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Tropical Storm NICOLE Forecast Discussion Number 15
2016-10-07 22:36:55| National Hurricane Center (Atlantic)
Issued at 500 PM AST FRI OCT 07 2016 000 WTNT45 KNHC 072036 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST FRI OCT 07 2016 Nicole is a heavily sheared tropical cyclone. The well-defined low-level center is partially exposed on the northwest side of a bursting mass of deep convection. Dvorak Final-T numbers have continued to decrease to T3.0 from both satellite agencies, and a blend of those with CI-numbers yields an initial intensity of 55 kt. Nicole has begun to move southward, and the initial motion estimate is 185/04. A blocking high north of Nicole should continue to push the cyclone slowly southward during the next couple of days. After that time, the mid-level ridge is forecast to rebuild east of Nicole, and there is the potential for a binary interaction with weakening Matthew to the west in 2 to 3 days. This should cause Nicole to do an about-face and begin moving northwestward or north-northwestward from days 2 to 4. A turn toward the north is expected by day 5 once the binary interaction ends and Nicole is on the cusp of entering a stronger mid-latitude southwesterly flow. Although the bulk of the model guidance is in basic agreement with this scenario, there are speed differences amongst the models that make the track forecast of lower confidence than average. Global models show no diminution of the northerly shear over Nicole for the next two days or so. A further complication is Nicole's interaction during this same time period with a fractured lobe of vorticity from a shortwave trough to the east that wraps around the circulation. The net result of all of this is that the cyclone could weaken a bit further or remain steady state as a weak tropical storm for 2 to 3 days, which is what the official forecast and SHIPS model output indicates. After that time, the shear is forecast to decrease and the flow aloft is likely to become much more diffluent, both of which support some re-intensification. This is shown in the latter part of the forecast period, which likewise is in good agreement with SHIPS model output. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 27.0N 65.2W 55 KT 65 MPH 12H 08/0600Z 26.2N 65.0W 45 KT 50 MPH 24H 08/1800Z 25.4N 64.8W 40 KT 45 MPH 36H 09/0600Z 25.1N 64.9W 40 KT 45 MPH 48H 09/1800Z 25.5N 65.3W 40 KT 45 MPH 72H 10/1800Z 27.4N 66.0W 45 KT 50 MPH 96H 11/1800Z 29.7N 66.7W 50 KT 60 MPH 120H 12/1800Z 32.6N 66.4W 60 KT 70 MPH $$ Forecaster Kimberlain
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