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Hurricane Epsilon Forecast Discussion Number 24
2020-10-24 22:56:26| National Hurricane Center (Atlantic)
Issued at 500 PM AST Sat Oct 24 2020 513 WTNT42 KNHC 242056 TCDAT2 Hurricane Epsilon Discussion Number 24 NWS National Hurricane Center Miami FL AL272020 500 PM AST Sat Oct 24 2020 Epsilon continues to exhibit an inner core of deep convection. In fact, only in the past couple of hours has the eye become difficult to locate in satellite images. A larger comma-shaped cloud shield surrounds the circulation, and extends several hundred miles from the center. Epsilon passed over a buoy array this morning where pressures as low as 957.6 mb were recorded. In addition, a pair of ASCAT overpasses late this morning showed a large area of winds of 60-65 kt in the southern semicircle. This data supported an intensity of 70 kt earlier, and the cyclone's appearance has not changed much since then. Therefore, the initial intensity remains 70 kt. The hurricane will likely hold its own for the next 6-12 h as it traverses over waters of about 24 C, while in a fairly favorable atmospheric environment downstream of a mid- to upper-level trough. After 12 h, Epsilon should begin to move over waters of 20 degrees C or less. The combination of the much cooler water temperatures and trough interaction should cause the cyclone to begin an extratropical transition that is forecast to complete by late Sunday. The NHC intensity forecast was nudged a little higher in the 24-48 h time frames due to a slight increase in the guidance, and the latest forecast is very near the HCCA and IVCN consensus models. Regardless of exactly when Epsilon becomes extratropical, it is still expected to remain a very large and powerful cyclone until it merges with a larger low to its north in a few days. Epsilon is accelerating and is now moving northeastward at 19 kt. The cyclone should continue accelerating toward the northeast through Sunday in the mid-latitude westerlies, and could reach a forward motion of about 40 kt toward the northeast or east-northeast by Sunday evening. This fast motion is expected to continue through early next week. The NHC track forecast is little changed from the previous one, and is in good agreement with the tightly clustered track guidance. FORECAST POSITIONS AND MAX WINDS INIT 24/2100Z 39.4N 58.2W 70 KT 80 MPH 12H 25/0600Z 41.5N 54.5W 70 KT 80 MPH 24H 25/1800Z 44.9N 46.7W 65 KT 75 MPH...POST-TROP/EXTRATROP 36H 26/0600Z 48.9N 35.9W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 26/1800Z 53.5N 25.2W 60 KT 70 MPH...POST-TROP/EXTRATROP 60H 27/0600Z 58.5N 19.1W 60 KT 70 MPH...POST-TROP/EXTRATROP 72H 27/1800Z...DISSIPATED $$ Forecaster Latto
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Hurricane Epsilon Forecast Discussion Number 23
2020-10-24 16:59:48| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Sat Oct 24 2020 543 WTNT42 KNHC 241459 TCDAT2 Hurricane Epsilon Discussion Number 23 NWS National Hurricane Center Miami FL AL272020 1100 AM AST Sat Oct 24 2020 The appearance of Epsilon has changed little since early this morning, with satellite images revealing an eye feature embedded in a small area of deep convection, while a much larger comma-shaped pattern extends several hundred miles to the north of the center. A drifting buoy array that was placed ahead of the hurricane has provided useful information on the intensity of Epsilon. At 1100 UTC, a buoy located very near the center of the cyclone reported a pressure of 957.6 mb. This pressure was much lower than the previous estimated pressure of 972 mb, which was made without the availability of the buoy data. Therefore, it is likely that Epsilon was a stronger hurricane last night. Based on this data, the initial intensity has been adjusted upward to 70 kt, and this value could still be conservative based on typical high-latitude pressure-wind relationships. Epsilon has made its anticipated turn to the northeast and is now moving at 050/11 kt. The cyclone should begin accelerating toward the northeast later today in the mid-latitude westerlies, reaching a forward motion of about 40 kt to the northeast or east-northeast by Sunday evening. This fast motion is expected to continue through early next week. The NHC track forecast is essentially unchanged from the previous one, and is in good agreement with the tightly clustered track guidance. The cyclone is forecast to move over waters of about 24-26 degrees C for the next 12 h or so, while encountering cooler temperatures aloft. This should allow Epsilon to maintain its current intensity today. After 12 h, the water temperatures below the cyclone are expected to decrease below 20 degrees C, while the system interacts with an mid- to upper-level trough. These factors should cause the inner-core convection to dissipate while the system transitions to a large and powerful extratropical cyclone sometime on Sunday. This cyclone is then expected to merge with a larger extratropical low over the far northern Atlantic by late Monday or Tuesday. That low pressure system will likely produce hazardous conditions over portions of far North Atlantic through the middle of next week. