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Monday, August 08, 2005 |
| At 5 PM EDT, the center of Tropical Depression Irene was at 22.5 North 51.5 West, 810 miles 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 1009 millibars (29.80"). While convection has increased, the low level center remains exposed so the system is held at tropical depression strength. Irene is struggling to reorganize in an enviroment that features moderate shear and dry air. Intensity forecast is essentially unchanged and is a compromise between the SHIPS model (which brings Irene near hurricane strength in the end of the period) and the GFDL (whick kills of Irene in 48 hours). New track forecast is essentially an update of the previous one. Models have come into slightly better agreement with the general scenario of Irene moving around the periphery of a low-mid level ridge of high pressure. Later part of the forecast is low confidence due to the great spread in the models In other news, the last Tropical Storm Harvey Advisory was issued by the National Hurricane center at 5 PM as he loses his tropical characteristics over the cold waters of the North Atlantic. As far as Irene goes, her skeletal appearanc continues even though the latest burst of convection is the most subsantive there has been in the past 24 hours. She's in a pretty fragile state, it is no surprise that some models want to dissipate her. At one point this afternoon her low-level circulation appeared to be open, which is certainly a bad thing (it has since closed off again). While the specifics remain to be a pain, the general idea of the track forecast is straight-forward. Extremely unlikely that Irene will affect the U.S. mainland; outside chance of affecting Bermuda. 2005 Hurricane Season, Weather comment []5:38:54 PM  trackback []
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| At 11 AM EDT, the center of Tropical Depression Irene was at 22.4 North 50.7 West, 855 miles east-northeast of the northern leeward islands and moving to the west-northwest at 16mph. Maximum sustained winds are 35 mph and minimum central pressure is 1009 millibars (29.80"). Low level circulation of Irene has become increasingly separated from the convection. An earlier Quikscat pass showed some 35 knot winds in the convection. However, since the convection has abated it is assumed that winds are currently no stronger than 30 knots. Track and intensity forecasts are more intertwined than usual. With Irene being weaker her motion is more westerly than before so the track forecast is shifted to the left (west). Track forecast is very similar to the forecasts of the GFDL, ECMWF and BAMS models. Irene's finest hours were about 24-30 hours ago. Since then it has been very rough. Every time convection fires up in the place where it should be happening (over the center) it quickly gets blown off by mid-upper level winds. Because of that Irene has had a skeletal appearance for most of the past day. The early 12Z model guidance is fairly spread out. (The tracks of the BAM and GFDLthat the official forecast is similar to are more or less in the middle). Part of the split in the model guidance is because of differing forecasts on how she will develop (and if she survives). If Irene remains very weak or her central circulation gets wiped out, then she and her remnants would move west. If she manages to stay together and develop then the track would be more northerly and eventually out to sea. The official forecast is a compromise of the two ideas. 2005 Hurricane Season, Weather comment []12:08:38 PM trackback []
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© Copyright
2005
Charles Fenwick
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Last update: 9/15/2005; 9:46:03 AM .
Last update: 9/15/2005; 9:46:03 AM .
