|Hurricane Barbara||Winds: 140 kt|
|Pressure: 930 mbar|
|Advisory 13 / 8:00 PM PDT Wed July 3, 2019|
Barbara continues to impress. Visible satellite imagery as the sun begins to set reveals an absolutely spectacular hurricane, with a large and fiery eye surrounded by a smooth and intense central dense overcast. The storm has taken on some aspects of an annular hurricane, and in fact SHIPS registers a 1 on its annular hurricane index, which represents a marginal case. Satellite intensity estimates at 0z were T6.5/125kt from SAB and T7.0/140kt from TAFB. The most recent value from UW-CIMSS ADT is T6.9/139kt. While a simple blend of these values would make Barbara an upper-end Category 4 hurricane, I have a hard time reproducing the value SAB assigned given the frame they used. Both the warmth of the eye and the smooth persistence of the central dense overcast argue that Barbara is an intense hurricane, and thus I have sided with CIMSS and TAFB to assign 140kt as the initial intensity, making Barbara a Category 5 hurricane.
Now that Barbara is near the theoretical maximum potential intensity given its location, it goes without saying that no further intensification is forecast. While wind shear remains under 10kt and ocean temperatures remain above 27C for the next 24 hours, mid-level relative humidity values will continue to fall. Two microwave passes from 21z and 0z showed that dry air had wrapped around the central dense overcast, separating that main feature from several spiral bands to the east of the center. This dry air should erode the central dense overcast over time, weakening convection and bringing down Dvorak estimates slowly over the next 24 hours. Thereafter, as wind shear increases and ocean temperatures cool, rapid weakening is expected. The environment becomes extremely hostile by day 4, when degeneration is now forecast as Barbara crosses into the Central Pacific.
Barbara is moving north of west-northwest, and this motion will continue or even become more poleward over the next 48 hours as mid-level ridging weakens over northern Mexico. By day 3, the ridge will restrengthen, and this will occur as Barbara rapidly falters and becomes steered by low-level easterly trade winds. Thus, a curve to the west and even west-southwest is expected on days 4 and 5.
FORECAST MAX WINDS
INIT 03/0300Z 140 KT 160 MPH
12H 03/1200Z 130 KT 150 MPH
24H 04/0000Z 120 KT 140 MPH
36H 04/1200Z 100 KT 115 MPH
48H 05/0000Z 85 KT 100 MPH
72H 06/0000Z 50 KT 60 MPH
96H 07/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW120H 08/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW