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Hurricane NICOLE Forecast Discussion Number 52
2016-10-17 04:44:33| National Hurricane Center (Atlantic)
Issued at 1100 PM AST SUN OCT 16 2016 000 WTNT45 KNHC 170244 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 52 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST SUN OCT 16 2016 Cloud tops have continued to cool around Nicole's eye, and the eye itself has become a little more distinct during the past several hours. AMSU data from 2029 UTC yielded a CIMSS intensity estimate of 71 kt, and since the convective pattern has improved since the last advisory, it is assumed that the cyclone has not lost any strength. The maximum winds therefore remain 70 kt. Global models fields indicate that Nicole should maintain its deep warm core for at least another 24 hours. By 36 hours, however, the cyclone is likely to become attached to a nearby frontal zone to its west, at which point Nicole would become extratropical. Neither the global models nor the SHIPS and LGEM models show much weakening during the next couple of days, and Nicole is expected to maintain hurricane intensity for the next 48 hours. Some weakening is forecast by day 3 with Nicole moving over very cold water, and then the cyclone is expected to be absorbed by a larger extratropical low by day 4 while it moves between Iceland and Greenland. No changes were made to the updated NHC intensity forecast compared to the previous advisory. Nicole took a jog toward the north since the last advisory, but the longer-term motion is estimated to be 040/8 kt. A shortwave trough moving eastward across Quebec is expected to emerge off the coast of Atlantic Canada late tomorrow, with the preceding flow causing Nicole to accelerate toward the northeast and then north-northeast by 36 hours. A north-northeastward motion should continue up until the time Nicole is absorbed by the larger extratropical low near Greenland. The updated NHC track forecast lies near the TVCN multi-model consensus, and it was nudged a bit west of the previous forecast primarily to account for the recent northward jog. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 40.5N 45.5W 70 KT 80 MPH 12H 17/1200Z 41.6N 44.4W 65 KT 75 MPH 24H 18/0000Z 44.3N 41.9W 65 KT 75 MPH 36H 18/1200Z 48.9N 39.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 48H 19/0000Z 53.6N 37.2W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 20/0000Z 62.2N 30.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 21/0000Z...ABSORBED BY A LARGER EXTRATROPICAL LOW $$ Forecaster Berg
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Hurricane NICOLE Forecast Discussion Number 51
2016-10-16 22:45:36| National Hurricane Center (Atlantic)
Issued at 500 PM AST SUN OCT 16 2016 000 WTNT45 KNHC 162045 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 51 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST SUN OCT 16 2016 Nicole's 70 nmi wide ragged eye remains distinct, surrounded by a nearly closed ring of convection consisting of cloud tops of -45C to -55C. However, the overall cloud pattern is beginning to look more like an extratropical low pressure system than that of a tropical cyclone. The initial intensity has been lowered to 70 kt, which is closer to the latest subjective and objective Dvorak intensity estimate of T4.0/65 kt from both TAFB and NHC. Nicole appears to have finally made the much anticipated turn to the northeast, and is now moving 045/08 kt. Nicole currently is trapped between two high-amplitude ridges -- one located offshore of eastern Canada and the other to the west of Europe. The latest 12Z model guidance remains in excellent agreement on this blocking ridge pattern breaking down over the next few days as a strong shortwave trough currently located over northeastern Canada moves quickly eastward. The increasing southwesterly deep-layer flow ahead of the trough should begin to accelerate Nicole northeastward tonight and Monday, and then turn the cyclone north-northeastward over the far North Atlantic on Tuesday. The track models are in very good agreement on this developing track scenario, so the new NHC forecast track is essentially just an extension of the previous advisory track, and lies close to a blend of the various consensus models and input from the NOAA Ocean Prediction Center (OPC) at 48-72h. Although Nicole is currently located over marginal sea surface temperatures of about 24 deg C, it is beneath a region of unusually cold upper-tropospheric temperatures, creating an unstable condition barely sufficient to support convection in the inner-core region of the cyclone. However, the latest SHIPS intensity guidance indicates that SSTs will be cooling to 22C and less by 24 h, after which the atmosphere is forecast to become too stable to produce convection. As a result, Nicole is expected to become an extratropical low by 36 hours. However, the intensity