Tag Archives: ENSO

Subdued 2016 Tropical Cyclone Activity so far in the Northern Hemisphere

A bit more than two weeks into the 2016 Northern Hemisphere summer we have three-named storms active over the larger Pacific Ocean basin, plus one tropical wave moving westward in the middle of hurricane alley in the Atlantic.

A tropical wave moves westward toward the Caribbean along 'hurricane alley'. Satellite images from NOAA on 07072016 using infrared filter
A tropical wave moves westward toward the Caribbean along ‘hurricane alley’. Satellite images from NOAA on 07072016 using infrared filter

Hurricane BLAS and AGATHA, now a tropical depression, are moving westward some 2000 kilometers east of the Big Island in Hawaii, while category 5 typhoon NEPARTAK, now weakening somewhat, is approaching landfall on the east coast of Taiwan over in the West Pacific on this Thursday 7 July 2016.

NOAA GOES satellite image of 07072016 showing Hurricane BLAS moving over the eastern Pacific approximately 2000 kilometers east of Hawaii
NOAA GOES satellite image of 07072016 showing Hurricane BLAS moving over the eastern Pacific approximately 2000 kilometers east of Hawaii

Tropical cyclone activity so far in 2016 in the northern hemisphere has been somewhat subdued in terms of actual cyclogenesis when compared to recent years.  As of today, Thursday 7 July 2016,  there have been 11 named tropical cyclones worldwide in the northern hemisphere compared to 19 during the same period in 2015. Three of the 2016 storms have only been generated over the past couple of days. The only basin that is a bit more active so far in 2016 versus 2015 is the northern Atlantic, which actually saw its first name tropical cyclone,  Alex, in January of this year, which ended up winding over the central North Atlantic and eventually impacting Greenland.

Satellite image [NOAA} of 07072016 showing Typhoon NEPARTAK approaching landfall on the east coast of Taiwan
Satellite image [NOAA} of 07072016 showing Typhoon NEPARTAK approaching landfall on the east coast of Taiwan
In my opinion, most of this change in tropical cyclone activity so far in 2016 may be attributed to the current neutral El Niño  conditions over the central to eastern Pacific near the equator, after a strong ENSO (El Niño Southern Oscillation) anomaly in 2015 and earlier this year.  Sea-surface temperatures (SST) at the equator are somewhat cooler than average in the central-to-eastern Pacific Ocean. Conditions are looking favorable for the development of La Niña during this 2016 summer in the Northern Hemisphere, perhaps by the fall and the 2016-2017 winter.

There were a total of sixty-six named tropical cyclones plus eleven tropical depressions in the Northern Hemisphere during 2015. Only time will tell how many named storms we will have in 2016, and which basin will see above or below average seasons this year.

Historically La Niña years have brought increased cyclogenesis over the northern Atlantic basin, and the forecast from the National Hurricane Center and others that have issued predictions calls for a somewhat above average 2016 Atlantic Hurricane season.

All interest in and around the Atlantic basin should pay attention,  remain alert, be prepared, and mitigate!

What is happening over the Atlantic?

Projected track for tropical storm DANNY as of 8/23/2015 [courtesy of the U.S. Naval Research Laboratory
Projected track for tropical storm DANNY as of 8/23/2015 [courtesy of the U.S. Naval Research Laboratory
Tropical cyclone DANNY has had quite an active life since it developed over the eastern Atlantic a few days ago. As DANNY moved westward along ‘hurricane alley’ it progressed rapidly from tropical wave to tropical depression, and then tropical storm becoming the 4th-named storm of the 2015 Atlantic hurricane season. Then, in a period of 24 hours DANNY became the first hurricane of the 2015 season, grew to a category 2 hurricane and just briefly became a category 3 storm as it approached the Lesser Antilles.

Based on the projected track for tropical storm DANNY, shown above, as of this Sunday 23 August the storm is forecast to emerge near  the Bahamas and Florida straits by Friday the 28th. It is too early to say what course it will follow then, but a couple of fronts mowing eastward across the eastern and central U.S.A.  (see image below) may indicate DANNY may be pushed to the north and then northeast as in interacts with these systems, but a lot will depend  on other factors affecting the atmosphere-ocean environment along DANNY’s track over the next 48 to 72 hours. So we’ll just have to wait and see, while remaining alert and prepared.

Satellite image [courtesy of NASA] of the central eastern United States showing weather fronts moving eastward across the country on 23 August 2015
Satellite image [courtesy of NASA] of the central eastern United States showing weather fronts moving eastward across the country on 23 August 2015

What should be relevant to all interest in the Caribbean, Gulf of Mexico, Florida and the U.S.A. eastern seaboard regions are the two tropical waves now riding ‘hurricane alley’ following on the tracks of DANNY (see image below) . Both of these tropical waves are showing some signs of potential further development, and are being investigated by the National Hurricane Center (NHC) as this brief report is being posted. It is possible that just as DANNY did one or both of these tropical waves may be strong enough and encounter the right combination of factors to overcome the effects of El Nino (ENSO), which has up to now considerably dampened tropical cyclone generation over the Atlantic basin.

Color-enhanced infraed satellite image (NOAA) of 8/23/2015 showing tropical storm DANNY as it continues to move WNW toward the major Antilles, as well as two tropical waves following in its wake along 'hurricane alley'
Color-enhanced infrared satellite image (NOAA) of 8/23/2015 showing tropical storm DANNY as it continues to move WNW toward the major Antilles, as well as two tropical waves following in its wake along ‘hurricane alley’

All of us here in Florida, and all interests affected by cyclonic activity in the Atlantic basin, will do well to monitor the progress of DANNY, as well as these two tropical waves in coming days. Be prepared! Remain alert! MITIGATE!