Home › discussion
 

Keywords :   


Tag: discussion

Tropical Storm Harvey Forecast Discussion Number 35

2017-08-29 04:46:15| National Hurricane Center (Atlantic)

Issued at 1000 PM CDT Mon Aug 28 2017 000 WTNT44 KNHC 290246 TCDAT4 Tropical Storm Harvey Discussion Number 35 NWS National Hurricane Center Miami FL AL092017 1000 PM CDT Mon Aug 28 2017 The center of Harvey has been moving east-southeastward over the extreme western Gulf of Mexico this evening. Although there is no deep convection near the center of Harvey, thunderstorm activity has continued to increase well north of the center, along the immediate northwest Gulf Coast and has spread inland over the Greater Houston area, worsening the catastrophic flooding situation. Another band of heavy rainfall is moving inland over portions of southern and southwestern Louisiana. Widespread rainfall totals of 30 to 36 inches have been observed in southeastern Texas and the Houston Metropolitan Area. Storm totals could reach 50 inches in some locations, which would be historic for the area. A NOAA National Ocean Service observing site near Matagorda Bay has continued to report sustained tropical-storm-force winds this evening, and data from this and other nearby stations still support an initial intensity of 40 kt. Given the current structure of the cyclone and the lack of convection near the center, little change in strength is expected while Harvey moves over the northwestern Gulf of Mexico. After landfall in about 36 hours, gradual weakening should occur as the circulation moves farther inland. Harvey has been moving east-southeastward or 120/3 kt. The storm is forecast to turn northeastward, then north-northeastward over the next couple of days as a ridge to the northwest of the system weakens and Harvey is steered around the western side of a ridge over the eastern Gulf of Mexico. The track guidance has shifted slightly eastward and the new NHC track has been adjusted in that direction. Key Messages: 1. Ongoing catastrophic and life-threatening flooding will continue across southeastern Texas. Additional rainfall accumulations of 10 to 20 inches are expected across the upper Texas coast, with isolated storm totals as high as 50 inches. Please heed the advice of local officials. Do not attempt to travel if you are in a safe place, and do not drive into flooded roadways. Refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard. A summary of rainfall totals compiled by the Weather Prediction Center can be found at: www.wpc.ncep.noaa.gov/discussions/nfdscc1.html 2. The flood threat has spreading farther east into Louisiana. Additional rainfall amounts of 10 to 20 inches are expected in southwestern Louisiana, with rainfall amounts of 5 to 15 inches expected in south-central Louisiana. Rainfall amounts of 5 to 10 inches are expected in southeast Louisiana and coastal Mississippi and Alabama. Please heed the advice of local officials and refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard in these areas. 3. While Tropical Storm Warnings have been extended eastward along the coast of Louisiana and a Storm Surge Watch has been issued, the impacts of winds and storm surge are expected to be secondary compared to that of the rains. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 28.2N 95.3W 40 KT 45 MPH 12H 29/1200Z 28.1N 95.0W 40 KT 45 MPH 24H 30/0000Z 28.5N 94.5W 40 KT 45 MPH 36H 30/1200Z 29.5N 94.0W 40 KT 45 MPH 48H 31/0000Z 30.7N 93.4W 35 KT 40 MPH...INLAND 72H 01/0000Z 33.4N 91.9W 30 KT 35 MPH...INLAND 96H 02/0000Z 35.5N 90.0W 25 KT 30 MPH...INLAND 120H 03/0000Z 38.0N 86.5W 20 KT 25 MPH...POST-TROP/INLAND $$ Forecaster Brown

Tags: number discussion storm tropical

 

Potential Tropical Cyclone Ten Forecast Discussion Number 6

2017-08-29 04:41:40| National Hurricane Center (Atlantic)

