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Hurricane MATTHEW Forecast Discussion Number 37
2016-10-07 10:57:46| National Hurricane Center (Atlantic)
Issued at 500 AM EDT FRI OCT 07 2016 000 WTNT44 KNHC 070857 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 37 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 AM EDT FRI OCT 07 2016 The satellite appearance of Matthew has become rather disheveled looking in infrared satellite imagery since the previous advisory. Land-based Doppler radar data indicate that Matthew has been going through an eyewall replacement cycle for the past 12 hours or so, but the inner eyewall has yet to dissipate within the 35-40 nmi wide outer eyewall. Both Doppler velocity data and recon SFMR surface winds and flight-level winds indicate that hurricane-force winds are and have been occuring within the outer eyewall just 5-10 nmi east of the Florida coastline. Although the central pressure has remained steady between 938-940 mb, the intensity has been lowered to 105 kt based on 700-mb flight-level winds of 118 kt and several patches of Doppler velocities of 120-122 kt between 5000-7500 feet. The initial motion estimate is 330/12 kt. For the next 48 hours, Matthew is expected to move northward and then northeastward around the western periphery of a deep-layer subtropical ridge. After that time, a weakening Matthew is expected to turn slowly southeastward and then southward as the cyclone gets cut off from the influence of the mid-latitude westerlies and becomes embedded within the aforementioned large-scale high pressure ridge. The latest model guidance has shifted to the left of the previous forecast track after 36 hours, and the official forecast has been nudged in that direction, but remains well to the right of the model consensus and close to the GFS-ECMWF consensus. Matthew is expected to slowly weaken some more during the next 12 hours or so while the cyclone completes the eyewall replacement cycle. By 24 hours and beyond, more significant weakening is expected due to the combination of strong southwesterly vertical shear increasing to more than 30 kt and entrainment of very dry mid-level air with humidity values less than 20 percent. The new intensity forecast closely follows the consensus model IVCN. Special thanks to the Air Force Reserve and NOAA Hurricane Hunters for their tireless efforts in having already completed more than 90 center or eye fixes. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains along extensive portions of the east-central and northeast coast of Florida today. 2. Evacuations are not just a coastal event. Strong winds will occur well inland from the coast, and residents of mobile homes under evacuation orders are urged to heed those orders. 3. Hurricane winds increase very rapidly with height, and residents of high-rise buildings are at particular risk of strong winds. Winds at the top of a 30-story building will average one Saffir-Simpson category higher than the winds near the surface. 4. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. Only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. Modest deviations to the right could keep much of the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch and warning areas in northeast Georgia and South Carolina. 5. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario -- the amount of inundation that has a 10 percent chance of being exceeded. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 28.2N 80.0W 105 KT 120 MPH 12H 07/1800Z 29.6N 80.6W 100 KT 115 MPH 24H 08/0600Z 31.5N 80.5W 90 KT 105 MPH 36H 08/1800Z 32.6N 79.2W 80 KT 90 MPH 48H 09/0600Z 33.1N 77.7W 65 KT 75 MPH 72H 10/0600Z 31.5N 74.5W 50 KT 60 MPH 96H 11/0600Z 29.0N 75.0W 40 KT 45 MPH 120H 12/0600Z 27.0N 76.5W 35 KT 40 MPH $$ Forecaster Stewart
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Hurricane NICOLE Forecast Discussion Number 13
2016-10-07 10:36:50| National Hurricane Center (Atlantic)
Issued at 500 AM AST FRI OCT 07 2016 000 WTNT45 KNHC 070836 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 AM AST FRI OCT 07 2016 Nicole no longer has an eye in infrared satellite imagery, and the cloud pattern suggests that 30 kt of northwesterly shear is beginning to offset the deep convection to the southeast of the center. Dvorak final-T numbers from TAFB and SAB have decreased, so the initial intensity is set at 85 kt as a blend of the final-T and CI numbers. Strong vertical shear is expected to persist over Nicole, increasing and turning out of the north during the next several days. As a result, continued weakening is anticipated, and the intensity models indicate that Nicole's winds should gradually diminish in strength through day 4. By day 5, the vertical shear may decrease, and Nicole could regain some strength at the end of the forecast period. The NHC intensity forecast closely follows the ICON intensity consensus, which puts it slightly below the previous forecast for much of the forecast period. There has been no recent microwave data to help locate the center, but cloud motions suggest that Nicole is drifting southward. The overall steering currents are expected to remain weak for several more days. However, for the next 48 hours, Nicole will be situated between a digging shortwave trough and a mid-level high