|Hurricane Barbara||Winds: 120 kt|
|Pressure: 941 mbar|
|Advisory 16 / 2:00 PM PDT Wed July 3, 2019|
Barbara remains a well-formed hurricane this afternoon, with a large and symmetric eye filled with mesovorticies. The central dense overcast remains round, with convection deeper than -60C wrapping around the center. As expected, dry air is having an influence on the intensity of the cyclone today, but the negative consequences of this dry air have been slow to destroy Barbara in the presence of warm ocean temperatures and low wind shear. A 1846z microwave pass indicated that the eyewall replacement cycle that started last night had regressed; the tightly-knit double eyewall structure on display then was reminiscent of Hurricane Irma in 2017, which also failed to complete its structural reconfiguration. This has also tempered weakening today. Satellite intensity estimates are T5.0/90kt from SAB and T5.5/102kt from TAFB, but current intensity values are higher at T6.0/115kt and T6.5/127kt, respectively. UW-CIMSS ADT has fallen to T5.7/107kt but it too has a higher CI value of T6.2/120kt. A blend of the current intensity values yields an advisory intensity of 120kt, but I would not be shocked if this was conservative given the organization on microwave imagery.
Barbara has been slow to weaken over the past 12 hours, and this trend is likely to continue a little longer while the hurricane remains over 27C ocean temperatures and in wind shear less than 5kt. However, in 12 to 18 hours, wind shear will begin a steady uptick, reaching 30kt by day 3. The SHIPS text output indicates Barbara will cross the 26C isotherm about a day from now. Meanwhile, mid-level relative humidity values are near 60 percent and should steadily decrease moving forward. The culmination of these factors should yield a weakening trend, increasing with time as the environment becomes ever hostile. Barbara should fall under hurricane strength within 48 hours and degenerate to a remnant low about 3 days from now. Dissipation is expected by day 5 as Barbara approaches the Hawaiian Islands, although feasibly this could occur sooner.
The hurricane has taken on a strict northwest motion today as mid-level ridging over northern Mexico remains weak. This trajectory should continue for about 48 more hours, until the area of high pressure extends west and restrengthens. This change, combined with Barbara's rapid weakening (therefore making it more susceptible to the low-level easterly trade wind flow across the East Pacific), should force the storm west by 72 hours and even south of west thereafter. On this path, Barbara is expected to pass close to the Big Island of Hawaii in about 5 days, although the consequences of this track are unlikely to be severe given the fact Barbara should be a remnant low or trough by that time.
FORECAST MAX WINDS
INIT 03/2100Z 120 KT 140 MPH
12H 04/0600Z 110 KT 125 MPH
24H 04/1800Z 90 KT 105 MPH
36H 05/0600Z 70 KT 80 MPH
48H 05/1800Z 50 KT 60 MPH
72H 06/1800Z 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 07/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW120H 08/1800Z...DISSIPATED