Clark
Meteorologist
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Tropical Storm Franklin, currently located about 240 miles due east of Melbourne, FL, is maintaining status quo this evening. The center, clearly evident on long-range radar out of Melbourne, continues to drift northward, lessening the threat to Florida as time goes along. Model guidance has come into better agreement on sending the storm to the north and east through time, recurving somewhat sharply around the subtropical ridge in the western Atlantic. I see no reason to go against this thinking at this time, given the erosion of the western extent of the ridge, current motion of the storm, and the evolution of the trough pattern in the eastern US. The storm may slow down considerably in a few days near Bermuda before accelerating ahead of a secondary trough, but right now I don't see anything out there to recurve it back towards the United States.
While satellite-derived shear values are rather low over the storm, a persistent southwesterly flow continues across the storm, limiting convective development on the south and west sides of the storm. This is clearly evident on infrared and water vapor imagery, particularly in noting the cloud tops over the Florida peninsula (due to this afternoon's seabreeze) being taken towards the storm by the upper-level flow. This coupled with the storm's current state of disorganization should keep the storm near or below the forecast for the next couple of days, with convective bursts during the diurnal convective cycle likely to result in much of the intensification until that point.
Franklin remains a small storm, meaning it can both spin-up and spin-down rather rapidly. Given the conditions it has persisted through to get to this point, spinning-down isn't terribly likely. If the shear were to relax, potentially as the storm speeds up towards the north and east, the storm may undergo some modest intensification. A threat to Bermuda in about 3 days is there, but it remains to be seen how much of one. As with Emily's initial forecasts and its forecasts coming off of the Yucutan, I believe the projections are a little high for the next 2-3 days and slightly low for the long-term. Waters aren't terribly warm past Bermuda and shear is expected to increase -- the storm may start to undergo transition near the end of the period; nevertheless, it likely won't be a major hurricane at 40 N as the 12Z predicts -- but mid-range category 1 status in 4-5 days is not out of the question.
Meanwhile, a weak low pressure area has formed along the axis of the wave currently crossing the Yucutan Peninsula. Located in northern Belize, the area of low pressure should enter the Bay of Campeche sometime on Saturday, with the current pattern favoring slow motion towards the west and northwest. The ridge over the Central Plains is retrograding somewhat towards the west, but given the flow around its southeastern periphery and the retrograding upper-low now over south-central Mexico, the disturbance should continue on a path that would take it not far from Emily's landfall position near the end of the weekend.
There has been some upwelling due to Emily near the Mexican east coast and north of the Yucutan, but this disturbance should stay sufficiently far south in the short-term to provide favorable SSTs for its development. SHear values are low, thanks to an upper-level anticyclone nearly coincident with the disturbancem and convective development is being aided by a diffluent upper-level flow provided by the upper-low to its west; this upper-low could help serve as an outflow channel for the storm as well. Depending upon how quickly it can get organized in the Gulf, the entire spectrum of TS intensities is possible out of this feature over the next three days, with the midrange (as always) being the most likely. The greatest threat is to Mexico, but those in Texas should stay tuned in case this changes.
Elsewhere in the tropics...
* The remnants of Emily have reached the northern end of the Gulf of California, helping to enhance the development of a mesoscale convective complex just south of Arizona and bringing about the start of the summer monsoon to the Southwest United States. Thunderstorm activity remains spotty at best over Arizona, Utah, and New Mexico, meaning the potential for excessive temperatures, fires, and heat index values remains.
* The low that emerged off of the coast of Africa several days ago has dissipated in the midst of the Saharan dust layer, but an area of convection has flared up just to its southeast along the . Conditions here are more favorable for development than they are further north, with warmer waters and lower shear ahead. Given the forcing from the parent tropical wave and convergence associated with the , this feature has potential for some slow development over the next couple of days. In a couple of days, we might be talking about yet another Central Atlantic tropical cyclone, likely to steer through the Caribbean in some shape or form over the next week or so on a path similar to the path of Emily. One to watch out for down the line.
More as events warrant...
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