je.st
news
Tropical Storm Kirk Forecast Discussion Number 3
2018-09-23 04:43:57| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Sat Sep 22 2018 605 WTNT42 KNHC 230243 TCDAT2 Tropical Storm Kirk Discussion Number 3 NWS National Hurricane Center Miami FL AL122018 1100 PM AST Sat Sep 22 2018 The overall organization of Kirk has changed little since the previous advisory. The deep convection that was over the western portion of the circulation has continued to race westward ahead of the low-level center while a new burst of convection has developed closer to the center this evening. A couple of ASCAT passes from just prior to 0000 UTC did not reveal any winds as strong as this morning, but given the recent increase in convection near the center the initial intensity is maintained at 35 kt, which could be a little generous. Recent satellite fixes show that Kirk is moving west-northwestward or 285 degrees at 14 kt. A narrow subtropical ridge that is forecast to build westward to the north of Kirk should steer the cyclone quickly westward during the next few days, with forward speeds increasing to around 20-22 kt. After that time, the global models predict that a weakness will develop in the ridge between 50W and 60W which is forecast to cause Kirk to slow down and turn west-northwestward. The updated NHC track forecast is a little north of the previous advisory, primarily due to a slightly more northward initial position as noted in the ASCAT data. Otherwise, the track forecast is similar to the previous advisory and is along the southern edge of the guidance, closest to a blend of the GFS and ECMWF, and the HFIP corrected consensus. Kirk is forecast to traverse warm waters and remain within a low shear environment during the next couple of days. These conditions favor strengthening, however as mentioned in the previous discussion, some dry air lurking just to the north of Kirk could get entrained into the circulation and limit intensification. There is still large spread in the intensity guidance with the statistical guidance showing much more intensification between 24 and 72 h. After 72 hours, increasing westerly shear is expected to cause weakening. The NHC intensity forecast remains near the HCCA and IVCN intensity guidance, and follows the trend of the ECMWF and GFS models that weaken Kirk later in the forecast period. Given the spread in the guidance, the intensity forecast is of low confidence. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 9.0N 26.4W 35 KT 40 MPH 12H 23/1200Z 9.4N 28.9W 40 KT 45 MPH 24H 24/0000Z 9.9N 33.0W 45 KT 50 MPH 36H 24/1200Z 10.1N 37.3W 50 KT 60 MPH 48H 25/0000Z 10.2N 41.8W 50 KT 60 MPH 72H 26/0000Z 10.6N 49.5W 50 KT 60 MPH 96H 27/0000Z 11.8N 55.0W 45 KT 50 MPH 120H 28/0000Z 13.3N 60.0W 40 KT 45 MPH $$ Forecaster Brown
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics