Atlantic Hurricane Season 2015

FWVT

Great GPM IMERG image of rainfall totals of Chapala, showing 500 mm over Socotra.

B17G

Another storm in the same region. This one will pass nearer to the island of Socotra than the last one did it seems.

http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/warnings/io0515.gif

FWVT

The combination of record warm ocean heat content in the Indian Ocean and a phase-3 MJO has led to interesting times in the Indian Ocean of late. It's remarkable, though, how Megh is following an identical track to Chapala. There is also another Invest area east of southern India which looks set to make it across the Indian landmass and come out the other side as another possible cyclone in the Arabian Sea next week.

These are two charts of Tropical Cyclone Heat Potential (in kJ/cm²) from both yesterday and before Chapala last week. Note how Chapala has churned up colder waters from below, and Megh is currently along the 50 kJ/cm² threshold just west of 60E. TCHP values of over 50 jK/cm² are required for rapid intensification, which is why Megh has been only intensifying slowly and will not reach the heights of Chapala.

Yesterday


Before Chapala

FWVT

It has managed to intensify rapidly overnight and is now 110 knots as it hits Socotra directly.

B17G

FWVT wrote: »

It has managed to intensify rapidly overnight and is now 110 knots as it hits Socotra directly.

FWVT

It has just crossed Socotra. Thankfully the strongest winds will have been out to sea.

85 GHz at 1039Z



Earlier rain-rates were around 1 - 1.2 inches per hour.

maquiladora

A late season one. TD 12, soon to be upgrade to a TS.

hatrickpatrick

What's going on here? We're supposed to be in an almost record breaking El Nino year and yet this season has now had an average number of named storms and a cat 4 (in the West Atlantic no less!) which is the strongest Atlantic system in four years.

Has El Nino been weaker than expected so far, or has the Atlantic surprisingly managed to fight it off?

maquiladora

hatrickpatrick wrote: »

What's going on here? We're supposed to be in an almost record breaking El Nino year and yet this season has now had an average number of named storms and a cat 4 (in the West Atlantic no less!) which is the strongest Atlantic system in four years.

Has El Nino been weaker than expected so far, or has the Atlantic surprisingly managed to fight it off?

The majority of the storms have been weak though and most of them had their development limited by adverse conditions, so El Nino has definitely had a significant impact. The number of storms that reached hurricane strength is half of what would be expected in an average season.

hatrickpatrick

maquiladora wrote: »

The majority of the storms have been weak though and most of them had their development limited by adverse conditions, so El Nino has definitely had a significant impact. The number of storms that reached hurricane strength is half of what would be expected in an average season.

True, but the fact that so many have managed to develop at all - more than the previous two years which weren't El Nino years - still strikes me as surprising.

I guess this means that dry air invasion of the Atlantic actually has a bigger impact on storm development than wind shear. That's the notable difference this year compared with previous years, apart from El Nino - the Sahara has been much quieter than in '13 or '14.

FWVT

hatrickpatrick wrote: »

True, but the fact that so many have managed to develop at all - more than the previous two years which weren't El Nino years - still strikes me as surprising.

I guess this means that dry air invasion of the Atlantic actually has a bigger impact on storm development than wind shear. That's the notable difference this year compared with previous years, apart from El Nino - the Sahara has been much quieter than in '13 or '14.

The fact that it's a Modoki El Niño probably has something to do with it.

maquiladora

FWVT wrote: »

The fact that it's a Modoki El Niño probably has something to do with it.

It isn't a Modoki.

maquiladora

TD 12 is now Tropical Storm Kate and even has a chance of reaching Hurricane strength for a while on her way out to the fishes.

maquiladora

Kate is now a hurricane, racing out to sea. Her remains will likely have an impact on our weather in the days ahead.