je.st
news
Tropical Storm NICOLE Forecast Discussion Number 56
2016-10-18 04:58:41| National Hurricane Center (Atlantic)
Issued at 1100 PM AST MON OCT 17 2016 000 WTNT45 KNHC 180258 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 56 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST MON OCT 17 2016 The old adage about tropical cyclones transitioning to extratropical once the latitude is larger than the longitude does not apply to Nicole. The system has been able to maintain a coherent inner core of deep convection, which wraps about two-thirds the way around its center. This is, however, somewhat reduced from earlier today and the Dvorak data-t numbers from TAFB and SAB have dropped. A just arriving ASCAT-A scatterometer pass from 0019Z indicates that peak winds are about 60 kt and this may be a bit generous. Thus Nicole has weakened to a tropical storm. Nicole's resilience as a tropical cyclone is likely due to it being embedded within very low vertical shear and in quite cold upper tropospheric temperatures, despite the SSTs dropping to near 20 deg C. However, Nicole should soon transition to an extratropical cyclone, as frontal boundaries develop near the center of the system by tomorrow. Even though it will become extratropical, it is anticipated that Nicole will remain a large and powerful system for the next couple of days before being absorbed by a separate extratropical cyclone in about three days. The intensity forecast is slightly less than that from the previous advisory because of the lowered initial intensity and is based upon a deterministic global model consensus. Nicole is moving toward the northeast at about 22 kt, as it is being advected along in the deep layer southwesterly flow ahead of a shortwave trough over eastern Canada. A 2019Z AMSU pass and the ASCAT-A scatterometer pass indicated that the surface center is somewhat west of where the center appears to be from the infrared imagery. Nicole should accelerate and turn toward the north by tomorrow. This track forecast is similar to that from the previous advisory and is based upon a blend of the deterministic and ensemble global models. The main hazard associated with Nicole will continue to be the large area of high seas. Swells from Nicole will affect much of the North Atlantic basin during the next couple of days. The post-tropical portion of the forecast is based on guidance from the NOAA Ocean Prediction Center. FORECAST POSITIONS AND MAX WINDS INIT 18/0300Z 44.8N 41.0W 60 KT 70 MPH 12H 18/1200Z 48.3N 37.9W 60 KT 70 MPH...POST-TROP/EXTRATROP 24H 19/0000Z 54.5N 36.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 19/1200Z 59.0N 34.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 20/0000Z 65.0N 33.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 72H 21/0000Z...ABSORBED BY A LARGER EXTRATROPICAL LOW $$ Forecaster Landsea
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics