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Tropical Storm NICOLE Forecast Discussion Number 26
2016-10-10 17:05:20| National Hurricane Center (Atlantic)
Issued at 1100 AM AST MON OCT 10 2016 000 WTNT45 KNHC 101505 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 26 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 AM AST MON OCT 10 2016 Nicole's cloud pattern has lost organization since late yesterday. A series of convective bursts over the last 24 hours faded away into a shallow and shapeless cloud mass earlier this morning. Since then, some deep convection has redeveloped over the low-level center but there has been no apparent increase to its organization. A blend of the Final-T and CI-number from the TAFB satellite classification and UW-CIMSS ADT values are used to lower the initial intensity estimate to 50 kt. Nicole has been moving slowly northward or 360/05 as it moves along the southwestern periphery of a mid-level ridge to its northeast. While this general motion should continue today, a shortwave trough trekking across Atlantic Canada is expected to bypass Nicole during the next 24 hours, and allow a weak mid-level ridge to build north and west of the cyclone during the next day or two. This synoptic pattern should result in a leftward bend of the track through about 48 hours. After that time, global models show Nicole turning northward and then northeastward with an increase in forward speed once it reaches a faster-paced westerly flow around 30N. Although the track guidance is in much better agreement than it has been during the last few days, the theme from yesterday of the ECMWF and its 0000 UTC ensemble members showing Nicole with a greater westerly component of motion from 24 to 72 hours persists. In fact, a majority of the ECMWF ensembles members are still, to varying degrees, left of the current forecast. The new track forecast is again adjusted to left of the previous one, closer to the ECMWF, and is west of the model consensus aids. During the last 24 hours, a piece of vorticity that fractured from a central Atlantic shortwave trough has been merging with Nicole. The interaction of this feature with Nicole and a continuation of strong northerly shear could explain the degraded satellite appearance of Nicole since yesterday. Nonetheless, the shear is still forecast to diminish during the next day or two, as the cyclone traverses near-record warm SSTs, finds itself in a reasonably moist environment and an increasingly diffluent flow aloft. These factors suggest that a significant re-intensification is still possible, as the global models continue to show. The only caveat would be to what degree a drier and more stable air in the wake of Post-Tropical Matthew would modify as it is at least partially ingested by Nicole's circulation. SHIPS model output shows the shear greatly increasing by 96 hours, which would likely result in an end to the predicted intensification phase unless baroclinic processes become dominant and result in just a little bit more. The new intensity forecast is similar to the previous one and is close to the multi-model consensus. It should be noted that global models show Nicole becoming a large hurricane in about 3 days, with a wide distribution of strong winds over the central Atlantic. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 25.7N 65.2W 50 KT 60 MPH 12H 11/0000Z 26.4N 65.4W 50 KT 60 MPH 24H 11/1200Z 27.2N 66.0W 60 KT 70 MPH 36H 12/0000Z 27.7N 66.5W 65 KT 75 MPH 48H 12/1200Z 28.5N 66.8W 75 KT 85 MPH 72H 13/1200Z 31.8N 65.2W 80 KT 90 MPH 96H 14/1200Z 36.7N 59.6W 75 KT 85 MPH 120H 15/1200Z 41.2N 53.9W 70 KT 80 MPH...POST-TROP/EXTRATROP $$ Forecaster Kimberlain
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