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Hurricane Jose Forecast Discussion Number 23

2017-09-11 04:49:57| National Hurricane Center (Atlantic)

Issued at 1100 PM AST Sun Sep 10 2017 000 WTNT42 KNHC 110249 TCDAT2 Hurricane Jose Discussion Number 23 NWS National Hurricane Center Miami FL AL122017 Issued by the NWS Weather Prediction Center College Park MD 1100 PM AST Sun Sep 10 2017 The eye of Hurricane Jose has been absent in satellite imagery since earlier today as increasing high-level northerly shear has weakened the cyclone. This shear is evident in the latest infrared imagery, with cold cloud tops streaming southward from the center. The initial intensity has been lowered to 100 kt with this advisory, based on a blend of subjective and objective Dvorak satellite intensity estimates. The initial motion for this advisory is 325/12 kt, with Jose expected to move toward the north on Monday as a mid-level ridge centered to the east erodes. As Jose moves north of this ridge in 36 hours or so, a complex and dynamic steering pattern is expected to result in Jose completing a clockwise loop over the western Atlantic through the 5-day forecast period. Despite the complexity, this solution is shared by all the guidance, and the current forecast cycle features better agreement amongst the reliable models. The official track forecast closely resembles the previous one, and lies close to the TVCN and GFEX consensus models. Jose is now experiencing about 20 kt of northerly shear, associated with an upper-level ridge centered to the west. Northerly shear is still expected to increase over the next 12 to 24 hours, and remain moderately strong for a couple of days. Additional weakening is therefore expected through 72 hours despite SSTs sufficiently warm (near 29C) to support an intense cyclone. There remains a chance that Jose moves over its own cold wake on days 3 and 4 as indicated by latest HWRF guidance, which would lead to a greater amount of weakening. Toward the latter part of the forecast period, the shear may relax enough to allow for some reintensification, but the confidence in this is somewhat low. The latest intensity forecast is very close to the IVCN consensus and the SHIPS model. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 23.7N 68.1W 100 KT 115 MPH 12H 11/1200Z 25.2N 69.1W 90 KT 105 MPH 24H 12/0000Z 26.5N 69.4W 80 KT 90 MPH 36H 12/1200Z 26.9N 68.7W 75 KT 85 MPH 48H 13/0000Z 26.5N 67.8W 70 KT 80 MPH 72H 14/0000Z 25.0N 67.0W 65 KT 75 MPH 96H 15/0000Z 24.5N 69.5W 70 KT 80 MPH 120H 16/0000Z 25.5N 72.5W 75 KT 85 MPH $$ Forecaster Birchard

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Hurricane Irma Forecast Discussion Number 48

2017-09-11 04:44:16| National Hurricane Center (Atlantic)

Issued at 1100 PM EDT Sun Sep 10 2017 000 WTNT41 KNHC 110244 TCDAT1 Hurricane Irma Discussion Number 48 NWS National Hurricane Center Miami FL AL112017 1100 PM EDT Sun Sep 10 2017 Irma's center has moved northward across the western Florida peninsula since it made landfall earlier this afternoon, and it is now located over west-central Florida. NOAA WSR-88D radar data from Tampa Bay are showing 95-100 kt winds at an elevation of about 3500 ft, so the hurricane's intensity is estimated to be 85 kt. Irma continues to have a large wind field, and exceptional hurricane- force wind gusts are still occurring well to the east of the center along the Florida east coast. Irma appears to be making some progress to the west of due north, and the longer-term initial motion is 350/12 kt. The cyclone is expected to swing around the eastern side of a mid-level disturbance currently located along the U.S. Gulf Coast, which should impart a north-northwestward to northwestward motion during the next 48 hours. Due to its recent more inland push, Irma's center is now forecast to remain over Florida and then move over the southeastern United States for the duration of its existence. Due to continued land interaction and strong shear of over 30 kt, Irma should continue to lose strength and fall below hurricane intensity on Monday. The cyclone is then expected to become a remnant low over western Tennessee by day 3 and dissipate by day 4. KEY MESSAGES: 1. There is the danger of life-threatening storm surge flooding along much of the Florida coast, including the Florida Keys, and portions of the coasts of Georgia and South Carolina, where a Storm Surge Warning remains in effect. 2. Irma will continue to bring life-threatening wind impacts to much of Florida, with hurricane-force winds near the center. Also, Irma is a large hurricane, and hurricane-force wind gusts and sustained tropical-storm force winds extend far from the center. Wind hazards from Irma will also spread northward through Georgia and into portions of Alabama, Tennessee, South Carolina, and North Carolina. 3. Irma continues to produce very heavy rain and inland flooding across much of Florida, and these rains will spread into the rest of the southeast United States. Intense rainfall rates of 2 to 4 inches per hour is leading to flash flooding and rapid rises on creeks, streams, and rivers. Significant river flooding is likely over the next five days in the Florida peninsula and southern Georgia, where average rainfall totals of 8 to 15 inches and isolated 20 inch amounts are expected. Significant river flooding is possible beginning Monday and Tuesday in much of eastern and central Georgia, western South Carolina, and western North Carolina, where average rainfall of 3 to 8 inches and isolated 12 inch amounts are expected. The southern Appalachian Mountains will be especially vulnerable to flash flooding. Irma is also expected to produce average amounts of 2 to 5 inches in parts of Mississippi, Alabama and Tennessee, where isolated higher amounts and local flooding may occur. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 27.5N 81.9W 85 KT 100 MPH...INLAND 12H 11/1200Z 29.4N 82.8W 65 KT 75 MPH...INLAND 24H 12/0000Z 31.9N 84.7W 45 KT 50 MPH...INLAND 36H 12/1200Z 33.9N 86.8W 30 KT 35 MPH...INLAND 48H 13/0000Z 35.0N 88.6W 25 KT 30 MPH...INLAND 72H 14/0000Z 37.5N 87.8W 20 KT 25 MPH...POST-TROP/INLAND 96H 15/0000Z...DISSIPATED $$ Forecaster Berg

