Tropical Storm Iba Discussion Number 18

Wiki-Hurricanes Forecast Center

12:00 AM AST Thu Mar 28 2019

Iba is refusing to die this evening. Recent satellite images show a system characterized with a partially exposed low-level circulation but persistent deep convection to the southeast. This is an impressive feat considering upper-level winds have increased to over 25kt, helping to impart mid-level dry air—with relative humidity values under 50 percent—into the center. Although SAB only analyzed a T1.5/25kt at 0z, a ScatSat pass from around that time, surprisingly, showed maximum winds have increased to near 40kt. So, against all odds, that is the initial intensity used for this advisory.

Although Iba has been a persistent little fella over the past 24 hours, I have no choice but to continue forecasting its quick demise. It should be noted that a combination of visible and shortwave infrared animations show that the low-level circulation is becoming increasingly elongated. I have prolonged Iba's transition to a non-convective remnant area of low pressure to 24 hours from now based on the storm's tenacity; an alternate scenario is that the low-level circulation becomes too elongated to meet the definition of a tropical cyclone. This could plausibly occur at any point as Iba drifts east. Dissipation is expected in about three days.


INIT 28/0300Z 40 KT 45 MPH

12H 28/1200Z 35 KT 40 MPH

24H 29/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW

36H 29/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW

48H 30/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW

72H 31/0000Z...DISSIPATED

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