000 WTNT41 KNHC 030236 TCDAT1 Tropical Storm Earl Discussion Number 1 NWS National Hurricane Center Miami FL AL062022 1100 PM AST Fri Sep 02 2022 Air Force Reserve and NOAA Hurricane Hunter aircraft each flew missions into the area of low pressure east of the Leeward Islands this afternoon into this evening, and the data from those flights indicated that the circulation and center of the low became well defined today. Deep convection has also persisted with the low, albeit sheared near and to the east of the center, which means the system has finally met the criteria of a tropical cyclone. Flight-level, surface, and dropsonde data from the reconnaissance flights all indicate that the system is producing tropical-storm-force winds in the convection well to the east of the center, and for good measure TAFB provided a Dvorak estimate of T2.5/35 kt. The low is therefore being designated as Tropical Storm Earl with maximum winds of 35 kt. The minimum pressure is estimated to be 1005 mb based on an Air Force dropsonde that measured a surface pressure of 1007 mb with 23-kt winds. Earl is moving toward the west-northwest, or 295/12 kt. The track guidance is in fairly good agreement during the next 3 days, with a low- to mid-level ridge expected to steer Earl west-northwestward and then northwestward at decreasing forward speed. The ridge to the north is forecast to weaken and shift westward around day 3, which should cause Earl to slow down to less than 5 kt and turn northward by day 4, and then north-northeastward by day 5 as it begins to feel the influence of the mid-latitude westerlies to the north. The biggest outliers on days 4 and 5 are the GFS and HMON, which show a stronger Earl moving faster toward the northeast. For now, the NHC official forecast favors a slower scenario on days 4 and 5, closer to the ECMWF, HWRF, HCCA, and TVCN. Moderate to strong shear is likely to continue affecting Earl for much of the next 5 days, possibly peaking in 3 to 4 days according to the SHIPS guidance. Mid-level relative humidity ahead of the system also remains lower than what is ideal for strengthening, and as a result, the NHC intensity forecast shows only modest intensification through the forecast period. This forecast is very close to the IVCN and HCCA consensus aids. 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, any southward shift of Earl's center would increase the risk of tropical-storm-force winds in those areas. 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 over the Leeward Islands, U.S. and British Virgin Islands, and Puerto Rico this weekend. Rapid rises on rivers are possible in Puerto Rico. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 18.4N 60.3W 35 KT 40 MPH 12H 03/1200Z 18.9N 62.0W 35 KT 40 MPH 24H 04/0000Z 19.5N 63.8W 40 KT 45 MPH 36H 04/1200Z 20.2N 65.3W 40 KT 45 MPH 48H 05/0000Z 20.9N 66.4W 40 KT 45 MPH 60H 05/1200Z 21.5N 67.2W 40 KT 45 MPH 72H 06/0000Z 22.2N 67.7W 40 KT 45 MPH 96H 07/0000Z 23.3N 67.8W 40 KT 45 MPH 120H 08/0000Z 24.7N 67.0W 45 KT 50 MPH $$ Forecaster Berg