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Remains of TD 7 kill two in Trinidad; 93L too dry to develop

By: Dr. Jeff Masters, 3:31 PM GMT on August 12, 2012

The remains of Tropical Depression Seven brought heavy rains to Trinidad on Saturday, unleashing flooding and mudslides that killed two people and left two others missing in Diego Martin. The storm is headed westward at 20 mph across the Caribbean, but high wind shear of 15 - 25 knots should prevent the system from regenerating. None of the reliable models forecasts that TD 7 will regenerate, and the storm should arrive in Mexico's Yucatan Peninsula on Wednesday. In their 8 am Tropical Weather Outlook, NHC gave ex-TD 7 a 10% chance of becoming a tropical depression by Tuesday morning.


Figure 1. An analysis of the Saharan Air Layer (SAL) from 8 am EDT August 12, 2012. Very dry air from the Sahara (yellow and orange colors) surrounds the tropical wave designated 93L in the Central Atlantic. Image credit: University of Wisconsin CIMSS and NOAA/Hurricane Research Division.

93L
A large tropical wave(Invest 93L) is located in the Central Atlantic about 700 miles west-northwest of the Cape Verde Islands. Satellite loops show a pronounced spin to the atmosphere at mid levels, but little in the way of heavy thunderstorm activity. The latest Saharan Air Layer Analysis from the University of Wisconsin shows that 93L is surrounded by a large area of dry air from the Sahara, which has infiltrated into the storm. This dry air will be a significant impediment to development, as the 8 am EDT run of the SHIPS model predicts that mid-levels of the atmosphere will remain very dry during the next four days. None of the reliable computer models develop 93L during the coming five days, and the storm is expected to move west-northwest and then north, recurving well to the east of Bermuda. In their 8 am Tropical Weather Outlook, NHC gave 93L a 10% chance of becoming a tropical depression by Tuesday morning. The GFS model is predicting 93L will develop into a tropical depression in about a week, once the storm recurves and begins heading northeast. At this point, it does not appear 93L will trouble any land areas.

I'll have a new post on Monday.

Jeff Masters

Hurricane

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