8/31 UPDATE - 94L and its Future; Cat 4 Jimena Heading for Baha California
August 30, 2009 10:30 AM EDT
94L's center is difficult to discern on satellite imagery. A large burst of convection has developed near the center and maintained cold cloud tops. Impressive high rain rate banding was also noted in all directions. After starring at RGB, I'll agree with the Navy’s position at 14.4N, 51.1W. This location is within the southwestern quarter of the burst of convection, which therefore could be seen as the start of a CDO. 94L is traversing warm waters of 28-29°C, with very warm SST’s of 29-30°C near the Lesser Antilles. Buoy 41040 is located about 120 miles SW of the center and is reporting an MSLP of 1009.9 mb and winds out of the NE.
The upper level anticyclone which has been moving along with 94L has become better established. Much of 94L's central region is under less than 10 knots of shear. The anticyclone's outflow is colliding with a shear axis well to the north, causing shear to rise to the north and west. However, the anticyclone is largely keeping that shear from preventing organization (see image below). Given that SHIPS keeps shear under 10 knots through 72 hours, 94L should slowly but steadily develop and intensify through Day 5.
The models continue struggling to get a good grip on 94L. There is much disagreement on precisely how much of a northerly component the developing weakness will induce. In my opinion CMC and HWRF show too much of a northerly track and are overaggressive with both 94L’s future intensity and the weakness. ECMWF is the only global model showing 94L crossing through the Leewards and into the NE Caribbean. The best performing models thus far (or, rather, the models with the least track errors) are LBAR and BAMS. While LBAR tracks 94L near Guadeloupe, BAMS has the system moving NW about 150 miles NE of Anguilla in 60 hours. I continue to favor the BAMS track which maintains a WNW to NNW movement and puts the ridge back in past 96 hours, shoving whatever may become of our invest back west north of the islands.
Taking into account current satellite presentation, I would not be surprised to see a depression today and ERIKA by Wednesday. A majority of the intensity guidance agree on a 50-65 mph TS in 72 hours, and given warm waters, I agree with this. I give this system a 65% chance of genesis within the next 48 hours.
******Hurricane JIMENA (CAT 4 - PACIFIC)******
Jimena continues to grow stronger in the Eastern Pacific, with winds now up to 145 mph and a minimum central pressure at 940 mb, and it's not out of the question that the storm will flirt with Cat 5 intensity. Hurricane wateches have been issued for the tip of Baja California including Cabo San Lucas. IR shows that the pinhole eye has filled in, a possible sign of an EWRC. Jimena is expected to landfall on the west coast of the peninsula as a major hurricane around 11 PM local time on Tuesday.
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(Full Resolution) IR overlayed with wind shear, from the University of Wisconsin.