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Hurricane MATTHEW Forecast Discussion Number 13
2016-10-01 10:47:52| National Hurricane Center (Atlantic)
Issued at 500 AM EDT SAT OCT 01 2016 000 WTNT44 KNHC 010847 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 AM EDT SAT OCT 01 2016 Matthew has changed little in organization since the past advisory, with a small eye surrounded by a central dense overcast featuring cloud tops colder than -80C. The eye has become a little less distinct, suggesting at least that the hurricane is no longer intensifying. In addition, the raw intensity estimates from the CIMSS ADT technique are slightly lower than they were six hours ago. Based on these trends, the initial intensity is reduced to 135 kt. An Air Force Reserve Hurricane Hunter aircraft is scheduled to reach Matthew near 1200 UTC. The initial motion is now 270/6. Matthew remains south of a low- to mid-level ridge over the western Atlantic. The dynamical models forecast this ridge to weaken over the next 72 hours as a mid- to upper-level trough develops over the Gulf of Mexico. This evolution should cause Matthew to turn northwestward after 24 hours and northward by 48-72 hours. The guidance generally agrees with this scenario. However, there is a spread between the GFS forecast of landfall in Jamaica and eastern Cuba and the ECMWF forecast landfall in southwestern Haiti. The guidance becomes more divergent after 72 hours. The GFS shows a turn toward the north-northwest, which brings the center closer to the northwestern Bahamas and Florida. This model is near the western edge of the guidance envelope. The ECMWF is near the eastern edge of the guidance envelope and shows the center east of the Bahamas by 120 hours. Adding to the uncertainty is the eastward shift of the Canadian model since its previous run. Given the uncertainty, the 96 and 120 hour forecast points are changed only slightly from the previous forecast. This part of the forecast track lies to the east of the GFS, but to the west of the Canadian, ECMWF, and NAVGEM models. It is also a little to the west of the various consensus models. Matthew should experience significant shear for the next 24 hours or so, as water vapor imagery shows westerly flow blowing into the hurricane underneath the impressive outflow pattern. This should cause some weakening. After that time, the dynamical models suggest the shear should decrease, which should allow Matthew to at least maintain its intensity. The new intensity forecast shows a slightly weaker intensity than the previous advisory through 72 hours based mainly on current trends. Subsequently, the hurricane is likely to interact with the land masses of Jamaica, Cuba, and Hispaniola, leading to some weakening and disruption of the structure. Between this and uncertainty about how much shear Matthew will encounter north of Cuba, the new forecast shows only modest strengthening after Matthew reaches the Atlantic north of Cuba. There is also the possibility of fluctuations in intensity caused by eyewall replacement cycles at any time during the forecast period. It is important to remind users that average NHC track forecast errors are around 175 miles at day 4 and 230 miles at day 5. Therefore, it is too soon to rule out possible hurricane impacts from Matthew in Florida. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 13.3N 72.8W 135 KT 155 MPH 12H 01/1800Z 13.3N 73.6W 130 KT 150 MPH 24H 02/0600Z 13.8N 74.5W 120 KT 140 MPH 36H 02/1800Z 14.9N 75.1W 110 KT 125 MPH 48H 03/0600Z 16.2N 75.7W 110 KT 125 MPH 72H 04/0600Z 19.5N 76.0W 110 KT 125 MPH 96H 05/0600Z 23.0N 76.0W 90 KT 105 MPH 120H 06/0600Z 26.0N 76.5W 95 KT 110 MPH $$ Forecaster Beven
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Category:Transportation and Logistics