Dry Air Dominates the Atlantic

There are two tropical waves in the Eastern Atlantic worth mentioning today--one right at the coast of Africa, and another about 700 miles to its west, a few hundred miles southwest of the Cape Verde Islands. Both of these waves are headed west-northwest towards much drier air, and none of the reliable models for tropical cyclone formation is predicting development during the coming five days--though the wave farther from the coast of Africa has the UKMET model and a few members of the GFS and European model ensembles showing some weak development. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave the disturbance near the coast of Africa 2-day and 5-day odds of development of 0% and 20%, respectively. Dry air dominates the tropical Atlantic, and it will be difficult for a tropical storm to form in the coming week.


Figure 1. The satellite-based Saharan Air Layer (SAL) analysis for 8 am EDT Friday, August 15, 2014, showed two tropical waves off the coast of Africa that were headed west-northwest towards very dry air. Image credit: University of Wisconsin CIMSS/NOAA Hurricane Research Division.

Tropical Storm Karina not threatening Hawaii
Tropical Storm Karina, which formed in the waters south of Mexico's Baja Peninsula on Wednesday, intensified into a hurricane for 12 hours on Thursday, but is now back down to tropical storm strength. None of the computer models are currently predicting the Karina will affect Hawaii, as the storm is expected to become entangled early next week with tropical disturbance 94C, which lies 1100 miles east-southeast of the Big Island of Hawaii. This tropical disturbance could also become a tropical storm this weekend; in their 8 am EDT Tropical Weather Outlook, the Central Pacific Hurricane Center gave 94C 2-day odds of development of 60%. Tropical Storm Julio, located about 770 miles north of Honolulu, Hawaii, is steadily disintegrating in the face of high wind shear, and should be dead by Saturday morning. Karina's intensification in a hurricane on Thursday gives the Eastern Pacific 11 named storms, 7 hurricanes, and 5 intense hurricane so far this season, which is well above average. In a typical Eastern Pacific hurricane season, there should have been 7 named storms, 4 hurricanes, and 1 intense hurricane by August 14.

Jeff Masters