By PDC’s Senior Weather
Specialist Glenn James
Tropical Cyclone 04S…is located approximately 1139 NM east-southeast of Diego Garcia
Northeast Pacific Ocean:
There are no tropical cyclones nor any areas of disturbed weather under investigation by the NHC
There are no tropical cyclones nor any areas of disturbed weather under investigation by the CPHC
Northwest and Southwest Pacific Ocean and Arabian Sea:
There are no tropical cyclones nor any areas of disturbed weather under investigation by the JTWC
South Indian Ocean
Tropical Cyclone 04S
According to the JTWC Warning number 3, sustained winds were 35 knots with gusts to near 45 knots.
Animated multi-spectral satellite imagery depicts a compact circulation, which has become fully exposed, after having been obscured to partially obscured over the previous 12 hours. The low-level circulation center is embedded within a larger region of cyclonic rotation, outlined by areas of flaring convection, particularly on the southwestern periphery.
Environmental conditions are marginal, and not highly favorable, with warm sea surface temperatures, moderate poleward outflow, offset by moderate (15-20 knot) northeasterly vertical wind shear.
After having been partially obscured over the past 12 hours, the current animated multi-spectral imagery shows that the low-level circulation center has become fully exposed and resides to the northeast of the flaring convection, as northeasterly shear has decoupled the convection from the low level.
TC 04S is currently tracking generally southwest along the western side of the ridge to the east. Over the next 24-36 hours the ridge to the east will direct the system southwesterly, before a deep ridge will set up to the south of the system centered near 20S 80E.
In response, TC 04S will then track in a more general westward direction throughout the forecast period. TC 04S will likely struggle to intensify over the next 24-36 hours as moderate vertical wind shear will continue to be the limiting factor, likely resulting in rounds of convective blow off.
However, the system taps into a slightly more favorable upper-level environment after 36 hours, and thus the system could slightly intensify. Thereafter, TC 04S will likely remain in a steady state until 96 hours, before shear starts to increase once more along with increasing dry air entrainment.
Therefore, the JTWC forecast calls for dissipation by 120 hours, with a remnant circulation is likely to persist beyond the forecast period.