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Hurricane Epsilon Forecast Discussion Number 17

2020-10-23 04:32:56| National Hurricane Center (Atlantic)

Issued at 1100 PM AST Thu Oct 22 2020 253 WTNT42 KNHC 230232 TCDAT2 Hurricane Epsilon Discussion Number 17 NWS National Hurricane Center Miami FL AL272020 1100 PM AST Thu Oct 22 2020 The eye became a little more apparent on satellite images but recently has become less defined. The system has a somewhat ragged-looking Central Dense Overcast with a broad outer cloud band wrapping around the western semicircle of the circulation. Upper-level outflow is fairly well-defined over the northern portion of the system. The current intensity estimate is kept at 75 kt in agreement with a Dvorak estimate from TAFB and objective ADT estimates from UW-CIMSS. Since Epsilon should be passing near a modestly warm oceanic eddy during the next day or so, some slight short-term restrengthening is allowed for in the official forecast. Later in the forecast period, gradual weakening should occur due to cooler waters, but the system is likely to remain a strong cyclone for the next few days. By around 72 hours, the GFS and SHIPS guidance indicates that Epsilon will have undergone extratropical transition over the north Atlantic. Afterward, the global models show the system merging with another cyclone at the higher latitudes. Epsilon continues to move just a bit to the west of due north, or at about 345/8 kt. The cyclone is expected to move mainly northward on the western side of a mid-tropospheric ridge during the next couple of days. By around 48 hours, Epsilon should turn northeastward and accelerate as it becomes caught up in the mid-latitude westerlies. The official track forecast is not much different from the previous one, and is very close to the latest corrected dynamical consensus, HCCA, prediction. 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. Winds at Bermuda will subside overnight, and the Tropical Storm Warning for that island has been discontinued. 2. 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 23/0300Z 32.6N 61.6W 75 KT 85 MPH 12H 23/1200Z 33.8N 61.6W 80 KT 90 MPH 24H 24/0000Z 35.8N 61.6W 80 KT 90 MPH 36H 24/1200Z 37.8N 60.6W 80 KT 90 MPH 48H 25/0000Z 40.5N 56.9W 75 KT 85 MPH 60H 25/1200Z 44.3N 50.0W 70 KT 80 MPH 72H 26/0000Z 48.4N 41.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 96H 27/0000Z...DISSIPATED $$ Forecaster Pasch

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Hurricane Epsilon Forecast Discussion Number 16

2020-10-22 22:33:54| National Hurricane Center (Atlantic)

Issued at 500 PM AST Thu Oct 22 2020 000 WTNT42 KNHC 222033 TCDAT2 Hurricane Epsilon Discussion Number 16 NWS National Hurricane Center Miami FL AL272020 500 PM AST Thu Oct 22 2020 Satellite images indicate that the eye of Epsilon has lost definition over the past several hours. While satellite intensity estimates haven't changed much yet, they were generally higher than the earlier reconnaissance data. The initial wind speed is set to 75 kt, on the lower side of the satellite estimates after placing more weight on the aircraft data. Epsilon is moving faster to the north-northwest this afternoon, at roughly 8 kt. The hurricane should turn northward overnight and continue on that heading for a day or two while it moves through a break in the central Atlantic ridge. Epsilon is likely to move considerably faster to the northeast over the weekend as it get caught in the mid-latitude flow. The only significant adjustment to this forecast is a small northward shift in a couple of days. The new NHC track is still south of the model consensus over the weekend and beyond, placing more emphasis on the global models than the regional hurricane guidance. After 72 hours, the cyclone is forecast to merge with a much larger extratropical cyclone over the far north Atlantic. The small core that Epsilon has maintained for the past couple of days seems to be degrading, and perhaps it is forming a larger secondary wind maximum based on AMSR microwave data. Otherwise, a trough interaction and a small warm eddy near the Gulf Stream could lead to a slight recovery in Epsilon's strength tomorrow or Saturday. Either way, the global models make this hurricane's wind field quite a bit larger (especially the 50- and 64-kt winds), and that's reflected in the latest wind radii forecast. The new NHC wind speed prediction is about the same as the previous one, adjusted slightly for a lower initial wind speed. Key Messages: 1. Tropical storm conditions are expected intermittently on Bermuda through this evening, when Epsilon is forecast to make its closest approach east of the island. A Tropical Storm Warning is in effect for Bermuda. 2. 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 22/2100Z 31.9N 61.4W 75 KT 85 MPH 12H 23/0600Z 33.0N 61.6W 75 KT 85 MPH 24H 23/1800Z 34.8N 61.6W 80 KT 90 MPH 36H 24/0600Z 36.8N 61.3W 80 KT 90 MPH 48H 24/1800Z 39.0N 59.0W 75 KT 85 MPH 60H 25/0600Z 42.2N 53.6W 70 KT 80 MPH 72H 25/1800Z 46.5N 45.0W 65 KT 75 MPH 96H 26/1800Z...DISSIPATED $$ Forecaster Blake/Papin

