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| #1149845 (Received by flhurricane at: 11:06 AM 28.Aug.2023) TCDAT3 Hurricane Franklin Discussion Number 32 NWS National Hurricane Center Miami FL AL082023 1100 AM EDT Mon Aug 28 2023 Visible, infrared and microwave imagery depict a strengthening major hurricane with a well-defined eye, a thick eyewall, and very cold cloud tops. This was further supported by data from the Air Force Reserve Hurricane Hunters, who have been investigating the storm this morning. Minimum pressure has decreased from the previous advisory based on a dropsonde measuring a pressure of 937 mb around 12 UTC. Flight-level, SFMR winds and dropsondes in the eyewall indicate maximum sustained winds have increased to 125 kt. Subjective and object satellite estimates also have drastically increased with this advisory. Given these data, the initial intensity is raised to 125 kt for this advisory, and Franklin has rapidly intensified into a Category 4 major hurricane. The hurricane continues to make a gradual turn northward, with the latest motion estimate northward at 350/8 kt. A northward then northeastward motion is forecast during the next 48 hours as Franklin rounds the western edge of the subtropical ridge. After 48 hours, a deep trough is expected to move off the U.S. northeast coast and Canada, and has Franklin becoming captured in the southwesterly flow, with an increase in forward motion to the northeast. There is better agreement in cross-track guidance compared to the previous few advisories. However, there is still a slight difference in the along track guidance with the GFS being faster, and the ECMWF a little slower. The latest NHC track forecast is similar to the previous forecast, with only a minor nudge to the north. Some additional intensification is possible today, as Franklin remains in a low shear environment and is over warm sea-surface temperatures. The latest intensity forecast peaks Franklin as a strong Category 4 major hurricane. However, inner core changes, such as eyewall replacement cycles, could occur at any time, making the peak intensity and short-term forecast a little more challenging. Some gradual weakening is forecast in about a day or so when models forecast a slight increase in northwesterly shear. Toward the end of the forecast period, further weakening is expected as Franklin encounters increased vertical wind shear and moves over cooler SSTs. The latest forecast shows the storm becoming a extratropical cyclone in 120 h, though this could occur sooner. KEY MESSAGES: 1.Tropical storm conditions are possible on Bermuda beginning Wednesday morning, when Franklin is forecast to make its closest approach to the island. 2. Life-threatening surf and rip currents are occurring along the coast of the southeast United States. These conditions are expected to spread northward along the remainder of the U.S. east coast, Atlantic Canada, and Bermuda during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 27.8N 71.0W 125 KT 145 MPH 12H 29/0000Z 29.0N 71.2W 135 KT 155 MPH 24H 29/1200Z 30.7N 70.8W 130 KT 150 MPH 36H 30/0000Z 32.5N 69.6W 120 KT 140 MPH 48H 30/1200Z 34.5N 67.4W 110 KT 125 MPH 60H 31/0000Z 36.3N 64.1W 100 KT 115 MPH 72H 31/1200Z 38.7N 59.9W 90 KT 105 MPH 96H 01/1200Z 44.5N 49.7W 75 KT 85 MPH 120H 02/1200Z 51.8N 39.8W 65 KT 75 MPH...POST-TROP/EXTRATROP $$ Forecaster Kelly/Brown |
