Tropical Depression Six is not yet a tropical storm, as evidenced by the maximum winds of 25-30 knots (30-35 mph) seen on this morning's 4:33am EDT QuikSCAT pass (Figure 1). TD 6 has managed to consolidate the two circulation centers it was struggling with yesterday into one large circulation center. The storm's maximum winds are occurring in bands well removed from this broad center, and it will probably take another day before the winds tighten up around the center and the TD 6 can intensify into a tropical storm. Interfering with this process will be about 10-15 knots of shear and some dry air to the north.
The computer models all forecast that TD 6 will pass north of the Lesser Antilles Islands, although it is too far in the future to be confident of this forecast. A complicating factor is the development of a new disturbance about 800 miles to the east-southeast. This new disturbance, officially designated "Invest 91L" this morning by NHC, is close enough to alter both the strength and track of TD 6. Anytime two storms get within 13 arc-degrees of each other (900 miles), the two storms tend to rotate around a common center (the Fujiwhara effect). The computer models do make some allowances for this effect, but are not very good at handling it. For this reason, one should be suspicious of the track forecasts for TD 6 and 91L as long as they are so close. The intensities of both storms can also change as a result of the interaction, with both storms intensifying at a slower rate than they otherwise would, or one storm growing at the expense of the other. If the two storms approach within about 7 arc-degrees of each other (480 miles), this is considered the "zone of death" where one cyclone will surely destroy the other. The surviving storm will not be a "superstorm" that has the combined size and strength of the two storms, however.
The long-range GFS model forecast continues to show TD 6 becoming a powerful hurricane that threatens Bermuda, but recurves out to sea well east of the U.S. East Coast. Again, it is too early to be confident of this forecast, given the interactions that may occur with 91L and the inherent uncertainties in long-range hurricane track forecasts. The wind shear later this week is forecast to drop significantly, so if TD 6 manages to survive the next 36 hours, it is likely to become a hurricane.
Figure 1. QuikSCAT satellite winds from 4:33am EDT Tuesday September 5 2006. Wind speed and direction are coded according to the standard station model, and are color coded (in knots) according to the color scale at the upper right (10 knots = 11.5 mph). Black winds barbs occur where there is rain, and one cannot trust the wind speeds measured in those areas. Tropical storm force winds (35 knots) are colored red and need to have 3 long bars and one short bar attached to the end of the "barb"; there is one barb like this on the east side of TD 6, but it is pointing a different direction than the other barbs around it, and is surrounded by rain-contaminated (black) barbs. One should be suspicious of the accuracy of this lone tropical storm force wind barb.
Figure 2. Preliminary model tracks for Invest 91L, a well-organized tropical wave a few hundred miles west of the Cape Verde Islands.
Cape Verdes Islands tropical wave
A strong new tropical wave emerged from the coast of Africa Saturday and is a few hundred miles west-southwest of the Cape Verde Islands. The wave has a closed circulation, and visible satellite imagery from this morning shows an increase in thunderstorm activity on the west side. The wave is over warm water and is under a modest 10 knots of wind shear, and could be Tropical Depression Seven by Wednesday. Due to its more southerly starting position, this system is more likely to be a threat to land than TD 6.
Carolinas
North Carolina is still suffering flooding problems from Ernesto. Where Ernesto came ashore at Cape Fear, North Carolina, the North Cape Fear River is at 16.6 feet, and flood stage is only 10 feet. This is the second highest flood on this river; only Hurricane Floyd of 1999 caused a higher flood. With a strong cold front expected to move through tonight and stall offshore, North Carolina will receive another 1-2" of rain that will make flooded areas slow to recover. Once this cold front does stall over the warm Gulf Stream waters, we need to watch the area off the Carolina coast for possible tropical storm development.
Ioke
Ioke continues its slide into oblivion, and is now a mere tropical storm. Ioke is caught in a large trough of low pressure that is weakening it and recurving it out to sea. Ioke is not a threat to any land.
Next update
I'll have an update Wednesday morning, unless there's something interesting to report on this afternoon.
Jeff Masters
Tropical depression Ernesto leaves downed trees ,broken branches and sunken vessels in its' wake...
Water Street, looking west. Abandoned sailboat.
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We got the bubble-headed-bleach-blonde who comes on at five
She can tell you bout the plane crash with a gleam in her eye
It's interesting when people die-
Give us dirty laundry
Flo is an odd looking creature........
statistics and history mean absolutly squat!
Yes it may be true until one does and then it becomes part of the history.
But doggone if lots of folks here don't forget that on a daily basis. No matter what the computers predict (and they're only as good as the info fed into them) or what the NHC, TWC, CNN, FBI, CIA, NAACP, etc. or anyone here predicts, it's pretty much guessing. Mother Nature plays by her own rules...and she's not showing them to any of us...at least she hasn't yet.
Look at your statement again and tell me who the fool is.
Also you have now proven you have taken zero formal met classes. the intro classes all focus heavily on statistics and history. Of course you are here on an amateur blog. You probably know far more than any professor or professional forcaster.
On a side note, I can only listen to Echoes after eating a handfull of magic mushrooms.
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RcDeer....I've been posting here for years dear. I just don't post that often. And I hardly ever post on this blog. There's only one forecaster I follow on WUBA and he's got his own blog. I post more on this blog when a major storm is nearing land and we get scared newcomers looking for assistance.
guess you're right....so then...we should pay no special mind to the tropics in oct and sept....there should be no "hurricane season"...models...based on statistics such as movements...because hey..they all boil down to a statistical equation..should not be looked at or even run...
personally...i think climatology is poo - pooed a bit much on this blog..but i still love ya
Any one remeber Gloria ? Looks just like
it.
More here Maps and tracks
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