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Hurricane Epsilon Forecast Discussion Number 14

2020-10-22 10:48:44| National Hurricane Center (Atlantic)

Issued at 500 AM AST Thu Oct 22 2020 000 WTNT42 KNHC 220848 TCDAT2 Hurricane Epsilon Discussion Number 14 NWS National Hurricane Center Miami FL AL272020 500 AM AST Thu Oct 22 2020 Epsilon's eye has lost some definition and become cloud filled in conventional satellite imagery during the past few hours, and an 0604 UTC AMSR2 microwave image showed that the eyewall has been eroded on the west side. Given the degradation of the cloud pattern and lowering Dvorak estimates, Epsilon's initial intensity is being set, likely generously, at 95 kt. A recent UW-CIMSS SATCON estimate suggests that the intensity could be 10-15 kt lower than that, but I'd rather we see the aircraft reconnaissance data in a few hours before reducing it any further. Epsilon's trochoidal wobbles have continued overnight, but a longer-term 12-hour motion suggests that the hurricane has turned toward the northwest (320/6 kt). A mid-tropospheric high over the central Atlantic will be Epsilon's main driver, causing the hurricane to turn toward the north-northwest later today and then toward the north tonight. Shorter-term deviations around this general trajectory will be possible if the trochoidal oscillations continue through the day. Epsilon is forecast to turn toward the northeast and accelerate on Saturday when it becomes embedded in the mid-latitude westerlies, taking it past southeastern Newfoundland and into the north Atlantic early next week. The new NHC track forecast is down the middle of the tightly clustered model guidance, and close to the TVCN multi-model consensus. However, because of the recent wobbles, this new forecast lies about 40 n mi to the east of the previous forecast during the first 36 hours. Epsilon's forecast track takes it over a rather homogeneous field of sea surface temperatures between 25-26 degrees Celsius for the next 48-60 hours as vertical shear increases somewhat. Gradual weakening is anticipated during that period, but a more sudden decrease in ocean temperatures after 60 hours should induce quicker weakening thereafter. Hurricane and global models both agree on this scenario, and the NHC intensity forecast is very close to the IVCN consensus and the HFIP Corrected Consensus. Epsilon is expected to merge with a frontal zone and become extratropical by day 4. Key Messages: 1. Tropical storm conditions are expected intermittently on Bermuda through this evening, when Epsilon is forecast to make its closest approach east of the island. A Tropical Storm Warning is in effect for Bermuda. 2. 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 22/0900Z 30.6N 60.9W 95 KT 110 MPH 12H 22/1800Z 31.6N 61.1W 90 KT 105 MPH 24H 23/0600Z 33.0N 61.4W 85 KT 100 MPH 36H 23/1800Z 34.7N 61.6W 80 KT 90 MPH 48H 24/0600Z 36.6N 61.4W 80 KT 90 MPH 60H 24/1800Z 38.7N 59.2W 80 KT 90 MPH 72H 25/0600Z 41.6N 54.3W 75 KT 85 MPH 96H 26/0600Z 50.0N 36.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 120H 27/0600Z 60.0N 22.5W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg

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Hurricane Epsilon Forecast Discussion Number 13

2020-10-22 04:41:22| National Hurricane Center (Atlantic)

Issued at 1100 PM AST Wed Oct 21 2020 000 WTNT42 KNHC 220241 TCDAT2 Hurricane Epsilon Discussion Number 13 NWS National Hurricane Center Miami FL AL272020 1100 PM AST Wed Oct 21 2020 The eye of the hurricane remains well-defined this evening, although the surrounding cloud tops are beginning to warm a bit. An Air Force Hurricane Hunter aircraft investigated Epsilon a little while ago and found peak 700 mb flight level winds of 110 kt, which continues to support an intensity of 100 kt. The central pressure had fallen slightly since this afternoon, but recent center fixes suggest that it is leveling off. Some fluctuations in intensity are possible over the next 12 hours or so due to inner-core processes. Later on Thursday, a slow weakening trend is expected to begin as vertical shear over Epsilon should gradually increase. The official intensity forecast is in good agreement with the latest model consensus. By 96 hours, the global models indicate that the strong cyclone will merge with a frontal zone over the mid-latitudes, and the NHC forecast shows the system as extratropical by that time. Epsilon's motion has exhibited what is likely a trochoidal wobble, which is typical of slow-moving intense hurricanes. This has resulted in a more westward track during the past 6 hours or so. The initial motion estimate is 285/7 kt, and is indeed more westward than previous estimates. However, recent satellite images indicate little short-term motion. The track model guidance is in very good agreement that Epsilon will move northwestward and then north-northwestward on Friday and Friday night. Later, the cyclone should move north of the subtropical ridge, and turn northward and northeastward. By days 4-5, the cyclone should accelerate northeastward under the influence of the mid-latitude westerlies. The official forecast is right on top of the latest corrected multi-model consensus guidance, HCCA and is only slightly west of the previous NHC track through 24 hours. This puts the closest approach of Epsilon to Bermuda between 00Z and 06Z Friday. Key Messages: 1. Tropical storm conditions are expected on Bermuda tonight, and continuing intermittently through late Thursday, when Epsilon is forecast to make its closest approach east of the island. A Tropical Storm Warning is in effect for Bermuda. 2. Dangerous surf and rip currents are likely occurring along the coasts of Bermuda, the Bahamas, the Greater Antilles, and the Leeward Islands. These conditions are expected to spread to portions of the east coast of the United States and Atlantic Canada during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 22/0300Z 29.6N 60.6W 100 KT 115 MPH 12H 22/1200Z 30.5N 61.4W 100 KT 115 MPH 24H 23/0000Z 31.8N 61.9W 95 KT 110 MPH 36H 23/1200Z 33.2N 62.2W 90 KT 105 MPH 48H 24/0000Z 34.9N 62.2W 85 KT 100 MPH 60H 24/1200Z 36.9N 61.3W 80 KT 90 MPH 72H 25/0000Z 39.2N 58.0W 75 KT 85 MPH 96H 26/0000Z 46.5N 42.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 27/0000Z 56.0N 25.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch

