Tropical Storm Flossie Winds: 35 kt
Pressure: 1004 mbar
Advisory 3 / 2:00 AM PDT Monday, July 29, 2019

The tropical depression has regained its composure, with deep convection firing near the low-level center of circulation and the old disorganized band shooting ahead of the circulation, with the potential to become a rainband on the western side of the system. Dvorak intensity estimates have risen, with SAB giving the system T2.5/35kt and TAFB giving T3.0/45kt at 06z, supporting an increase to tropical storm strength. The ASCAT-C pass at 0414z though only revealed a broad region of 30kt winds. With the recent organization, the support of the Dvorak estimates, and the potential for some higher winds closer to the center, Seven-E has been upgraded to Tropical Storm Flossie with winds of 35kt.

Flossie is expected to track generally westward for the next two days or so south of strong mid-level ridging. A weakeness in the ridging will allow for the storm to gain latitude and track more west-northwest by around day three to the end of the forecast period.

Flossie is currently in an environment of high mid-level moisture, low upper-level winds, and warm sea surface temperatures of 28-29C, of which the latter are expected to persist for the next three days or so before they become a more marginal 27C. Mid-level moisture should remain plentiful within Flossie's environment throughout the forecast period. One issue that Flossie may face is a strong upper-level anticyclone which is forecast to be located to the storms west at about 60h. There it may induce a northerly jet which may impinge upon the system and threaten its prospects for strengthening over the course of a day or so. If the storm can consolidate before this point and generate its own strong upper-level outflow and associated anticyclone, this could mitigate the impact on the storm significantly. Modeling seems to be going with this solution. Beyond this, the storm will weaken slowly even as this potential shear lets up as instability decreases as a result of decreasing sea surface temperatures.


INIT 29/0900Z 35 KT 35 MPH

12H 29/1800Z 40 KT 40 MPH

24H 30/0600Z 45 KT 45 MPH

36H 30/1800Z 55 KT 60 MPH

48H 31/0600Z 70 KT 75 MPH

72H 01/0600Z 95 KT 110 MPH

96H 02/0600Z 90 KT 105 MPH

120H 03/0600Z 85 KT 100 MPH

Forecaster Kalassak
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