May 16th, 2013 Category: Tropical Cyclones

Tropical Storm Mahasen (01B) – May 14th, 2013

Enhanced image

Track of TC 01B

Tropical Storm Mahasen (01B), located approximately 246 nm southward of Kolkata, India, has tracked north-northeastward at 12 knots over the past six hours. Maximum significant wave height is 12 feet.

Animated multispectral satellite imagery indicates the low level circulation center (LLCC) remains under an area of deep convection, but is difficult to identify as the organization of the convection remains poorly defined. A series of scatterometry passes support 35 to 40 knot winds near the center of the LLCC. The current intensity has been maintained at 45 knots based on Dvorak estimates and the persistent convection over the LLCC.

Tags: 01B Bangladesh India Mahasen Tropical Storm | Comments |

February 26th, 2013 Category: Tropical Cyclones

Tropical Cyclone Eighteen (18S) – February 26th, 2013

Enhanced image

Track of TC 17S

Tropical Cyclone Eighteen (18S), located approximately 1000 nm west-northwest of Learmonth, Australia, has tracked south-southeastward at 04 knots over the past six hours.

Animated multispectral satellite imagery shows the main convection remains detached from a fully exposed low level circulation that has become more elongated and irregular, making it difficult to pinpoint the center. The initial position is based on the above animation with poor confidence. The initial intensity, assessed higher than multi-agency subjective Dvorak estimates, is extrapolated from recent scatterometer data. Upper level analysis indicates the system is in an area of strong (30-40 knot) easterly vertical wind shear (VWS).

The cyclone is currently in a weak steering environment between the near-equatorial ridge (NER) to the north and a subtropical ridge (STR) to the south resulting in a very slow eastward drift. It is expected to remain in this state over the next 48 hours until the STR recedes to the east. At that stage, the NER will rebuild and resume steering and track the cyclone faster eastward.

Tags: 18S Eighteen Tropical Cyclone | Comments |

February 20th, 2013 Category: Tropical Cyclones

Tropical Cyclone Haruna (16S) – February 19th, 2013

Enhanced image

Track of TC 16S

Tropical Cyclone Haruna (16S) (click here for previous images) is forecast to weaken due to land interaction near TAU 72, then more significant weakening as it tracks over cooler SSTs and encounters increasing vertical wind shear south of Madagascar.

The system is forecast to complete ETT by TAU 120. Overall, the dynamic model guidance is in fair agreement and supports the JTWC forecast track; however, there is low confidence in the JTWC forecast due to the weak steering enviroment and uncertainties in track speed after TAU 72. The system is now expected to intensify to a peak of 75 knots by TAU 36 due to favorable conditions. Maximum significant wave height is 20 feet.

Tags: 16S Area of convection Haruna Madagascar Tropical Cyclone | Comments |

February 18th, 2013 Category: Tropical Storms

Area of convection – February 18th, 2013

Enhanced image

Track of TC 15S

The area of convection previously located near 19.4S 40.0E (click here for previous images) is now located near 19.7S 41.1E, approximately 335 nm west of Antananarivo, Madagascar.

Animated infrared satellite imagery indicates a consolidating low-level circulation center (LLCC) with curved, deep convective banding over the eastern semi-circle. An SSMIS image depicts tightly-curved banding wrapping into a well-defined LLCC.

Recent scatterometer imagery as well as microwave- derived winds support 25 to 30 knot winds. Upper-level analysis indicates a point source near the center with near-radial outflow enhanced by an upper-level low positioned south of Madagascar. Vertical wind shear remains moderate (20 knots) and continues to hamper convective development over the western semi-circle. SST remains favorable at 29 to 30 degrees celsius.

Numerical models indicate development is likely over the next 12-24 hours. Maximum sustained surface winds are estimated at 25 to 30 knots. Minimum sea level pressure is estimated to be near 1000 mb. The potential for the development of a significant tropical cyclone within the next 24 hours remains high.

Tags: Antananarivo Area of convection Madagascar Tropical Cyclone | Comments |