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 37.9N 60.3W 70 KT 80 MPH 12H 25/0000Z 39.7N 57.6W 70 KT 80 MPH 24H 25/1200Z 42.8N 51.1W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 26/0000Z 46.7N 41.4W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 26/1200Z 50.9N 30.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 60H 27/0000Z 55.6N 21.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 27/1200Z...DISSIPATED $$ Forecaster Latto
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Hurricane Epsilon Forecast Discussion Number 20
2020-10-23 22:51:08| National Hurricane Center (Atlantic)
Issued at 500 PM AST Fri Oct 23 2020 000 WTNT42 KNHC 232051 TCDAT2 Hurricane Epsilon Discussion Number 20 NWS National Hurricane Center Miami FL AL272020 500 PM AST Fri Oct 23 2020 The satellite structure of Epsilon has evolved over the last 6 hours, with visible imagery suggesting concentric eyewalls, and recent 89 GHz GMI and AMSR2 microwave imagery indicating the secondary eyewall has nearly closed off around the smaller core. The current intensity of Epsilon was kept at 75 kt for this advisory, close to the satellite estimates, although the 50-kt wind field has expanded significantly in the northern semicircle as indicated by recent scatterometer data. Epsilon has maintained its northward heading with a bit faster forward motion (360/10 kt). The track reasoning remains the same, where the cyclone will be steered to the north around the westward extent of a deep-layer ridge and then will move quite quickly to the northeast as it encounters stronger deep-layer westerly flow ahead of a broad mid-latitude trough. This same mid-latitude trough will interact with Epsilon after 60 h and contribute to the formation of a large and powerful baroclinic cyclone by the end of the forecast period. No significant changes were made to the track forecast. Vertical wind shear is expected to remain low over the next two days and intensity changes will likely be influenced by inner core fluctuations. The intensity guidance does suggest some modest intensification is possible in the short-term as Epsilon moves over a warm eddy in the Gulf Stream, assuming the current secondary eyewall consolidates. Based on this reasoning, the official intensity forecast was nudged slightly upward for the first 24 h. Afterwards, slow weakening is expected but Epsilons 34- and 50-kt wind field should continue to expand to the south while it undergoes extratropical transition, completing the process by early Monday. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 35.5N 61.7W 75 KT 85 MPH 12H 24/0600Z 37.0N 61.6W 80 KT 90 MPH 24H 24/1800Z 38.9N 59.0W 80 KT 90 MPH 36H 25/0600Z 41.9N 53.9W 75 KT 85 MPH 48H 25/1800Z 45.6N 45.6W 70 KT 80 MPH 60H 26/0600Z 50.0N 34.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 26/1800Z 54.0N 24.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 96H 27/1800Z...DISSIPATED $$ Forecaster Papin/Blake
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Hurricane Epsilon Forecast Discussion Number 19
2020-10-23 16:56:38| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Fri Oct 23 2020 000 WTNT42 KNHC 231456 TCDAT2 Hurricane Epsilon Discussion Number 19 NWS National Hurricane Center Miami FL AL272020 1100 AM AST Fri Oct 23 2020 Epsilon's structure has not changed appreciably in the last 12 hours, with a small eye intermittently appearing in geostationary satellite and polar-orbiting microwave imagery with additional well-defined curved outer bands. The initial intensity is kept at 75 kt based on SAB and TAFB satellite estimates and the satellite trends. The cyclone continues to move to the north but at a slightly faster speed (360/09 kt). This northward track is expected for the next day or so as the hurricane is primarily steered by a deep-layer ridge located to its east. Thereafter, Epsilon is forecast to turn toward the northeast and accelerate due to strong mid-latitude westerlies ahead of an approaching longwave trough. By 60 h, Epsilon will be moving rapidly over cooler waters and is expected to be completing extratropical transition. The latest NHC official track is very similar to the previous one and is near the corrected-consensus models. Epsilon remains in a low vertical wind shear environment