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Tropical Storm NICOLE Forecast Discussion Number 8
2016-10-06 10:41:46| National Hurricane Center (Atlantic)
Issued at 500 AM AST THU OCT 06 2016 000 WTNT45 KNHC 060841 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 AM AST THU OCT 06 2016 Nicole is maintaining its intensity. The cloud pattern has generally changed little since the previous advisory, and it consists of a central dense overcast feature with some curved bands to the east of the center. Earlier microwave data did show a mid-level eye, but this feature is not apparent in geostationary satellite images. The Dvorak classifications from TAFB and SAB remain 4.0/65 kt and 3.5/55 kt, respectively, and therefore, the initial wind speed is held at 60 kt. Although not explicitly forecast, Nicole could reach hurricane strength today before it moves into an area of stronger shear on Friday. The expected increase in shear and a drier air mass should lead to a slow weakening trend beginning in about 24 hours. The NHC intensity forecast is an update of the previous one and is in line with the bulk of the guidance. Nicole is still moving northwestward at 8 kt on the southwest side of a mid-level ridge. A trough currently off the coast of New England is expected to move southeastward and erode the ridge. This pattern change will likely leave Nicole in weak steering currents beginning in about 24 hours. As a result, the storm is expected to move slowly and erratically throughout much of the forecast period. The guidance is very divergent and shows solutions in nearly every direction. The NHC official track forecast is a little to the west of the previous one, trending toward the latest consensus aids. Given the large model spread, the NHC track forecast is of low confidence. The 34- and 50-kt wind radii were modified based on an ASCAT pass around 0100 UTC. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 26.5N 64.7W 60 KT 70 MPH 12H 06/1800Z 27.3N 65.2W 60 KT 70 MPH 24H 07/0600Z 27.8N 65.3W 55 KT 65 MPH 36H 07/1800Z 27.8N 65.1W 55 KT 65 MPH 48H 08/0600Z 27.2N 64.7W 55 KT 65 MPH 72H 09/0600Z 26.7N 65.2W 50 KT 60 MPH 96H 10/0600Z 27.5N 66.0W 45 KT 50 MPH 120H 11/0600Z 29.5N 66.5W 35 KT 40 MPH $$ Forecaster Cangialosi
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Hurricane MATTHEW Forecast Discussion Number 32
2016-10-06 04:54:15| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT WED OCT 05 2016 000 WTNT44 KNHC 060254 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 32 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 PM EDT WED OCT 05 2016 Data from Air Force Reserve and NOAA Hurricane Hunter aircraft showed lower winds in Matthew than seen during the previous mission, with peak 700-mb flight-level winds of 103 kt and estimates near 95 kt from the SFMR instrument. Based on these, the initial intensity is reduced to 100 kt. However, satellite imagery indicates that the hurricane is becoming better organized, with the eye trying to re-appear and cooling cloud tops near the center. In addition, the eye has contracted to 15 n mi wide and the central pressure has fallen to 961 mb. This suggests that the winds are about to increase. The initial motion is 320/9. There is little change to the synoptic reasoning or the forecast track through 48 hours. Matthew is expected to move around the western side of the subtropical ridge, which should move slowly eastward during the next couple of days. This evolution should steer Matthew generally northwestward for the next 24 hours or so, followed by a turn toward the north-northwest. This forecast track takes the center near Andros Island and New Providence in about 12 hours, and then very near the eastern coast of the the Florida peninsula. This part of the forecast track is west of the various consensus models, but it lies near the GFS, ECMWF, and ECMWF ensemble mean. From 48-72 hours, the cyclone is expected to recurve northeastward along the southern edge of the mid-latitude westerlies. After 72 hours, the track guidance become very divergent, with solutions ranging from a continued eastward motion out to sea to a turn back to the southwest. The new forecast track shows a slow southeastward motion during this time in best agreement with the ECMWF. As mentioned above, Matthew is getting better organized, and during the next 36 hours or so it should be moving through an area of light vertical wind shear. This should allow strengthening, and the new intensity forecast calls for the system to reach an intensity near 115 kt in about 36 hours. This is near the upper end of the intensity guidance. After 36 hours, proximity to land and increasing shear should cause weakening, and the cyclone is now expected to be down to tropical storm strength by 120 hours. Overall, the intensity forecast is in best agrement with the SHIPS model. