Tropical weather analysis - July 24, 2012
An area of low pressure centered about 950 miles south-southwest of Manzanillo has the potential to become a tropical depression over the next day or two. Considering its heroics and longevity, I remain unimpressed with this system, with the broad low-level center along the northern edge of the convective mass.
Figure 1. Latest infrared satellite image of Invest 90E. Image credit: NOAA
It is not immediately clear what is holding this system back. Waters are warm, shear is seemingly low, and an abundance of moisture surrounds the system. It could be due to local competition from the Intertropical Convergence Zone (ITCZ). Regardless, I have to assume that this system will organize further amidst the seemingly favorable environmental factors.
Based on the conglomeration of the various global model forecasts, 90E will be yet another system that crosses 140W longitude into the central Pacific basin. But before it actually gets there, there is a bit of disagreement concerning the evolution of a trough forecast to evolve off the west coast. The NOGAPS, GFS, and ECMWF have a less amplified, more zonal flow north of 90E, which would portend a westward track. The CMC and GFDL, on the other hand, have a more northerly solution underneath a more amplified steering regime. Based on current synoptic trends observed on water vapor imagery, I tend to favor the more western solution. By Friday, 90E is expected to turn north as it nears 135W, where cooler water and westerly shear are expected to bring out a swift demise.
I note that none of the global models have been particularly enthusiastic regarding development with this system, with the only real infatuation being with the GFS. Given the system's failed efforts to organize thus far, they may be onto something.
Probability of genesis in 48 hours: 70%
Atlantic waking up?
An area of convection over western Africa, possibly a tropical wave, was shown by the 0z GFS to develop into a hurricane and threaten Florida in the long-range. While this kind of pattern seems to thematic this year, it is far too early to speculate. But given that this model has been hinting that the eastern Atlantic should become more convectively active, this is something that cannot be ignored. Climatologically, we are only a couple weeks behind the typical arrival of the Cape Verde season, where some of the strongest hurricanes in the basin originate.
There is also a non-tropical low several hundred miles east-northeast of Bermuda. Although the system possesses a fairly robust circulation, environmental conditions are not conducive for significant development as it moves steadily northeastward.
Probability of genesis in 48 hours: 10%