694 
 WTPZ42 KNHC 020234
 TCDEP2
 
 Hurricane Barbara Discussion Number   7
 NWS National Hurricane Center Miami FL       EP022019
 800 PM PDT Mon Jul 01 2019
 
 Passive microwave imagery over the past 6 hours indicates that the
 inner-core convection of Barbara has continued to consolidate and a
 ragged low- to mid-level eye has formed.  However, a pronounced dry
 intrusion has periodically worked its way into the center of the
 convective cloud mass, resulting in brief erosions of the eyewall.
 Despite the dry air, bursts of deep convection have been developing
 near the center and the most recent hi-resolution GOES-17 visible
 satellite images suggest that a more robust eyewall is possibly
 developing.  Dvorak satellite intensity estimates are T4.5/77 kt
 from TAFB and SAB, and UW-CIMSS ADT and SATCON values are T4.5/77
 kt and 80 kt, respectively.  Given the occasional appearance of a
 ragged cloud-filled eye in visible satellite imagery, the initial
 intensity has been increased to 85 kt for this advisory, meaning
 that Barbara has rapidly intensified during the past 24 hours.
 
 Barbara's initial motion is 280/13 kt.  There remains no significant
 change to the previous track forecast rationale.  Barbara should
 turn toward the west-northwest shortly, and that general motion is
 forecast to continue for the next 36-48 hours.  After that time, a
 passing shortwave trough is expected to weaken the ridge to the
 north of the hurricane, allowing Barbara to move more poleward. In
 the 96-120 hour period, however, the ridge is forecast to build back
 in, forcing Barbara back toward the west.  The new NHC track
 forecast is very similar to the previous advisory track, and lies
 close to a blend of the TVCN, HCCA, and FSSE consensus models.
 
 The combination of low vertical wind shear, an expanding upper-level
 outflow regime, a moist mid-level environment, and SSTs greater than
 28 deg C is expected to persist for at least the next 36 hours,
 allowing Barbara to continue to rapidly strengthen during that time.
 By 48 hours, however, steady weakening is expected to begin due to a
 probable eyewall replacement cycle, the beginning of cold upwelling,
 and increasing southwesterly wind shear.  On days 4 and 5, more
 rapid weakening is forecast due to Barbara moving over sub-26 deg C
 water temperatures and into vertical wind shear conditions of more
 than 20 kt.  The new official intensity forecast is similar to the
 previous advisory, and is a little above the consensus guidance
 throughout the entire forecast period, closer to the Decay-SHIPS
 model.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  02/0300Z 11.7N 119.8W   85 KT 100 MPH
  12H  02/1200Z 12.3N 121.7W   95 KT 110 MPH
  24H  03/0000Z 12.9N 124.0W  110 KT 125 MPH
  36H  03/1200Z 13.6N 125.9W  120 KT 140 MPH
  48H  04/0000Z 14.4N 127.7W  115 KT 130 MPH
  72H  05/0000Z 16.4N 131.0W   85 KT 100 MPH
  96H  06/0000Z 18.0N 134.7W   65 KT  75 MPH
 120H  07/0000Z 18.7N 139.6W   45 KT  50 MPH
 
 $$
 Forecaster Stewart