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Hurricane Beryl Forecast Discussion Number 5
2018-07-06 16:36:35| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Fri Jul 06 2018 000 WTNT42 KNHC 061436 TCDAT2 Hurricane Beryl Discussion Number 5 NWS National Hurricane Center Miami FL AL022018 1100 AM AST Fri Jul 06 2018 Beryl is a compact hurricane that had a pinhole eye for a few hours before more recently becoming cloud filled again. Satellite intensity estimates from TAFB and SAB were T4.0/65 kt at 12Z, but the Dvorak technique is constrained by width requirements of the convective cloud tops. That may not be applicable in this case given Beryl's extremely small size. By disregarding the width constraints, TAFB was able to provide a data-T number of T4.5/77 kt. As a compromise, the initial intensity is raised to 70 kt. Beryl has not gained much latitude and is still moving quickly westward with a 12-hour motion estimate of 275/13 kt. Mid-level ridging over the subtropical Atlantic is expected to steer Beryl on a westward to west-northwestward course through the forecast period. An acceleration is forecast to begin in 36-48 hours once Beryl becomes situated to the south of the core of the mid-level anticyclone. Some of the track models have already shown a northward bias since the cyclone formed yesterday, and the updated NHC track forecast is therefore south of the typically better- performing models. This new forecast is not too different from the previous NHC track and is also just south of the HCCA model and the various model consensus aids. Despite the SHIPS model diagnostics showing increasing shear in a few days, global model fields show a well-defined upper-level anticyclone following the system at least for the next 3 days. Although Beryl's expected acceleration may contribute to some increased shear, the SHIPS model is also probably calculating deep-layer shear over too large an area to accurately capture the shear isolated to the cyclone's scale. Given that, the NHC intensity forecast is at or above nearly all of the guidance through 48 hours, which is also higher than what we've been depicting in previous forecasts. Needless to say, it's becoming more likely that Beryl will maintain hurricane strength when it reaches the Lesser Antilles between 48 and 72 hours. The cyclone is also now likely to persist beyond the 72-hour forecast point, and a 96-hour point has therefore been added to the official forecast, showing Beryl near or over Hispaniola by day 4. By that point, either increased shear or the terrain of Hispaniola would likely lead to dissipation. But we shall see. Key Messages: 1. Beryl is now expected to be a hurricane when it moves through the Lesser Antilles Sunday night or Monday, and the chance of some islands receiving direct impacts from wind and rainfall are increasing. However, Beryl is a very small hurricane, and it is too early to determine exactly where those impacts will occur. Hurricane watches could be needed for portions of the Lesser Antilles as soon as tonight. 2. Due to its very small size, there is greater-than-usual uncertainty in the analysis of Beryl's current intensity, and confidence in the official intensity forecast is also lower than normal. Rapid changes in intensity, both up and down, that are difficult to predict are possible during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 10.7N 46.5W 70 KT 80 MPH 12H 07/0000Z 11.3N 47.9W 75 KT 85 MPH 24H 07/1200Z 12.2N 50.1W 80 KT 90 MPH 36H 08/0000Z 13.3N 53.0W 85 KT 100 MPH 48H 08/1200Z 14.2N 56.6W 85 KT 100 MPH 72H 09/1200Z 16.2N 64.6W 60 KT 70 MPH 96H 10/1200Z 18.5N 72.0W 40 KT 45 MPH...INLAND OVER HISPANIOLA 120H 11/1200Z...DISSIPATED $$ Forecaster Berg
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Post-Tropical Cyclone Fabio Forecast Discussion Number 24
2018-07-06 16:33:33| Tropical Depression LIDIA
Issued at 800 AM PDT Fri Jul 06 2018
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fabio
Hurricane Beryl Forecast Discussion Number 4
2018-07-06 10:55:02| National Hurricane Center (Atlantic)
Issued at 500 AM AST Fri Jul 06 2018 000 WTNT42 KNHC 060854 TCDAT2 Hurricane Beryl Discussion Number 4 NWS National Hurricane Center Miami FL AL022018 500 AM AST Fri Jul 06 2018 Deep convection associated with the tiny tropical cyclone has continued to become better organized overnight. An earlier AMSR2 microwave overpass showed a well-defined mid-level eye and a pinhole eye has been apparent in the various GOES-16 satellite channels since shortly after 0600 UTC and was most evident around 0715 UTC. Although the clarity of the eye has waxed and waned since that time, there is enough convective organization to increase the initial intensity to 65 kt, making Beryl the first hurricane of the 2018 Atlantic hurricane season. The cyclone has another 18-24 hour within very low vertical wind shear conditions and over SSTS of 26-27 degrees Celsius. These favorable conditions suggest that the tiny hurricane is likely to intensify further today. The NHC intensity forecast calls for additional strengthening and is at the upper-end of the intensity guidance, but I would not be too surprised if the compact hurricane reaches a slightly higher peak intensity than indicated below. By 36 hours, the shear is forecast to increase to more than 15 kt, and it is expected to be greater than 20 kt shortly after that time. This should cause the very small tropical cyclone to quickly weaken, however as mentioned in the Key Messages below there is greater uncertainty than usual regarding Beryl's intensity forecast. Although the updated NHC forecast shows Beryl reaching the Lesser Antilles as a tropical storm it is highly possible that the system will have degenerated into an open trough by that time. Regardless of the system's status at 72 h, it is likely to bring strong gusty winds and locally heavy rains to portions of the Lesser Antilles Sunday and Monday. The initial motion estimate remains 275/12 kt. The track guidance is in good agreement taking Beryl west-northwestward to the south of a deep-layer ridge over the central Atlantic. There has been little overall change in the latest dynamical guidance and the new NHC track forecast is similar to the previous advisory and lies along the southern edge of the guidance envelope closest to the latest ECMWF and HFIP correct consensus models. Key Messages: 1. Due to its very small size, there is greater-than-usual uncertainty in the analysis of Beryl's current intensity. Confidence in the official intensity forecast is also much lower than normal. Rapid changes in intensity, both up and down, that are difficult to predict are possible during the next couple of days. 2. While Beryl is still to forecast to quickly weaken or dissipate as a tropical cyclone on Monday before reaching the Lesser Antilles, there will likely be some rain and wind impacts on those islands early next week. Residents there should monitor products from their local weather office for more information. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 10.6N 45.1W 65 KT 75 MPH 12H 06/1800Z 11.0N 46.6W 75 KT 85 MPH 24H 07/0600Z 11.7N 48.6W 75 KT 85 MPH 36H 07/1800Z 12.7N 51.0W 65 KT 75 MPH 48H 08/0600Z 13.6N 54.4W 55 KT 65 MPH 72H 09/0600Z 15.4N 61.9W 45 KT 50 MPH 96H 10/0600Z...DISSIPATED $$ Forecaster Brown
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Tropical Storm Fabio Forecast Discussion Number 23
2018-07-06 10:49:00| Tropical Depression LIDIA
Issued at 200 AM PDT Fri Jul 06 2018
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Tropical Storm Fabio Forecast Discussion Number 22
2018-07-06 04:34:25| Tropical Depression LIDIA
Issued at 800 PM PDT Thu Jul 05 2018
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tropical
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