Home › discussion
 

Keywords :   


Tag: discussion

Tropical Storm HILARY Forecast Discussion Number 8

2017-07-23 10:49:42| National Hurricane Center (East Pacific)

Issued at 400 AM CDT Sun Jul 23 2017 000 WTPZ44 KNHC 230849 TCDEP4 Tropical Storm Hilary Discussion Number 8 NWS National Hurricane Center Miami FL EP092017 400 AM CDT Sun Jul 23 2017 The cloud pattern of Hilary is gradually becoming better organized, with some convective banding features beginning to develop. The upper-level outflow is well defined over all but the southeastern semicircle of the circulation. Dvorak T-numbers from TAFB and SAB remain at 2.5 so the current intensity is held at 35 kt. This is also consistent with ASCAT data from a few hours ago. The atmospheric and oceanic environment should be quite favorable for intensification during the next few days. The SHIPS guidance indicates that the vertical shear should remain below 10 kt throughout the forecast period, and the global models show a large upper-level anticyclone over Hilary through 4-5 days. Late in the period Hilary is expected to move over cooler SSTs, and this should halt the intensification process. The official intensity forecast shows the system approaching major hurricane status in 72 hours and some of the guidance, including the corrected consensus models, suggest that this could be conservative. Overnight microwave data indicate a bit of a jump to the west-northwest, perhaps as a result of reformation of the center as opposed to large-scale motion. The initial motion estimate is 300/13 kt. A large mid-level anticyclone centered over the southwestern United States or northwestern Mexico should maintain the west-northwestward heading throughout the forecast period. The track model guidance is in agreement on a decrease in forward speed, and the official forecast shows this as well. Later in the period, there is a possibility of some binary interaction with Tropical Storm Irwin currently located some 800 n mi to the west. This, along with a substantial spread in the track models at 4-5 days, adds some uncertainty to the forecast. In any event, the official track forecast is not far from the latest model consensus, and keeps the system well offshore of the coast of Mexico. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 12.5N 101.6W 35 KT 40 MPH 12H 23/1800Z 13.1N 102.8W 45 KT 50 MPH 24H 24/0600Z 13.9N 104.3W 55 KT 65 MPH 36H 24/1800Z 14.7N 105.8W 65 KT 75 MPH 48H 25/0600Z 15.5N 107.3W 80 KT 90 MPH 72H 26/0600Z 17.0N 111.0W 95 KT 110 MPH 96H 27/0600Z 18.0N 115.0W 95 KT 110 MPH 120H 28/0600Z 19.0N 118.5W 85 KT 100 MPH $$ Forecaster Pasch

Tags: number discussion storm tropical

 

Tropical Storm Hilary Forecast Discussion Number 7

2017-07-23 04:53:54| National Hurricane Center (East Pacific)

Issued at 1000 PM CDT Sat Jul 22 2017 000 WTPZ44 KNHC 230253 TCDEP4 Tropical Storm Hilary Discussion Number 7 NWS National Hurricane Center Miami FL EP092017 1000 PM CDT Sat Jul 22 2017 A persistent area of convection has developed near and over the center of the depression since the last advisory. In addition, a recent SSMI/S overpass shows the low- to mid-level convective banding has become better defined. Based on this, the initial intensity is increased to 35 kt, the upper end of the satellite intensity estimates, and the depression is upgraded to Tropical Storm Hilary. Hilary should remain in an environment of light vertical shear and warm sea surface temperatures for the next 4 days, and thus it should at least steadily, if not rapidly, strengthen. After day 4, the cyclone should move over decreasing sea surface temperatures and into stronger shear, and the new intensity forecast shows weakening at that time. The new intensity forecast lies below that of the SHIPS model and the HCCA corrected consensus, and it is possible an upward adjustment of the forecast intensities may be required in later advisories. The initial motion is 300/12. The main steering feature should be a mid-level ridge extending from Mexico westward into the Pacific, and this should steer the cyclone generally west-northwestward through the forecast period. Near the end of the period, there is a possibility of interaction with Tropical Depression Ten-E, although present indications in the large-scale guidance are this should have a minimal impact on Hilary's track. The new forecast track is similar to, but a little north of, the previous track, and it lies near the various consensus models. The new track keeps the core of the cyclone well south of the coast of Mexico. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 11.5N 100.2W 35 KT 40 MPH 12H 23/1200Z 12.1N 101.5W 40 KT 45 MPH 24H 24/0000Z 13.0N 103.2W 45 KT 50 MPH 36H 24/1200Z 13.7N 104.6W 55 KT 65 MPH 48H 25/0000Z 14.4N 106.2W 70 KT 80 MPH 72H 26/0000Z 16.0N 110.0W 90 KT 105 MPH 96H 27/0000Z 17.0N 113.5W 95 KT 110 MPH 120H 28/0000Z 18.5N 116.5W 90 KT 105 MPH $$ Forecaster Beven