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the Bahamas. Please consult statements from the meteorological service and other government officials in that country. 2. 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. For example, 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. However, a small deviation to the right could keep the hurricane- force winds offshore. Similarly large variations in impacts are possible in the hurricane watch area in northern Florida and Georgia. 3. Tropical storm or hurricane conditions could affect South Carolina and North Carolina later this week or this weekend, even if the center of Matthew remains offshore. It is too soon to determine what, if any, land areas might be directly affected by Matthew next week. At a minimum, dangerous beach and boating conditions are likely along much of the U.S. east coast during the next several days. 4. 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 06/0300Z 23.4N 76.4W 100 KT 115 MPH 12H 06/1200Z 24.6N 77.6W 105 KT 120 MPH 24H 07/0000Z 26.4N 79.2W 115 KT 130 MPH 36H 07/1200Z 28.2N 80.4W 115 KT 130 MPH 48H 08/0000Z 30.1N 81.0W 110 KT 125 MPH 72H 09/0000Z 32.5N 78.5W 90 KT 105 MPH 96H 10/0000Z 32.0N 75.5W 70 KT 80 MPH 120H 11/0000Z 30.5N 73.5W 55 KT 65 MPH $$ Forecaster Beven
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Tropical Storm NICOLE Forecast Discussion Number 7
2016-10-06 04:42:17| National Hurricane Center (Atlantic)
Issued at 1100 PM AST WED OCT 05 2016 000 WTNT45 KNHC 060241 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST WED OCT 05 2016 Nicole has continued to become better organized during the past several hours with a warm spot appearing on the night visible images. The latest microwave data also show that the storm has maintained a mid-level eye, although the eye still isn't very well- defined in the low-level channels. Subjective Dvorak estimates range from 55 to 65 kt, so the initial intensity is raised to 60 kt. The storm is starting to take on a more asymetric appearance, a sign that the long-awaited shear might finally be starting to impact the cyclone. Still, the shear is not forecast to increase much over the next day or so, and Nicole has the opportunity to strengthen into a hurricane during that time, although not explicitly forecast below. Vertical wind shear should become rather strong by the end of the forecast period, and Nicole's winds should gradually decrease by early next week. It is a little puzzling that, with such strong shear in all of the global models, a lot of guidance don't show much weakening. Given the likelihood of such an unfavorable environment, the latest official forecast is very similar to the previous one, on the low side of the guidance closest to the LGEM model. The initial motion has turned to the right, now 320/8. Most of the guidance move the system to the north-northwest or north at a decreasing forward speed over the next 36 hours as a ridge collapses to the north of Nicole. After that time, northerly flow related to a trough over the central Atlantic is forecast to steer Nicole slowly southward for a couple of days. Up to about 72 hours, the model guidance is in reasonable agreement on this solution. Thereafter, the model spread becomes increasingly large very quickly, with a massive 1000 mile spread between the HWRF and the ECMWF models by day 5. This appears to be related to Nicole's possible interaction with Matthew and/or the southern portion of the trough, resulting in tracks primarily toward the southwest, west, or northeast. The latest long-range NHC forecast is very close to a blend of the GFS, UKMET and ECMWF ensemble means, with more weight on the ECMWF solution. This forecast shows a slow northward motion by the end of the period, ending up pretty close to the previous NHC prediction. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 26.0N 64.1W 60 KT 70 MPH 12H 06/1200Z 26.9N 64.8W 60 KT 70 MPH 24H 07/0000Z 27.7N 65.3W 60 KT 70 MPH 36H 07/1200Z 27.8N 65.2W 55 KT 65 MPH 48H 08/0000Z 27.5N 64.5W 55 KT 65 MPH 72H 09/0000Z 26.5N 64.5W 55 KT 65 MPH 96H 10/0000Z 27.5N 65.5W 45 KT 50 MPH 120H 11/0000Z 29.0N 65.5W 35 KT 40 MPH $$ Forecaster Blake
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Hurricane MATTHEW Forecast Discussion Number 31
2016-10-05 22:40:22| National Hurricane Center (Atlantic)
