198 
 WTNT41 KNHC 020241
 TCDAT1
 
 HURRICANE JOAQUIN DISCUSSION NUMBER  17
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL112015
 1100 PM EDT THU OCT 01 2015
 
 The eye of Joaquin contracted in satellite imagery late this
 afternoon, but has become obscured by cirrus clouds since that time.
 Recent microwave imagery and aircraft observations have not shown
 any indications of an eyewall replacement, but the intensity appears
 to have leveled off for now.  The aircraft has measured peak 700-mb
 flight-level winds of 123 kt and reliable SFMR surface winds of 116
 kt, which support an initial wind speed of 115 kt.  Satellite images
 show that the outflow is well established over the hurricane and
 some additional strengthening is possible during the next 12 hours
 or so.  After that time, there could be some fluctuations in
 intensity due to eyewall replacement cycles.  Joaquin is forecast to
 encounter increasing southwesterly shear in 2 to 3 days, which is
 expected to cause some weakening during that time. However, Joaquin
 is expected to remain a large and powerful hurricane for the next
 several days. The NHC intensity forecast is near the upper-end of
 the guidance in the short-term, and is close to the intensity
 consensus throughout the remainder of the forecast period.
 
 Recent reconnaissance fixes suggest that Joaquin has turned westward
 and slowed down, with an initial motion of 260/3.  The mid- to
 upper-level ridge that has been steering Joaquin southwestward is
 expected to quickly weaken overnight while a mid- to upper-level
 trough over the southeastern United States deepens and cuts off.
 This should cause Joaquin to turn northward on Friday, and move
 north-northeastward at a faster forward speed Friday night and
 Saturday.  The model envelope has again shifted eastward, with the
 GFDL and NAVGEM models now joining the other dynamical models which
 keep Joaquin offshore of the United States east coast.  This has
 required another eastward shift to the NHC forecast, but it still
 lies to the west of the multi-model consensus and the most recent
 runs of the GFS and ECMWF models.  The updated track is closest to
 the GFS ensemble mean.  Additional eastward adjustments could be
 required to the official forecast overnight.
 
 Surface and reconnaissance aircraft data indicate that Joaquin's
 wind field has expanded during the past 24 hours.  The initial and
 forecast wind radii have been adjusted outward accordingly.  The
 increase in size has resulted in the issuance of a Tropical Storm
 Warning for eastern Cuba where wind gusts above tropical-storm-
 force have already been observed.
 
 
 KEY MESSAGES:
 
 1.  Joaquin's slow motion means that extremely dangerous conditions
 will continue over portions of the warning areas in the Bahamas well
 into Friday.
 
 2.  The forecast models continue to indicate a track farther away
 from the United States east coast and the threat of direct impacts
 from Joaquin in the Carolinas and mid-Atlantic states appears to be
 decreasing.  However, the threat of impacts in Bermuda has increased
 and a Tropical Storm or Hurricane Watch could be required for that
 island on Friday.
 
 3.  Efforts to provide the forecast models with as much data as
 possible continue, with twice daily NOAA G-IV jet missions in the
 storm environment, and extra NWS balloon launches.
 
 4.  Even if Joaquin moves out to sea, strong onshore winds
 associated with a frontal system will create minor to moderate
 coastal flooding along the coasts of the mid-Atlantic and
 northeastern states through the weekend.  In addition, very heavy
 rains, not associated with Joaquin, are expected to produce flooding
 over portions of the Atlantic coastal states.  Please see products
 issued by local NWS Forecast Offices.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  02/0300Z 22.9N  74.6W  115 KT 130 MPH
  12H  02/1200Z 23.2N  74.7W  120 KT 140 MPH
  24H  03/0000Z 24.7N  74.4W  120 KT 140 MPH
  36H  03/1200Z 26.6N  73.4W  115 KT 130 MPH
  48H  04/0000Z 29.0N  72.0W  105 KT 120 MPH
  72H  05/0000Z 33.4N  70.2W   90 KT 105 MPH
  96H  06/0000Z 37.0N  68.3W   70 KT  80 MPH
 120H  07/0000Z 42.0N  61.0W   60 KT  70 MPH
 
 $$
 Forecaster Brown