T'storms N. Gulf... Wave Over Yucatan.....
Very disorganized t'storms are stretched out east/west over the Northern Gulf of Mexico. Weak low pressure might evolve just off the Gulf Coast but true significant tropical development is unlikely. As upper level high pressure -- & more importantly (because the system is weak & shallow) -- as surface high pressure moves to the U.S. east coast (see map below, 3rd image), the Northern Gulf disturbance will be steered to the west away from Fl
.A tropical wave
has moved into the Yucatan Peninsula. This wave will move into the Bay of Compache & has the potential to quickly develop Sunday in the far SW Gulf of Mexico before being steered by the large & strong upper high across the U.S. into Mexico to the south of Mexico. Despite favorable conditions for development, the short period over warm water should limit overall development.
Large areas of dry mid & upper level air (black & rust colored areas on the water vapor satellite image below) remain over the Central Atlantic. Overall conditions remain unsuitable for significant tropical development in the short term.
Most forecast models continue to point to tropical development in the far Eastern Atlantic during the last few days of Aug. & especially into Sept. The troughing (or possible reinforcement of the trough) or a remaining "pinched" trough in the W. Atlantic might play a role in any possible movement across the Atlantic....or lack thereof.
Shear has lessened over the Central/Southern Gulf of Mexico but is still strong over much of the Atlantic Basin -- as can be seen below -- exceeding 40 knots over parts of the Caribbean...exceeding 20 knots over the Central Atlantic but generally not as hostile as past weeks.
The frequency of tropical waves moving off Africa is increasing but still lacks much organization. While no substantive development is likely in the short term, this is an area that could -- & should -- become quite active in the next 1-3 weeks.
Velocity potential anomalies can give us a clue to when there might be an uptick in tropical cyclones.
The map below shows upward vertical velocities (rising air) in the green area – look how nicely this correlates with thunderstorm clusters that can be seen in IR satellite imagery superimposed on the map.
The brown lines represent sinking air which is not as conducive to convection & tropical development.
The large area of positive vertical velocities will gradually spread eastward, & we're already seeing an increase in the vertical velocities over the Central & E. Pacific with tropical development just west of Mexico.
We’re probably looking at about the end of Aug. & first couple weeks or so -- at least -- of Sept. for the Atlantic to become more active.
Speaking of the E. Pacific (& related to the vertical velocities mentioned above)...tropical storm "Ivo" is moving west of the Baja of California producing heavy rain, gusty winds & rough surf. Moisture from this soon to weaken tropical storm will spread into the SW U.S. increasing heavy rain & the flooding threat for parts of S. Ca., Az., Utah & NM.