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| #1105687 (Received by flhurricane at: 4:44 AM 04.Sep.2022) TCDAT1 Tropical Storm Earl Discussion Number 6 NWS National Hurricane Center Miami FL AL062022 500 AM AST Sun Sep 04 2022 Satellite imagery, surface observations, and WSR-88D radar data from Puerto Rico indicate that Earl remains disorganized due to ongoing southwesterly vertical wind shear, and that the center is rather tricky to locate. One vorticity center, associated with a fresh convective burst, is located just north of the Virgin Islands. However, TAFB and SAB fixed on another cloud area farther north, while the radar data suggests another vorticity center in the deep convection to the northeast of the Virgin Islands. The advisory position is a mean center between these features and is a little north of the new burst. The satellite intensity estimates are unchanged from earlier, so the initial intensity remains 45 kt. The storm has slowed its forward motion, which is now 285/7 kt. The track guidance is in good agreement that a break will form in the subtropical ridge as a mid- to upper-level trough develops to the northwest of Earl beginning later today. This should cause the cyclone to turn northwestward during the next 12-24 h, with a northward motion likely from 24-72 h and a north-northeastward motion from 72-120 h. The track models are in good agreement on the general direction of motion. However, while the GFS is slower than its previous forecast it is still faster than the rest of the guidance. The new forecast track is nudged to the right of the previous forecast based on the overall shift of the guidance envelope. During the first 72 h, it is in best agreement with the GFS and UKMET ensemble means, and after that time it lies close to the various consensus models. The ongoing shear is expected to continue through at least the next 72 h, and thus only gradual strengthening is likely during this time as Earl moves over warm sea surface temperatures in a moist environment. After that time, the cyclone could interact with the aforementioned trough in such a way to leave Earl in a more favorable environment for intensification, and the dynamical models forecast significant strengthening toward the end of the forecast period. The new intensity forecast has only minor adjustments from the previous forecast, and for the first 72 h it is close to the bulk of the intensity guidance. After it time, the forecast is below that of most of the guidance due to the uncertainty of how favorable the environment will be. Tropical-storm-force winds are still forecast to remain on the northern and eastern side of the circulation, and are not expected to move across the northern Leeward Islands, the Virgin Islands, or Puerto Rico. However, gusty winds in squalls are possible at these locations through tonight. KEY MESSAGES: 1. Heavy rainfall from Earl is expected to lead to limited flash, urban, and small stream flooding impacts over the Leeward Islands, U.S. and British Virgin Islands, and Puerto Rico today. Rapid rises on rivers and mudslides in areas of steep terrain are possible in Puerto Rico. 2. Earl is forecast to pass to the north of the the Virgin Islands and Puerto Rico today, and gusty winds, especially in squalls, area possible on those islands. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 19.5N 64.9W 45 KT 50 MPH 12H 04/1800Z 20.1N 65.6W 45 KT 50 MPH 24H 05/0600Z 21.1N 66.2W 50 KT 60 MPH 36H 05/1800Z 22.0N 66.5W 50 KT 60 MPH 48H 06/0600Z 23.0N 66.6W 55 KT 65 MPH 60H 06/1800Z 24.0N 66.7W 60 KT 70 MPH 72H 07/0600Z 25.0N 66.5W 60 KT 70 MPH 96H 08/0600Z 26.5N 65.5W 70 KT 80 MPH 120H 09/0600Z 28.5N 63.5W 85 KT 100 MPH $$ Forecaster Beven |