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Hurricane Jose Forecast Discussion Number 22

2017-09-10 23:00:50| National Hurricane Center (Atlantic)

Issued at 500 PM AST Sun Sep 10 2017 000 WTNT42 KNHC 102100 TCDAT2 Hurricane Jose Discussion Number 22 NWS National Hurricane Center Miami FL AL122017 Issued by the NWS Weather Prediction Center College Park MD 500 PM AST Sun Sep 10 2017 The eye of Jose has become cloud filled and indistinct in the visible satellite imagery and is no longer discernible in the infrared imagery. A 1536Z GPM pass showed the eye and inner core were degrading. Not surprisingly, current satellite intensity estimates have trended down, with ADT carrying 5.3, CPHC and SAB at 5.5, and TAFB at 6.0. The initial intensity has been lowered to 105 kt for this advisory. The initial motion estimate is 315/15. Global models show that the mid level high which has been responsible for the persistent northwest track will gradually build southward over the next 36 hours, causing the system to slow down on Monday and begin turning more toward the north. After 48 hours, the high will build to the west of Jose, forcing the hurricane into a slow anticyclonic loop between 48 and 96 hours. After 96 hours, mid-level ridging becomes reestablished north of Jose, causing the system to resume more of a west to west-northwest track through the end of the forecast period. One minor adjustment is that the models suggest this loop may occur a little slower than previously indicated, and the forecast reflects this change which is closer to the models. Jose is now experiencing about 20 kt of northerly shear, having outrun the narrow zone of weaker shear it was under previously. This shear will increase further over the next 12 to 24 hours and additional weakening appears likely through the next few days despite SSTs over 29C over the entire forecast track. During the latter part of the forecast period, the shear may relax enough to allow for some reintensification, but the confidence in this is somewhat low. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 22.8N 66.9W 105 KT 120 MPH 12H 11/0600Z 24.4N 68.3W 95 KT 110 MPH 24H 11/1800Z 26.0N 69.3W 85 KT 100 MPH 36H 12/0600Z 26.8N 69.1W 80 KT 90 MPH 48H 12/1800Z 26.7N 68.1W 75 KT 85 MPH 72H 13/1800Z 25.4N 67.3W 70 KT 80 MPH 96H 14/1800Z 24.2N 68.8W 75 KT 85 MPH 120H 15/1800Z 25.1N 71.7W 80 KT 90 MPH $$ Forecaster R Ballard

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Hurricane Irma Forecast Discussion Number 47

