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| #969333 (Received by flhurricane at: 6:35 PM 20.May.2019) TCDAT1 Subtropical Storm Andrea Special Discussion Number 1 NWS National Hurricane Center Miami FL AL012019 630 PM AST Mon May 20 2019 Satellite and aircraft data indicate that the area of low pressure that the National Hurricane Center has been monitoring to the southwest of Bermuda has developed into a subtropical storm. The Air Force Hurricane Hunters have recently exited the cyclone and found that the system has developed a well-defined center and has a minimum pressure of about 1006 mb. The maximum adjusted flight-level and surface SFMR winds support an intensity of about 35 kt. The cyclone is considered subtropical at this time because it is interacting with an upper-level low pressure system to its west, has a relatively large radius of maximum wind, and its overall appearance in satellite images. Based on satellite and aircraft fixes today, the initial motion of Andrea is estimated to be northward at 12 kt as it has been moving in the flow between a subtropical ridge to its east and a mid- to upper-level low to its west. The models show Andrea slowing down and gradually turning to the northeast on Tuesday and eastward by Tuesday night as it moves on the northern periphery of the ridge. Andrea could strengthen slightly through early Tuesday while it remains in a fairly moist and unstable atmosphere. However, after that time, gradual weakening should commence due to less favorable conditions, and all of the reliable models show Andrea opening into a trough and becoming absorbed by a cold front on Wednesday. The NHC official track forecast lies near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 20/2230Z 28.8N 68.7W 35 KT 40 MPH 12H 21/0600Z 30.2N 68.9W 40 KT 45 MPH 24H 21/1800Z 31.1N 68.3W 35 KT 40 MPH 36H 22/0600Z 31.5N 66.4W 30 KT 35 MPH 48H 22/1800Z...DISSIPATED $$ Forecaster Cangialosi |