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Hurricane MATTHEW Forecast Discussion Number 33
2016-10-06 11:01:49| National Hurricane Center (Atlantic)
Issued at 500 AM EDT THU OCT 06 2016 000 WTNT44 KNHC 060901 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 33 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 AM EDT THU OCT 06 2016 The satellite presentation of Matthew has improved markedly overnight with eye reappearing and warming within the past couple of hours. The eye is also embedded within a very symmetric central dense overcast with cloud tops colder than -70C. An Air Force Reconnaissance Hurricane Hunter that just flew through the center reported peak 700 mb flight-level winds of 132 kt, SFMR winds around 103 kt, and a pressure of 944 mb, which is down about 18 mb from last evening. Using a blend of the flight-level and SFMR winds, the initial intensity is set at 110 kt. Environmental conditions appear favorable for continued strengthening today and Matthew is expected to become an extremely dangerous category 4 hurricane while it moves over the northwestern Bahamas and approaches the east coast of Florida. After 24 hours, land interaction is likely to cause some weakening, and later in the period increasing shear should cause a more rapid decrease in winds. The NHC forecast is above the most of guidance during the first 24 hours due to the recent increase in organization, but is close to the consensus thereafter. Aircraft and satellite fixes show that Matthew is moving northwestward or 320/10 kt. Matthew is expected to move around the western periphery of a subtropical ridge that is forecast to gradually retreat eastward during the next day or two. This pattern should steer Matthew northwestward over the northwestern Bahamas today, then north-northwestward very near the east coast of Florida late today through Friday night. The models are tightly clustered through 48 hours, and the NHC track is near the consensus of the GFS and ECMWF models through that time. After 48 hours, the hurricane should turn northeastward as a broad trough approaches the Great Lakes region. The trough is expected to pass north of Matthew in about 72 hours, which is expected to cause the cyclone to turn eastward, then southeastward late in the forecast period. There is still significant spread in the long-range guidance so there is lower than normal confidence in the days 4 and 5 track prediction. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the central and northwestern Bahamas today, and along portions of the east coast of Florida tonight. 2. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. For example, only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. However, a small deviation to the right could keep the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch area in northeast Georgia and South Carolina. 3. Tropical storm or hurricane conditions could affect eastern North Carolina later this week or this weekend, even if the center of Matthew remains offshore. 4. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario - the amount of inundation that has a 10 percent chance of being exceeded. In addition, because the Flooding Map is based on inputs that extend out only to about 72 hours, it best represents the flooding potential in those locations within the watch and warning areas in Florida and Georgia. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 24.2N 77.1W 110 KT 125 MPH 12H 06/1800Z 25.5N 78.4W 120 KT 140 MPH 24H 07/0600Z 27.2N 79.9W 125 KT 145 MPH 36H 07/1800Z 29.0N 80.7W 115 KT 130 MPH 48H 08/0600Z 30.7N 80.7W 95 KT 110 MPH 72H 09/0600Z 32.4N 77.6W 80 KT 90 MPH 96H 10/0600Z 31.0N 75.0W 60 KT 70 MPH 120H 11/0600Z 29.5N 75.0W 50 KT 60 MPH $$ Forecaster Brown
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