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Hurricane MATTHEW Forecast Discussion Number 32
2016-10-06 04:54:15| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT WED OCT 05 2016 000 WTNT44 KNHC 060254 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 32 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 PM EDT WED OCT 05 2016 Data from Air Force Reserve and NOAA Hurricane Hunter aircraft showed lower winds in Matthew than seen during the previous mission, with peak 700-mb flight-level winds of 103 kt and estimates near 95 kt from the SFMR instrument. Based on these, the initial intensity is reduced to 100 kt. However, satellite imagery indicates that the hurricane is becoming better organized, with the eye trying to re-appear and cooling cloud tops near the center. In addition, the eye has contracted to 15 n mi wide and the central pressure has fallen to 961 mb. This suggests that the winds are about to increase. The initial motion is 320/9. There is little change to the synoptic reasoning or the forecast track through 48 hours. Matthew is expected to move around the western side of the subtropical ridge, which should move slowly eastward during the next couple of days. This evolution should steer Matthew generally northwestward for the next 24 hours or so, followed by a turn toward the north-northwest. This forecast track takes the center near Andros Island and New Providence in about 12 hours, and then very near the eastern coast of the the Florida peninsula. This part of the forecast track is west of the various consensus models, but it lies near the GFS, ECMWF, and ECMWF ensemble mean. From 48-72 hours, the cyclone is expected to recurve northeastward along the southern edge of the mid-latitude westerlies. After 72 hours, the track guidance become very divergent, with solutions ranging from a continued eastward motion out to sea to a turn back to the southwest. The new forecast track shows a slow southeastward motion during this time in best agreement with the ECMWF. As mentioned above, Matthew is getting better organized, and during the next 36 hours or so it should be moving through an area of light vertical wind shear. This should allow strengthening, and the new intensity forecast calls for the system to reach an intensity near 115 kt in about 36 hours. This is near the upper end of the intensity guidance. After 36 hours, proximity to land and increasing shear should cause weakening, and the cyclone is now expected to be down to tropical storm strength by 120 hours. Overall, the intensity forecast is in best agrement with the SHIPS model. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the Bahamas. Please consult statements from the meteorological service and other government officials in that country. 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. 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 northern Florida and Georgia. 3. Tropical storm or hurricane conditions could affect South Carolina and North Carolina later this week or this weekend, even if the center of Matthew remains offshore. It is too soon to determine what, if any, land areas might be directly affected by Matthew next week. At a minimum, dangerous beach and boating conditions are likely along much of the U.S. east coast during the next several days. 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 06/0300Z 23.4N 76.4W 100 KT 115 MPH 12H 06/1200Z 24.6N 77.6W 105 KT 120 MPH 24H 07/0000Z 26.4N 79.2W 115 KT 130 MPH 36H 07/1200Z 28.2N 80.4W 115 KT 130 MPH 48H 08/0000Z 30.1N 81.0W 110 KT 125 MPH 72H 09/0000Z 32.5N 78.5W 90 KT 105 MPH 96H 10/0000Z 32.0N 75.5W 70 KT 80 MPH 120H 11/0000Z 30.5N 73.5W 55 KT 65 MPH $$ Forecaster Beven
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