Issued at 1100 PM EDT Mon Aug 28 2017 000 WTNT45 KNHC 290241 TCDAT5 Potential Tropical Cyclone Ten Discussion Number 6 NWS National Hurricane Center Miami FL AL102017 1100 PM EDT Mon Aug 28 2017 Although the disturbance continues to produce a fairly large area of deep convection, this activity is far from the estimated center and the circulation remains poorly defined. Surface observations and radar data suggest that the circulation of the system is stretched from north-northeast to south-southwest, and the position used in this advisory is near the estimated minimum pressure location. The initial intensity remains 35 kt based on the earlier aircraft data and a Dvorak classification from TAFB. Since the system does not have a clear center, the initial motion is an uncertain 020/6 kt. A faster northeastward motion is expected to begin overnight or early Tuesday as a mid- to upper-level trough over the Great Lakes moves closer to the system. The NHC forecast track takes the disturbance across the South Carolina and North Carolina coastline overnight and on Tuesday. By late Tuesday, the cyclone is forecast to move offshore and accelerate over the Atlantic in the mid-latitude westerlies. The NHC track forecast lies near the middle of the guidance envelope. Given the poor organization of the disturbance and the strong wind shear environment that it is embedded within, the chances of this disturbance becoming a tropical cyclone appear to be decreasing. Nonetheless, the potential impacts of tropical-storm-force winds and heavy rains across portions of the Carolinas are likely tonight and on Tuesday even if the system does not become a tropical cyclone. The system is expected to become post-tropical in about 24 hours when it interacts with the aforementioned mid- to upper-level trough. Significant strengthening as an extratropical cyclone is forecast for a couple of days due to baroclinic forcing. The track, intensity, and wind radii forecasts from 36 to 120 h are based on guidance provided by NOAA's Ocean Prediction Center. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 32.5N 80.0W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 29/1200Z 34.5N 77.6W 35 KT 40 MPH...INLAND 24H 30/0000Z 36.9N 73.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 36H 30/1200Z 39.0N 69.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 31/0000Z 40.5N 64.0W 70 KT 80 MPH...POST-TROP/EXTRATROP 72H 01/0000Z 43.8N 53.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 02/0000Z 48.5N 39.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 03/0000Z 53.0N 23.0W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Cangialosi

Tags: number discussion potential tropical

 
 

Tropical Storm Harvey Forecast Discussion Number 34

2017-08-28 22:51:41| National Hurricane Center (Atlantic)

Issued at 400 PM CDT Mon Aug 28 2017 000 WTNT44 KNHC 282051 CCA TCDAT4 Tropical Storm Harvey Discussion Number 34...Corrected NWS National Hurricane Center Miami FL AL092017 400 PM CDT Mon Aug 28 2017 Corrected initial intensity in first paragraph Radar and surface data show that the center of Harvey remains near or just off the Texas coast south of Matagorda. The associated convection has increased in intensity and coverage in a cluster extending from just north of the center northeastward into the Houston metropolitan area. Surface observations indicate that the central pressure is around 997 mb, and there are recent reports of sustained tropical-storm-force winds about 50-60 n mi southwest of the center. Based on these, the initial intensity is increased to 40 kt. Very heavy rains and life-threatening flash flooding continue over southeastern Texas and southwestern Louisiana. There have been reports of 2-day rainfall totals of close to 35 inches in the Greater Houston area. With the additional rains that are expected over the next several days, rainfall totals could reach 50 inches in some locations, which would be historic for the area. While Harvey continues to produce widespread heavy rain, the convective structure is not well organized in terms of being a tropical cyclone. In addition, a dry slot is seen in water vapor imagery over the southern and southeastern parts of the circulation, and the intensity guidance is not showing much additional development as Harvey crosses the northwestern Gulf of Mexico. The intensity forecast reflects these issues by showing little change in strength before landfall. Weakening and eventual decay into a remnant low are expected after landfall. The center has drifted erratically eastward since the last advisory, although a longer-term motion is 110/3. Harvey is currently between the subtropical ridge over the Gulf of Mexico and a large deep-layer ridge over the western United States, with a large trough in the westerlies weakening the Gulf ridge just enough to allow an east-southeastward motion. The large-scale models suggest that the westerlies should erode the western ridge to some extent during the forecast period, which should allow Harvey to turn north-northeastward under the greater influence of the Gulf ridge. The track guidance has changed little since the previous advisory except to show a faster motion from 96-120 h. The new forecast track remains close to that of the previous track, except for an increased forward speed by 120 h. Key Messages: 1. Ongoing catastrophic and life-threatening flooding will continue across southeastern Texas. Additional rainfall accumulations of 15 to 25 inches are expected across the upper Texas coast, with isolated storm totals as high as 50 inches. Please heed the advice of local officials. Do not attempt to travel if you are in a safe place, and do not drive into flooded roadways. Refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard. A summary of rainfall totals compiled by the Weather Prediction Center can be found at: www.wpc.ncep.noaa.gov/discussions/nfdscc1.html 2. The flood threat is spreading farther east into Louisiana. Additional rainfall amounts of 15 to 25 inches are expected in southwestern Louisiana, with rainfall amounts of 5 to 15 inches expected in south-central Louisiana and 5 to 10 inches in southeastern Louisiana. Please heed the advice of local officials and refer to products from your local National Weather Service office and the NOAA Weather Prediction Center for more information on the flooding hazard in these areas. 3. While Tropical Storm Warnings have been extended eastward along the coast of Louisiana and a Storm Surge Watch has been issued, the impacts of winds and storm surge are expected to be secondary compared to that of the rains. FORECAST POSITIONS AND MAX WINDS INIT 28/2100Z 28.5N 95.7W 40 KT 45 MPH 12H 29/0600Z 28.4N 95.5W 40 KT 45 MPH 24H 29/1800Z 28.6N 95.0W 40 KT 45 MPH 36H 30/0600Z 29.2N 94.5W 40 KT 45 MPH 48H 30/1800Z 30.3N 94.1W 35 KT 40 MPH...INLAND 72H 31/1800Z 32.5N 93.0W 30 KT 35 MPH...INLAND 96H 01/1800Z 34.5N 91.5W 25 KT 30 MPH...INLAND 120H 02/1800Z 37.0N 89.0W 20 KT 25 MPH...POST-TROP/INLAND $$ Forecaster Beven

