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Tropical Storm NICOLE Forecast Discussion Number 27
2016-10-10 22:36:08| National Hurricane Center (Atlantic)
Issued at 500 PM AST MON OCT 10 2016 000 WTNT45 KNHC 102035 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST MON OCT 10 2016 While Nicole's convective organization has not changed much over the last several hours, satellite data indicate that the cyclone is maintaining a well-defined inner-core structure. Several bands have also developed over the eastern half of the circulation. An ASCAT pass received after the previous advisory's issuance indicated a couple of reliable 50-kt wind vectors, and the initial intensity estimate is set to this value in basic agreement with satellite classifications. Nicole appears to have turned slightly west of due north, and the initial motion estimate is 355/05. This general motion is expected to continue through tonight or early Tuesday while a shortwave trough treks across Atlantic Canada and bypasses the storm to the north. In the wake of this weather system, a weak low- to mid-level ridge is forecast to build north and west of Nicole for a short time, allowing the track to bend more toward the left. The ECMWF continues to predict a greater westerly component motion than the other guidance for the next 3 days, with still about half of the the 0000 UTC ensemble members left of the current forecast. Before Nicole reaches 30N, it should encounter a stronger mid-latitude flow and recurve into the westerlies with increasing forward speed over the next few days. The new track forecast continues to place greater weight on the ECMWF guidance suite, which results in the track being adjusted slightly left of the previous one through the forecast period. It is in the middle of the 0000 UTC ECMWF ensemble output and to the left of the latest multi-model consensus. Nicole is still struggling partially from mid- to upper-level dry air associated with a lobe of vorticity from a mid-latitude shortwave trough that has been wrapping around the cyclone's circulation. In addition, oceanic upwelling beneath the cyclone has also likely contributed to the cyclone's lack of convective vigor. Once Nicole starts to move farther west over untapped waters and its interaction with the above-mentioned feature ends, the strong northerly shear affecting Nicole for days will have decreased significantly. With the tropical cyclone moving over near-record warm SSTs at that time, in a reasonably moist large-scale environment, and under a diffluent flow at upper levels, a significant intensification is likely. Global models maintain the theme of showing substantial deepening over the next few days. By 72 hours, or shortly thereafter, strong southwesterly shear could bring the predicted intensification to a close unless baroclinic processes counteract the shear enough to allow for some further increase in strength. Extratropical transition in shown by day 5. The new intensity forecast is an update of the previous one and generally near or just above the model consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 26.3N 65.4W 50 KT 60 MPH 12H 11/0600Z 26.9N 65.7W 55 KT 65 MPH 24H 11/1800Z 27.5N 66.3W 65 KT 75 MPH 36H 12/0600Z 28.2N 66.7W 70 KT 80 MPH 48H 12/1800Z 29.5N 66.7W 80 KT 90 MPH 72H 13/1800Z 33.2N 64.3W 80 KT 90 MPH 96H 14/1800Z 38.1N 58.3W 80 KT 90 MPH 120H 15/1800Z 42.0N 54.2W 70 KT 80 MPH...POST-TROP/EXTRATROP $$ Forecaster Kimberlain
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