je.st
news
Tropical Storm DARBY Forecast Discussion Number 4
2016-07-12 16:32:45| National Hurricane Center (East Pacific)
Issued at 900 AM MDT TUE JUL 12 2016 000 WTPZ45 KNHC 121432 TCDEP5 TROPICAL STORM DARBY DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016 900 AM MDT TUE JUL 12 2016 Recent microwave data indicate that the depression has a well- defined circulation with the center located to the northeast of the strongest convection. Subjective Dvorak intensity estimates are T2.0 from TAFB and T3.0 from SAB, and the latest ADT estimate is right at the tropical storm threshold. A consensus of these values supports upgrading the depression to a tropical storm, with the initial intensity set at 35 kt. After starting off May and June very quietly, the eastern North Pacific season has already caught up to where it should be climatologically in terms of named storms. Darby appears to have turned westward with an initial motion of 270/9 kt. A subtropical ridge extending westward from northern Mexico is expected to strengthen during the next three days, which will steer Darby westward, or even a little south of due west, during that time. The model fields continue to show differences in the strength of the ridge at the end of the forecast period. The ECMWF maintains a stronger ridge, with Darby possibly continuing a westward motion, while the GFS erodes the ridge and allows Darby to gain some latitude. The track model envelope has again shifted southward on this cycle, and the updated NHC track forecast has been nudged in that direction close to a consensus of the GFS and ECMWF. Darby will be moving over a warm pool of SSTs around 29.5 degrees Celsius during the next 24 hours, and the northeasterly vertical shear affecting the cyclone should abate a bit. Depending on its exact track, Darby could move over the cold wake left behind by Hurricanes Blas and Celia in a couple of days. Some shear could also persist for a few days, therefore only steady strengthening is expected through 72 hours. Colder water should then cause weakening on days 4 and 5. There is still a lot of spread among the intensity models, so for now no significant changes are being made to the previous NHC intensity forecast. This scenario is a little above the intensity consensus during the first three days and then close to the consensus on days 4 and 5. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 16.0N 108.5W 35 KT 40 MPH 12H 13/0000Z 15.9N 110.0W 40 KT 45 MPH 24H 13/1200Z 15.7N 112.3W 50 KT 60 MPH 36H 14/0000Z 15.5N 114.5W 60 KT 70 MPH 48H 14/1200Z 15.4N 116.8W 65 KT 75 MPH 72H 15/1200Z 15.9N 121.1W 75 KT 85 MPH 96H 16/1200Z 16.5N 125.0W 65 KT 75 MPH 120H 17/1200Z 17.5N 128.5W 55 KT 65 MPH $$ Forecaster Berg
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||