TropicalWxWatcher
08-09-2004, 06:41 PM
http://www.independentwx.com/atlanticdiscussion.html
Note: Our forecast products are unofficial. Please read our disclaimer.
IWIC Atlantic Tropical Weather Discussion - 09 August 2004 - 8:15 PM EDT
The remnants of Tropical Depression 2 was upgraded to Tropical Storm status by the Tropical Prediction Center as of 5PM EDT. Earlier this morning, it was mentioned that once the mid-level circulation reached the surface, we could easily have Bonnie on our hands. Sure enough, the reconnaissance aircraft that has been flying through the storm all day found maximum sustained winds near 55MPH. The reasoning behind keeping winds only at 45MPH is a good question. Winds near 55MPH are continuing to be reported. In fact, the recon is now indicating that a closed eyewall is present, certainly indicitive of a well-defined storm. Maximum sustained winds should increase 5-10MPH by the 11PM EDT advisory. It should also be noted that the center is only 8 miles across.
We discussed a lot in the morning discussion. One of the things we mentioned, was the possibility of rapid strengthening and the potential of the storm reaching minimal hurricane status. There has been no rapid intensification thus far. However, we now have a moderate tropical storm with approximately 72 hours remaining for further intensification. The GFDL has since backed off on the idea of the storm becoming a Category 1 just prior to landfall. Then again, the model was not initialized with tropical storm force winds in the last run. Meanwhile, the dynamical SHIPS model is forecasting an 83 knot hurricane in 72 hours. Water vapor imagery and shear data indicate that upper level winds are very light, with perhaps just a slight northerly wind, certainly not enough to hinder development. Dry air in the area could also keep things somewhat in check. But a hurricane still cannot be ruled out. Compact tropical systems can develop in a hurry as long as favorable conditions are in place. A strong tropical storm and possibly even a minimal hurricane is expected at landfall.
The forecast track is not yet certain, but we are now at the point to where we can narrow down the area that is most at risk. Bonnie is being guided by the subtropical ridge over the western Atlantic. The cold front that is stalled along the Gulf Coast weakened the western flank of the ridge quite a bit over the past week. The longwave troughing over the eastern United States is expected to be reinforced by more upper level energy diving out of western Canada. A curve to the north and northeast is expected to begin within 36-60 hours. But it is difficult to pinpoint exactly when the curve will be made, and that is critical. Based on satellite trends and the available tropical models, the center of Bonnie is expected to graze extreme southeast Louisiana before hitting the Florida panhandle between Pensacola and Panama City. We are in line with the Tropical Prediction Center forecast path. Any change would only be a very slight deviation to the west through 48 hours.
Tropical Depression 3 has formed in the eastern Caribbean Sea. TD3 has continued to become better defined over the course of the day. Both the poleward and equatorward outflow channels are perfect, with a strong anticyclone in the upper levels enhancing the ventilation process. Upper level wind shear does not appear to be a problem in the forseeable future. In addition, the abundant level of moisture associated with the depression will protect the core from any dry air entrainment. Atmospheric conditions are simply excellent for significant development. As stated earlier, the only problem the depression currently has is relative shear...the depression is moving too fast. As the depression continues moving westward underneath the subtropical ridge, the low level steering pattern will weaken, and the storm will begin to slow down. This is a cause for concern in terms of rapid intensification. We are highly awaiting the data that a reconnaissance aircraft will send the TPC tomorrow afternoon. It would not at all be surprising if the hurricane hunters find a moderate to strong tropical storm. It is quite possible for Charlie to become a hurricane within 72 hours and possibly even a major hurricane once it begins to approach the southeast Gulf of Mexico.
It is fairly likely that TD3 will take a path towards the Yucatan Channel, with the eyewall likely passing just south of Jamaica. In about 36 hours, hurricane watches and warnings will likely be issued for the entire island of Jamaica and the southern coast of Cuba. By day five, the storm will be entering the southeast Gulf of Mexico. The main question is, where will the depression head once in the Gulf? The system is still five days away from the Gulf, and at least seven days away from a landfall along the US Gulf Coast. Any forecast this far out can change dramatically by the time the weekend comes around. This is a very general forecast, but all Gulf Coast residents between Morgan City, Louisiana and Tampa, Florida should be especially concerned about this developing cyclone. The exact location of landfall will be decided based upon the timing of when the second wave of upper level energy in the southeast pulls out and how quickly the ridge begins to build west. In all likelyhood, the US drought of having no major hurricane landfalls is coming to an end.
