Hurricane Flossie Winds: 75 kt
Pressure: 986 mbar
Advisory 11 / 2:00 AM PDT Wednesday, July 31, 2019

Flossie continues to have a large central dense overcast with deep convection. A MHS microwave pass from 0546z shows what appears to be an organizing inner mid-level core with a formative eye sheared nearly a degree to the east-southeast of the low-level center of circulation. Dvorak satellite intensity estimates from both SAB and TAFB are T4.5/77kt as of 06z. With the slight increase in organization indicated by microwave imagery and the agreement from Dvorak, the initial intensity of Flossie has been raised to 75kt.

On the other hand, as indicated previously and confirmed by microwave data Flossie is moderately sheared from the west and north. This shear is forecast to increase in the short term over the day today. This will likely stall even the slow strengthening that we have seen over the past day. There is a possibility that once Flossie moves under the upper-level anticyclone to its west, the shear will reduce back down to a more manageable level, but by this time sea surface temperatures and mid-level relative humidity values are expected to be lower, leaving Flossie with an environment even less favorable than it is currently. Nonetheless, the tropical models HWRF and HMON show Flossie peaking with those conditions on day 4. Overall, the forecast has been adjusted to show very little strengthening throughout the day today as conditions becoming increasingly less favorable, and beyond this, slow weakening is indicated. Some adjustment even further downward in the short term may be necessary, and perhaps more strengthening toward the end as a better handle on the situation is gained.

Flossie has begun to track west-northwest since the last advisory. It should continue in this general direction for the duration of the forecast period south of mid-level ridging. This track continues to place Flossie very close to the Hawaiian Islands beyond day 5.


INIT 31/0900Z 75 KT 85 MPH

12H 31/1800Z 80 KT 90 MPH

24H 01/0600Z 80 KT 90 MPH

36H 01/1800Z 80 KT 90 MPH

48H 02/0600Z 70 KT 80 MPH

72H 03/0600Z 65 KT 75 MPH

96H 04/0600Z 65 KT 75 MPH

120H 05/0600Z 60 KT 70 MPH

Forecaster Kalassak
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