000 WTNT41 KNHC 041459 TCDAT1 Tropical Storm Earl Discussion Number 7 NWS National Hurricane Center Miami FL AL062022 1100 AM AST Sun Sep 04 2022 This morning, Earl developed a large convective burst, with cold convective cloud tops below -80 C and the larger cirrus plume obscuring the low-level center. A NOAA-P3 mission has also be flying through Earl this morning, showing that the center may be in the process of reorganizing closer to this recent convective burst. WSR-88D radar imagery from Puerto Rico earlier showed a well-defined mid-level vortex associated with this convective burst up at 20 k feet, which matched the NOAA-P3 TDR data, but it is unclear how close the surface vortex is relative to this mid-level center. Subjective Dvorak estimates from TAFB and SAB are T3.0/45-kt and T3.5/55-kt respectively, though objective estimates are somewhat lower, with ADT only at 33-kt and SATCON at 44-kt. A blend of these estimates and the wind data from the NOAA-P3 mission support maintaining the intensity at 45 kt for this advisory. Earl appears to have slowed down further this morning, and may be in the process of relocating closer to the convective burst, with the latest motion an uncertain 310/3 kt. As mentioned previously, there is a weakness in the mid-level ridging to the north of the storm, and this should enable Earl to make a gradual turn to the north-northwest and north over the next 24-72 hours. The mid-level ridging then shifts mostly east of the cyclone, allowing a continued slow north-northeastward motion thereafter. The latest track guidance has shifted east in the short term due in part to the initial position, and the latest NHC track forecast has been shifted in that direction and lies just west of TVCN consensus. However, the latest track forecast is not as far to the east as the HFIP Corrected Consensus (HCCA), GFS or HWRF forecasts, and additional eastward adjustments may be needed in subsequent forecasts. The large convective burst this morning makes the short-term intensity forecast somewhat tricky. If the low-level center is able to reform and become better aligned with the mid-level center, some intensification could occur. If and when this occurs is important, with the latest HWRF and GFS forecasts suggesting this could occur as soon as later today, resulting in more significant intensification. However, the HMON, HAFS-S, and ECMWF suggest it may take a few days for a more aligned structure to occur, likely delayed by continued moderate (15-25 kts) southwesterly vertical wind shear, which is expected to persist for the next 2-3 days. The latest NHC intensity forecast opts to split the difference, now showing gradual intensification over the next 24-48 hours, making Earl a hurricane in 48 hours. This is higher than the previous NHC intensity forecast, but is under the latest HCCA, HWRF, and GFS-SHIPS guidance. After 72 h, shear is expected to decrease, and more robust intensification is possible thereafter, with the latest intensity forecast now making Earl a major hurricane by 120 h, in good agreement with the IVCN and HCCA consensus aids. At this juncture, 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, but gusty winds, especially in squalls, remain possible on those islands. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 19.5N 64.4W 45 KT 50 MPH 12H 05/0000Z 20.4N 65.0W 50 KT 60 MPH 24H 05/1200Z 21.5N 65.2W 55 KT 65 MPH 36H 06/0000Z 22.6N 65.4W 60 KT 70 MPH 48H 06/1200Z 23.5N 65.5W 65 KT 75 MPH 60H 07/0000Z 24.7N 65.4W 70 KT 80 MPH 72H 07/1200Z 25.7N 65.0W 75 KT 85 MPH 96H 08/1200Z 27.2N 64.0W 85 KT 100 MPH 120H 09/1200Z 29.6N 61.8W 100 KT 115 MPH $$ Forecaster Papin