UPDATE/5:00 p.m. Emily downgraded to post-tropical cyclone, Gert falters to tropical depression; Gulf storm now tropical depression 9.
Following the weather activity in the Atlantic and Gulf of Mexico the past several days has been like a large-scale game of musical chairs — first there's Emily the chair, then there's not. Then there's Gert the chair, then there's not. It's enough to make a journalist's head spin like a, well, hurricane.
There are still five areas of interest that are dominating the tropics today, they are just in different configurations then they were even Monday morning.
"So let’s start with INVEST-92, which is a tropical wave off the west coast of Africa and has a high chance of becoming a depression soon," Jeff George, meteorologist for the Florida Public Radio Emergency Network, said.
"But Post-Tropical Cyclone Emily and Tropical Storm Gert will continue to weaken over the open waters of the Atlantic this week. Now, Tropical Storm Franklin will start turning away from the U.S. the next couple days, but has a chance to become a hurricane before weakening this weekend," George said.
"Then finally we have Potential Tropical Cyclone 9 in the Gulf, that will likely turn into a Tropical Storm Harold before ramming into the southeast coast of Texas tomorrow."
George said that none of these areas are forecasted to impact Florida, but the tropics are expected to stay active as we head towards peak season the next few weeks.
Since FPREN's George made those remarks this afternoon Gert has spun down to tropical depression status. And that Potential Tropical Cyclone 9 is now Tropical Depression 9.
More from The National Hurricane Center's Monday forecast on the current active systems:
Tropical Storm Franklin:
Franklin is the most interesting of the bunch, but not an especially well-organized tropical cyclone Monday afternoon. The NOAA reconnaissance mission has been sampling the storm for a large part of the afternoon, and found a center to the south of where the position was estimated earlier today. In addition, the winds on the southwest side of the circulation are more diffuse, and overall the circulation is a bit more elongated than what the plane found yesterday at this time. Peak 850-mb flight level winds were at 48 kt just to the northwest of the circulation, which supports an intensity between 40-45 kt after using a standard reduction. The initial intensity will remain at 45 kt for this advisory.
The tropical storm has been meandering today, and my best guess at an initial motion is a drift south of due west at 265/4 kt. Given the current elongated nature of the surface circulation, the short- term track forecast is tricky, ranging from the GFS on the east side of the guidance envelope that has a center reformation to the northeast, and the CMC and ECMWF which are on the western side of the guidance envelope. The steering currents are also poorly defined currently due to a large mid-oceanic trough in the western Atlantic disrupting the flow pattern. Mid-level ridging eventually builds in to the east of Franklin, which should ultimately induce a northward motion by 24-36 h, and then northeastward between 48-96 h, as a mid-latitude trough reinforces the weakness to the north of the storm.
The track guidance has slowed down again compared to the previous cycle, prolonging the time the system will remain over the Caribbean Sea before it moves over Hispaniola. The NHC track forecast is once again slower than the previous cycle and has also been nudged a touch westward compared to the previous one, but is now a bit east of the simple and corrected consensus aids.
Given Franklin's current structure, here is skepticism that there will be a lot of meaningful near-term intensification, especially while moderate vertical wind shear continues to disrupt the convective structure. However, both the GFS- and ECMWF-based SHIPS guidance indicate that the shear will briefly drop under 10 kt in about 24 hours, and when combined with warm 29 C sea-surface temperatures, it still seems prudent to show some intensification before Franklin moves inland over Hispaniola. Significant land interaction over the higher terrain will then lead to weakening, which could be underdone here given the current track over some of the most mountainous terrain. After Franklin emerges into the western Atlantic, another round of southwesterly shear may slow the rate of reintensification, and the latest NHC intensity forecast is a bit more subdued than the previous one, once again electing to follow the HCCA consensus aid. Given the complex intensity factors mentioned above, this is a low confidence forecast.
