For the first time in two weeks, it is Friday and the Atlantic has quieted down. That means it is time to take a look at the Atlantic. The Atlantic has quieted down after Tropical Storms Bret and Cindy. Cindy has transitioned into a post-tropical low this evening. The Atlantic is soon going to enter its normal “summer quiescence” with no development expected until at least mid-July. Due to a suppressed MJO phase, Atlantic activity during early July is not likely, and the area of focus for tropical cyclone activity will be the Pacific.  Last season, the Atlantic had Tropical Storms Colin and Danielle by the end of June, but no named storms formed in the month of  July.  While July is not likely to be quite as quiet as last season, I expect 1 or 2 storms to form in the Atlantic at most this July.

Sea Surface Temperatures

Sea surface temperatures have now passed the 26°C (78.8°F) threshold for tropical development throughout most of the Atlantic basin. The 26°C isotherm extends along the U.S. East Coast as far north as the Outer Banks, and as far north as Bermuda. Sea surface temperatures have cooled slightly, however, in the Caribbean, Gulf of Mexico and Atlantic Main Development Region (MDR) as a result of Tropical Storms Bret and Cindy, due to upwelling. These regions should warm back up during the next few weeks during the Atlantic’s summer quiescence period.

Sea surface temperature anomalies remain positive throughout the Atlantic Main Development Region (MDR), Caribbean Sea and subtropical western Atlantic. They are also positive in the northeastern Atlantic Ocean. Sea surface temperature anomalies are negative in the northeastern Gulf of Mexico and in the northwestern Atlantic south of Greenland. The tropical Pacific remains in a warm-neutral ENSO state as of this time, and El Nino development is unlikely by the peak of hurricane season. Aside from an area of warmer than normal sea surface temperatures off the U.S. East Coast, the overall Atlantic sea surface temperature pattern resembles a positive phase of the Atlantic Multidecadal Oscillation (AMO), consistent with the active era of Atlantic hurricane seasons since 1995. While the MDR has anomalously cooled since early June, it still remains well above the long-term average in sea surface temperatures.

Wind Shear

Wind shear has begun to drop throughout the Atlantic basin. Most of the Caribbean Sea and Gulf of Mexico currently has favorable wind shear – less than 15 knots (~15 mph). Wind shear is also low in the low latitudes of the Atlantic MDR. However, wind shear is unfavorable (above 25 knots) in most of the Atlantic subtropics. Wind shear should continue to decrease over the next couple months as the Atlantic becomes ready for the peak season.

African Tropical Waves

The African wave train has quieted down a bit after being very active for June last week. Most of the eastern Atlantic is dry at the moment due to an outbreak of Saharan Air Layer (SAL). However, a fairly strong wave is expected to emerge off the coast this weekend. The GFS model and its ensembles were previously predicting development of this wave, but have since dropped development. Development of this wave is not expected, at least not in the near future. As a suppressed MJO phase moves in soon, the wave train will likely be much quieter than recent days.

I will be back tomorrow for a post on Invest 93E in the Eastern Pacific which is likely to become Tropical Storm Dora during the next couple of days.