je.st
news
Tropical Storm IDA Forecast Discussion Number 23
2015-09-24 04:31:39| National Hurricane Center (Atlantic)
Issued at 1100 PM AST WED SEP 23 2015 000 WTNT45 KNHC 240231 TCDAT5 TROPICAL STORM IDA DISCUSSION NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102015 1100 PM AST WED SEP 23 2015 Ida is not a well-organized tropical storm. The center is on the western side of a small area of deep convection, with a few banding features noted in the southeastern quadrant of the cyclone. The initial intensity remains 35 kt since a recent partial ASCAT pass showed maximum winds of 30-35 kt. The storm continues to experience moderate-to-strong westerly shear. While the shear could relax somewhat over the next couple of days, very dry air is present in the mid- to upper-levels near and to the northwest of the cyclone, which could prevent Ida from fully taking advantage of the more favorable shear conditions for a few days. The latest NHC intensity forecast is close to the previous one and the intensity consensus. At longer range, some of the models are showing a resumption of the stronger shear, with only the GFDL forecasting significant intensification. Overall, the trend has been toward a less favorable environment at day 5, and the NHC intensity forecast is reduced at that time. Ida is moving eastward at about 4 kt while it remains embedded within the base of a mid- to upper-level trough. This trough is expected to lift out tomorrow with a ridge rebuilding over the central Atlantic. This pattern should cause the storm to move to the north by late Thursday, followed by a turn to the northwest on Friday around the ridge. After that time, another mid-latitude trough is expected to affect the cyclone. This feature, however, is not as deep as the last trough, and with the vertical representation of Ida being shallower in the model fields, much of the guidance is only show Ida stalling for a short amount of time rather than turning with the trough. Another ridge builds in by late weekend, which then forces Ida to move west-northwestward and westward by early next week. The guidance has shifted notably westward on this cycle in response to this pattern, and the NHC forecast is shifted that direction at long range, but is still pretty far east of the model consensus due to continuity concerns. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 19.9N 46.0W 35 KT 40 MPH 12H 24/1200Z 20.3N 45.5W 35 KT 40 MPH 24H 25/0000Z 21.0N 45.7W 35 KT 40 MPH 36H 25/1200Z 21.8N 46.2W 35 KT 40 MPH 48H 26/0000Z 22.7N 46.9W 35 KT 40 MPH 72H 27/0000Z 24.2N 48.4W 40 KT 45 MPH 96H 28/0000Z 24.5N 49.0W 45 KT 50 MPH 120H 29/0000Z 24.5N 50.5W 45 KT 50 MPH $$ Forecaster Blake
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics
Latest from this category |
All news |
||||||||||||||||||
|
|||||||||||||||||||