000 WTNT45 KNHC 220246 TCDAT5 Hurricane Maria Discussion Number 24 NWS National Hurricane Center Miami FL AL152017 1100 PM EDT Thu Sep 21 2017 Satellite images show that the eye has become more distinct and is surrounded by a ring of deep convection. An Air Force Hurricane Hunter plane has penetrated the eye a couple of times this evening and the crew reported that the eye had a diameter of 35 nmi and that it has become better defined. Flight-level winds increased a little bit during the last penetration and supported an intensity of 110 or 115 kt. At this time, I prefer the keep the winds at 110 kt since the SFMR measurements were a little lower. The central pressure is estimated at 955 mb. The atmosphere diagnosed by the models, as well as a warm ocean along the forecast track, should favor an increase in intensity. However, most of the models, suggest that Maria will change little and will remain a category 3 hurricane for the next day or two. The NHC forecast follows the intensity consensus ICON and shows no significant change through that time. Gradual weakening should begin later in the forecast period as Maria reaches higher latitudes and cooler waters. Satellite and reconnaissance fixes indicate that Maria is moving toward the northwest or 320 degrees at 7 kt. The track of the hurricane has been and will be controlled by the flow around a narrow subtropical ridge to the northeast of the hurricane. Maria is reaching the western edge of that high, and this should cause the hurricane to turn north-northwestward and then northward with no significant change in forward speed for the next 3 days. After that time, Maria should encounter the mid-latitude southwesterly flow and recurve. The reliable guidance is remarkably clustered during the next 4 days. This significantly increases the confidence in the track forecast which is in between the multi-model consensus TVCX and the HFIP corrected consensus. KEY MESSAGES: 1. Flash flood warnings continue in portions of Puerto Rico due to persistent heavy rainfall from Maria's trailing rainbands. Everyone in Puerto Rico should continue to follow advice from local officials to avoid these life-threatening flooding conditions. 2. Swells from Maria are expected to begin reaching the coast of the southeastern United States on Friday. These swells are likely to cause dangerous surf and life-threatening rip currents along the coast for the next several days, even with Maria forecast to remain well offshore over the western Atlantic Ocean. FORECAST POSITIONS AND MAX WINDS INIT 22/0300Z 21.0N 70.2W 110 KT 125 MPH 12H 22/1200Z 22.0N 70.8W 110 KT 125 MPH 24H 23/0000Z 23.5N 71.5W 105 KT 120 MPH 36H 23/1200Z 25.1N 72.0W 100 KT 115 MPH 48H 24/0000Z 26.7N 72.3W 95 KT 110 MPH 72H 25/0000Z 29.3N 72.1W 90 KT 105 MPH 96H 26/0000Z 31.2N 71.0W 85 KT 100 MPH 120H 27/0000Z 33.0N 70.0W 75 KT 85 MPH $$ Forecaster Avila