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| #877313 (Received by flhurricane at: 11:10 PM 07.Oct.2016) TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST FRI OCT 07 2016 Strong northerly shear continues to cause all of Nicole`s deep convection to be located in the southern semicircle of the storm. The deep convection has been going up and down, very typical for this type of sheared tropical cyclone. ASCAT showed a sizable area of winds near 45 kt, and after considering the low bias of the instrument for a small tropical cyclone, the initial wind speed is reduced to 50 kt. This is also consistent with a blend of the Dvorak T- and CI-numbers from TAFB. Nicole is moving southward at about 6 kt. A motion toward the south or south-southeast is anticipated for the next day or so while the tropical cyclone is steered on the east side of a mid-level high between Nicole and Matthew. The forecast gets very tricky in a couple of days, with the mid-level high breaking down and Matthew probably moving toward Nicole. The possibility of tropical cyclone binary interaction appears to be increasing, which could cause Nicole to move toward the north or north-northwest in the 3 to 5 day period. The details of this interaction, however, are very sketchy, with models presenting a variety of fairly divergent solutions. The new NHC forecast is close to the ensemble means of the UKMET, ECMWF and GFS, which ends up south of the previous forecast at short range, and to the east of the previous forecast at long range. These are relatively small changes since it is probably best not to move the forecast very much until the models come into better agreement on the final phase of Matthew. Northerly shear is forecast to continue near Nicole over the next two or three days. Models do not show as much weakening as one might think, perhaps due to the very warm water that Nicole will be traversing, or due to Nicole`s possible interaction with a shortwave trough. After that time, global models generally show a decrease in shear and a diffluent upper-level pattern, which would support some restrengthening. The model guidance is slightly higher than the last cycle, and the latest NHC prediction is nudged in that direction, although the new forecast is on the low side of the guidance. Needless to say, this is a fairly uncertain forecast overall because Matthew could play a large role in a few days. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 26.3N 65.3W 50 KT 60 MPH 12H 08/1200Z 25.5N 65.1W 45 KT 50 MPH 24H 09/0000Z 24.7N 64.9W 45 KT 50 MPH 36H 09/1200Z 24.8N 65.2W 45 KT 50 MPH 48H 10/0000Z 25.5N 65.5W 45 KT 50 MPH 72H 11/0000Z 27.7N 65.8W 45 KT 50 MPH 96H 12/0000Z 30.5N 66.0W 50 KT 60 MPH 120H 13/0000Z 33.5N 65.5W 60 KT 70 MPH $$ Forecaster Blake |
