ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM IVETTE DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102016 800 AM PDT FRI AUG 05 2016 Ivette continues to have a ragged appearance on satellite imagery, and recent microwave data showed that all the deep convection is located to the south and southeast of the center. Still, Dvorak CI numbers from TAFB and SAB, as well as the UW-CIMSS ADT, support maintaining an intensity of 45 kt. Vertical shear does not appear very high (about 10 kt according to SHIPS guidance and UW-CIMSS), but it is from a westerly direction, which is not great for intensification. Since sea surface temperatures remain warm, only modest strengthening is anticipated during the next 24 hours. After that time, deep-layer westerly shear increases over 20 kt, and this should cause Ivette to weaken quickly. In fact, the NHC forecast now calls for the cyclone to degenerate to a remnant low in about 4 days. This forecast is very similar to the previous one, and it lies close to the IVCN intensity consensus. Ivette continues to move westward (275 degrees), but its speed has decreased to 11 kt. Subtropical high pressure located to the north of the cyclone is causing the current westward motion, but Ivette is approaching a break in the ridge located northeast of Hawaii. Therefore, the cyclone is expected to turn west-northwestward and slow down some more very soon, with that heading continuing through day 3. Once Ivette becomes a remnant low, it should turn westward in the low-level trade winds. The track guidance remains in good agreement on this scenario, and the updated NHC track forecast is very close to the TVCN multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 15.1N 130.8W 45 KT 50 MPH 12H 06/0000Z 15.4N 132.2W 50 KT 60 MPH 24H 06/1200Z 16.1N 134.0W 55 KT 65 MPH 36H 07/0000Z 16.8N 135.8W 55 KT 65 MPH 48H 07/1200Z 17.5N 137.4W 50 KT 60 MPH 72H 08/1200Z 18.6N 140.5W 35 KT 40 MPH 96H 09/1200Z 18.8N 143.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 10/1200Z 18.5N 148.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Berg NNNN