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Hurricane Jose Forecast Discussion Number 58

2017-09-19 22:48:56| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Tue Sep 19 2017 000 WTNT42 KNHC 192048 TCDAT2 Hurricane Jose Discussion Number 58 NWS National Hurricane Center Miami FL AL122017 500 PM EDT Tue Sep 19 2017 Satellite imagery indicate that Jose's cloud pattern has improved since the previous advisory. Curved band features have become more evident in all quadrants and the upper-level outflow has also expanded and become more anticyclonic. Jose actually looks more like a tropical cyclone now. Satellite intensity estimates have increased and were a consensus T3.5/55 kt at 1800Z. Since that time, the convective pattern has continued to improve, including a burst of convection with cloud tops colder than -60C having developed near and over the well-defined low-level center. Given the much improved satellite cloud pattern, the intensity will remain 65 kt. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate Jose by 2300Z. Jose has made the much anticipated turn toward the north-northeast and is now moving 025/07 kt. There is no significant change to the previous track forecast or reasoning. The latest NHC model guidance remains in good agreement on Jose slowing down and turning toward the northeast by Wednesday morning, followed by a turn toward the east on Thursday as the cyclone moves around the north side of deep-layer ridge. During the 72-120 hour period, a high-latitude ridge is forecast to build to the north of Jose, forcing the cyclone slowly southward and southwestward over the far North Atlantic. The new official forecast track lies a little to the east of the consensus models, closer to the ECMWF solution. The center and much of the inner core of Jose will be moving over 21-22C SSTs by 36-48 h. However, a large portion of the hurricane's circulation will still be located over much warmer water, which will maintain a long, southerly fetch of unstable air into and to the north of the center. Since the vertical wind shear is expected to be 20 kt or less, only gradual weakening is expected as per the previous intensity forecasts, and the intensity models IVCN and HCCA. The 34-kt wind radii were increased slightly in the northwestern quadrant based on 14-15Z ASCAT scatterometer wind data, offshore buoy reports, and a 40-45 kt wind report from ship VRGH3. KEY MESSAGES: 1. While the center of Jose is forecast to remain offshore of the U.S. east coast, the large cyclone is expected to cause some direct impacts in portions of New England, and a tropical storm warning is in effect for Cape Cod, Block Island, Martha's Vineyard, and Nantucket. Any deviation to the left of the NHC forecast track would increase the likelihood and magnitude of impacts along the coast from Long Island to southern New England. 2. Minor to moderate coastal flooding is possible from Delaware to southern New England during the next several days. Please see products issued by local National Weather Service forecast offices. 3. Swells generated by Jose are affecting Bermuda, the Bahamas, and much of the U.S. east coast. These swells are likely to cause dangerous surf and rip current conditions for the next several days in these areas. 4. Jose will produce heavy rain over a small part of southern New England and eastern Long Island as it passes offshore of these locations on Tuesday and Wednesday. Total accumulations of 1 to 3 inches are expected over eastern Long Island, southeast Connecticut, southern Rhode Island, and southeast Massachusetts. 3 to 5 inches are expected for Martha's Vineyard, Nantucket, and Cape Cod. This rainfall could cause isolated flooding. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 37.2N 71.3W 65 KT 75 MPH 12H 20/0600Z 38.2N 70.6W 65 KT 75 MPH 24H 20/1800Z 39.2N 69.2W 60 KT 70 MPH 36H 21/0600Z 39.7N 68.0W 55 KT 65 MPH 48H 21/1800Z 39.5N 67.5W 50 KT 60 MPH 72H 22/1800Z 39.0N 67.6W 45 KT 50 MPH...POST-TROPICAL 96H 23/1800Z 38.6N 68.1W 40 KT 45 MPH...POST-TROPICAL 120H 24/1800Z 38.3N 69.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Stewart

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Hurricane Maria Forecast Discussion Number 15

2017-09-19 22:47:26| National Hurricane Center (Atlantic)