Note: Our forecast products are unofficial. Please read our disclaimer.
IWIC Atlantic Tropical Weather Discussion - 09 August 2004 - 8:15 PM EDT
The remnants of Tropical Depression 2 was upgraded to Tropical Storm status by the Tropical Prediction Center as of 5PM EDT. Earlier this morning, it was mentioned that once the mid-level circulation reached the surface, we could easily have Bonnie on our hands. Sure enough, the reconnaissance aircraft that has been flying through the storm all day found maximum sustained winds near 55MPH. The reasoning behind keeping winds only at 45MPH is a good question. Winds near 55MPH are continuing to be reported. In fact, the recon is now indicating that a closed eyewall is present, certainly indicitive of a well-defined storm. Maximum sustained winds should increase 5-10MPH by the 11PM EDT advisory. It should also be noted that the center is only 8 miles across.
We discussed a lot in the morning discussion. One of the things we mentioned, was the possibility of rapid strengthening and the potential of the storm reaching minimal hurricane status. There has been no rapid intensification thus far. However, we now have a moderate tropical storm with approximately 72 hours remaining for further intensification. The GFDL has since backed off on the idea of the storm becoming a Category 1 just prior to landfall. Then again, the model was not initialized with tropical storm force winds in the last run. Meanwhile, the dynamical SHIPS model is forecasting an 83 knot hurricane in 72 hours. Water vapor imagery and shear data indicate that upper level winds are very light, with perhaps just a slight northerly wind, certainly not enough to hinder development. Dry air in the area could also keep things somewhat in check. But a hurricane still cannot be ruled out. Compact tropical systems can develop in a hurry as long as favorable conditions are in place. A strong tropical storm and possibly even a minimal hurricane is expected at landfall.
The forecast track is not yet certain, but we are now at the point to where we can narrow down the area that is most at risk. Bonnie is being guided by the subtropical ridge over the western Atlantic. The cold front that is stalled along the Gulf Coast weakened the western flank of the ridge quite a bit over the past week. The longwave troughing over the eastern United States is expected to be reinforced by more upper level energy diving out of western Canada. A curve to the north and northeast is expected to begin within 36-60 hours. But it is difficult to pinpoint exactly when the curve will be made, and that is critical. Based on satellite trends and the available tropical models, the center of Bonnie is expected to graze extreme southeast Louisiana before hitting the Florida panhandle between Pensacola and Panama City. We are in line with the Tropical Prediction Center forecast path. Any change would only be a very slight deviation to the west through 48 hours.
Tropical Depression 3 has formed in the eastern Caribbean Sea. TD3 has continued to become better defined over the course of the day. Both the poleward and equatorward outflow channels are perfect, with a strong anticyclone in the upper levels enhancing the ventilation process. Upper level wind shear does not appear to be a problem in the forseeable future. In addition, the abundant level of moisture associated with the depression will protect the core from any dry air entrainment. Atmospheric conditions are simply excellent for significant development. As stated earlier, the only problem the depression currently has is relative shear...the depression is moving too fast. As the depression continues moving westward underneath the subtropical ridge, the low level steering pattern will weaken, and the storm will begin to slow down. This is a cause for concern in terms of rapid intensification. We are highly awaiting the data that a reconnaissance aircraft will send the TPC tomorrow afternoon. It would not at all be surprising if the hurricane hunters find a moderate to strong tropical storm. It is quite possible for Charlie to become a hurricane within 72 hours and possibly even a major hurricane once it begins to approach the southeast Gulf of Mexico.
It is fairly likely that TD3 will take a path towards the Yucatan Channel, with the eyewall likely passing just south of Jamaica. In about 36 hours, hurricane watches and warnings will likely be issued for the entire island of Jamaica and the southern coast of Cuba. By day five, the storm will be entering the southeast Gulf of Mexico. The main question is, where will the depression head once in the Gulf? The system is still five days away from the Gulf, and at least seven days away from a landfall along the US Gulf Coast. Any forecast this far out can change dramatically by the time the weekend comes around. This is a very general forecast, but all Gulf Coast residents between Morgan City, Louisiana and Tampa, Florida should be especially concerned about this developing cyclone. The exact location of landfall will be decided based upon the timing of when the second wave of upper level energy in the southeast pulls out and how quickly the ridge begins to build west. In all likelyhood, the US drought of having no major hurricane landfalls is coming to an end.