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Eastern Pacific Tropical Cyclone Outlook # 5 for July 29th, 2019

The National Hurricane Center (NHC) continues to monitor 2 Tropical Cyclones in the Eastern Pacific basin:

- Tropical Storm Erick: currently 1,470 miles ESE of Hilo & moving to the west at 17 mph. With maximum sustained winds of 65 mph and expected to become hurricane by tomorrow afternoon.

- Tropical Storm Flossie: currently 2,780 miles ESE of Hilo & moving westward at 20 mph. With maximum sustained winds of 40 mph. Flossie is expected to become hurricane in the coming days.

Based on the latest models reviewed, Tropical Storm Erick is still expected to past to the south of the Island of Hawaii around Friday morning into Saturday, exactly how far south still remains unknown at this time. Wet Weather Associated with Erick is expected to come onshore Thursday night going into the weekend.

Tropical Storm Flossie: it's again still too early to determine the exact track of Flossie and it impacts to Hawaii Island, we will have a better idea of the projected forecast around Friday and Saturday at the earliest as it expected to cross into the Central Pacific basin on Saturday.

Currently, No Watches or Warnings are in effect at this time related to these disturbances.

The next HIRSC Team Update will be made at 06:00 Hours (6:00 am) Monday Morning.

Update on Tropical Storm Erick as of 11:00 pm HST July 28th, 2019:

Tropical Storm Erick Discussion Number 8 NWS National Hurricane Center Miami FL EP062019 1100 PM HST Sun Jul 28 2019 The storm's cloud pattern is becoming better organized and has taken on a comma shape, with very cold cloud tops to at least -80 deg C. There is prominent upper-tropospheric outflow, except over the northeastern quadrant of the circulation. An eye is not yet evident in the imagery, however. Erick's current intensity estimate is set at 60 kt in general agreement with objective Dvorak estimates from UW-CIMSS. The dynamical guidance indicates that the vertical shear will remain below 10 kt for the next 48 hours and SSTs should remain near 28 deg C, which would favor steady strengthening. Additionally, the SHIPS Rapid Intensification Index continues to show a high probability, near 70 percent, of rapid strengthening. Thus the official wind speed forecast shows a significant increase during the next 1 to 2 days, with the system predicted to attain major hurricane status within that time frame. This is in agreement with the corrected consensus, HCCA, and the FSU Superensemble guidance, FSSE, along with the HWRF model simulation. Erick continues to move westward, or around 270/14 kt. A mid-level ridge is predicted to remain to the north of the tropical cyclone over the next several days which should maintain a mainly westward track. The track models suggest a slight bend toward the west-northwest in 36-72 hours, but with no substantial northward excursions. The new official track forecast is quite similar to the previous one, and is a little south of the latest dynamical model consensus. It should be noted that the latest ECMWF model run shows a track that is even a little farther to the south. The wind radii have been adjusted based on data from a recent ASCAT-C overpass which depicted a slightly larger storm than previously estimated. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 11.7N 134.5W 60 KT 70 MPH 12H 29/1800Z 12.2N 136.7W 70 KT 80 MPH 24H 30/0600Z 12.8N 139.7W 85 KT 100 MPH 36H 30/1800Z 13.5N 142.3W 95 KT 110 MPH 48H 31/0600Z 14.1N 144.6W 100 KT 115 MPH 72H 01/0600Z 15.3N 148.9W 85 KT 100 MPH 96H 02/0600Z 16.0N 153.5W 60 KT 70 MPH 120H 03/0600Z 16.9N 158.2W 40 KT 45 MPH

Tropical Storm Flossie Update as of 11pm HST July 28th, 2019:

Tropical Storm Flossie Discussion Number 4 NWS National Hurricane Center Miami FL EP072019 1100 PM HST Sun Jul 28 2019 Over the past several hours, deep convection has developed near the center of circulation with a large curved band composed of cloud tops as cold as -80 C enveloping the western semicircle of the cyclone. A recent ASCAT-C scatterometer pass partially captured the northeastern quadrant of the system and measured winds of 30 kt over 75 n mi from the center and it is likely that higher winds were occurring at that time in the unsampled area closer to the center. In addition, the mean of the subjective Dvorak satellite intensity estimates have increased to tropical storm force and therefore the depression has been upgraded to Tropical Storm Flossie with an initial intensity of 35 kt. The initial motion is 275/17 kt. Ridging will persist north of the cyclone throughout the next several days which will continue to steer it west to west-northwestward with some decrease in forward speed by later today as the ridge weakens slightly. The track guidance is in very good agreement and the official NHC forecast track is similar to the previous forecast which is very near the center of the consensus aids. The environment around Flossie is favorable for strengthening over the next 72 hours or so, and if the current deep convection can persist near the center today during the diurnal minimum, then the inner core of the cyclone will likely become well established over the next 24 hours. This would allow for steady strengthening to occur, with Flossie becoming a hurricane sometime on Tuesday. Although not implicitly shown in the forecast, it is possible that Flossie could undergo rapid intensification during the next 72 hours which could result in intensities higher than currently forecast at those time frames. By day 4, the cyclone is forecast to move over marginal sea surface temperatures and into a drier, more stable environment while undergoing increasing northwesterly shear. This should result in a weakening trend beginning around hour 96 of the forecast period. The official NHC intensity forecast was changed little from the previous forecast, and remains on the higher end of the intensity guidance. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 12.5N 113.0W 35 KT 40 MPH 12H 29/1800Z 12.7N 115.6W 45 KT 50 MPH 24H 30/0600Z 12.6N 118.5W 55 KT 65 MPH 36H 30/1800Z 12.8N 121.1W 65 KT 75 MPH 48H 31/0600Z 13.3N 123.7W 75 KT 85 MPH 72H 01/0600Z 14.5N 128.9W 95 KT 110 MPH 96H 02/0600Z 15.8N 134.5W 95 KT 110 MPH 120H 03/0600Z 17.5N 140.5W 90 KT 105 MPH