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Hurricane NICOLE Forecast Discussion Number 32
2016-10-12 04:36:58| National Hurricane Center (Atlantic)
Issued at 1100 PM AST TUE OCT 11 2016 000 WTNT45 KNHC 120236 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 32 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST TUE OCT 11 2016 Nicole's cloud pattern was quite impressive after the release of the previous advisory, with a distinct eye surrounded by a ring of cloud tops of around -70C. However, by 00Z the eye was no longer apparent in geostationary imagery, and the Dvorak classifications from TAFB and SAB were T4.5/77 kt. The eye has reappeared recently, but the convective tops are a bit more ragged. The initial intensity is set to 80 kt, between the subjective Dvorak estimates and the latest UW-CIMSS ADT of around 90 kt. Environmental conditions appear conducive for some additional strengthening in the next 24 hours or so, with the cyclone over 28-29C waters and the shear 15 kt or less. The NHC intensity forecast is similar to the previous one during this time and is above the consensus. The SHIPS model shows southwesterly shear increasing to 45-50 kt by 48 hours, which should result in some weakening. Nicole will interact with an upper-level trough in 3-4 days, but global model fields and the FSU phase space diagrams suggest that Nicole won't complete extratropical transition when it is left behind by the progressive trough by day 5. Therefore, the NHC forecast shows Nicole as post-tropical at days 4 and 5, but baroclinic forcing is expected to keep cyclone near hurricane intensity through the end of the forecast period. Nicole has moved little during the past few hours, as the cyclone is caught in a region of weak steering currents. In fact, a slow looping motion has been noted since the previous advisory, and the best estimate of the initial motion is a westward drift at around 2 kt. The synoptic reasoning has not changed, as Nicole is expected to gradually recurve into the mid-latitude westerlies in the next 48 hours and then turn east-northeastward ahead of an upper-level trough moving off the U.S. east coast. By the end of the period, the trough leaves Nicole behind to the south of a ridge centered over the Davis Strait, which should result in a slow southeastward drift at day 5. The NHC track has been shifted a little to the right of the previous one and is a little slower during the first 36-48 hours, bringing Nicole near or over Bermuda. Late in the period, a larger rightward shift was made to the NHC track. The new official forecast remains near the middle of the guidance envelope and is close to the latest multi-model consensus aid TVCN. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 27.3N 66.6W 80 KT 90 MPH 12H 12/1200Z 28.2N 66.9W 85 KT 100 MPH 24H 13/0000Z 29.6N 66.8W 90 KT 105 MPH 36H 13/1200Z 31.5N 65.7W 90 KT 105 MPH 48H 14/0000Z 33.9N 63.3W 85 KT 100 MPH 72H 15/0000Z 38.5N 56.5W 80 KT 90 MPH 96H 16/0000Z 40.5N 52.0W 70 KT 80 MPH...POST-TROPICAL 120H 17/0000Z 40.0N 51.5W 65 KT 75 MPH...POST-TROPICAL $$ Forecaster Brennan
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