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| #1105911 (Received by flhurricane at: 5:12 PM 05.Sep.2022) TCDAT1 Tropical Storm Earl Discussion Number 12 NWS National Hurricane Center Miami FL AL062022 500 PM AST Mon Sep 05 2022 Earl`s structure continues to evolve this afternoon and looks a little better organized on convectional satellite imagery. The deepest convective activity now is located primarily north of the low-level circulation center which still appears partially exposed, but has become increasingly shrouded by the growing cirrus canopy. GLM lightning data suggests that these cold convective tops are continuing to rotate up-shear against the moderate westerly vertical wind shear and may be helping to better align the low and mid-level centers, though the lack of recent microwave data makes this improved structure hard to confirm. However, data received by this afternoon`s Air Force Reserve Reconnaissance aircraft suggests the pressure has not yet fallen much from this morning. Subjective satellite intensity estimates have a wide range, with TAFB at T4.0/65-kt while SAB is at T3.0/45-kt. The initial intensity this advisory will remain 55 kt. Another NOAA-P3 reconnaissance mission is en route to investigate Earl further this evening. Earl appears to now be moving due north, with the latest motion estimated at 360/5 kt. The short-term track forecast reasoning remains unchanged, with only a general slow northward motion anticipated for the next 24-36 hours as the storm moves into a weakness created in the larger-scale ridging over Earl currently. The biggest change beyond that time period is that the latest ECMWF run has come in better agreement with the GFS showing a more significant deep-layer trough digging northeast of Earl, resulting in more acceleration to the northeast in the latter portion of the forecast period. The overall track guidance this cycle is now much faster in the day 3-5 time-frame, and the latest NHC track has also been made faster to the northeast. However, this forecast is not yet quite as fast as the consensus aids. Further adjustments may be needed in subsequent forecasts if this more progressive trend persists in the guidance. Regardless, along-track uncertainty for Earl remains larger than normal during this time frame. The current satellite structure suggests that Earl may be able to hold its own or even intensify a bit more in the short term, especially if the low and mid-level centers continue to become better aligned. While vertical wind shear in the ECMWF- and GFS-SHIPS is rather high the next 36 hours, between 25-30 kt, this shear is more driven by the high westerly upper-level winds at 200 mb. The more shallow mid-level shear layer appears to be lower magnitude over the next 36 hours, and some recent research suggests that mid-level shear is more influential for tropical cyclone intensity change. Regardless, even the deep-layer shear decreases to under 10 kt after 60 hours, and Earl is still forecast to to peak in intensity in about 4-5 days as a Category 3 hurricane. During the forecast period, Earl is also expected to grow in size significantly, with the 34-kt wind radii extending more than 250 n mi by day 5. The latest intensity forecast has also moved the intensification rate to earlier in the forecast period, in general agreement with the latest HCCA and ICON consensus aids. KEY MESSAGES: 1. Ongoing Heavy rainfall from Earl`s feeder bands still could lead to limited flash, urban, and small stream flooding impacts over the Leeward Islands, U.S. and British Virgin Islands, and Puerto Rico this afternoon and evening. Rapid rises on rivers and mudslides in areas of steep terrain are possible in Puerto Rico. Considerable flood impacts cannot be ruled out in areas that receive heavier rainfall totals. 2. Earl`s center is expected to pass to the southeast of Bermuda in around 3-4 days. However, the wind field of the tropical cyclone is expected to increase significantly, and interests on the island should continue to monitor the progress of the storm closely. FORECAST POSITIONS AND MAX WINDS INIT 05/2100Z 22.2N 65.2W 55 KT 65 MPH 12H 06/0600Z 22.9N 65.3W 60 KT 70 MPH 24H 06/1800Z 23.8N 65.5W 60 KT 70 MPH 36H 07/0600Z 24.8N 65.5W 65 KT 75 MPH 48H 07/1800Z 26.0N 65.4W 70 KT 80 MPH 60H 08/0600Z 27.6N 65.2W 75 KT 85 MPH 72H 08/1800Z 29.2N 64.4W 90 KT 105 MPH 96H 09/1800Z 33.0N 60.5W 105 KT 120 MPH 120H 10/1800Z 37.0N 56.5W 100 KT 115 MPH $$ Forecaster Papin |
