je.st
news
Hurricane OLAF Forecast Discussion Number 16
2015-10-18 22:55:23| National Hurricane Center (East Pacific)
Issued at 200 PM PDT SUN OCT 18 2015 000 WTPZ44 KNHC 182055 TCDEP4 HURRICANE OLAF DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL EP192015 200 PM PDT SUN OCT 18 2015 Olaf hasn't changed much in organization during the past few hours, with satellite imagery still showing a CDO and a large, but broken, convective band in the western and southern semicircles of the cyclone. There appears to be a dry slot working into the western side of the circulation, and the eye has been less distinct in recent microwave imagery than it was earlier. The initial intensity remains 70 kt, a little higher than the latest Dvorak estimates from TAFB, SAB, and the UW-CIMSS ADT. The initial 34- and 50-kt wind radii were adjusted based on a timely 1815Z ASCAT-B overpass. The pause in strengthening could be due to the aforementioned dry air and moderate west-northwesterly to northwesterly shear analyzed over the cyclone by the SHIPS model and UW-CIMSS. Given the shear and an inner-core that may be a little less organized, the new NHC intensity forecast shows a slower rate of strengthening in the first couple of days, and is now closer to the bulk of the intensity guidance. The forecast still shows Olaf becoming a major hurricane in 2-3 days followed by a slow decay as the hurricane moves over somewhat cooler SSTs late in the period. The NHC prediction is close to the SHIPS model through much of the period, but a little above it at peak intensity. Olaf continues to move quickly westward, with a motion now estimated at 280/12. This continues a trend of the hurricane moving faster and to the left of the previous couple of forecasts. While the subtropical ridge to the north weakens is still expected to weaken and lift northward, the track model guidance continues to shift westward given the initial motion and Olaf failing to gain as much latitude as previously thought in the short term. The new NHC track forecast has been adjusted to the left of the previous one, especially at days 3 through 5, and is now close to a blend of the latest ECMWF and GFS forecasts. FORECAST POSITIONS AND MAX WINDS INIT 18/2100Z 9.7N 134.3W 70 KT 80 MPH 12H 19/0600Z 9.9N 135.7W 75 KT 85 MPH 24H 19/1800Z 10.3N 137.5W 85 KT 100 MPH 36H 20/0600Z 11.0N 139.1W 95 KT 110 MPH 48H 20/1800Z 11.8N 140.6W 105 KT 120 MPH 72H 21/1800Z 13.7N 143.4W 105 KT 120 MPH 96H 22/1800Z 16.0N 145.0W 95 KT 110 MPH 120H 23/1800Z 18.0N 145.0W 85 KT 100 MPH $$ Forecaster Brennan
Tags: number
discussion
forecast
hurricane
Category:Transportation and Logistics