Tags: number discussion storm tropical

 

Potential Tropical Cyclone Ten Forecast Discussion Number 5

2017-08-28 22:40:39| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Mon Aug 28 2017 000 WTNT45 KNHC 282040 TCDAT5 Potential Tropical Cyclone Ten Discussion Number 5 NWS National Hurricane Center Miami FL AL102017 500 PM EDT Mon Aug 28 2017 An Air Force Hurricane Hunter plane has been flying through the disturbance and so far the aircraft data depicts a sharp trough with a few spots of tropical-storm-force winds east of the trough axis. The overall cloud pattern has not become any better organized, and most of the weather is located in bands well to the northeast and southeast of the trough. With the shear increasing, the chances for the system to become a tropical storm are diminishing, but if it does occur it should happen within the next 24 hours or so while the system moves near the Outer Banks of North Carolina. Regardless of whether tropical cyclone formation occurs, tropical storm conditions are still expected in the warning area in North Carolina. Beyond 24 hours, the system should acquire extratropical characteristics. However, the exact timing of the transition is uncertain since the cyclone will still be moving over warm waters. In reality, we can not track a center of circulation that does not exist and NHC is following an area of minimum pressure. This makes the initial motion highly uncertain and the best estimate is toward the northeast or 040 degrees at 10 kt. The system is already embedded within the mid-latitude southwesterly flow ahead of a trough, and this pattern will steer the disturbance toward the northeast with a gradual increase in forward speed. FORECAST POSITIONS AND MAX WINDS INIT 28/2100Z 32.2N 79.9W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 29/0600Z 33.4N 78.7W 35 KT 40 MPH...TROPICAL CYCLONE 24H 29/1800Z 35.6N 75.7W 35 KT 40 MPH...TROPICAL CYCLONE 36H 30/0600Z 38.0N 71.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 30/1800Z 40.0N 66.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 31/1800Z 43.0N 56.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 01/1800Z 47.0N 44.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 02/1800Z 51.6N 28.5W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Avila

Tags: number discussion potential tropical

 

Potential Tropical Cyclone Ten Forecast Discussion Number 4

2017-08-28 16:51:38| National Hurricane Center (Atlantic)

Issued at 1100 AM EDT Mon Aug 28 2017 000 WTNT45 KNHC 281451 TCDAT5 Potential Tropical Cyclone Ten Discussion Number 4 NWS National Hurricane Center Miami FL AL102017 1100 AM EDT Mon Aug 28 2017 The disturbance has not developed a well-defined center yet, and it still consists of a sharp trough extending from northern Florida northeastward across the adjacent Atlantic. The area of minimum pressure appears to be located just east of the Georgia coast. Nearby observations suggest that the winds remain about 30 kt. The disturbance is moving over warm waters but the shear is quite strong for the system to develop significantly. On this basis, the NHC forecasts the disturbance to become a tropical depression and a tropical storm during the next 12 hour to 24 hours. Thereafter, the shear will increase considerably, and most likely the system will intensify as an extratropical cyclone. However, the exact timing of the transition is uncertain since the cyclone will be moving over warm waters. It appears that the area of minimum pressure is moving toward the north-northeast at 8 kt, but this is highly uncertain since we do not have a center. This system is already embedded within the mid-latitude southwesterly flow ahead a trough, and this pattern will steer the disturbance toward the northeast with a gradual increase in forward speed. An Air Force reconnaissance plane is schedule to be in the disturbance later today. The track and intensity forecast, primarily during the extratropical stage, is a blend of NHC forecast with the OPC guidance. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 31.4N 80.3W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 29/0000Z 32.4N 79.7W 30 KT 35 MPH...TROPICAL DEPRESSION 24H 29/1200Z 34.5N 77.0W 35 KT 40 MPH...TROPICAL STORM 36H 30/0000Z 36.5N 73.5W 40 KT 45 MPH...TROPICAL STORM 48H 30/1200Z 38.5N 69.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 31/1200Z 42.5N 58.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 01/1200Z 46.0N 48.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 02/1200Z 50.0N 32.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Avila

Tags: number discussion potential tropical

 

Sites : [704] [705] [706] [707] [708] [709] [710] [711] [712] [713] [714] [715] [716] [717] [718] [719] [720] [721] [722] [723] next »