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Post-Tropical Cyclone Elsa Forecast Discussion Number 39
2021-07-09 22:42:41| National Hurricane Center (Atlantic)
Issued at 500 PM AST Fri Jul 09 2021 000 WTNT45 KNHC 092042 TCDAT5 Post-Tropical Cyclone Elsa Discussion Number 39 NWS National Hurricane Center Miami FL AL052021 500 PM AST Fri Jul 09 2021 Surface, satellite, and radar data indicate that Elsa's deep convection remains limited to a shield north of its center and that a front extends through the center of the cyclone. For those reasons, Elsa was designated as a post-tropical cyclone at 1800 UTC. Surface observations of sustained winds a little above 40 kt were reported across portions of southern Massachusetts and the nearby waters as Elsa crossed the state, so the intensity estimate remains 45 kt. Elsa is moving quickly just off the northeast coast of the U.S. with an initial motion estimate of 040/27 kt. A faster northeastward motion is expected tonight and on Saturday while the system remains embedded within a deep mid-latitude trough. Very little change was made to the NHC track forecast. All available guidance indicates that Elsa will gradually weaken during the next couple of days. The GFS, ECMWF, and CMC global models now indicate the cyclone will open into a trough within the next 48 h or so, and this is reflected in the NHC forecast. It is estimated that center of Elsa made landfall along the coast of Long Island near Southampton around 1430 UTC (10:30 am EDT), and again near Watch Hill, Rhode Island near 1615 UTC (12:15 pm EDT). Elsa's classification at the time the center crossed the coast will be determined in the post-storm analysis. It should also be noted that the landfall position had little bearing on the location or timing of the strong winds and heavy rain which were well removed from the cyclone's center. Since Elsa is now post-tropical and all coastal tropical storm warnings have been discontinued, this is the last NHC advisory. Additional information on this system can be found in High Seas Forecasts issued by the National Weather Service, under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php Key Messages: 1. As Elsa moves off the coast of Maine through this evening, heavy rainfall could lead to considerable flash and urban flooding. 2. Gusty winds will continue across portions of the southern New England coast during the next couple of hours. The post-tropical cyclone is also expected to bring gusty winds to portions of Atlantic Canada tonight and Saturday. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 43.0N 69.5W 45 KT 50 MPH...POST-TROPICAL 12H 10/0600Z 46.2N 64.7W 40 KT 45 MPH...POST-TROP/EXTRATROP 24H 10/1800Z 50.3N 56.1W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 11/0600Z 54.7N 46.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 11/1800Z...DISSIPATED $$ Forecaster Zelinsky
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