Tags: number discussion storm tropical

 
 

Tropical Depression Ten-E Forecast Discussion Number 3

2017-07-23 04:49:10| National Hurricane Center (East Pacific)

Issued at 900 PM MDT Sat Jul 22 2017 000 WTPZ45 KNHC 230249 TCDEP5 Tropical Depression Ten-E Discussion Number 3 NWS National Hurricane Center Miami FL EP102017 900 PM MDT Sat Jul 22 2017 Last-light visible images indicate that the low-level center of Tropical Depression Ten-E remains exposed just to the north of the main convective mass due to the effects of 10-15 kt of northerly vertical wind shear. Satellite intensity estimates are 30 kt from TAFB and SAB, so that will remain the initial intensity. The intensity forecast is low confidence due to a large spread in the guidance and the possibility of interaction with Tropical Storm Hilary to the east late in the forecast period. All guidance agrees that northerly shear produced by a nearby upper-level trough should continue for the next 36 h, and based on this, the forecast is for slow strengthening. The models forecast a somewhat more favorable environment from 36-72 h, but the guidance becomes very divergent on how this will affect the cyclone. By 72 hr, the LGEM forecasts a 35 kt intensity, the HWRF an 85 kt intensity, and several other reliable models in between those extremes. After 72 hr, the cyclone may feel the impact of outflow from Hilary, which would likely stop any strengthening. The new intensity forecast is only slightly changed from the previous forecast, and it lies near the center of a well spread out guidance envelope. The initial motion is 280/7. A ridge between the depression and Tropical Storm Greg to the west is forecast to steer Ten-E to the west or west-southwest over the next several days. Near the end of the forecast period, the track could be affected by interaction with Hilary, although only the GFS shows a major impact before 120 h and thus it is to the southeast of the other models. The new forecast track is little changed from the previous track and uses the premise that the main track impact from the aforementioned interaction will be after 120 h. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 14.6N 114.2W 30 KT 35 MPH 12H 23/1200Z 14.6N 115.1W 35 KT 40 MPH 24H 24/0000Z 14.6N 116.2W 40 KT 45 MPH 36H 24/1200Z 14.7N 117.2W 45 KT 50 MPH 48H 25/0000Z 14.7N 118.2W 55 KT 65 MPH 72H 26/0000Z 14.5N 120.5W 60 KT 70 MPH 96H 27/0000Z 14.0N 123.0W 60 KT 70 MPH 120H 28/0000Z 13.5N 126.0W 55 KT 65 MPH $$ Forecaster Beven

Tags: number discussion tropical depression

 

Tropical Depression Nine-E Forecast Discussion Number 6

2017-07-22 22:44:09| National Hurricane Center (East Pacific)

