|Hurricane Barbara||Winds: 125 kt|
|Pressure: 939 mbar|
|Advisory 15 / July 3, 2019|
Hurricane Barbara Discussion Number 15
Wiki-Hurricanes Forecast Center
8:00 AM PDT Wed Jul 03 2019
Although powerful Barbara continues to present a circular and cloud-free eye this morning, its central dense overcast is becoming more ragged. Microwave imagery shows that the eyewall replacement cycle noted in the previous advisory is in progress, with a distinct double eyewall structure and dry air channel noted at 0959z. In response, cloud tops have warmed progressively despite the diurnal maximum. SAB reported a CI value of T6.5/127kt with CIMSS-ADT indicating a similar T6.4/125kt. With SATCON member consensus in near agreement with these values and noting the increased robustness of the secondary eyewall, the intensity for Barbara has been lowered further to 125 kt.
Track guidance remains tightly clustered, anticipating the continued west-northwest to northwest trajectory about a nearby steering ridge. A gradual turn westward roughly along 19N should take hold after day 3 as this ridge extends westward and the system shallows over time. Some slight southerly motion may occur late in the forecast window as ridging sags southward towards Hawaii, though by this time the predominant steering would derive from the low-level westerlies.
Barbara is departing more favorable waters and engaging the sharp sea surface temperature gradient to its north and northwest. Current temperatures are near 27.5C but are expected to fall below 26C tomorrow. Concurrent with this trend is an increase in upper-air temperatures and a decrease in relative humidity, decreasing convective buoyancy and limiting storm development. Conditions will remain marginal today, so the eyewall replacement cycle will serve to hurry along the weakening process. Weakening is depicted throughout the forecast period as Barbara moves into and remains within a stable regime.
INIT 03/1500Z 125 KT 140 MPH
12H 04/0000Z 110 KT 125 MPH
24H 04/1200Z 100 KT 115 MPH
36H 05/0000Z 85 KT 100 MPH
48H 05/1200Z 65 KT 75 MPH
72H 06/1200Z 40 KT 45 MPH
96H 07/1200Z 30 KT 35 MPH120H 08/1200Z 20 KT 25 MPH