000 WTNT45 KNHC 300858 TCDAT5  Tropical Depression Ten Discussion Number   9 NWS National Hurricane Center Miami FL       AL102021 500 AM AST Mon Aug 30 2021  The deep convection with Tropical Depression Ten is in a sheared  bursting pattern this morning, associated with overshooting cloud  top temperatures below -80 C. A 0518 UTC AMSR-2 microwave pass did  show a bit of banding associated with this activity on the 37 GHz  low-level channel. However, Proxy-Vis satellite imagery indicates  this convective activity remains located downshear of the low-level  center thanks to very strong 30-50 kt northwesterly flow associated  with a subtropical jet at 200 mb. The latest round of subjective  Dvorak estimates were 25 kt from SAB and 35 kt from TAFB. Taking a  blend of these estimates and the earlier ASCAT wind data supports  keeping the intensity at 30 kt for this advisory.  The depression has resumed a northward motion this morning, with the  latest estimate at 360 degrees at 7 kt. A deep-layer trough passing  by well to the north is continuing to provide a weakness in the  subtropical ridge, allowing the cyclone to escape northward. The  system could even move a bit east of due north over the next 24-36  hours if down-shear convective bursts help to drag the low-level  center a bit right of the steering flow. After 36 hours, the  deep-layer trough moves eastward, allowing the subtropical ridge to  build back in. The net result is that the depression should turn  leftward and begin a more northwestward motion by the latter part of  this week. The latest track guidance has once again made another  westward shift this cycle after 36 hours, and the NHC track  forecast has been nudged in that direction as well. However, the  latest track is still not as far west as the GFS & ECMWF models, and  further westward adjustments may be needed in subsequent forecasts.   Strong upper-level flow is the primary hindrance for the depression  currently. In fact, both GFS & ECMWF-based SHIPS guidance shows the  vertical wind shear remaining above 30 kt for the next 24 hours as  the cyclone moves through the core of a subtropical jet streak.  Interestingly, this shearing flow seems to be mostly based in the  upper-levels, with much lower mid-level shear diagnosed by UW-CIMSS.  This lower mid-level shear may help explain why deep-convection has  not yet been completely stripped away from the low-level center.  After 36 hours, most of the guidance agrees that an upper-level low  will cut off to the southwest of the depression, providing a more  favorable upper-level environment over the system. However, it  remains unclear what will be left of the depression by that time,  and the latest 00z ECMWF, HWRF, and HMON runs suggest the vortex  will be too weak and diffuse to take advantage of the more favorable  conditions. For now, the latest NHC intensity forecast will maintain  the current intensity through 48 hours, with only modest  intensification beginning after that time assuming the circulation  is coherent enough to take advantage of the more favorable  environment. The latest intensity forecast is just a bit lower than  the previous forecast, and is also lower than the HCCA and IVCN  consensus aids. It remains distinctly possible that the depression  could become a remnant low if its convection is completely stripped  away.   FORECAST POSITIONS AND MAX WINDS  INIT  30/0900Z 20.8N  50.6W   30 KT  35 MPH  12H  30/1800Z 21.7N  50.6W   30 KT  35 MPH  24H  31/0600Z 22.6N  50.3W   30 KT  35 MPH  36H  31/1800Z 23.6N  50.1W   30 KT  35 MPH  48H  01/0600Z 24.8N  50.7W   30 KT  35 MPH  60H  01/1800Z 26.1N  51.7W   35 KT  40 MPH  72H  02/0600Z 27.6N  53.1W   40 KT  45 MPH  96H  03/0600Z 30.8N  55.3W   45 KT  50 MPH 120H  04/0600Z 35.1N  53.6W   50 KT  60 MPH  $$ Forecaster Papin