forecast shows only slight weakening during the next 48 h due to the system receiving a shot of baroclinic energy from the aforementioned shortwave trough. By 96 h, if not sooner, Nicole is expected to be absorbed by a larger extratropical low near the east coast of Greenland. Guidance from the NOAA OPC was used for the forecast wind radii at 48 h and 72 h. The primary hazard associated with Nicole will be high seas. Recent wave-height altimeter data indicate that a large area of 20-ft seas exist near the hurricane. In addition, swells from Nicole are spreading far from the system, and High Seas Forecasts from OPC and TAFB indicate that long-period swells will continue to radiate outward and affect much of the North Atlantic basin during the next few days. FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 39.7N 45.6W 70 KT 80 MPH 12H 17/0600Z 40.5N 44.5W 65 KT 75 MPH 24H 17/1800Z 42.6N 42.5W 65 KT 75 MPH 36H 18/0600Z 46.3N 39.6W 65 KT 75 MPH...POST-TROP/EXTRATROP 48H 18/1800Z 51.3N 37.3W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 19/1800Z 59.6N 32.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 20/1800Z...ABSORBED BY LARGER EXTRATROPICAL LOW $$ Forecaster Stewart
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Hurricane NICOLE Forecast Discussion Number 50
2016-10-16 16:56:34| National Hurricane Center (Atlantic)
Issued at 1100 AM AST SUN OCT 16 2016 000 WTNT45 KNHC 161456 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 50 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 AM AST SUN OCT 16 2016 Nicole appears to be maintaining its strength this morning. The satellite presentation of the hurricane is slightly better organized than several hours ago. A large ragged eye of the cyclone is still evident in visible satellite images, surrounded by patches of cold cloud tops. The initial wind speed is held at 75 kt, which is a little higher than the latest Dvorak estimates. Although Nicole is over 24 deg C SSTs and is headed for even colder waters during the next day or two, there should be enough instability for the continuation of some deep convection near the center of the cyclone. Therefore, only slow weakening is expected before Nicole completes the transition to an extratropical cyclone in about two days when it is absorbed by an upper-level trough. Nicole is moving slowly east-southeastward as the hurricane is now largely cut off from the stronger mid-latitude flow. A slow northeastward motion is expected later today and tonight, followed by an acceleration to the north-northeast on Tuesday and Wednesday. The expected turn and increase in forward speed are due to the approach of the aforementioned large upper-level trough that is currently located over eastern Canada. The track models are in relatively good agreement, and the new NHC forecast is a little slower than the previous one to come into better agreement with the latest consensus aids. The initial wind radii were adjusted based on a 1230 UTC ASCAT-B pass. Guidance from the NOAA Ocean Prediction Center (OPC) was used for the forecast wind radii. The primary hazard associated with Nicole will be high seas. Recent wave-height altimeter data indicate that a large area of 20-ft seas exist near the hurricane. In addition, swells from Nicole are spreading far from the system, and High Seas Forecasts from OPC and TAFB suggest that long-period swells will continue to radiate outward and affect much of the North Atlantic basin during the next few days. FORECAST POSITIONS AND MAX WINDS INIT 16/1500Z 39.1N 46.6W 75 KT 85 MPH 12H 17/0000Z 39.5N 46.0W 70 KT 80 MPH 24H 17/1200Z 41.0N 44.4W 65 KT 75 MPH 36H 18/0000Z 43.8N 41.7W 65 KT 75 MPH 48H 18/1200Z 48.5N 38.5W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 19/1200Z 58.6N 35.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 20/1200Z...DISSIPATED $$ Forecaster Cangialosi
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Hurricane NICOLE Forecast Discussion Number 48
2016-10-16 04:35:59| National Hurricane Center (Atlantic)
Issued at 1100 PM AST SAT OCT 15 2016 000 WTNT45 KNHC 160235 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 48 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST SAT OCT 15 2016 Nicole appears to be trying to develop some inner-core convection with cloud tops cooling near the center during the past several hours. Although there is cold advection occurring on the back side of the cyclone, recent AMSU data confirm that Nicole has a well-defined warm core. CIMSS intensity estimates from the AMSU data indicated that Nicole was still producing maximum winds between 68-77 kt, and the latest classification from TAFB increased from six hours ago. Based on these data, the initial intensity remains 75 kt. Global model fields show that Nicole is likely to maintain its warm core for another 48 hours. Even though sea surface temperatures will be decreasing from 24C to 20C during