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Pacific Tropical Cyclone Outlook for September 6th, 2019

2 Tropical Cyclones continue to churn but slowly dissipate in both the Eastern and Central Pacific Basin.


Tropical Depression Akoni, with maximum, sustained winds of 35 mph and moving to the west at 16 mph. Akoni, peaked becoming a tropical storm yesterday afternoon and slowly dissipated overnight. No impacts from Akoni is expected as it continues to pass to the south of the islands. However, stronger trade winds and an increase in showers are still expected this weekend and early next week.


Hurricane Juliette, a category 1 hurricane with maximum sustained winds of 75 mph moving to the west at 12 mph, is expected to continue to dissipate over the next 5 days and no impacts to the islands are expected.


No watches or warnings are in effect at this time associated with both tropical cyclones.

Discussion on Twelve-E (Akoni) as of 5:00 am HST Friday:

Post-Tropical Cyclone Akoni Discussion Number 10 NWS Central Pacific Hurricane Center Honolulu HI EP122019 500 AM HST Fri Sep 06 2019 Although showers and thunderstorms continue to pulse near Akoni's elongated low-level circulation center (LLCC), they have not been sufficiently persistent or organized to continue to classify the system as a tropical cyclone, and Akoni is being downgraded to a post-tropical remnant low. An overnight ASCAT-C pass showed southerly winds to 30 kt in an area east of the center, and that will be the initial intensity for this advisory. The initial motion estimate is a very uncertain 270/14 kt, as it appears that the LLCC has re-formed west of its previous location. A low- to mid-level ridge will strengthen far north of the remnant low over the next couple of days, and the associated gradient will likely support 30 kt winds in the northern semicircle. The high will also drive the system toward the west to west-northwest, with an increase in forward speed expected over the weekend. Little change in strength is expected until the system encounters increased vertical wind shear toward the latter part of the forecast period. This is expected to cause the low to weaken and open into a trough by day 4 or 5, similar to the solutions presented by GFS and ECMWF guidance. This is the last advisory issued by the Central Pacific Hurricane Center on this system, unless regeneration occurs. For additional information on the remnant low, please see High Seas Forecasts issued by the National Weather Service Honolulu, under AWIPS header HFOHSFNP, WMO header FZPN40 PHFO, and available on the Web at weather.gov/hfo/HSFNP. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 11.2N 149.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 12H 07/0000Z 11.2N 151.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 07/1200Z 11.4N 153.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 08/0000Z 12.0N 156.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 08/1200Z 12.9N 159.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 09/1200Z 15.0N 166.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 10/1200Z 17.0N 172.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 11/1200Z...DISSIPATED


Discussion on Hurricane Juliette as of 5:00 am HST, Friday:

Hurricane Juliette Discussion Number 22 NWS National Hurricane Center Miami FL EP112019 500 AM HST Fri Sep 06 2019 Deep convection associated with Juliette has decreased in coverage over the past 24 hours, however, the remaining convection still wraps completely around the center. Subjective and objective raw T-numbers from TAFB and UW/CIMSS have fallen below 4.0, however the current intensity (CI) numbers are still at 4.5. Using a blend of these T- and CI-numbers, as NHC typically does during the weakening phase, yields an initial wind speed of 65 kt for this advisory. Juliette is currently over SSTs of around 24.5 degrees Celsius, with even cooler waters and a more stable and drier air mass along the predicted path of the storm. These conditions should cause gradual weakening over the next day or so, and Juliette is forecast to become post-tropical in 36 to 48 hours. Recent fixes show that Juliette has turned west-northwestward or 300/10 kt. A subtropical ridge to the north of the cyclone should continue to steer Juliette west-northwestward during the next 24 hours. After that time, the cyclone should turn westward within the low-level tradewind flow. The dynamical models are in better agreement today on the both the track and forward speed of the cyclone, and the NHC forecast is near the middle of the envelope. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 22.8N 123.4W 65 KT 75 MPH 12H 07/0000Z 23.4N 125.2W 60 KT 70 MPH 24H 07/1200Z 23.8N 127.3W 50 KT 60 MPH 36H 08/0000Z 23.9N 129.4W 40 KT 45 MPH 48H 08/1200Z 23.8N 131.5W 35 KT 40 MPH...POST-TROPICAL 72H 09/1200Z 23.5N 135.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 10/1200Z 23.5N 139.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 11/1200Z 24.0N 142.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

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