Issued at 500 PM EDT WED OCT 05 2016 000 WTNT44 KNHC 052040 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 31 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 PM EDT WED OCT 05 2016 Data from an Air Force Hurricane Hunter plane a couple of hours ago indicated that the structure of Matthew had not changed very much, and the initial intensity remains at 105 kt. Another Hurricane Hunter plane will be in the eye soon. The environment continues to be favorable for Matthew to restrengthen while it approaches the the east coast of Florida during the next day or so. After that time, the shear is forecast to increase significantly, resulting in gradual weakening of the hurricane. Satellite images indicate that Matthew is moving toward the northwest or 325 degrees at about 10 kt. The subtropical ridge over the western Atlantic is still strong, and the flow pattern around this ridge should continue to steer the hurricane toward the northwest during the next day or two with no significant change in forward speed. After that time, the ridge will shift eastward, allowing Matthew to move northward very near or over the north Florida east coast, and then near or to the east of the Georgia and South Carolina coasts. By the end of the forecast period, models diverge considerably, with the GFS moving the cyclone southwestward toward land, and the ECMWF keeping Matthew over the Atlantic a good distance from the coast. The NHC forecast keeps Matthew over water in the middle of these two model solutions. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the Bahamas. Please consult statements from the meteorological service and other government officials in that country. 2. 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. For example, 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. However, a small deviation to the right could keep the hurricane- force winds offshore. Similarly large variations in impacts are possible in the hurricane watch area in northern Florida and Georgia. 3. Tropical storm or hurricane conditions could affect South Carolina and North Carolina later this week or this weekend, even if the center of Matthew remains offshore. It is too soon to determine what, if any, land areas might be directly affected by Matthew next week. At a minimum, dangerous beach and boating conditions are likely along much of the U.S. east coast during the next several days. 4. 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 05/2100Z 22.5N 75.7W 105 KT 120 MPH 12H 06/0600Z 24.0N 76.9W 110 KT 125 MPH 24H 06/1800Z 25.6N 78.5W 115 KT 130 MPH 36H 07/0600Z 27.2N 79.8W 115 KT 130 MPH 48H 07/1800Z 29.0N 80.8W 115 KT 130 MPH 72H 08/1800Z 32.0N 79.5W 90 KT 105 MPH 96H 09/1800Z 32.6N 76.4W 80 KT 90 MPH 120H 10/1800Z 30.0N 74.0W 65 KT 75 MPH $$ Forecaster Avila
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Tropical Storm NICOLE Forecast Discussion Number 6
2016-10-05 22:31:51| National Hurricane Center (Atlantic)
Issued at 500 PM AST WED OCT 05 2016 000 WTNT45 KNHC 052031 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST WED OCT 05 2016 A 1846 UTC SSMI microwave pass showed that Nicole has a well-defined mid-level eye with the deepest convection to the southeast of the center. Nicole's visible satellite presentation has also improved, and there has been a recent burst of convection right over the center. Dvorak intensity estimates are now T3.0 from SAB and T3.5 from TAFB, so the initial intensity is raised to 50 kt. It's often difficult to estimate the strength of small cyclones like Nicole based on satellite alone, and it's possible that the intensity could be higher. As discussed this morning, Nicole is located beneath an upper-level shear axis, so the vertical shear directly over the cyclone is actually not that high. Since Nicole could stay in this type of environment for another 12-24 hours, and due to the cyclone's small size, the maximum winds could increase in the short term. The new NHC intensity forecast is higher than the previous forecast during the first 24 hours, and it is above all of the guidance during that period. In fact, it would not be surprising if Nicole was to become a hurricane some time soon, especially since it already has a eye in microwave imagery. After 24 hours, a larger area of strong upper-level winds should overspread Nicole, and the maximum winds should therefore decrease through the end of the forecast period. The initial motion remains 300/7 kt. Nicole's forward motion is expected to slow down to a crawl by 36 hours, and after that time, there is considerable spread in the guidance. For example, by day 5, the ECMWF pulls Nicole well northward, absorbed by Matthew and a nearby frontal zone, while the UKMET, HWRF, and GFDN models push Nicole southward or southwestward. Given this uncertainty, the NHC track forecast continues to show a slow meandering motion on days 2-5. FORECAST POSITIONS AND MAX WINDS INIT 05/2100Z 25.3N 63.5W 50 KT 60 MPH 12H 06/0600Z 26.3N 64.5W 60 KT 70 MPH 24H 06/1800Z 27.4N 65.2W 60 KT 70 MPH 36H 07/0600Z 27.9N 65.3W 55 KT 65 MPH 48H 07/1800Z 27.7N 64.8W 55 KT 65 MPH 72H 08/1800Z 27.0N 64.0W 55 KT 65 MPH 96H 09/1800Z 27.5N 65.0W 45 KT 50 MPH 120H 10/1800Z 29.5N 65.0W 35 KT 40 MPH $$ Forecaster Berg
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