Weekend Argus (Saturday Edition)
Cyclone heralds some big swells out east
THE CYCLONE season off the East Coast kicks off with a bang next week, if the forecasts are to be believed.
Something caught my eye – excuse the pun – while monitoring my favourite weather app Windy this week.
It was an area of tropical disturbance 400 nautical miles northeast of Madagascar this coming Wednesday. Watching the animation chart, this area deepens on Wednesday and Thursday into the perfect storm: a tropical cyclone so concentric and tight, it looks like a purple punch hole in the planet.
In fact, never mind the purple shades denoting wind gusts blowing stronger than gale-force, the winds immediately around the eye where white, which indicated gusts in excess of 100kts.
Now, that is proper wind, with white an appropriate colour – if you count it as a colour of course – because the ocean turns white with foam when blasted by such violent velocities of wind.
Rendering the raw data supplied by the Wave Watch 3 (WW3) model in the United States, the animated Windy chart showed the virulent storm tracking southwards down the side of Madagascar’s east coast some distance out to sea.
This marine melee, which has not been named yet by the authorities on Reunion, Mauritius or Madagascar but is set to be named Funani by my reckoning, is due to slow down and park for a day or two off the southern tip of Madagascar, spewing out swell that will light up the entire east coast of the country.
When you look at the chart, it seems that the big island is blocking the swell from South Africa. However, according to the great circle path the swell will propagate across (taking into account the curvature of the earth), the swell will begin to arrive in Durban from roughly tomorrow in a week’s time.
Surfers in Durban, especially the organisers of the Cell C Goodwave event which never ran last year, will no doubt be stoked at the prospect of a sublime run of epic surf, not least because it must travel 2 000 miles. Over such distances, the viscosity of the ocean decays the swell to manageable sizes, stripping away the original brute force and size it possessed when first lurching from the giant conveyor belt of the generating storm.
The central pressure of Funani, with its extremely compressed energy over a comparatively small area, is forecast to reach 965 millibars. While not impressive compared to the gigantic and much more powerful cold weather storms we get in the Roaring Forties in winter, this typically tight tropical wind gradient means proper wind. More than 100kts is pretty much three times the velocity of galeforce. Scary stuff.
With winds at this speed, it’s only the duration of the wind and the distance over which it blows that need to align for the East Coast to get a Mr Delivery they’ll remember for a long time.
However, of course, we’re talking about a highly volatile summer weather system in the tropics predicted one week before it becomes even a blip on the surface of the sea. The forecast may just as easily downgrade the storms’s power and whisk it away in the opposite direction.
It’s early days, but this could be one to remember.
WIND FIZZLES
Calling weather-dependent events is a tough ask. Just ask the Contest Director of the Red Bull King of the Air, Sergio Cantagalli. A pumping southeaster blasted through as predicted and the event was called on for Thursday at Blouberg. However, by 6pm when the wind normally peaks at its most intense, Oom Hunks had other ideas, and the furious bluster died into a tame breeze. The event is on hold until next week.
WEATHER TIP
Today the southeaster has eased dramatically into a crisp clean offshore brushing back a frigid ocean along the western Peninsula. The wind yesterday has blown the swell more or less flat, barring some freezing 2-3’ peaks at best. Muizenberg is still onshore and messy despite a lot of smeared 2-5’ windswell. Tomorrow a light SSE puffs to moderate but the surf is small – maybe 2’. However, signs of a new groundswell appear early afternoon, with a chance of occasional 3 if not 4 foot sets by 3pm. Muizenberg remains crumbly and onshore, but at least the wind is not pumping.