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Tropical Storm MATTHEW Forecast Discussion Number 3
2016-09-29 04:52:06| National Hurricane Center (Atlantic)
Issued at 1100 PM AST WED SEP 28 2016 000 WTNT44 KNHC 290251 TCDAT4 TROPICAL STORM MATTHEW DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 PM AST WED SEP 28 2016 Matthew crossed a portion of the Lesser Antilles today, and tropical-storm-force winds were experienced in various islands for several hours. The strongest winds appeared to have occurred in Martinique which was located in the northeastern quadrant of the storm. An Air Force plane currently investigating Matthew measured a peak wind at 850-mb of 73 kt, while the SFMR instrument measured 54 kt. The minimum central pressure was 1004 mb. There are no signs of an inner core yet, but the cloud pattern has increased in organization, and the initial intensity was adjusted upward to 55 kt. Matthew is forecast to move over warm waters and relatively low shear during the next few days, and these conditions should lead to gradual strengthening. There is a possibility, however, that Matthew encounters some westerly shear in the central Caribbean well south of Haiti in a day or two. This is an area climatologically unfavorable for storms to intensify, and Matthew could reduce its rate of strengthening there. After that, most of the models show a more conducive upper-level environment, and Matthew could intensify at a faster rate. The NHC forecast is not very different from its predecessor and follows closely the intensity consensus. Fixes from an Air Force plane indicate that Matthew is moving toward the west or 270 degrees at 13 kt. A strong subtropical ridge over the Atlantic is steering Matthew westward, and some models even move the cyclone south of due west. Most of the guidance is very consistent with this track during the next 48 hours. After that time, guidance becomes more divergent, but in general, all models turn the cyclone toward the northwest and north. Of the historically reliable models, the westernmost track is the ECMWF ensemble mean while the easternmost is the HWRF. The NHC track forecast is in the middle of the TVCX and TVCN multi-model consensus, and does not depart very much from the previous official forecast. There will be very interesting days ahead as Matthew moves toward the central and western Caribbean Sea, and users are reminded that the average NHC track errors at days 4 and 5 are on the order of 180 and 240 miles, respectively. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 13.9N 63.1W 55 KT 65 MPH 12H 29/1200Z 14.3N 65.3W 60 KT 70 MPH 24H 30/0000Z 14.4N 67.9W 65 KT 75 MPH 36H 30/1200Z 14.3N 70.0W 70 KT 80 MPH 48H 01/0000Z 14.1N 71.5W 75 KT 85 MPH 72H 02/0000Z 14.5N 73.5W 75 KT 85 MPH 96H 03/0000Z 16.8N 75.0W 90 KT 105 MPH 120H 04/0000Z 20.0N 75.5W 90 KT 105 MPH $$ Forecaster Avila
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