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Hurricane GASTON Forecast Discussion Number 27
2016-08-29 10:59:03| National Hurricane Center (Atlantic)
Issued at 500 AM AST MON AUG 29 2016 000 WTNT42 KNHC 290858 TCDAT2 HURRICANE GASTON DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016 500 AM AST MON AUG 29 2016 Gaston remains a well-organized hurricane. However, the satellite appearance is slightly less impressive than 6 hours ago, with the eye becoming less distinct and the deep convection eroding in the northwestern quadrant. While the various satellite intensity estimates have changed little since the last advisory, the initial intensity is lowered to 100 kt based on the degraded appearance. The hurricane is currently drifting northward. A slow motion is likely to continue for the next 12 hours or so as Gaston is caught between two segments of the subtropical ridge. After that time, a mid-latitude trough moving southeastward from eastern Canada is expected to weaken the ridge northwest of Gaston, allowing the cyclone to move generally east-northeastward along the southern edge of the westerlies. The model guidance remains tightly packed through 72 hours, and little change was made to the previous forecast for that time. After 72 hours, the guidance envelope has shifted a little to the north, and the forecast track was likewise nudged to stay near the middle of the guidance envelope. Gaston is expected to remain is a light shear/warm water environment for the first 24 hours. During this time, the intensity forecast calls for slight weakening due to dry air entrainment and the possibility that the slow-moving hurricane will upwell cold water. After 24 hours, Gaston is likely to move over decreasing sea surface temperatures and into increasing shear, which should cause a gradual weakening. The new forecast intensity is an update of the previous forecast. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 30.8N 55.2W 100 KT 115 MPH 12H 29/1800Z 31.1N 55.1W 95 KT 110 MPH 24H 30/0600Z 31.8N 54.2W 95 KT 110 MPH 36H 30/1800Z 32.5N 52.5W 95 KT 110 MPH 48H 31/0600Z 33.5N 50.2W 90 KT 105 MPH 72H 01/0600Z 36.5N 44.0W 85 KT 100 MPH 96H 02/0600Z 38.0N 36.5W 70 KT 80 MPH 120H 03/0600Z 38.5N 30.5W 55 KT 65 MPH $$ Forecaster Beven
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Tropical Depression NINE Forecast Discussion Number 3
2016-08-29 10:57:05| National Hurricane Center (Atlantic)
Issued at 500 AM EDT MON AUG 29 2016 000 WTNT44 KNHC 290856 TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092016 500 AM EDT MON AUG 29 2016 The satellite presentation of the depression is quite ragged this morning, with little deep convection over the southeastern Gulf of Mexico or Straits of Florida. The thunderstorm activity that was located to the east and southeast of the center yesterday afternoon and evening, has propagated southwestward and is now located over Cuba and the extreme northern Caribbean Sea, well south of the center due to moderate to strong northerly shear. Data from a NOAA Hurricane Hunter aircraft have been very helpful in locating the low-level center overnight, and wind reports from the aircraft indicate that the depression still has winds of 25 to 30 kt. The intensity forecast for the depression remains of lower confidence than normal. The strong northerly upper-level winds currently over the system are forecast to decrease today, and the depression should be in a more conducive upper-level environment for a day or two. However, the global models indicate that dry mid-level air will remain near and to the northwest of the system, and that, combined with the current poor organization of the depression, suggests that any intensification should be slow to occur during the next day or so. After 48 hours, the upper-level winds should turn southwestward and become more diffluent over the system due to a mid- to upper-level trough that will be digging southward over the eastern United States. This could result in a little more favorable environment, and the NHC forecast calls for gradual intensification between 72 and 120 hours. The NHC forecast remains on the conservative side, and is between the more aggressive statistical guidance and the global models, which do not