2017-09-10 22:54:53| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Sun Sep 10 2017 000 WTNT41 KNHC 102054 TCDAT1 Hurricane Irma Discussion Number 47 NWS National Hurricane Center Miami FL AL112017 500 PM EDT Sun Sep 10 2017 Irma made landfall a couple of hours ago near Marco Island, Florida with an estimated intensity of 100 kt. The eye just passed over Naples, and assuming some decay over land, the current intensity estimate is 95 kt. The interaction with the Florida Peninsula along with strong southwesterly shear should cause significant weakening, but Irma's large and powerful circulation will likely maintain hurricane strength until Monday morning at the earliest. Irma should be well inland and weaken to a remnant low in 72 hours. The official intensity forecast is above the model consensus. Center fixes indicate a slightly west of due northward motion at about 350/12 kt. Global models indicate that Irma is embedded within a broader cyclonic mid-level gyre. The cyclone is expected to be steered around the eastern side of this gyre over the next few days. This will take the system inland over the southeastern United states within a day or so. The track guidance remains in good agreement, and the official forecast is close to the model consensus with a slight lean toward the ECMWF solution. This is very close to the previous NHC track. KEY MESSAGES: 1. Life-threatening wind and storm surge from Irma will continue in the Florida Keys and southwestern Florida and spread into central and northwestern Florida tonight and Monday. 2. There is imminent danger of life-threatening storm surge flooding along much of the Florida west coast, including the Florida Keys, where a Storm Surge Warning is in effect. The threat of catastrophic storm surge flooding is highest along the southwest coast of Florida, where 10 to 15 feet of inundation above ground level is expected. This is a life-threatening situation. 3. Irma will bring life-threatening wind impacts to much of Florida regardless of the exact track of the center. Wind hazards from Irma are also expected to spread northward through Georgia and into portions of Alabama, Tennessee, South Carolina, and North Carolina. 4. Irma is producing very heavy rain and inland flooding across much of Florida, which will quickly spread to the rest of the southeast United States. Intense rainfall rates of 2 to 4 inches per hour is leading to flash flooding and rapid rises on creeks, streams, and rivers. Significant river flooding is likely over the next five days in the Florida peninsula and southeast Georgia, where average rainfall of 8 to 15 inches and isolated 20 inch amounts are expected. Significant river flooding is also possible beginning Monday and Tuesday in much of eastern and central Georgia, western South Carolina, and western North Carolina, where average rainfall of 3 to 8 inches and isolated 12 inch amounts are expected. Mountainous parts of these states will be especially vulnerable to flash flooding. Farther west, Irma is expected to produce average amounts of 2 to 5 inches in parts of Mississippi, Alabama and Tennessee, where isolated higher amounts and local flooding may occur. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 26.2N 81.8W 95 KT 110 MPH...INLAND 12H 11/0600Z 28.0N 82.5W 75 KT 85 MPH...INLAND 24H 11/1800Z 30.7N 83.9W 55 KT 65 MPH...INLAND 36H 12/0600Z 33.1N 86.0W 35 KT 40 MPH...INLAND 48H 12/1800Z 34.5N 88.3W 30 KT 35 MPH...INLAND 72H 13/1800Z 36.5N 89.0W 25 KT 30 MPH...POST-TROP/INLAND 96H 14/1800Z 39.0N 86.5W 20 KT 25 MPH...POST-TROP/INLAND 120H 15/1800Z...DISSIPATED $$ Forecaster Pasch

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Hurricane Jose Forecast Discussion Number 21

2017-09-10 16:55:20| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Sun Sep 10 2017 000 WTNT42 KNHC 101455 TCDAT2 Hurricane Jose Discussion Number 21 NWS National Hurricane Center Miami FL AL122017 Issued by the NWS Weather Prediction Center College Park MD 1100 AM AST Sun Sep 10 2017 Jose remains an impressive hurricane this morning. A 1019z SSMI microwave pass continued to show a very well defined inner core, but a more recent 1132z pass showed some erosion of the CDO on the northwest side. The well defined eye seen earlier in the first light visible imagery is beginning to constrict and become rather ragged. Satellite intensity estimates were 6.0 (115 kt) from SAB and CPHC, and 6.5 (127 kt) at TAFB. We have maintained an intensity of 115 kt for this advisory. The initial motion continues to be rather steady at 305/15. Jose is located to the southeast of a mid-level high, which has continued to steer the tropical cyclone on this persistent northwest track. Changes are ahead, however. Global models agree that the mid-level high will first build southward, allowing Jose to turn more toward the north in about 36 hours and causing the system to slow considerably. After 48 hours, the high will build to the west of Jose, forcing the hurricane into a slow anticyclonic loop between 48 and 72 hours. After 72 hours, mid-level ridging becomes reestablished north of Jose, causing the system to resume more of a west to west-northwest track through the end of the forecast period. Our latest forecast is similar to the previous package, with some northward adjustment at the end of the period to be in better agreement with the TVCN consensus model. The UW-CIMSS wind shear analysis and satellite derived high level wind fields indicate that Jose is reaching the western end of a narrow zone of weak shear. Although Jose will remain over SSTs over 29C throughout the forecast period, increasing northerly shear should induce a weakening trend through the next 72 hours. Global models show the shear relaxing beyond 72 hours, which may be enough to allow Jose to reintensify. The IVCN shows a bit more dramatic weakening, followed by reintensification. Although this is plausible, the official forecast shows a more modest weakening and intensification than the IVCN in deference to the uncertainty. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 21.7N 65.8W 115 KT 130 MPH 12H 11/0000Z 23.1N 67.3W 110 KT 125 MPH 24H 11/1200Z 24.9N 68.7W 100 KT 115 MPH 36H 12/0000Z 26.1N 69.2W 95 KT 110 MPH 48H 12/1200Z 26.4N 68.8W 90 KT 105 MPH 72H 13/1200Z 25.4N 67.6W 85 KT 100 MPH 96H 14/1200Z 24.2N 68.7W 90 KT 105 MPH 120H 15/1200Z 24.8N 71.0W 95 KT 110 MPH $$ Forecaster R Ballard

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