Tropical Storm Emilia Discussion Number 5

Wiki-Hurricanes Forecast Center

200 PM PDT Thu Jun 28 2018

Emilia continued to gradually become better organized this afternoon, and a close analysis of the exposed cumuliform cloud lines east of the center show the circulation has become less elongated. A fairly typical banding presentation has taken shape on visible imagery with a persistent band in the western semicircle, and the center has become a bit more colocated with the center of convection, though it remains displaced slightly eastward under central convection's cirrus canopy. Microwave imagery from 1410Z and 1901Z show improving internal structure, with banding beginning to wrap around the center of circulation's southern periphery. Though displaced, the mid-level circulation for Emilia has also organized further, which should provide a persistent focus for convective activity. SAB subjective intensity estimates are at T3.0/45kt on a shear pattern, and in-house Dvorak estimation on a curved band yields the same results. UW-CIMSS ADT estimates T2.7/39kt while UW-CIMSS AMSU on microwave data estimated 37 kt at 1710Z. Based on this data, the current intensity for Emilia has been set at 40 kt.

Emilia continues to the west-northwest at 290/13, presently ensconsed in a subtropical ridge-guided easterly steering flow. Upper-analyses suggest that heights associated with the upper-trough over the western coast of the United States have not begun to dive southward, but models are in general agreement that this feature will dig into the tropics in around two to three days, pulling Emila northwestward before the storm shallows out and is carted to its burial grounds by the subtropical easterlies. Intensity guidance has continued to grow a bit more optimistic when it comes to Emilia's future, though sea surface temperatures and dry conditions remain the primary barrier as temperatures quickly fall after around 36 hours; as the oceanic conditions quickly deteriorate, Emilia will have to put on a quick show in the limited time until the waters grow tepid. The tropical storm is making decent use its currently moderately sheared but warm and moist environment, and should continue to steadily intensify as it develops an upper-level anticyclone out until two or so days, after which convection should thin out with winds falling in response to a lack of atmospheric support and oceanic capacity. HWRF and HMON show a Category 1 hurricane ramping up to a peak at a remarkably late 72 or so hours, which seems atypical given that sea surface temperatures would have fallen well before then. GFS is a bit more realistic in this regard, with a similar peak occuring beforehand, though this is precipitated by some abnormal antecdent intensification. ECMWF-IFS and UKMO-G have held their ground for the most part with a moderate TS, as have statistical guidance. For now, the intensity forecast for Emilia has been slightly raised given today's structural developments, but continue to show fairly precipitous weakening after peak intensity.


INIT 28/2100Z 40 KT 45 MPH

12H 29/0600Z 45 KT 50 MPH

24H 29/1800Z 50 KT 60 MPH

36H 30/0600Z 55 KT 65 MPH

48H 30/1800Z 55 KT 65 MPH

72H 01/1800Z 40 KT 45 MPH

96H 02/1800Z 30 KT 35 MPH

120H 03/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW