|
Show Selection: |
| #1105763 (Received by flhurricane at: 5:15 PM 04.Sep.2022) TCDAT1 Tropical Storm Earl Discussion Number 8 NWS National Hurricane Center Miami FL AL062022 500 PM AST Sun Sep 04 2022 The large bursting pattern that was observed this morning with Earl has evolved more into a shear pattern this afternoon, with the low-level center becoming partially exposed to the west of the coldest cloud tops that are displaced about 50 n mi east of the center. An Air Force Reconnaissance aircraft conducted an afternoon mission through the storm and found the highest 850 mb flight-level winds of 51 kt with SFMR winds up to 48 kt. Satellite intensity estimates remain unchanged from this morning, and the initial intensity will remain 45 kt for this advisory. The last several fixes from the aircraft indicate Earl has resumed a slow northwestward motion at 310/4 kt. The forecasting reasoning has not changed much from the previous forecast cycle, as a mid-level ridge is expected to result in Earl turning to the north-northwest over the next 12 to 24 hours. This slow motion should continue thereafter as the ridge continues to slowly break down and shift gradually eastward through the early part of this week. Towards the end of the forecast, the strongest ridging is expected to be east of Earl, allowing the cyclone to slowly recurve to the north-northeast. The latest track guidance this cycle has narrowed somewhat, with the latest ECMWF forecast shifting east, while the most recent GFS shifted a touch west. Thus, little change was made to the NHC track forecast this advisory, which lies quite close to the latest TVCN and HCCA consensus aids. It appears that this morning`s convective burst was unsuccessful in helping to vertically align Earl`s vortex, and the mid-level center noted on Puerto Rico radar is still located east of the aircraft fixes. This failure was likely due to continued westerly vertical wind shear undercutting the outflow layer and importing dry air into Earl`s core. However, most of the global and regional hurricane models suggest that additional convective bursts will continue over the next 24-48 hours, resulting in gradual intensification as the cyclone becomes better vertically aligned. Thus, the latest NHC intensity forecast continues to show slow intensification in the short-term, with Earl possibly attaining hurricane intensity in a couple of days. After 72 hours, both the GFS and ECMWF suggest the shear will decrease, while the cyclone may also undergo a favorable trough interaction. The guidance responds to this pattern by indicating more significant intensification, and the latest advisory shows a somewhat higher peak intensity of 105 kt by day 5. While tropical-storm-force winds are still forecast to stay north of the northern Leeward Islands, the Virgin Islands, and Puerto Rico, training rain-bands are producing heavy rainfall over these islands. Users should refer to products issued by local weather offices in these areas. 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. Locally considerable flood impacts cannot be ruled out in areas that receive heavier rainfall totals. 2. Earl is forecast to pass to the north of the the Virgin Islands and Puerto Rico tonight, but gusty winds, especially in squalls, remain possible on those islands overnight. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 20.0N 65.2W 45 KT 50 MPH 12H 05/0600Z 21.1N 65.2W 50 KT 60 MPH 24H 05/1800Z 22.3N 65.4W 55 KT 65 MPH 36H 06/0600Z 23.5N 65.5W 60 KT 70 MPH 48H 06/1800Z 24.6N 65.6W 65 KT 75 MPH 60H 07/0600Z 25.4N 65.5W 70 KT 80 MPH 72H 07/1800Z 26.4N 65.1W 75 KT 85 MPH 96H 08/1800Z 28.2N 64.0W 85 KT 100 MPH 120H 09/1800Z 31.4N 61.5W 105 KT 120 MPH $$ Forecaster Papin |
