Tropical Storm Iba Discussion Number 12
Wiki-Hurricanes Forecast Center
12:00 PM AST Tue Mar 26 2019
Iba is not well organized this morning, with the entirety of its low-level cumulus circulation exposed and well-removed from any stout convective activity, largely limited to a single spiral band to the south. Cirrus streaming from Brazil and passing largely unabated over Iba's center of circulation are indicative of the rather hostile shearing environment caused by the nearby subtropical jet, and mid-level conditions are particularly dry. SAB has estimated a current intensity value of T3.0/45kt, lagged off of their previous estimates. Iba has built slightly more convection since dawn, but certainly not enough to induce any uptick in the winds. A 12:30z scatterometer pass from ASCAT-A showed no explicit gale-force points However, given the size of this 30 kt region, weakening is likely slowed somewhat so the intensity for Iba remains at 35 kt.
We're nearing the end of the road for Iba as it curves east and then southeastward into the drier and less favorable conditions of the South Atlantic subtropics -- conditions which are normally reflective of the South Atlantic as a whole. Iba will likely drop below tropical storm intensity later today and taper off as it transitions into a post-tropical remnant low by Thursday. Whatever is left -- probably not much at all -- may be absorbed by a developing trough feature late in the forecast.
FORECAST MAX WINDS
INIT 26/1500Z 35 KT 40 MPH
12H 27/0000Z 30 KT 35 MPH
24H 27/1200Z 30 KT 40 MPH
36H 28/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 28/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 30/1200Z 15 KT 25 MPH...POST-TROP/REMNT LOW