Hurricane Barbara Discussion Number 10
Wiki-Hurricanes Forecast Center
2:00 AM PDT Tue Jul 2 2019
Barbara has recently experienced another large convective burst, which briefly clouded over a ragged eye on satellite imagery, but which has resumed making itself apparent and a deep convective ring is in the making. The spiral banding to the south and west of the storm a few hours ago has decreased in prominence likely as a result of mixing with the most recent intrusion of dry air. Nonetheless, SAB came in at a surprising T5.5/102kt at 06z, possibly from a particularly lucky placement of a dry region of air. In more recent frames, the infrared cloud top temperatures there have decreased. A microwave pass at 0431z was from the low resolution MHS aboard METOP-A, which appears to show maybe a slight consolidation of the core structure and corroborates infrared satellite observations of the weakening outer rainband and convective burst focused on the eastern side of the storm. Barbara is still on an intensification trend and based on the increasingly apparent eye, its initial intensity is set to 90 kts.
Recent motion of Barbara has been almost due westerly, even perhaps with a southerly component. If this trend continues for a significant time, it may have an influence on the future of the storm, however, this is not expected at this time. The hurricane should move west-northwesterly for the next two days or so before the ridge to the northeast weakens and it begins to track more northwesterly, into cooler waters much quicker. By day 4, the ridge is expected to build out further west, resulting in a more westerly motion again and as Barbara is expected to be weak by this time, low-level trade winds will also influence this turn.
Despite the issues with dry air, Barbara continues to intensify. Warm sea surface temperatures will continue to fuel the storm for the next two days before the storm begins to reach the strong SST gradient which will remove the energy source for the storm by day 3. Shear should remain low for the next three days before an upper trough will induce some southwesterly shear which should induce further weakening as Barbara runs over cooler waters. The storm itself is embedded directly in a very moist environment, but as mentioned previously is surrounded by very dry air particularly to the west, which has been ingested by the system intermittently. This will continue to remain the significant threat to intensification although given the current steady intensification trend in the face of dry air, the hurricane may be able to consolidate a strong inner core later today which should allow for further intensification to category 4 strength by tomorrow, followed by slow weakening. Around day 3 though, shear will allow for significant ingestion of dry, stable air, and the combination of unfavorable factors expected to occur at this time will result in rapid weakening.
FORECAST MAX WINDS
INIT 02/0900Z 90 KT 105 MPH
12H 02/1800Z 100 KT 115 MPH
24H 03/0600Z 115 KT 130 MPH
36H 03/1800Z 115 KT 130 MPH
48H 04/0600Z 110 KT 125 MPH
72H 05/0600Z 90 KT 105 MPH
96H 06/0600Z 60 KT 70 MPH
120H 07/0600Z 30 KT 35 MPH