000 WTNT44 KNHC 030257 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 PM EDT SUN OCT 02 2016 Although an Air Force Reserve reconnaissance aircraft investigating Matthew this evening has yet to report flight-level or surface winds anywhere close to the 130-kt winds measured in the previous flight, recent aircraft data have indicated that the surface pressure and 700-mb height have both decreased since the previous flight. The eye has cleared out in infrared satellite imagery and cloud tops have cooled around the 8-12 nmi diameter eye. Given the lower central pressure of 943 mb, which corresponds to about 120 kt on the Dvorak pressure-wind relationship, the small eye, and recent NHC objective T-numbers of T6.3/123 kt to T6.5/127 kt, the initial intensity will remain at 125 kt for this advisory. Matthew has continued to meander and wobble over the past several hours, but the best estimate of the forward motion based on recent recon fixes is 360/04 kt. Although some erratic motion could still occur due to Matthew interacting with a large convective complex and mid-/upper-level vortex located about 150 nmi east of Matthew, the cyclone is expected to move in a general northward direction for the next 48 hours or so. After clearing the northeastern coast of Cuba, Matthew is expected to turn toward the north-northwest within southeasterly flow between the western periphery of a strong ridge located over the southwestern Atlantic and a weak mid- to upper-level trough currently located over the eastern Gulf of Mexico. The 12Z UKMET and 18Z GFS and GFS-ensemble mean models now show a weaker trough over the Gulf of Mexico on days 3-5 as a larger storm system currently located over the northwestern U.S. is forecast to not be as strong or as far south as previously expected. This has resulted in more downstream ridging in those models over the southeastern United States, and the model tracks of Matthew have responded by shifting westward. The new NHC track forecast has been shifted slightly to the west or left of the previous advisory track, mainly to account for the more westward initial position. However, the forecast track remains to the east of the UKMET, GFS, and GFS-ensemble mean models, and lies near the TVCX consensus model. Matthew is forecast to remain in a low vertical wind shear environment for the next 36-48 hours, with the shear reaching near zero values by 24 hours. This condition, along with the very favorable upper-level outflow pattern noted in water vapor imagery, should allow for the cyclone to at least maintain its current intensity, barring the eye making any direct interactions with Jamaica or Haiti. By 48 hours, however, land interaction with eastern Cuba should induce more significant weakening. The official intensity forecast remains near or above the latest model consensus. Although the official forecast continues to show a track east of Florida, it is still too soon to rule out possible hurricane impacts there. It is also too soon to know whether, or how, Matthew might affect the remainder of the United States east coast. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 14.7N 75.0W 125 KT 145 MPH 12H 03/1200Z 15.7N 75.1W 125 KT 145 MPH 24H 04/0000Z 17.1N 75.0W 125 KT 145 MPH 36H 04/1200Z 18.8N 74.8W 120 KT 140 MPH 48H 05/0000Z 20.6N 74.9W 105 KT 120 MPH...INLAND 72H 06/0000Z 24.0N 75.6W 105 KT 120 MPH...OVER WATER 96H 07/0000Z 27.1N 76.6W 95 KT 110 MPH 120H 08/0000Z 30.1N 76.7W 90 KT 105 MPH $$ Forecaster Stewart