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| #1062694 (Received by flhurricane at: 4:47 PM 21.Sep.2021) TCDAT2 Tropical Storm Rose Discussion Number 11 NWS National Hurricane Center Miami FL AL172021 500 PM AST Tue Sep 21 2021 Shear continues to disrupt Rose`s deep convection, with only a small cluster remaining in the eastern quadrant of the storm. Dvorak estimates support holding the intensity at 35 kt for one more advisory, and hopefully the evening scatterometer passes will get a good look at the cyclone`s wind field. Rose is moving more slowly to the northwest, now about 10 kt. The storm should gradually turn northward during the next couple of days around the southwestern side of a subtropical ridge. Somewhat surprisingly, guidance has shifted westward during this time, perhaps due to a weaker Rose not feeling as much of the southwesterly flow aloft. This westward shift in the track also puts Rose in a position to either get shunted east like the ECMWF solution, or uprooted more to the northeast at long range similar to the GFS. Given the recent and large model changes since the last cycle, this forecast conservatively moves westward toward the model mean at most time ranges, not too far from a 50/50 blend of the GFS/ECMWF models (GFEX). The cyclone has a difficult environment ahead, with persistent moderate westerly or northwesterly shear, plentiful dry air aloft and only marginally warm waters. All of the guidance shows Rose decaying into a tropical depression fairly soon, and it could even wither into a remnant low tomorrow or Thursday in the harsh conditions. However, the shear could let up just enough, along with some upper divergence from an upcoming trough interaction, to continue to produce deep convection for a few days. This isn`t an easy forecast because some of the guidance actually re-intensifies Rose due to the trough, while other guidance completely dissipates the tropical cyclone. Given the considerable uncertainty, I`ve kept the previous forecast the same at long range until more clarity emerges in the model suite. FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 22.5N 37.7W 35 KT 40 MPH 12H 22/0600Z 23.5N 38.6W 30 KT 35 MPH 24H 22/1800Z 24.8N 39.8W 30 KT 35 MPH 36H 23/0600Z 26.2N 40.8W 30 KT 35 MPH 48H 23/1800Z 27.5N 41.3W 30 KT 35 MPH 60H 24/0600Z 28.8N 40.7W 30 KT 35 MPH 72H 24/1800Z 29.8N 38.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 25/1800Z 31.5N 33.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 26/1800Z...DISSIPATED $$ Forecaster Blake |