between it and Hurricane Matthew, which should cause Nicole to move slowly southward. After that time, the cyclone could be close enough to Matthew's circulation to cause it to turn northward. While the track models don't agree on how far south Nicole will move, they do all generally show the same solutions of very little net motion through five days. The updated NHC track is adjusted from the previous track forecast toward the various consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 27.3N 65.2W 85 KT 100 MPH 12H 07/1800Z 27.0N 65.2W 80 KT 90 MPH 24H 08/0600Z 26.1N 65.0W 70 KT 80 MPH 36H 08/1800Z 25.2N 64.8W 65 KT 75 MPH 48H 09/0600Z 24.8N 65.0W 65 KT 75 MPH 72H 10/0600Z 25.4N 65.9W 60 KT 70 MPH 96H 11/0600Z 27.5N 66.5W 55 KT 65 MPH 120H 12/0600Z 30.0N 66.5W 60 KT 70 MPH $$ Forecaster Berg
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Hurricane MATTHEW Forecast Discussion Number 36
2016-10-07 04:57:55| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT THU OCT 06 2016 000 WTNT44 KNHC 070257 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 36 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 PM EDT THU OCT 06 2016 The satellite appearance of Matthew has improved during the past several hours, with an eye embedded within a more circular central dense overcast and an increase in the outer banding. Reports from a NOAA Hurricane Hunter aircraft and coastal radar data show the presence of centric eyewalls with diameters of about 8 and 60 n mi respectively. The NOAA aircraft earlier reported a minimum pressure of 937 mb, and an Air Force Reserve Hurricane Hunter just reported estimated surface winds of 109 kt from the SFMR and a pressure of 939 mb. Based on these data, the initial intensity is 115 kt. The initial motion is 325/11 kt. For the next 24-48 hours, Matthew should move around the western end of the subtropical ridge, with the motion gradually turning northward and then northeastward. During this time, the center of the guidance envelope and the various consensus models have shifted a little to the east. However, the ECMWF, GFS, and UKMET continue to suggest the possibility of the hurricane making landfall in Florida and then moving near the coasts of Georgia and South Carolina. This part of the forecast is nudged a little to the east and lies between the model consensus and the previous forecast. After 48 hours, a mid- to upper-level ridge is forecast to build north and west of Matthew, and the track guidance forecasts a southeasterly to southerly motion in response. While there is still a large spread, the GFS, ECMWF, and UKMET are in better agreement that Matthew should move south between the ridge and Hurricane Nicole to the east. This part of the forecast follows this guidance and lies between the GFS and ECMWF. During the next 12-24 hours, Matthew will likely weaken a little as it undergoes an eyewall replacement cycle. After that time, it is expected to encounter strong southwesterly vertical shear, and later in the forecast period dry air is likely to entrain into the cyclone. This combination should cause steady weakening, and Matthew is forecast to drop below hurricane strength by 72 hours. The new intensity forecast is in best agreement with the SHIPS model. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the northwestern Bahamas today, and along extensive portions of the east coast of Florida tonight. 2. Evacuations are not just a coastal event. Strong winds will occur well inland from the coast, and residents of mobile homes under evacuation orders are urged to heed those orders. 3. Hurricane winds increase very rapidly with height, and residents of high-rise buildings are at particular risk of strong winds. Winds at the top of a 30-story building will average one Saffir-Simpson category higher than the winds near the surface. 4. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. Only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. Modest deviations to the right could keep much of the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch and warning areas in northeast Georgia and South Carolina. 5. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario -- the amount of inundation that has a 10 percent chance of being exceeded. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 27.1N 79.2W 115 KT 130 MPH 12H 07/1200Z 28.5N 80.2W 110 KT 125 MPH 24H 08/0000Z 30.3N 80.8W 105 KT 120 MPH 36H 08/1200Z 31.8N 80.2W 90 KT 105 MPH 48H 09/0000Z 32.6N 78.7W 75 KT 85 MPH 72H 10/0000Z 31.5N 75.5W 60 KT 70 MPH 96H 11/0000Z 29.0N 75.5W 50 KT 60 MPH 120H 12/0000Z 27.0N 77.0W 40 KT 45 MPH $$ Forecaster Beven
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Hurricane NICOLE Forecast Discussion Number 12
2016-10-07 04:42:00| National Hurricane Center (Atlantic)