Issued at 400 PM CDT Sat Jul 22 2017 000 WTPZ44 KNHC 222044 TCDEP4 Tropical Depression Nine-E Discussion Number 6 NWS National Hurricane Center Miami FL EP092017 400 PM CDT Sat Jul 22 2017 Recent ASCAT data confirmed that the depression has not become any better organized and that the low-level center is on the southern edge of the main convection. T-numbers have remain either steady or decrease slightly, so the initial intensity has been kept at 30 kt at this time. Despite the current lack of organization, the cyclone is expected to be in a very favorable environment of low shear and over warm waters. With these conditions, I have no option but to forecast strengthening. This process will probably be slow during the next day or so, but after that time, the cyclone should strengthen at a faster pace and become a hurricane. This follows the latest intensity guidance which suggest that the most rapid increase in the winds should occur beyond 48 hours. The depression appears to be moving toward the west-northwest or 290 degrees at 11 kt. The steering pattern has not changed, and global models continue to forecast a strong ridge extending from Mexico westward across the Pacific. This flow pattern will keep the cyclone on the same general west-northwestward track for the next 5 days, as indicated by the general guidance. This solution is not different from the previous NHC track forecasts which have been keeping the core of the cyclone well south of the coast of Mexico. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 10.5N 99.3W 30 KT 35 MPH 12H 23/0600Z 11.2N 100.7W 30 KT 35 MPH 24H 23/1800Z 12.2N 102.5W 40 KT 45 MPH 36H 24/0600Z 13.0N 104.0W 50 KT 60 MPH 48H 24/1800Z 13.7N 105.5W 65 KT 75 MPH 72H 25/1800Z 15.0N 109.0W 85 KT 100 MPH 96H 26/1800Z 16.5N 113.0W 90 KT 105 MPH 120H 27/1800Z 17.5N 116.0W 95 KT 110 MPH $$ Forecaster Avila

Tags: number discussion tropical depression

 

Tropical Depression Ten-E Forecast Discussion Number 2

2017-07-22 22:39:09| National Hurricane Center (East Pacific)

Issued at 300 PM MDT Sat Jul 22 2017 000 WTPZ45 KNHC 222039 TCDEP5 Tropical Depression Ten-E Discussion Number 2 NWS National Hurricane Center Miami FL EP102017 300 PM MDT Sat Jul 22 2017 Satellite images indicate that the center of the depression remains sheared, with the complex center on the northeast side of the main convective mass. Cirrus cloud blowoff from the band in the northwestward quadrant of the cyclone is pretty clearly moving right into the center, causing the asymmetric appearance. Satellite intensity estimates are unchanged, so the initial wind speed will stay at 30 kt. The upper-level environment is not ideal for strengthening with a trough located north of the cyclone. Most of the models lift the trough northward during the next couple of days, which generally causes lighter shear. However, in a few days, increasing easterly shear from the outflow of TD Nine-E is expected to arrest the strengthening of the cyclone. Model guidance, however, is rather divergent, with the statistical-based tools showing little strengthening, while the regional hurricane models all turn the depression into a significant hurricane in a few days. Given that this forecast also depends on how much Nine-E strengthens and a questionable environment, the regional hurricane models look overdone, so the official forecast will stay on the conservative side of the guidance. The depression is moving toward the west at about 6 kt. A ridge between the depression and TS Greg is forecast to steer Ten-E to the west or west-southwest over the next several days. Guidance is not in great agreement, with the GFS and ECMWF showing very different solutions. The GFS has the strongest ridge, which causes the depression to take a sharper turn to the southwest, while the ECMWF is north of all of the other guidance with a weaker ridge and more of an interaction with TD Nine-E. Despite these significant differences, the model consensus remains close to the previous NHC forecast, so little change is made to the latest NHC track prediction. Given the potential binary track interaction, there is a lot of uncertainty at long range with the track forecast. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 14.4N 113.5W 30 KT 35 MPH 12H 23/0600Z 14.5N 114.5W 35 KT 40 MPH 24H 23/1800Z 14.5N 115.6W 40 KT 45 MPH 36H 24/0600Z 14.5N 116.6W 45 KT 50 MPH 48H 24/1800Z 14.5N 117.7W 55 KT 65 MPH 72H 25/1800Z 14.5N 119.8W 60 KT 70 MPH 96H 26/1800Z 14.0N 122.5W 55 KT 65 MPH 120H 27/1800Z 13.5N 125.0W 50 KT 60 MPH $$ Forecaster Blake

Tags: number discussion tropical depression

 

Sites : [744] [745] [746] [747] [748] [749] [750] [751] [752] [753] [754] [755] [756] [757] [758] [759] [760] [761] [762] [763] next »