Issued at 500 PM AST Tue Sep 19 2017 000 WTNT45 KNHC 192046 TCDAT5 Hurricane Maria Discussion Number 15 NWS National Hurricane Center Miami FL AL152017 500 PM AST Tue Sep 19 2017 Maria has continued to strengthen this afternoon, with surface and flight-level winds from an Air Force Reserve Hurricane Hunter aircraft supporting an intensity of 145 kt, and the central pressure inside the 5 n mi wide eye falling to 916 mb. The aircraft data also indicates that an outer wind maximum is present about 20-30 n mi from the center, but this has not yet developed into enough of an outer eyewall to stop the intensification in the inner eyewall. The initial motion remains 300/9. The forecast track philosophy remains the same, with the eye of Maria expected to move near the U. S. Virgin Islands tonight and across Puerto Rico on Wednesday, followed by a motion just north of the eastern Dominican Republic Wednesday night and Thursday. Subsequently, a break in the subtropical ridge caused in part by Hurricane Jose should allow Maria to turn north-northwestward and northward by the end of the forecast period. Only minor changes have occurred in the track guidance since the last advisory, and the new track has only minor adjustments from the previous track. Some additional strengthening is possible this evening before the outer eyewall becomes better defined or the cyclone reaches its maximum potential intensity. It now appears likely that Maria will be at category 5 intensity when it moves over the U. S. Virgin Islands and Puerto Rico, although there is a chance that the start of the eyewall replacement cycle might reduce the intensity a little bit. The hurricane should weaken as it crosses Puerto Rico, and after that proximity to Hispaniola and less favorable upper-level winds are likely to lead to continued slow weakening. The new intensity forecast remains at the upper edge of the intensity guidance. KEY MESSAGES: 1. Maria's core is expected to move near or over St. Croix and Puerto Rico tonight and Wednesday, bringing life-threatening wind, storm surge, and rainfall impacts to portions of those islands. Everyone in these areas should follow advice from local officials to avoid life-threatening flooding from storm surge and rainfall. 2. Wind speeds atop and on the windward sides of hills and mountains and on high-rise buildings could be much stronger than the near-surface winds indicated in this advisory. 3. A hurricane warning also in effect for the remainder of the Virgin Islands and the northern coast of the Dominican Republic, where Maria is expected to bring dangerous wind, storm surge, and heavy rainfall. 4. A hurricane watch is in effect for the southeastern Bahamas and the Turks and Caicos, where Maria could bring hurricane conditions on Thursday. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 16.8N 64.0W 145 KT 165 MPH 12H 20/0600Z 17.5N 65.2W 145 KT 165 MPH 24H 20/1800Z 18.4N 66.7W 130 KT 150 MPH...OVER PUERTO RICO 36H 21/0600Z 19.3N 68.1W 125 KT 145 MPH...OVER WATER 48H 21/1800Z 20.2N 69.4W 120 KT 140 MPH 72H 22/1800Z 22.5N 71.0W 115 KT 130 MPH 96H 23/1800Z 25.5N 72.0W 110 KT 125 MPH 120H 24/1800Z 28.5N 72.5W 95 KT 110 MPH $$ Forecaster Beven

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Tropical Depression Norma Forecast Discussion Number 22

2017-09-19 22:34:27| Tropical Depression LIDIA

Issued at 200 PM PDT Tue Sep 19 2017

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Hurricane Jose Forecast Discussion Number 57

2017-09-19 17:00:01| National Hurricane Center (Atlantic)

Issued at 1100 AM EDT Tue Sep 19 2017 000 WTNT42 KNHC 191459 TCDAT2 Hurricane Jose Discussion Number 57 NWS National Hurricane Center Miami FL AL122017 1100 AM EDT Tue Sep 19 2017 Satellite imagery and reports from an Air Force Reserve Hurricane Hunter aircraft indicate that Jose's overall structure and wind field have changed little since the previous advisory. Although the highest 700-mb flight-level wind and SFMR surface winds reported by the aircraft were 66 kt and 57 kt, respectively, these winds were observed in areas of little or no convection. Given the large size of Jose's wind field, it unlikely that the aircraft sampled the strongest winds, and the initial intensity is held at 65 kt. The aircraft also measured a central pressure of 976 mb, indicating that Jose remains a strong cyclone. The low-level center has been wobbling around inside the larger inner-core circulation, resulting in a forward motion a little west of due north or 350/06 kt. Overall there is no significant change to the previous track forecast. The global and regional models remain in good agreement on Jose slowing down and turning toward the northeast and east over the next couple days as it moves around a ridge over the western Atlantic. On days 3-5, the models agree on a high-latitude ridge building to the north of the cyclone, forcing Jose to move slowly or drift southward over the North Atlantic. The official forecast track is similar to the previous advisory, and lies close to a blend of the various consensus models. Since the previous advisory, shallow convection has been increasing in both depth and areal coverage in the southeastern semicircle, while deeper convection has remained over the northwestern semicircle. The recent formation of convection to the southeast is beginning to give Jose the appearance of developing a large truck-tire eye with a diameter of approximately 100 nmi. Such eye patterns typically indicate a fairly stable cyclone that doesn't weaken or weakens only slowly. Although the center of Jose will be moving over 21C SSTs by 36-48 h, a significant portion of the large circulation will still be situated over water south of the Gulf Stream that is positioned along 40N latitude, which will maintain a southerly feed of warm, moist, unstable air into and north of the center. Given the combination of the aforementioned favorable thermodynamic conditions and only modest vertical wind shear of 15-20 kt, the intensity forecast remains basically unchanged from the previous advisory, and is close to a blend of the IVCN and HCCA consensus models. KEY MESSAGES: 1. While the center of Jose is forecast to remain offshore of the U.S. coast, the large cyclone is expected to cause some direct impacts in portions of New England, and a tropical storm warning is in effect for the coast of Rhode Island and a part of the Massachusetts coast, including Cape Cod. Any deviation to the left of the NHC forecast track would increase the likelihood and magnitude of impacts along the U.S. east coast from Long Island to southern New England. 2. Minor to moderate coastal flooding is possible from Delaware to southern New England during the next several days. Please see products issued by local National Weather Service forecast offices. 3. Swells generated by Jose are affecting Bermuda, the Bahamas, and much of the U.S. east coast. These swells are likely to cause dangerous surf and rip current conditions for the next several days in these areas. 4. Jose will produce heavy rain over a small part of southern New England and eastern Long Island as it passes offshore of these locations on Tuesday and Wednesday. Total accumulations of 1 to 3 inches are expected over eastern Long Island, southeast Connecticut, southern Rhode Island, and southeast Massachusetts. 3 to 5 inches are expected for Martha's Vineyard, Nantucket, and Cape Cod. This rainfall could cause isolated flooding. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 36.5N 71.7W 65 KT 75 MPH 12H 20/0000Z 37.8N 70.9W 65 KT 75 MPH 24H 20/1200Z 39.1N 69.7W 60 KT 70 MPH 36H 21/0000Z 39.9N 68.1W 55 KT 65 MPH 48H 21/1200Z 39.9N 67.1W 50 KT 60 MPH 72H 22/1200Z 39.2N 66.9W 45 KT 50 MPH...POST-TROPICAL 96H 23/1200Z 38.7N 67.2W 40 KT 45 MPH...POST-TROPICAL 120H 24/1200Z 38.4N 67.7W 40 KT 45 MPH...POST-TROPICAL $$ Forecaster Stewart