KEY MESSAGES:
1. Heavy rainfall from Franklin is expected across portions of Puerto Rico and Hispaniola through the middle of the week. The heavy rainfall may produce areas of flash and urban flooding as well as river rises and mudslides. Across Hispaniola, significant and potentially life-threatening flash flooding is possible Tuesday into Wednesday.
2. Franklin is expected to bring tropical storm conditions to portions of the Dominican Republic and Haiti beginning on Tuesday where Tropical Storm Warnings are in effect.
Post-Tropical Cyclone Emily:
Emily has been devoid of deep convection for nearly 15 hours and no longer meets the definition of a tropical cyclone.
Although sea surface temperatures are sufficiently warm to support occasional bursts of convection, strong wind shear and a very dry environment should prevent it from re-organizing as a tropical cyclone for at least the next couple days.
In about 3 days, the remnant low is forecast to turn northward as it encounters a deep-layer trough over the central Atlantic. While it turns, Emily could briefly encounter a more favorable upper-level wind pattern, which could support the redevelopment of convection.
However, the low-level center may also become stretched and ill-defined at the same time. Regeneration as a tropical cyclone does not appear likely enough to explicitly forecast it at this time. Information on the potential for regeneration will be included in future Tropical Weather Outlooks, if necessary.
Tropical depression Gert:
Gert continues to be sustained by a very small but persistent area of convection east of its surface wind center. ASCAT data that came in 5 minutes after the release of the previous advisory showed peak winds of just above 25 kt well to the north of Gert's center. South of Gert is mostly light and variable winds. Assuming Gert has weakened further a little since then, its intensity has been lowered to 25 kt.
All models continue to suggest that Gert will struggle in the face of strong upper-level winds and a very dry surrounding environment.
The small tropical depression will likely either lose organized deep convection and become a remnant low or dissipate at almost any time.
There is a chance that Gert could persist as a remnant low beyond the 24 h shown in the NHC forecast, but it is unlikely that Gert will have sufficient organized deep convection to be classified as a tropical cyclone in that case. Gert is moving west-northwestward, but the depression or its remnants should turn more northwestward by tomorrow. No noteworthy changes were made to the NHC track or
intensity forecasts with this advisory.
1. Tropical Depression 9:
An ASCAT pass from a few hours ago and data from the Air Force Hurricane Hunters indicate that the system now has a closed and fairly well-defined center of circulation. In addition, deep convection has been persisting over the central and western Gulf of Mexico. The system now meets the definition of a tropical depression, and the initial intensity is estimated to be 30 kt. The far outer bands of the depression are nearing the coast of Texas and northern Mexico, and they are expected to begin moving inland tonight.
The depression is moving fairly quickly to the west at 16 kt on the south side of a strong mid-level ridge located over the centralUnited States. A continued quick west or west-northwest motion is expected, taking the system over southern Texas by midday Tuesday.
The models are in fairly good agreement, and little change was made to the previous NHC track forecast.
Strengthening is expected, but the limited time over water and its current broad structure suggest that rapid intensification is unlikely. The system is expected to move inland between the 12- and 24-hour points so it is possible that the system gets a little stronger than the forecast intensity values.
KEY MESSAGES:
1. Heavy rainfall from the depression is expected across South Texas on Tuesday and Wednesday, and may produce areas of flash and urban flooding. Across portions of northern Coahuila and northern Nuevo Leon in Mexico, flash flooding with possible landslides in mountainous terrain is expected Tuesday into Wednesday.
2. Coastal flooding is possible along the south Texas coast tonight through Tuesday morning.
3. Tropical storm conditions are expected in the warning area and are possible in the watch area beginning early Tuesday.
2. Eastern Tropical Atlantic (AL92):
A large area of disorganized showers and thunderstorms over the far eastern tropical Atlantic is associated with a tropical wave located near the Cabo Verde Islands. Environmental conditions appear conducive for gradual development of this system, and a tropical depression is likely to form later this week while it moves west-northwestward across the eastern tropical Atlantic.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...high...70 percent.
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