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Hurricane Paulette Forecast Discussion Number 28
2020-09-13 22:39:28| National Hurricane Center (Atlantic)
Issued at 500 PM AST Sun Sep 13 2020 000 WTNT42 KNHC 132039 TCDAT2 Hurricane Paulette Discussion Number 28 NWS National Hurricane Center Miami FL AL172020 500 PM AST Sun Sep 13 2020 Paulette has recovered from the dry air intrusion that was eroding the eastern eyewall this morning. A ring of deep convection with cloud tops ranging from about -50 to -65 C now completely surrounds a partially cleared eye. An Air Force Hurricane Hunter aircraft investigating the hurricane earlier this afternoon measured peak flight-level winds of 84 kt, which reduces to about 67 kt at the surface. However, since that time there has been steady improvement in the satellite presentation, and the latest Dvorak satellite T-numbers from TAFB and SAB are now at 4.5, supporting increasing the initial intensity to 75 kt for this advisory. Paulette is expected to remain in a low-shear environment over warm SSTs for the next 24-36 h, so gradual strengthening is likely during that time. Around 48 h from now, vertical wind shear is forecast to rapidly increase ahead of an approaching mid- upper level trough. This should cause the cyclone to begin weakening. By 72 h, Paulette is expected to be over waters less that 26 degrees C and should remain over cooler waters for the remainder of the forecast period. Around that same time, global models are indicating that the cyclone will begin to interact with a frontal boundary associated with the aforementioned trough. This should induce a gradual transition of Paulette to an extratropical cyclone, and that transition should be completed by 120 h, if not sooner. The latest NHC intensity forecast is little changed from the previous one and shows Paulette continuing to strengthen as it passes near or over Bermuda early Monday. The forecast also shows Paulette becoming a major hurricane by Monday night, after the cyclone has moved away from Bermuda. This intensity forecast is in good agreement with the HFIP corrected consensus, HCCA. Paulette is moving northwestward at 11 kt, to the southwest of a mid-level ridge. There is no change to the forecast track reasoning. This northwest motion should continue until just after the cyclone passes Bermuda Monday morning. Later on Monday, the hurricane should turn north, then northeastward, as it rounds the periphery of the ridge. After turning northeastward, the cyclone is expected to accelerate as it gets picked up in the mid-latitude flow ahead of the approaching trough. Later on in the forecast period a slower eastward motion is indicated once the trough bypasses the cyclone. The latest NHC forecast was nudged only slightly to the left of the previous one, and is in agreement with tightly clustered global and regional track guidance. Tropical storm conditions should reach Bermuda in the next couple of hours, with hurricane force winds arriving there overnight. Key Messages: 1. Paulette is expected to approach Bermuda as a hurricane today and will be near the island tonight and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning this evening, and a hurricane warning is in effect for the island. Preparations to protect life and property should be rushed to completion. 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 30.6N 63.1W 75 KT 85 MPH 12H 14/0600Z 31.8N 64.5W 85 KT 100 MPH 24H 14/1800Z 33.9N 64.8W 95 KT 110 MPH 36H 15/0600Z 36.1N 62.4W 100 KT 115 MPH 48H 15/1800Z 38.1N 57.8W 100 KT 115 MPH 60H 16/0600Z 40.3N 52.6W 95 KT 110 MPH 72H 16/1800Z 42.4N 47.4W 80 KT 90 MPH 96H 17/1800Z 45.5N 38.7W 60 KT 70 MPH 120H 18/1800Z 44.4N 34.1W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Latto
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