827 
 WTNT41 KNHC 051439
 TCDAT1
 
 HURRICANE JOAQUIN DISCUSSION NUMBER  32
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112015
 1100 AM AST MON OCT 05 2015
 
 Joaquin's cloud pattern and overall structure has remained intact
 based on conventional and microwave satellite data. Recent SSMIS
 and SSMI microwave passes showed a well-defined small eye still
 exists, which is also indicated in reflectivity data from the
 Bermuda Doppler radar. As a result, the intensity of Joaquin is
 being maintained at 75 kt, which is supported by Dvorak satellite
 current intensity estimates of T4.5/77 kt from both TAFB and SAB.
 
 The initial motion estimate is 030/11 kt. The forecast track and
 reasoning basically remain unchanged. Joaquin is expected to turn
 northeastward today and begin moving at a slightly faster forward
 speed tonight and Tuesday as the hurricane rounds the northwestern
 periphery of a weakening ridge and begins to feel the effects of the
 faster flow in the mid-latitude westerlies. By 36 hours, Joaquin
 should begin to accelerate east-northeastward at a faster forward
 speed of more than 25 kt. The official forecast track is essentially
 just an extension of the previous advisory track guidance and lies
 close to the consensus models TCVA and GFEX through 48 hours. After
 that time, the extratropical forecast track is based on guidance
 provided by the NOAA Ocean Prediction Center.
 
 Deep convection has persisted and even expanded somewhat since the
 previous advisory, with a small area of cloud tops colder than -70C
 having developed just west of the center. With the vertical wind
 shear expected to remain between 10 to 15 kt for the next 24 hours
 or so, only slight weakening is forecast. By 48 hours and beyond,
 however, westerly vertical wind shear is forecast to increase to
 more than 30 kt when the cyclone will be moving over SSTs less than
 23C. The result should be steady weakening and a transition to a
 large and expanding extratropical low pressure system over the north
 Atlantic. Extratropical transition could occur sooner if Joaquin
 interacts or merges with a frontal system currently located a few
 hundred n mi north of the hurricane. The NHC intensity forecast is
 similar to the previous advisory and follows the intensity consensus
 model IVCN through 48 hours, and is based on guidance provided by
 the Ocean Prediction Center for days 3-5.
 
 The tropical storm force wind radii were expanded outward slightly
 in the southwestern quadrant based on surface observation and radar
 data from Bermuda.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  05/1500Z 35.0N  64.6W   75 KT  85 MPH
  12H  06/0000Z 36.3N  63.0W   70 KT  80 MPH
  24H  06/1200Z 38.0N  59.6W   70 KT  80 MPH
  36H  07/0000Z 39.3N  54.1W   65 KT  75 MPH
  48H  07/1200Z 40.5N  47.2W   60 KT  70 MPH...POST-TROP/EXTRATROP
  72H  08/1200Z 42.5N  32.6W   55 KT  65 MPH...POST-TROP/EXTRATROP
  96H  09/1200Z 44.0N  21.4W   50 KT  60 MPH...POST-TROP/EXTRATROP
 120H  10/1200Z 45.1N  15.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Stewart