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| #1105574 (Received by flhurricane at: 11:14 AM 03.Sep.2022) TCDAT1 Tropical Storm Earl Discussion Number 3 NWS National Hurricane Center Miami FL AL062022 1100 AM AST Sat Sep 03 2022 Earl is a sheared tropical cyclone this morning, as the low-level center is fully exposed to the west of the convective mass. NOAA Hurricane Hunter aircraft data indicate the vortex remains tilted due to about 15 kt of deep-layer southwesterly shear over the cyclone. Recently, a more vigorous burst of convection has developed closer to the center. The initial intensity is held at 35 kt based on a blend of flight-level, SFMR, and dropsonde data from the aircraft. It is noted that the surface pressure near the center has fallen a couple of millibars since the previous advisory. The cyclone remains on a west-northwestward heading as it is being steered by the subtropical ridge. The guidance remains in very good agreement that Earl will maintain a west-northwestward to northwestward motion with a decrease in forward speed over the next couple of days. As a weakness develops in the subtropical ridge early next week, Earl is forecast to turn slowly northward and then northeastward by days 3-5 as a mid- to upper-level trough develops over the western Atlantic. Although there is increasing spread in the track guidance during this period as to how quickly Earl recurves, there is good overall agreement that the cyclone track will remain over the open Atlantic waters. The official NHC forecast has been adjusted slightly to the right of the previous one during the 36-72 h window, based on similar trends noted in the guidance consensus aids. It appears that moderate deep-layer shear will continue to impact Earl during the next couple of days. Therefore, only modest strengthening is forecast during this time as the cyclone could struggle to become vertically aligned and sustain convection near its center. The intensity forecast is of lower confidence later in the period once Earl begins turning northward. Although the vertical shear is expected to persist or even strengthen, the potential for favorable interaction with the upper trough should allow for additional strengthening during this period, while the wind field of the cyclone broadens. Most of the dynamical models support this strengthening trend, and the latest NHC intensity forecast has been adjusted upward some during this period. However, there remains large spread in the intensity guidance at days 3-5, and the NHC forecast remains on the lower end of the models. Tropical-storm-force winds are forecast to remain on the northern and eastern side of the circulation, and as a result, 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 over the weekend. KEY MESSAGES: 1. Tropical Storm Earl is forecast to pass near or just to the north of the northern Leeward Islands, the Virgin Islands, and Puerto Rico over the weekend. Gusty winds, especially in squalls, area possible on those islands over the next day or two. 2. 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 this weekend. Rapid rises on rivers and mudslides in areas of steep terrain are possible in Puerto Rico. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 19.0N 62.4W 35 KT 40 MPH 12H 04/0000Z 19.5N 63.6W 40 KT 45 MPH 24H 04/1200Z 20.3N 65.0W 40 KT 45 MPH 36H 05/0000Z 21.0N 65.7W 40 KT 45 MPH 48H 05/1200Z 21.8N 66.3W 45 KT 50 MPH 60H 06/0000Z 22.7N 66.6W 45 KT 50 MPH 72H 06/1200Z 24.0N 66.6W 50 KT 60 MPH 96H 07/1200Z 25.3N 65.9W 55 KT 65 MPH 120H 08/1200Z 27.0N 64.5W 60 KT 70 MPH $$ Forecaster Reinhart |
