A weak trough of low pressure over the Northern Gulf of Mexico has created a small area of heavy thunderstorms off the coast of Alabama, which are moving west at 10 - 15 mph. Surface pressures are high in the region, wind shear is a moderately high 15 - 20 knots, and an upper level low is centered over the Yucatan Channel is bringing some dry air to the Gulf of Mexico. These factors will discourage development, and in their 8 am EDT Friday Tropical Weather Outlook, NHC gave the disturbance just a 10% chance of development by Wednesday.Figure 1.
A weak trough of low pressure over the Northern Gulf of Mexico created a modest area of heavy thunderstorms on Thursday afternoon, August 22, 2013. Image crest: NASA.
A tropical wave that emerged form the coast of Africa on Thursday night could develop by Wednesday the 28th midway between Africa and the Lesser Antilles Islands, according to this morning's 00Z run of the Navy's NAVGEM model. However, this forecast is dubious, as none of the other models is calling for tropical cyclone formation in the Atlantic during the coming week. The tropical Atlantic is dominated by dry, stable air, and a new outbreak of dust and dry air is exiting the coast of Africa this weekend, which will keeping the Tropical Atlantic dry though at least Thursday, August 29. Another tropical wave will come off the coast of Africa on Monday August 26, and these two tropical waves may be able to prime the tropical Atlantic for higher chances of development by leaving a moister environment for a vigorous tropical wave predicted to move off the coast of Africa on Thursday, August 29.
In the Eastern Pacific, Tropical Depression 9-E
is headed northwards along the coast of Baja California. Cold waters off the coast of Baja California will likely keep TD 9-E from strengthening into a hurricane, and the storm is not expected to make landfall in Mexico. However, moisture from TD 9-E will stream into Northwest Mexico over the weekend, increasing the odds of flash flooding. The models predict formation of a new tropical storm that will follow a similar path to TD 9-E along the west coast of the Baja Peninsula during the last few days of August.
I'll have a new post later today on the hurricane flood risk from Florida's Lake Okeechobee this year.