this scenario. On day 5 shear is forecast to strengthen some and slow down further intensification.
A mid-level ridge in the eastern Atlantic is forecast to strengthen and this will keep TS Igor on a westerly track. This will also increase the forward speed of Igor. After a fews, a trough that is over the central Atlantic may cause the ridge to weaken and this may allow a more NW track. Beyond 5 days, any forecast would be prone to major error.
