Tropical Storm Flossie Winds: 50 kt
Pressure: 999 mbar
Advisory 6 / 8:00 PM PDT Monday, July 29, 2019

Flossie continues to move rapidly westward across the East Pacific this evening. There have been a few changes in its satellite appearance, with an uptick in organization around 21z followed by a decline in cohesiveness over the past hour or so. Recent satellite intensity estimates were T3.0/45kt from SAB, T3.5/55kt from TAFB, and T3.9/63kt from UW-CIMSS ADT. A simple blend of these values would yield an initial intensity of 55kt. However, given the continued lack of an inner core on microwave imagery, coupled with the decrease in organization lately, I have instead set the intensity to a possibly conservative 50kt.

Flossie is expected to remain in an environment of warm ocean waters, adequate mid-level relative humidity, and moderate wind shear for the next 48 to 60 hours. This should allow at least steady intensification, although the prospect for rapid intensification still exists, especially in the short term given a 6-in-10 chance of a 25kt increase in strength over the next day according to the SHIPS. After 60 hours, ocean temperatures are expected to cool, the airmass is expected to become increasingly dry, and wind shear will increase further. This should result in weakening. The updated forecast is largely a translation of the previous one except to move the forecast peak forward in time.

Broad and intense mid-level ridging north of Flossie should continue to direct the storm westward tomorrow. Thereafter, the brunt of the area of high pressure should shift eastward, placing Flossie on the southwestern periphery and inducing a west-northwest motion. That trajectory should continue for the remainder of the period.


INIT 30/0300Z 50 KT 60 MPH

12H 30/1200Z 60 KT 70 MPH

24H 31/0000Z 70 KT 80 MPH

36H 31/1200Z 80 KT 90 MPH

48H 01/0000Z 95 KT 110 MPH

72H 02/0000Z 90 KT 105 MPH

96H 03/0000Z 85 KT 100 MPH

120H 04/0000Z 75 KT 85 MPH

Forecaster TAWX14
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