significantly deepen the system until it moves into the western Atlantic. The aircraft fixes indicate that the depression is moving generally westward at about 8 kt. The tropical cyclone should move westward to west-northwestward today to the south of a low- to mid-level ridge. The depression should turn northwestward and then northward around the western portion of the ridge on Tuesday. After that time, the aforementioned digging trough should begin to steer the cyclone northeastward at a faster forward speed. Most of the track guidance is in agreement with this scenario, although there are some differences on how fast the system will move northeastward toward the Florida peninsula. The update NHC track is close to a consensus of the global models, and is not very different than the previous NHC advisory. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 23.5N 83.9W 30 KT 35 MPH 12H 29/1800Z 23.7N 85.0W 30 KT 35 MPH 24H 30/0600Z 24.1N 86.3W 35 KT 40 MPH 36H 30/1800Z 24.7N 87.1W 35 KT 40 MPH 48H 31/0600Z 25.4N 87.3W 40 KT 45 MPH 72H 01/0600Z 27.8N 85.3W 45 KT 50 MPH 96H 02/0600Z 30.5N 81.0W 50 KT 60 MPH 120H 03/0600Z 33.0N 74.0W 55 KT 65 MPH $$ Forecaster Brown
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Tropical Depression EIGHT Forecast Discussion Number 4
2016-08-29 10:55:35| National Hurricane Center (Atlantic)
Issued at 500 AM EDT MON AUG 29 2016 000 WTNT43 KNHC 290855 TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082016 500 AM EDT MON AUG 29 2016 There has been little change in the structure of the depression since the last advisory, as it is comprised of a swirl of low-level clouds accompanied by minimal shower activity. Satellite intensity estimates from TAFB and SAB remain 30 kt, so that again is the initial intensity for this advisory. An Air Force Reserve Hurricane Hunter aircraft is currently enroute to investigate the cyclone. The initial motion now is 300/9. For the next 36-48 hours, the depression is expected to move generally northwestward toward a weakness in the subtropical ridge near the North Carolina coast. After that time, a mid-latitude shortwave trough moving through the northeastern United States is forecast to erode the ridge and cause the cyclone to recurve northeastward into the westerlies. The track guidance is in good agreement with this scenario, and no significant changes have been made to the forecast track through 48 hours. After that time, the guidance shows a more eastward motion, and the forecast has been nudged to the right of the previous forecast. The dynamical models still forecast the shear to decrease during the next 48 hours and for the depression to move into a more moist environment. Based on this, the intensity guidance is showing modest strengthening as the system approaches the coast of North Carolina. The intensity forecast also shows some strengthening, but it is on the low side of the guidance envelope due to uncertainty about whether the environment will become as favorable as the models are suggesting, and about whether the cyclone will be able to maintain organized convection. After recurvature, the cyclone is forecast to merge with a cold front and dissipate after 72 hours. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 32.6N 73.0W 30 KT 35 MPH 12H 29/1800Z 33.2N 74.1W 30 KT 35 MPH 24H 30/0600Z 33.8N 75.0W 35 KT 40 MPH 36H 30/1800Z 34.4N 75.3W 35 KT 40 MPH 48H 31/0600Z 35.4N 74.6W 40 KT 45 MPH 72H 01/0600Z 38.0N 70.0W 40 KT 45 MPH 96H 02/0600Z...DISSIPATED $$ Forecaster Beven
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Hurricane LESTER Forecast Discussion Number 19
2016-08-29 10:53:55| National Hurricane Center (East Pacific)
