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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

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