that time, upper-level temperatures will also be cooling, which should keep the environment unstable enough for Nicole to generate convection within its core. Therefore, only slow weakening is anticipated during the next few days, and the NHC intensity forecast most closely follows the GFS and ECMWF forecast intensities. Nicole is expected to lose its warm core and become extratropical by 72 hours, and it should then be absorbed by another weather system by 120 hours between Iceland and Greenland. Nicole's center has turned eastward and slowed down with an initial motion of 080/9 kt. Nicole is cut off from the faster mid-latitude flow to its north, and it is therefore expected to move only slowly eastward or northeastward during the next 36 hours. After that time, a shortwave trough moving across eastern Canada should cause Nicole to accelerate toward the north-northeast and north between 48-96 hours. The updated NHC track forecast is close to the various consensus models and not too different from the previous forecast. Nicole's initial tropical-storm-force wind radii have been expanded based on a recent ASCAT-B pass. Guidance from the NOAA Ocean Prediction Center was used for the forecast wind radii. Swells from Nicole will affect Bermuda and portions of the U.S. east coast and Atlantic Canada during the next couple of days. By early next week, wave models suggest that long-period swell from Nicole will radiate outward and affect much of the North Atlantic basin. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 39.4N 48.3W 75 KT 85 MPH 12H 16/1200Z 39.4N 47.2W 70 KT 80 MPH 24H 17/0000Z 39.9N 46.0W 70 KT 80 MPH 36H 17/1200Z 41.0N 44.4W 65 KT 75 MPH 48H 18/0000Z 43.8N 42.0W 65 KT 75 MPH 72H 19/0000Z 53.7N 36.3W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 20/0000Z 63.0N 32.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 21/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW $$ Forecaster Berg
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Hurricane NICOLE Forecast Discussion Number 47
2016-10-15 22:35:28| National Hurricane Center (Atlantic)
Issued at 500 PM AST SAT OCT 15 2016 000 WTNT45 KNHC 152035 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 47 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST SAT OCT 15 2016 Nicole is currently showing a hybrid structure. On the larger scale, the system has the appearance of an extratropical low, with cold air advection occurring over the southern semicircle and a developing frontal cloud band east through south of the center. However, the system has secluded an area of warm air near the center where a tropical cyclone wind and temperature structure exists. The earlier scatterometer overpass showed the radius of maximum winds to be about 75 n mi, and the warm core is strong enough to produce hurricane-strength AMSU intensity estimates. Based on little change in the appearance of the cloud pattern since the last advisory, the intensity is held at 75 kt. The GFS and the ECMWF continue to forecast organized central convection for the next 36-48 hours, indicating that Nicole is likely to maintain tropical cyclone characteristics. After that time, the cyclone should move over sea surface temperatures of 16 deg C or less that should cause the central convection to dissipate. Based on this, the intensity forecast calls for Nicole to become post-tropical by 72 hours and then fully extratropical by 96 hours. The latest dynamical model guidance forecasts the cyclone to be absorbed by another extratropical low by 120 hours, and that is now reflected in the intensity forecast. The new forecast is otherwise an update of the previous forecast. The initial motion is now 075/10. A slow easterly motion is expected during the next 36 hours or so while the cyclone is in an area of weaker flow in the mid-latitude westerlies. After that time, a large mid-latitude trough moving into eastern Canada should steer Nicole north-northeastward with an increase in forward speed. The new forecast track is again similar to the previous track and lies near the various consensus models. Guidance from the NOAA Ocean Prediction Center was used for the forecast wind radii. Swells from Nicole will affect Bermuda and portions of the U.S. east coast and Atlantic Canada during the next couple of days. By early next week, wave models suggest that long-period swell from Nicole will radiate outward and affect much of the North Atlantic basin. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 39.4N 49.4W 75 KT 85 MPH 12H 16/0600Z 39.5N 48.0W 75 KT 85 MPH 24H 16/1800Z 39.8N 46.7W 70 KT 80 MPH 36H 17/0600Z 40.6N 45.5W 65 KT 75 MPH 48H 17/1800Z 42.5N 43.7W 65 KT 75 MPH 72H 18/1800Z 50.0N 38.0W 60 KT 70 MPH...POST-TROPICAL 96H 19/1800Z 60.0N 34.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 20/1800Z...ABSORBED BY EXTRATROPICAL LOW $$ Forecaster Beven
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