Issued at 200 AM PDT MON AUG 29 2016 000 WTPZ43 KNHC 290853 TCDEP3 HURRICANE LESTER DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016 200 AM PDT MON AUG 29 2016 Lester has made a comeback. A ragged eye that had formed around the time of the last advisory has cleared out and warmed significantly. The hurricane's central dense overcast has also expanded and become more axisymmetric while the cyclone has shed its outer bands. Overall, the characteristics exhibited by Lester are those that typify annular hurricanes. The Dvorak T-number from TAFB increased to T5.5/102 kt at 0600 UTC, with the latest UW-CIMSS ADT values around T5.4/100 kt. Given these data, the initial intensity estimate is raised to 100 kt, making Lester the fourth major hurricane of the 2016 eastern North Pacific hurricane season. The initial motion estimate is 270/13. A strong subtropical ridge north of Lester should continue to steer the hurricane nearly due west for the next 3 days. After that time, a probable binary interaction with Madeline should result in a west-northwestward shift in the cyclone's heading as it approaches the Hawaiian Islands. Except for the UKMET and HWRF models, the guidance is relatively tightly clustered through 5 days. The NHC track forecast is nearly identical to the previous one and is closest to a blend of the GFS and ECMWF solutions. In general, Lester should be embedded in a light easterly shear environment during the next several days while it moves over nearly constant sea surface temperatures between 26-27 deg C. These conditions suggest that Lester could maintain its current annular characteristics for some time, even though the large-scale environment is only marginally conducive for it to do so. Lester's current intensification phase has caused the NHC intensity forecast to be increased quite a bit over the previous one. It is also above nearly all of the guidance throughout the period, especially in the short term, given the tendency of forecasts for annular hurricanes to overestimate their future filling rate. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 18.0N 127.8W 100 KT 115 MPH 12H 29/1800Z 18.0N 129.9W 105 KT 120 MPH 24H 30/0600Z 18.1N 132.4W 100 KT 115 MPH 36H 30/1800Z 18.1N 134.9W 95 KT 110 MPH 48H 31/0600Z 18.1N 137.2W 90 KT 105 MPH 72H 01/0600Z 18.2N 141.9W 85 KT 100 MPH 96H 02/0600Z 18.7N 146.5W 80 KT 90 MPH 120H 03/0600Z 20.2N 151.4W 80 KT 90 MPH $$ Forecaster Kimberlain
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Tropical Depression EIGHT Forecast Discussion Number 3
2016-08-29 04:55:03| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT SUN AUG 28 2016 000 WTNT43 KNHC 290254 TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082016 1100 PM EDT SUN AUG 28 2016 Satellite imagery shows that Tropical Depression Eight is currently comprised of a swirl of low-level clouds accompanied by minimal shower activity. This structure is due to the impacts of 20-25 kt of southeasterly vertical wind shear and abundant mid- to upper-level dry air seen in water vapor imagery. Satellite intensity estimates from TAFB and SAB remain 30 kt, so that is the initial intensity for this advisory. The initial motion is 285/9. For the next 48 hours, the depression is expected to move west-northwestward to northwestward toward a weakness in the subtropical ridge near the North Carolina coast. After that time, a mid-latitude shortwave trough moving through the northeastern United States is forecast to erode the ridge and cause the cyclone to recurve northeastward into the westerlies. The track guidance is in good agreement with this scenario, and the new track forecast lies near the consensus models through 48 hours. The dynamical models forecast the shear to decrease during the next 48 hours and for the depression to move into a more moist environment. Based on this, the intensity guidance is showing strengthening as the system approaches the coast of North Carolina. The intensity forecast also shows some strengthening, but it is on the low side of the guidance envelope due to uncertainty about whether the environment will become as favorable as the models are suggesting. After recurvature, the cyclone is forecast to merge with a cold front and dissipate after 72 hours. The 48 hour position is about 35 n mi from Cape Hatteras. This, combined with the various uncertainties in the forecast, requires a tropical storm watch for portions of the North Carolina coast at this time. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 32.2N 72.1W 30 KT 35 MPH 12H 29/1200Z 32.8N 73.4W 30 KT 35 MPH 24H 30/0000Z 33.5N 74.6W 35 KT 40 MPH 36H 30/1200Z 34.1N 75.3W 35 KT 40 MPH 48H 31/0000Z 34.9N 75.1W 40 KT 45 MPH 72H 01/0000Z 37.6N 71.5W 40 KT 45 MPH 96H 02/0000Z...DISSIPATED $$ Forecaster Beven
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