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Tropical Storm Beryl Forecast Discussion Number 13
2018-07-08 16:49:35| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Sun Jul 08 2018 000 WTNT42 KNHC 081449 TCDAT2 Tropical Storm Beryl Discussion Number 13 NWS National Hurricane Center Miami FL AL022018 1100 AM AST Sun Jul 08 2018 An Air Force Reserve reconnaissance aircraft investigating Beryl earlier this morning was unable to find a closed low-level center. However, the wind data from the aircraft indicated that a sharp through did exist northeastward of the deep convection located in the northeastern quadrant of the larger circulation. Since that time, a stronger burst of convection has developed over the sharp trough, and the assumption is that the convection could have spun up a new center. For that reason, the system is still being considered as a tropical cyclone for this advisory. The highest 850-mb flight-level wind measured was 56 kt in the northeast quad, which equates to about a 45-kt surface wind. However, the advisory intensity is being maintained at 40 kt in case the recent convective development doesn't persist. Another reconnaissance mission into Beryl is scheduled for this evening. The initial motion estimate is 290/20 kt. Beryl is expected to maintain this quick west-northwestward motion through dissipation due to the strong and broad deep-layer ridge that extends east-to-west across most of the subtropical Atlantic Ocean. The latest model guidance remains tightly packed about the previous advisory track, so no significant changes were required. For now, Beryl seems to have found a sweet spot where the vertical wind shear is a little lower and more difluent based on water vapor imagery. However, this localized favorable upper-level wind flow pattern is expected to be short-lived and give way to more hostile shear conditions by 12 hours and beyond when the shear is forecast to increase to more than 25 kt from the west. The result should be a rapid degeneration of the cyclone into an open wave by 24 h when the system will be moving over the eastern Caribbean Sea. However, the system will likely produce strong gusty winds and locally heavy rainfall across the Leeward Islands, the Virgin Islands, and Puerto Rico during the next couple of days. On days 3-5, there appears to be an opportunity for the remnants of Beryl to regenerate into a tropical cyclone when the system moves through the Bahamas and into the southwestern Atlantic. Vertical wind shear conditions are forecast by most of the models to be light, with even the possibility of the development of a weak upper-level anticyclone across the Bahamas. The combination of the favorable upper-level wind flow pattern in conjunction with sea-surface temperatures of 28-29 deg C should yield conditions conducive for the reformation of a tropical cyclone, although Beryl's low-level remnants are likely to be significantly disrupted by Hispaniola and could take some time to reform. Key Messages: 1. Tropical storm warnings and watches are in effect for portions of the Lesser Antilles where Beryl is forecast to bring impacts from wind and rainfall to some of the islands beginning late today or tonight. 2. Although Beryl is forecast to degenerate into a trough of low pressure over the eastern Caribbean, the system is likely to produce strong gusty winds and locally heavy rainfall across the remainder of the Leeward Islands, the Virgin Islands, Puerto Rico, and Hispaniola through Tuesday. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 14.4N 57.9W 40 KT 45 MPH 12H 09/0000Z 15.4N 60.8W 40 KT 45 MPH 24H 09/1200Z 16.8N 64.9W 35 KT 40 MPH...TROPICAL WAVE 36H 10/0000Z 18.4N 68.8W 30 KT 35 MPH...TROPICAL WAVE 48H 10/1200Z...DISSIPATED $$ Forecaster Stewart
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