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Saturday, August 06, 2005 |
| At 5 PM EDT, the center of Tropical Depression Nine was relocated to 19.0 North 43.2 West, 1305 miles east of the northern Leeward Islands and moving to the west-northwest at 13 mph. Maximum sustained winds are 35 mph and minimum central pressure is 1008 millibars (29.77"). Circulation became better defined to the north of the position given in the 11 AM advisory, hence the relocation. While the depression continues to be sheared, the depression does look stronger than it did this morning. There may be 35 knot winds in the system, however, no intensity estimates based on satellite imagery suggest a strength greater than 25 knots, so the official intensity estimate remains 30 knots. Dry air and shear will continue to plague the system through the next 48 hours though Sea Surface Temperatures will be gradually increasing. Model guidance has come in better agreement on a track that turns the storm north through the weakness in the ridge left by Tropical Storm Harvey. Because of the relocation to the north and the better agreeement in the models, the official forecast is to the north of the previous one. No surprises here. Impressive amounts of convection fired up today, though with the heavy shear, it is well to the east of the center. This depression will probably intensify fairly significantly once it clears this shear on Monday or so. As far as track goes, things are following my expectations expressed in my previous update, which more or less resemble the current NHC forecast. 2005 Hurricane Season, Weather comment []5:11:55 PM  trackback []
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| At 11 AM EDT, the center of Tropical Depression Nine was at 17.9 North 42.3 West, 1365 miles east of the northern Leeward Islands and moving to the west-northwest at 12 mph. Maximum sustained winds are 35 mph and minimum central pressure is 1008 millibars (29.77"). The depression's structure has not changed much. Relatively cool Sea Surface Temperatures, shear from the west, and dry air have conspired to keep the storm in check. Track forecast is problematic. The depression will soon be south of the weakness in the high pressure ridge due to the passage of Tropical Storm Harvey. Most models take the depression northward into this weakness. Confidence in the long-term forecast is low. Satellite imagery is suggesting that the center may be a bit further north than reasoned when the forecast was made. If that proves to be the case, then the forecast would have to be adjusted northward. The depression has fared well in the face of adversity. The situation is about as bad as it can and will get for the depression and it has held together. This despite a couple of forecast models predicting its demise. As far as the adverse factors go, the depression should have worked its way through it by Monday. The SST analysis shows warmer waters west of 50 West. Also by Monday, the depression should be clear of the shear being genrated by the upper level low that is at 40 West. For those reasons, development until a tropical storm until then. As far as the track forecast goes, I am in high confidence that this will not affect the east coast of the United States. A look at the last 11 storms to pass near the position of TD 9 at 11 AM shows that only one, Esther of 1961, affected land. That climatology plus the output of the forecast models (near unaminous in curving the storm away) plus my own analysis of the storm's progress and the synoptic situation in the Atlantic lead me to think that the storm will curve to sea, the only question is when. That said, the storm is still worth keeping an eye on for east coast residents. Any surprises to my expectations, however, will develop well before the storm is close to land, so it is not necessary to check up on the storm every six hours, once or twice a day will suffice. 2005 Hurricane Season, Weather comment []12:22:19 PM trackback []
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© Copyright
2005
Charles Fenwick
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Last update: 9/15/2005; 9:44:25 AM .
Last update: 9/15/2005; 9:44:25 AM .
