Tropical Activity Looking Ahead August September

We are closing out the month of July on what for the Atlantic Basin was a deceptively active July in that we had 2 hurricanes early in the month in Beryl & Chris. Beryl essentially was a glorified severe thunderstorm. Chris on the other hand formed off the Southeast Coast of the US and got to Category 2 status before going to the North Atlantic graveyard for tropical systems. Statistically the second hurricane of the season doesn’t show up until late August so we are ahead of the game from that respect. Looking short term at the satellite loops there doesn’t appear to be anything worth noting. Upper air lows across the Atlantic are creating a belt of strong upper air winds which is unfavorable for tropical storm formation. Dust from the Sahara Desert has been a big issue as well. The presence of large masses of dust over the Tropical Atlantic prevents thunderstorm development which is central to tropical storm formation. We have seen a decrease in dust in the last week or so which would lead to a more favorable environment for convection to develop. Satellite loops below show a rather quiet tropical scene across the Atlantic basin.

WIDE ATLANTIC TROPICAL SATELLITE

WESTERN ATLANTIC TROPICAL SATELLITE

As far as where we are going in the coming weeks it is always a bit of a guessing game but we do try to look for clues by looking at the current environment. We have written several times in the past few months about the large area of below average sea surface temperatures in the Tropical Atlantic. In the last 2 months we have actually seen the area of below average sea surface temperatures expand across the Tropical Atlantic and into parts of the subtropical Atlantic.

SEA SURFACE TEMPERATURE ANOMALIES

Sea surface temperatures across the Atlantic south of 30 degrees north (where most tropical storms develop) are averaging about 1 degree C below normal. While the number is small it can be significant in two regards. The first is that 1 degree below average does effectively shrink the area of ocean water above 26C (79F) which would support tropical storm development.

SEA SURFACE TEMPERATURES

When we look at the actual temperatures across the Tropical Atlantic the area of 26C water is confined to the Tropical Atlantic south of 10 degrees north. You have to go west of 50W to find supportive water temperatures. The second issue is with regards to ocean water temperatures that can effectively support major hurricanes, usually above 28C. That area at least for the moment is smaller than last year although ocean water temperatures in the subtropics and tropics will rise further in the next 6 weeks so expect this to change in the coming weeks.

As far as the short range is concerned, the tropical Atlantic will continue to deal with its issues so we don’t expect tropical activity to come from there. However the subtropics could see some tropical activity as a system separates from the main band of westerly winds in the Atlantic and drops southwestward in the Central Atlantic.

JET STREAM LATE THIS WEEK

With the large upper high off the East Coast it would seem that this Central Atlantic system will likely move westward. However do remember a couple of things. First is that this is going to be one of those system that would have to transition from a cold core system to a warm core system. That process can take a long time. The second is that systems that form in this part of the Atlantic have a very low statistical chance of ever impacting weather in the US though they do occasional create issues for Bermuda.

Other than this possibility the conditions across the tropics would suggest the quiet to continue at least for awhile longer. Also the relative quiet doesn’t mean that a major burst of activity won’t occur at some point later in August and September.

Please consult your local National Weather Service office at weather.gov for the latest information on any tropical or storms or hurricanes that could be a threat to your area. Consult your local government officials regarding action you may need to take to secure life and property

FiOS1 News Weather Forecast For Long Island

FiOS1 News Weather Forecast For New Jersey

FiOS1 News Weather Forecast For Hudson Valley