Thursday, July 27, 2006

Atlantic Quiet For Now

The area of disturbed weather that brought heavy rain to southeastern Texas and parts of Louisiana on Wednesday is now well inland. Moisture from this system will feed more showers and thunderstorms today through the southern Plains.

Elsewhere across the tropical Atlantic we are tracking tropical waves along 35 west, south of 15 north, along 46 west, south of 22 north, along 67 west, south of 24 north and along 84 west, south of 20 north. All waves with the exception of the wave along 64 west are moving west at about 6-7 degrees longitude per day.

The wave along 67 west is moving west at 8-10 degrees longitude per day as it starts to interact with the Atlantic high to the north. This high is producing a stronger pressure gradient over the Greater Antilles. This wave will bring the eastern and northeastern Caribbean a few showers and thunderstorms, but it is moving too fast to bring any prolonged rainfall. A large mass of African Dust showing up on both the United States and European satellite images of the Atlantic is causing any showers and thunderstorms with this wave to diminish quickly. This wave will bring showers into the southern Bahamas and Hispaniola tomorrow and tomorrow night, then might enhance shower and thunderstorm development over the northern Bahamas and perhaps into southeastern Florida, Friday night into Saturday morning.

Tuesday, July 25, 2006

Disturbed weather in the western Gulf of Mexico might become an organized tropical system

An area of disturbed weather in the western Gulf of Mexico is being watched for possible development within the next 24 to 36 hours. We are carefully monitoring a couple of low pressure areas along or just off the coast of Mexico just east and northeast of Tampico crawling northward toward the south Texas coast. This area of low pressure could be evolving into a tropical depression. As long as the low pressure areas stay near the coast frictional forces will slow and perhaps inhibit development. An upper level low over northeast Mexico is creating southwest upper level winds over the system. This is creating some shear over the feature and this is another inhibiting factor for development. We believe the shear being caused by the upper level low will decrease over the next 24 hours. If the shear diminishes enough and the surface low pressure moves a bit more off the coast then this feature could wrap up into an organized tropical system very quickly. Since the system is disorganized all the stronger winds and persistent heavy rainfall is well to the east and northeast, well offshore. In a system like this the heavier rainfall will remain north and east of the weak low pressure center. If the thunderstorms and rain start to wrap around the surface low pressure area that will be a sign of organization. We did not see that happen during Monday afternoon. Reguardless of whether this becomes better organized the system will bring heavy rainfall to parts of coastal Texas during the next 36 hours. We expect the surface low pressure area to track northward which will bring that feature just east of Brownsville by Tuesday morning then due east of Corpus Christi by late Tuesday afternoon. The surface low pressure area will move into east Texas during Wednesday. So, if it's going to organize and devleop it will have to do so by Wednesday morning.

Monday, July 24, 2006

Calm in the Atlantic, For Now

There is only one area of concern in the Atlantic basin. Thunderstorms are clustered in the Bay of Campeche in the wake of a tropical wave that has moved into Mexico. Currently, upper-level westerly winds are strong, shearing the thunderstorms apart and preventing further development. However, should the thunderstorms persist for another 24 hours, the upper-level winds should eventually relax and become more favorable for development as a ridge builds over the region. Whether or not development occurs, some of this moisture will be pulled northward into southern Texas tonight and Tuesday, resulting in heavy thunderstorms in those areas.
Another tropical wave is moving through the eastern Caribbean and is located along 79 west south of 20 north, moving west-northwest at 15 knots. There is very little thunderstorm activity along this wave.

Another couple of waves are progressing westward through the Atlantic. One wave is located along 67 west south of 18 north, moving west at 15 knots. There is little thunderstorm activity along this wave as well because of very dry air aloft over the region. The other wave has moved east of the Cape Verde Islands and is along 43 west south of 20 north. This wave has a well-defined low pressure area in association with it, but Saharan dust has become entrained with the system, choking off the thunderstorms that were along the wave earlier. So, development cannot occur along this wave anytime soon.