|Hurricane Barbara||Winds: 90 kt|
|Pressure: 959 mbar|
|Advisory 20 / 2:00 PM PDT Thu July 4, 2019|
Barbara's rapid weakening should begin shortly. Infrared satellite imagery shows a storm that is increasingly weighted to the northern semicircle, an indication that upper-level winds are beginning to become hostile. Although deep convection continues to persist within the central dense overcast, the eye has cooled and is becoming less symmetrical with time. Satellite intensity estimates from both SAB and TAFB at 18z were T4.5/77kt, although the latter organization had a current intensity value of T5.0/90kt. Both indices from UW-CIMSS ADT were steady at T5.3/97kt. A blend of these values supports lowering the initial intensity to 90kt.
SHIPS assesses southwesterly wind shear at 20kt, with a further increase still to come. The hurricane is currently in the process of crossing the 26C isotherm, where it will interact with a more stable airmass characterized by mid-level relative humidity values around 55 percent. The combination of these factors should promote a quick decline for Barbara, which is expected to be little more than a remnant low about 48 hours from now. Dissipation has been brought forward to day 4, when the system is expected to be east of the Big Island of Hawaii.
The hurricane continues on its northwest trajectory this afternoon, and this motion should continue for the next day or so as mid-level ridging remains weak. By late tomorrow, high pressure should build north of Barbara, forcing it to the west. After 48 hours, as the cyclone degenerates to a remnant area of low pressure, it should be steered a little south of west as it becomes entangled in the low-level easterly trade wind flow.
FORECAST MAX WINDS
INIT 04/2100Z 90 KT 105 MPH
12H 05/0600Z 70 KT 80 MPH
24H 05/1800Z 50 KT 60 MPH
36H 06/0600Z 35 KT 40 MPH
48H 06/1800Z 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 07/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 08/1800Z...DISSIPATED120H 09/1200Z....DISSIPATED