Because of the recent active tropics, especially in the Eastern Pacific, I have not been able to release a typical “A Look at the Atlantic” post. I decided to do one today to give an update on the current state of the Atlantic and when we can expect to see our next tropical cyclone form.

Sea surface temperatures

Sea surface temperatures have continued to warm throughout the Atlantic basin, and are now warm enough to support development in most areas where tropical cyclones typically form. Sea surface temperatures in the Gulf of Mexico have recently warmed to as high as 30-31°C (86-87.8°F), which is the warmest sea surface temperatures in the basin and warm enough to support a very strong tropical cyclone. Sea surface temperatures are now averaging about 27-28°C (80.6-82.4°F) in the Atlantic Main Development Region (MDR), which is warm enough to support development of tropical waves. Sea surface temperatures in the Caribbean and Western Atlantic are also warm enough to support a strong tropical cyclone, around 28-29°C (82.4-84.2°F).

The sea surface temperature anomaly pattern in the Atlantic continues to be favorable. Sea surface temperatures remain above normal in the Atlantic MDR, Caribbean Sea, and have recently increased to above normal in the Gulf of Mexico. Sea surface temperatures are also above normal in the far Northeastern Atlantic and the off the United States East Coast. While the warmer than normal sea surface temperatures along the U.S. East Coast is not ideal for tropical cyclone formation in the deep tropics, the MDR is just as anomalously warm and this should prevent any major detrimental effects for development from this “warm blob.”  The current Atlantic sea surface temperature pattern resembles the positive AMO phase, consistent with the active era of Atlantic hurricane activity since 1995. The Pacific remains in mostly an ENSO-neutral state which should not have a major effect on the season.

Wind shear

Wind shear over the Atlantic basin is currently typical of July, if not slightly lower than normal. Unfavorable wind shear of over 25 knots (30 mph) currently is over the central and western Caribbean Sea, but shear has fallen into the favorable range in the eastern Caribbean Sea. In the MDR, wind shear is mostly favorable south of 15°N, and has been fairly consistently below normal since June. If this current below-normal shear in the MDR persists we could be looking at some strong long-tracked hurricanes in the deep tropics this year, which recent seasons have lacked many of.

African tropical waves

The African tropical wave “train” has quieted down in recent weeks compared to June but remains fairly active. There are currently two inland tropical waves with scattered moderate convection. There is also a tropical wave which has recently emerged into the far eastern Atlantic. Models currently do not develop any of these waves. Tropical waves should continue to increase in strength as we approach the active part of the Atlantic season, which typically gets started around the third week of August. Rainfall in the Sahel region of Africa has been above average for most of this summer, which is often an indicator of active Atlantic hurricane seasons. In addition, Saharan Air Layer (SAL) outbreaks have been weaker than normal this year, which is a major difference compared to the last few years. All of these factors suggest the Atlantic MDR could be more favorable than recent seasons as we approach the active part of the season.

So, when will Emily form?

There is a low chance we could see a weak spin-up along the Gulf Stream in a week or so, but I doubt it will become anything. I personally think it is unlikely we will see Emily until early to mid August. Models have been on and off with the arrival of a more favorable Madden-Julian Oscillation (MJO) phase by that time. However, as we get towards mid-August, the MJO begins to become less important as the Atlantic transitions into its “peak season” state. I think that the first half of August could bring our first hurricane of the season. We will have to keep watching.

I will be back tomorrow for an update on the Pacific, which remains very active with seven (eight earlier today) tropical cyclones.