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Tropical Storm Xavier Forecast Discussion Number 3
2018-11-03 09:36:51| National Hurricane Center (East Pacific)
Issued at 300 AM MDT Sat Nov 03 2018 000 WTPZ45 KNHC 030836 TCDEP5 Tropical Storm Xavier Discussion Number 3 NWS National Hurricane Center Miami FL EP252018 300 AM MDT Sat Nov 03 2018 A large burst of deep convection has developed over the northeastern and eastern portions of Xavier's circulation overnight. An earlier GMI microwave overpass indicated that the center was located near the southwestern edge of the convection, but there was evidence of an increase in banding over the northeastern portion of the storm. Dvorak data T-numbers from TAFB and SAB were T2.5 and T3.0, respectively, so the initial intensity has been increased to 40 kt for this advisory. Xavier is expected to remain embedded within an area of moderate to strong southwesterly shear during the next 24 to 36 hours, and these conditions are likely to prevent significant strengthening. Although the statistical guidance shows no additional intensification, the dynamical models deepen the system over the next day or so, and the NHC forecast calls for a slight increase in wind speed today, followed by little change in strength through Sunday. This is in good agreement with the latest HFIP corrected consensus model. By 48 hours the shear is expected to become even stronger, and as a result, gradual weakening should occur thereafter. Xavier is forecast to degenerate into a remnant low by day 4, if not sooner. The aforementioned microwave pass was very helpful in locating the center of Xavier. Based on that data and recent satellite fixes, the initial motion estimate is east-northeastward at about 6 kt. The track forecast reasoning has not changed from the previous advisory. Xavier should turn northeastward, then northward by tonight toward a weakness in the subtropical ridge created by a deep-layer trough over central Mexico. After Xavier weakens, the cyclone should turn toward west-northwestward or westward as it is steered by the low-level flow. Since there is still a fair amount of spread among the track models as to how far north Xavier will move before it weakens and turns westward, the NHC track is close to the various consensus aids at 48 hours and beyond. Most of the track models have trended a little faster after 48 hours, and the official forecast has been adjusted accordingly. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 14.7N 107.7W 40 KT 45 MPH 12H 03/1800Z 15.2N 107.0W 45 KT 50 MPH 24H 04/0600Z 16.0N 106.4W 45 KT 50 MPH 36H 04/1800Z 16.6N 106.3W 45 KT 50 MPH 48H 05/0600Z 17.1N 106.5W 40 KT 45 MPH 72H 06/0600Z 17.5N 107.7W 30 KT 35 MPH 96H 07/0600Z 17.6N 110.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 08/0600Z 18.0N 112.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown
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