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Hurricane Maria Forecast Discussion Number 14

2017-09-19 16:49:19| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Tue Sep 19 2017 000 WTNT45 KNHC 191449 TCDAT5 Hurricane Maria Discussion Number 14 NWS National Hurricane Center Miami FL AL152017 1100 AM AST Tue Sep 19 2017 Reports from an Air Force Reserve Hurricane Hunter Aircraft indicate that Maria regained category 5 status shortly after the last advisory, and that it is currently maintaining an intensity near 140 kt with a central pressure near 927 mb. The aircraft data suggests an outer wind maximum that could be the start of an eyewall replacement cycle, but this feature does not yet have a good signature in radar data or microwave imagery. The eye of Maria has been wobbling quite a bit, but a smoother long-term motion is 300/9. There is little change to the track forecast reasoning or the forecast track since the previous advisory. A weak ridge situated over the western Atlantic is expected to steer Maria west-northwestward through 48 hours, and on this track the center of the hurricane is forecast to pass near or over the Virgin Islands and Puerto Rico on Wednesday. After that time, the western portion of the ridge is forecast to weaken, partially due to the influence of the large circulation of Hurricane Jose off the U.S. east coast. This pattern should cause Maria to turn northwestward and then north-northwestward by days 4-5. The track guidance is tightly clustered through 72 h and fairly well clustered at 120 h, and the new track is to the left of center of the cluster mainly between the GFS and ECMWF models. Maria should remain in a generally favorable environment through 48 h, and based on this and the latest guidance the new intensity forecast keeps Maria at 135-140 kt up to the time of landfall in Puerto Rico. After crossing Puerto Rico, the upper-level winds are expected to become less favorable, and the intensity forecast shows a slow weakening that follows the upper edge of the guidance. A complication to the intensity forecast is that there will likely be fluctuations caused by eyewall replacement cycles superimposed on top of the general trends shown in the official forecast. KEY MESSAGES: 1. Maria will continue to affect portions of the Leeward Islands today and the core of the hurricane is expected to move near or over Puerto Rico and the Virgin Islands tonight and Wednesday. Everyone in these areas should follow advice from local officials to avoid life-threatening flooding from storm surge and rainfall. 2. Wind speeds atop and on the windward sides of hills and mountains and on high-rise buildings could be much stronger than the near- surface winds indicated in this advisory. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 16.3N 63.1W 140 KT 160 MPH 12H 20/0000Z 17.0N 64.1W 140 KT 160 MPH 24H 20/1200Z 18.0N 65.7W 135 KT 155 MPH 36H 21/0000Z 18.8N 67.1W 125 KT 145 MPH 48H 21/1200Z 19.6N 68.4W 125 KT 145 MPH 72H 22/1200Z 21.5N 70.5W 120 KT 140 MPH 96H 23/1200Z 24.5N 72.0W 105 KT 120 MPH 120H 24/1200Z 27.5N 72.5W 95 KT 110 MPH $$ Forecaster Beven

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