175 
 WTNT42 KNHC 300858
 TCDAT2
 
 TROPICAL DEPRESSION BONNIE DISCUSSION NUMBER  11
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022016
 500 AM EDT MON MAY 30 2016
 
 Radar and surface observations indicate that Bonnie has moved
 eastward and is now located along the coastline just east of
 Charleston, South Carolina. A late-arriving RapidSCAT pass from 0029
 UTC showed several 25-27 kt surface wind vectors in a rain-free area
 50-80 nmi south-southwest of the center. Since that time, some
 modest shower activity has developed in that same region, which
 supports maintaining Bonnie as a 25-kt depression on this advisory.
 
 The initial motion estimate is 040/04 kt. Bonnie is expected to
 remain a vertically shallow low pressure system throughout the
 forecast period, and should be steered slowly northeastward to
 east-northeastward by an approaching 700-500 mb shortwave trough
 that is expected to capture the small cyclone within the next 12
 hours or so based on recent trends in water vapor satellite imagery.
 By Wednesday, Bonnie's forward speed is expected to increase as the
 cyclone moves along the northern side of the Bermuda-Azores
 subtropical ridge. This steering pattern should take Bonnie and its
 remnants across the coastline of the Carolinas during the next 2-3
 days, and then offshore into the western Atlantic Ocean by days 4
 and 5. The NHC track forecast is similar to the previous advisory
 track, and remains close to the GFS-ECMWF model consensus.
 
 Bonnie has been convectively challenged for the past 12 hours. Only
 narrow bands of weak to moderate convection have persisted near the
 center over land during the past 6 hours, and limited convection
 been developing over adjacent Atlantic waters. Furthermore, the 0000
 UTC Charleston, South Carolina upper-air sounding showed than Bonnie
 was barely holding on to warm-core, tropical cyclone status with
 only 1 deg C warmer temperatures than the surrounding environment
 indicated between 500-300 mb. Given the dry mid-level air that
 overlays the cyclone and continued moderate-to-strong southerly
 vertical wind shear for the next 48 hours or so, any significant
 re-strengthening appears unlikely while Bonnie remains over near the
 cool coastal shelf waters. The SHIPS and LGEM models re-strengthen
 Bonnie back to tropical storm status by 36 hours, but this seems
 unlikely given that the cyclone will be over 22-24 deg C sea-surface
 temperatures and in proximity to land. The official intensity
 forecast calls for Bonnie to maintain its current intensity of 25 kt
 throughout the forecast period and become a remnant low pressure
 system by  48 hours. However, the latter could occur sooner than
 the official forecast is indicating.
 
 The primary concern from Bonnie continues to be locally heavy
 rainfall. Rainfall amounts of 6 to 8 inches have already been
 reported in portions of eastern Georgia and southern South Carolina,
 and additional rainfall amounts of 2 to 4 inches will be possible.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  30/0900Z 33.0N  79.5W   25 KT  30 MPH
  12H  30/1800Z 33.3N  79.0W   25 KT  30 MPH
  24H  31/0600Z 33.5N  78.4W   25 KT  30 MPH
  36H  31/1800Z 33.8N  77.8W   25 KT  30 MPH
  48H  01/0600Z 34.4N  77.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
  72H  02/0600Z 35.7N  75.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  03/0600Z 37.3N  72.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  04/0600Z 38.7N  69.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Stewart