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Hurricane Epsilon Forecast Discussion Number 12

2020-10-21 22:55:09| National Hurricane Center (Atlantic)

Issued at 500 PM AST Wed Oct 21 2020 000 WTNT42 KNHC 212055 TCDAT2 Hurricane Epsilon Discussion Number 12 NWS National Hurricane Center Miami FL AL272020 500 PM AST Wed Oct 21 2020 Epsilon has continued to defy expectations and rapidly intensify this afternoon. The satellite presentation of the hurricane is very impressive, with a warm well-defined eye and a closed ring of eyewall convection with cloud tops colder than -60 deg C. An Air Force Hurricane Hunter aircraft that investigated Epsilon earlier today measured SFMR winds of around 100 kt and max flight level winds of 100 kt. Dropsonde data indicated peak surface winds of 106 kt with deeper-layer averages of 95-100 kt, which also lends support to the higher SFMR winds, and surface pressures have fallen since the special advisory. Therefore the initial intensity is raised to 100 kt, making Epsilon the 4th major hurricane of the season. Epsilon's estimated motion is 305/9 kt, and the hurricane is expected to gradually turn more northwestward tonight as it is steered by a mid-level ridge building to its north and east. Epsilon is forecast to pass east of Bermuda and make its closest approach to the island Thursday afternoon or evening. As the ridge becomes oriented east of the hurricane, Epsilon will turn northward and move into the mid-latitudes, where it is expected to accelerate northeastward across the central Atlantic this weekend. There was a westward shift noted in a couple of the track models, and the NHC track forecast has been adjusted slightly westward in the near-term period to better reflect the guidance consensus. As Epsilon continues to gain latitude, environmental conditions will become increasingly unfavorable for additional strengthening. The hurricane is forecast to move over cooler waters beginning tonight, and southerly deep-layer shear is expected within the next 24-48 h. With that being said, small intensity fluctuations cannot be completely ruled out tonight given Epsilon's development trends and well-organized structure. The NHC intensity forecast lies closest to the SHIPS guidance for the first 24-36 h of the forecast period. Afterwards, the official forecast shows more steady weakening with the possibility of an eyewall replacement cycle, and the new NHC intensity prediction follows the intensity consensus. Epsilon could begin its extratropical transition by Sunday night, and it is forecast to be a powerful extratropical cyclone over the northeastern Atlantic by day 5. Key Messages: 1. Tropical storm conditions are expected on Bermuda beginning this evening and continuing intermittently through late Thursday, when Epsilon is forecast to make its closest approach east of the island. A Tropical Storm Warning is in effect for Bermuda. 2. Dangerous surf and rip currents are likely occurring along the coasts of Bermuda, the Bahamas, the Greater Antilles, and the Leeward Islands. These conditions are expected to spread to portions of the east coast of the United States and Atlantic Canada during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 29.6N 60.0W 100 KT 115 MPH 12H 22/0600Z 30.5N 60.9W 100 KT 115 MPH 24H 22/1800Z 31.8N 61.6W 95 KT 110 MPH 36H 23/0600Z 33.0N 62.0W 90 KT 105 MPH 48H 23/1800Z 34.4N 62.1W 85 KT 100 MPH 60H 24/0600Z 36.2N 61.8W 85 KT 100 MPH 72H 24/1800Z 38.3N 59.8W 80 KT 90 MPH 96H 25/1800Z 44.5N 47.5W 70 KT 80 MPH 120H 26/1800Z 54.0N 28.5W 65 KT 75 MPH...POST-TROP/EXTRATROP $$ Forecaster Reinhart/Blake

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