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#877400 (Received by flhurricane at: 11:04 AM 08.Oct.2016) TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 42 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 AM EDT SAT OCT 08 2016 Aircraft reconnaissance and land-based radar data indicate that the center of circulation has crossed the coast of South Carolina near the Cape Romain National Wildlife Refuge. The cloud pattern associated with Matthew is beginning to acquire some extratropical characteristics. The wind field is expanding, and the area of heavy rains is now northwest of the center. Data from NOAA and Air Force reconnaissance aircraft around 1200 UTC indicated that the surface winds have decreased to around 65 kt. (Very recent SFMR winds of 78 kt were taken over shallow water where the instrument is affected by shoaling and provides unreliable output). Most of the global models, primarily the GFS and the UKMET, forecast that Matthew will become entangled with a cold front, and the new NHC forecast calls for Matthew to become absorbed within this frontal system within the next couple of days. During the next 12 to 24 hours, while the Matthew is hugging the US coast and taking on a more extratropical structure, the tropical-storm-force winds are expected to expand and strengthen in the western semicircle and continue to affect portions of the coast within the warning area. Matthew is already embedded in the mid-latitude westerly flow and is moving toward the northeast or 050 degrees at 10 kt. The steering pattern is forecast to persist for the next day or two, and on this basis the NHC forecast moves the cyclone eastward until it becomes absorbed. Previous NHC official forecasts followed the EMCWF in keeping the cyclone a distinct entity longer and looping it southward, but even if this the case the system will likely be only a broad area of low pressure. Due to the degradation of Matthew's radar signature, the hourly Tropical Cyclone Updates will not longer be issued. KEY MESSAGES: 1. As Matthew's structure changes, the system's strongest winds will shift to the back side of the circulation. These winds will persist over land even after the center begins to move away from the coastline, and has also increased the threat of storm surge in portions of the North Carolina Outer Banks. Please see the Prototype Storm Surge Watch/Warning Graphic for a depiction of the areas at risk. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 33.0N 79.4W 65 KT 75 MPH 12H 09/0000Z 33.6N 78.0W 60 KT 70 MPH 24H 09/1200Z 34.0N 75.5W 60 KT 70 MPH 36H 10/0000Z 34.0N 73.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 10/1200Z 33.0N 72.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 11/1200Z...DISSIPATED $$ Forecaster Avila |