je.st
news
Tropical Storm RACHEL Forecast Discussion Number 9
2014-09-26 16:52:40| National Hurricane Center (East Pacific)
Issued at 800 AM PDT FRI SEP 26 2014 000 WTPZ43 KNHC 261452 TCDEP3 TROPICAL STORM RACHEL DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP182014 800 AM PDT FRI SEP 26 2014 The organization of Rachel's cloud pattern has not changed this morning. The center of the cyclone remains on the northeast (upshear) side and outside of a large mass of very cold-topped convection, presumably a result of some northeasterly vertical wind shear. The deep convection continues to regularly burst, a trend that has been observed for a few days now. The initial intensity estimate is held at 45 kt in agreement with the 1200 UTC Dvorak fix from TAFB. Global models show Rachel moving underneath an upper- level ridge axis during the next 24 hours or so, which should result in a relaxation of the persistent shear and allow for some intensification since the storm will still be over warm enough waters. In 2-3 days, Rachel will have moved far enough to the north to experience an increase of southwesterly shear in response to a mid-latitude trough over the western United States. That shear and increasingly unfavorable thermodynamics factors, including somewhat cooler waters, are expected to hasten its weakening beyond 48 hours. The NHC intensity forecast is not much different than the previous one, and still shows remnant low status at the end of the forecast period. Rachel continues on a west-northwesterly track of 295/12. The cyclone is forecast to turn toward the northwest and north- northwest with a significant decrease in forward speed during the next couple of days when it encounters a weakness caused by the earlier-mentioned western United States trough. By 48 hours, there is a rather distinct split in the track guidance, with the GFS-based model solutions carrying the cyclone quickly northward and northeastward while the ECMWF/UKMET suggest a weaker cyclone steered toward the west-northwest and west. The NHC track forecast stays left of but closer to the GFS through 48 hours due to Rachel's forecast intensification and then shows slow motion for the remainder of the forecast period. The 48-120 hour portion of the track forecast is very near the multi-model consensus, TVCE, and it could trend westward in future forecasts if confidence in a weaker cyclone at that time frame increases. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 18.2N 114.4W 45 KT 50 MPH 12H 27/0000Z 19.0N 115.2W 50 KT 60 MPH 24H 27/1200Z 20.0N 116.1W 55 KT 65 MPH 36H 28/0000Z 20.9N 116.8W 60 KT 70 MPH 48H 28/1200Z 21.8N 117.1W 50 KT 60 MPH 72H 29/1200Z 22.8N 117.2W 40 KT 45 MPH 96H 30/1200Z 23.0N 117.2W 30 KT 35 MPH 120H 01/1200Z 22.8N 117.4W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Kimberlain
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||