Issued at 1100 PM AST THU OCT 06 2016 000 WTNT45 KNHC 070241 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST THU OCT 06 2016 Nicole has rapidly intensified during the day, with a pinhole eye apparent in satellite and microwave imagery. Although the eye has recently become obscured, Dvorak satellite estimates support an initial intensity of 90 kt for this advisory. All of the guidance suggests that the shear near Nicole should increase during the next couple of days since the tropical cyclone will be in an environment of increasingly strong upper-level northerly winds. Thus Nicole is probably near its peak intensity, and slow weakening is forecast from Friday through the weekend. The large-scale environment could become more conducive for re-intensification by days 4 or 5, and some restrengthening is shown around that time. The new intensity forecast is very close to the previous one, slightly above the model consensus. Nicole has moved very little during the past several hours. The hurricane will likely begin to drift southward by tomorrow afternoon due to steering from the western side of a mid-level trough. Thereafter, Nicole could gradually turn toward the southwest, west, and northwest over the next few days around a ridge over the western Atlantic Ocean. There is better agreement in the guidance than yesterday, although the ECMWF remains a bit of an outlier solution to the east. Since a stronger system would likely respond more to the deep-layer northerly flow, the new NHC track is shifted a bit to the south of the previous forecast in a couple of days, but ends up close to the last NHC advisory by day 5. A climate note: This is the first time since September 10, 1964 that two Category 2 (or stronger) hurricanes have occurred simultaneously in the Atlantic basin west of 65W. Interestingly, those hurricanes in 1964, Dora and Ethel, were in similar positions as Matthew and Nicole are now. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 27.4N 65.2W 90 KT 105 MPH 12H 07/1200Z 27.3N 65.2W 85 KT 100 MPH 24H 08/0000Z 26.8N 65.1W 80 KT 90 MPH 36H 08/1200Z 26.1N 64.7W 75 KT 85 MPH 48H 09/0000Z 25.5N 64.7W 70 KT 80 MPH 72H 10/0000Z 26.0N 66.0W 60 KT 70 MPH 96H 11/0000Z 27.5N 67.0W 60 KT 70 MPH 120H 12/0000Z 29.0N 68.0W 65 KT 75 MPH $$ Forecaster Blake
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Hurricane MATTHEW Forecast Discussion Number 35
2016-10-06 22:53:17| National Hurricane Center (Atlantic)
Issued at 500 PM EDT THU OCT 06 2016 000 WTNT44 KNHC 062052 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 35 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 PM EDT THU OCT 06 2016 A NOAA Hurricane Hunter plane just reached Matthew and measured 121 kt at the 700-mb level and a minimum pressure of of 936 mb. Until the plane finishes sampling the circulation, the initial intensity is kept at 120 kt. There some indications that an outer eyewall is trying to form, and perhaps an eyewall cycle will occur. If so, some weakening could occur, but there could also be fluctuations in intensity while the hurricane moves toward the east coast of Florida that are not explicitly shown here. After 24 hours, the combination of land interaction and a significant increase in the shear should cause weakening. The NHC intensity forecast is very similar to the SHIPS guidance during the next day or so, and it follows the trend of the consensus thereafter. Satellite and aircraft fixes show that Matthew is still moving toward the northwest or 325 degrees at 11 kt. The steering flow has not changed, and Matthew should continue to move around the western periphery of the subtropical ridge located over the western Atlantic during the next 24 to 36 hours. This portion of the NHC forecast is very close to the multi-model consensus. After that time, the hurricane will become embedded within the mid-latitude westerlies and should turn sharply eastward for a day or so. Then the steering pattern is forecast to change again, and the track forecast becomes highly uncertain. Both the GFS and the ECMWF turn a much weaker Matthew southward and southwestward. The NHC forecast follows the southwestward trend, and is in the middle of these two global models. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the northwestern Bahamas today, and along extensive portions of the east coast of Florida tonight. 2. Evacuations are not just a coastal event. Strong winds will occur well inland from the coast, and residents of mobile homes under evacuation orders are urged to heed those orders. 3. Hurricane winds increase very rapidly with height, and residents of high-rise buildings are at particular risk of strong winds. Winds at the top of a 30-story building will average one Saffir-Simpson category higher than the winds near the surface. 4. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. Only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. Modest deviations to the right could keep much of the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch and warning areas in northeast Georgia and South Carolina. 5. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario - the amount of inundation that has a 10 percent chance of being exceeded. In addition, because the Flooding Map is based on inputs that extend out only to about 72 hours, it best represents the flooding potential in those locations within the watch and warning areas in Florida and Georgia. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 26.2N 78.6W 120 KT 140 MPH 12H 07/0600Z 27.6N 79.9W 115 KT 130 MPH 24H 07/1800Z 29.6N 81.0W 110 KT 125 MPH 36H 08/0600Z 31.2N 81.0W 95 KT 110 MPH 48H 08/1800Z 32.1N 80.0W 80 KT 90 MPH 72H 09/1800Z 31.5N 76.5W 60 KT 70 MPH 96H 10/1800Z 29.0N 76.5W 50 KT 60 MPH 120H 11/1800Z 27.5N 77.5W 40 KT 45 MPH $$ Forecaster Avila
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