Tropical Storm Iba Discussion Number 11
Wiki-Hurricanes Forecast Center
6:00 AM AST Tue Mar 26 2019
If there was any question of whether the window for intensification has closed, the satellite presentation of Iba tonight highlights the answer. Unlike the past two nights, deep convection has not continued to expand through the diurnal maximum. In fact, ever-increasing westerly wind shear is shearing this convection well east of the exposed low-level circulation. Multiple vortices of a broader gyre appear evident on the shortwave infrared imagery. Given the decrease in organization since the previous advisory, when the ScatSat pass only showed one 40kt barb, the initial intensity has finally been changed to 35kt.
Wind shear is only expected to increase over the next day as Iba finds itself embedded within a strong westerly jet stream. These strong upper-level winds will also inject very dry mid-level air into the storm's circulation, limiting convective potential. Therefore, a rapid spin-down is expected. Iba is expected to degenerate to a non-convective remnant area of low pressure in 36 hours now, with dissipation by day five; it is possible this dissipation could occur sooner. Iba is expected to drift south over the next day before meandering east.
FORECAST MAX WINDS
INIT 26/0900Z 35 KT 40 MPH
12H 26/1800Z 35 KT 40 MPH
24H 27/0600Z 30 KT 35 MPH
36H 27/1800Z 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 28/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/0600Z 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 30/0600Z 15 KT 20 MPH...POST-TROP/REMNT LOW