and will actually be moving over slightly warmer waters over the next day as it passes across a warm Gulf Stream eddy. It is unclear, however, that the current storm structure would allow for any strengthening. Thus, the official forecast maintains the current intensity for the next 36 h, and it is likely that inner-core processes will dictate any short-term fluctuations in intensity. After 36 h, slow weakening should begin as southwesterly vertical wind shear gradually increases and Epsilon reaches the north edge of the Gulf Stream. However, the system is likely to merge with another mid-latitude cyclone and become a powerful extratropical low at the end of the forecast period. The new NHC intensity forecast closely mirrors the previous one and the latest global model wind speed consensus forecast. FORECAST POSITIONS AND MAX WINDS INIT 23/1500Z 34.1N 61.6W 75 KT 85 MPH 12H 24/0000Z 35.6N 61.7W 75 KT 85 MPH 24H 24/1200Z 37.5N 60.7W 75 KT 85 MPH 36H 25/0000Z 40.3N 56.7W 75 KT 85 MPH 48H 25/1200Z 43.7N 49.9W 70 KT 80 MPH 60H 26/0000Z 48.1N 39.3W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 26/1200Z 52.5N 27.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 27/1200Z...DISSIPATED $$ Forecaster Papin/Blake
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Hurricane Epsilon Forecast Discussion Number 18
2020-10-23 10:39:03| National Hurricane Center (Atlantic)
Issued at 500 AM AST Fri Oct 23 2020 000 WTNT42 KNHC 230838 TCDAT2 Hurricane Epsilon Discussion Number 18 NWS National Hurricane Center Miami FL AL272020 500 AM AST Fri Oct 23 2020 Although Epsilon is moving over 25.5 deg C sea-surface temperatures (SST), the hurricane has continued to generate deep convection around the small 15-nmi-wide eye. Upper-level outflow also remains impressive in all quadrants, but especially in the northern semicircle where a pronounced poleward outflow channel has become established. The initial intensity remains at 75 kt based on a Dvorak classifications from TAFB and SAB yielding a Current Intensity (CI) number of T4.5/77 kt. The 34-kt and 50-kt wind radii were expanded based on recent ASCAT scatterometer wind data between 0100-0300 UTC. Epsilon is now moving northward, or 360/07 kt. The hurricane is forecast to continue moving northward today around the western periphery of a deep-layer subtropical ridge located east of the cyclone. On Saturday, Epsilon is expected to turn northeastward and accelerate ahead of an approaching shortwave trough and associated frontal system that will be moving off the U.S. east coast on Sunday. That motion will take Epsilon over increasingly cooler SSTs as low as 20 deg C by Sunday morning, resulting in extratropical transition by 60 h, if not sooner. The new NHC official track forecast is very similar to the previous advisory track, and lies close to the middle of the tightly packed simple- and corrected- consensus models. The current relatively low southerly vertical wind shear of about 10 kt is forecast to gradually increase to more than 20 kt by this evening. Although Epsilon will be moving over a modestly warm oceanic eddy today, which could result in some brief restrengthening of the cyclone, the official intensity forecast calls for the intensity to remain steady for the next 36 h, followed by slow weakening thereafter due to the hurricane moving over near-20 deg C SSTs by 48 hours. By 60 hours, the global models and the GFS- and ECMWF-based SHIPS guidance indicate that Epsilon will have undergone extratropical transition over the far north Atlantic. Afterward, the global models continue to show Epsilon getting absorbed by a larger extratropical cyclone at the higher latitudes, resulting in a very powerful low developing with a central pressure near 940 mb. That low then moves eastward, possibly menacing northern Europe by the middle of next week. The forecast wind radii, which show the cyclone expanding over the next few days, are in good agreement with the dynamical consensus radii guidance, RVCN. Key Messages: 1. Dangerous and potentially life-threatening surf and rip currents are expected along the coasts of Bermuda, the Bahamas, the Greater Antilles, the Leeward Islands, the east coast of the United States, and Atlantic Canada during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 33.1N 61.6W 75 KT 85 MPH 12H 23/1800Z 34.7N 61.5W 75 KT 85 MPH 24H 24/0600Z 36.7N 61.2W 75 KT 85 MPH 36H 24/1800Z 38.8N 58.9W 75 KT 85 MPH 48H 25/0600Z 42.0N 54.0W 70 KT 80 MPH 60H 25/1800Z 46.0N 45.7W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 26/0600Z 49.9N 34.8W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 27/0600Z...ABSORBED BY LARGER EXTRATROPICAL LOW $$ Forecaster Stewart
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