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Tropical Depression Kate Forecast Discussion Number 14
2021-08-31 16:45:46| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Tue Aug 31 2021 000 WTNT45 KNHC 311445 TCDAT5 Tropical Depression Kate Discussion Number 14 NWS National Hurricane Center Miami FL AL102021 1100 AM AST Tue Aug 31 2021 Strong west-northwesterly shear continues to displace the limited convective activity associated with Kate well to the east of its center, which is fully exposed and becoming less well-defined in visible satellite imagery. A small burst of deep convection from earlier this morning appears to be waning, as infrared cloud top temperatures are warming to the east of Kate's center. Consensus T2.0/30 kt Dvorak classifications from TAFB and SAB, in addition to the latest objective UW-CIMSS ADT estimates, suggest that Kate is now likely a tropical depression. Therefore, the initial intensity is lowered to 30 kt for this advisory. Kate's center has jogged a little east of due north this morning, and its initial estimated 12-h motion is northward, or 010/4 kt. A mid-level ridge is forecast to build to the northeast and east of Kate later today through Wednesday, which should steer the cyclone more north-northwestward through midweek. Then, Kate should turn toward the north on Thursday night and early Friday within the flow associated with a mid- to upper-level trough that will be moving across the western Atlantic. The official NHC forecast track is very similar to the previous one, and it lies near the reliable consensus aids TVCA and HCCA. The only minor track adjustment has Kate turning a little earlier and faster toward the north late this week. Even though the vertical shear is expected to diminish over Kate during the next 12-24 h, the cyclone remains embedded within a relatively dry mid-level environment. This will make it difficult for Kate to sustain enough organized convection to strengthen much. In fact, numerous models including the GFS, HWRF, and HMON show the low weakening in the coming days, as the model simulated satellite imagery suggests only sporadic bursts of convection will occur even after the shear subsides. However, the possibility of Kate briefly re-intensifying into a weak tropical storm cannot be completely ruled out, since the cyclone will remain over warm SSTs around 28 deg C for at least the next couple of days. The official NHC intensity forecast remains consistent with the consensus aids IVCN and HCCA and shows no explicit change in intensity, although some fluctuation is possible. If Kate survives this week, the global models indicate that it will likely open up into a trough by Saturday morning, shortly before being absorbed by an approaching frontal system. FORECAST POSITIONS AND MAX WINDS INIT 31/1500Z 23.5N 50.8W 30 KT 35 MPH 12H 01/0000Z 24.3N 51.0W 30 KT 35 MPH 24H 01/1200Z 25.7N 51.7W 30 KT 35 MPH 36H 02/0000Z 27.3N 52.7W 30 KT 35 MPH 48H 02/1200Z 29.0N 53.6W 30 KT 35 MPH 60H 03/0000Z 30.7N 54.1W 30 KT 35 MPH 72H 03/1200Z 32.5N 53.9W 30 KT 35 MPH 96H 04/1200Z...DISSIPATED $$ Forecaster Reinhart
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