je.st
news
Tropical Storm Nicholas Forecast Discussion Number 3
2021-09-13 04:59:47| National Hurricane Center (Atlantic)
Issued at 1000 PM CDT Sun Sep 12 2021 000 WTNT44 KNHC 130259 TCDAT4 Tropical Storm Nicholas Discussion Number 3 NWS National Hurricane Center Miami FL AL142021 1000 PM CDT Sun Sep 12 2021 Nicholas is not yet a well-organized tropical cyclone, with little evidence of convective banding features on satellite imagery. Observations from the Air Force Hurricane Hunter aircraft indicate that the center is still not very well-defined, and appears to have reformed again, this time farther south. Data from the aircraft indicate that the central pressure has not changed much since earlier today, and the maximum winds remain near 35 kt. This is above the latest Dvorak intensity estimates from TAFB and SAB. Nicholas will be traversing very warm waters during the next day or so, and within a moist, unstable atmosphere. These factors would favor strengthening. However, moderate southwesterly shear associated with an upper-level trough over northern Mexico could be an inhibiting factor for strengthening. In spite of the shear, the GFS model forecasts the system to strengthen while it nears the Texas coast. The official intensity forecast is at the upper end of the current model guidance. Given the uncertainties in the future strength of Nicholas, a Hurricane Watch is in effect for a portion of the Texas coast. The current location of Nicholas is quite uncertain since the aircraft-reported center position is within a broad area of light winds and is well south of most of the deep convection. Although the fixes show little motion this evening, based on the model predictions, it appears likely that the center will shift or re-form significantly northward as early as Monday morning. This is at least partially accounted for in the latest NHC track forecast, but some northward adjustments are possible over night. The storm is expected to move toward a weakness in the subtropical ridge during the next 36 hours or so. The track guidance and the model consensus has shifted eastward somewhat since the earlier advisory package. This has necessitated an eastward shift in the official track, and a northeastward extension of the watches and warnings. Key Messages: 1. Periods of heavy rainfall are expected to impact portions of the Texas and Louisiana coasts through the middle of the week. Significant rainfall amounts are possible, potentially resulting in areas of considerable flash and urban flooding, especially in highly urbanized metropolitan areas. Isolated minor to moderate river flooding is also expected. 2. There is the danger of life-threatening storm surge inundation along the coast of Texas from Port Aransas to San Luis Pass. Residents in these areas should follow any advice given by local officials. 3. Nicholas is forecast to approach the middle Texas coast as a strong tropical storm late Monday and early Tuesday, and could be near hurricane intensity if it moves to the right of the forecast track and remains over water longer. Tropical storm conditions are expected along portions of the middle Texas coast beginning Monday afternoon, with hurricane conditions possible from Port Aransas to Freeport late Monday and Monday night. 4. Tropical storm conditions are expected along portions of the northeastern coast of Mexico and the coast of south Texas beginning Monday morning. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 22.5N 95.5W 35 KT 40 MPH 12H 13/1200Z 24.7N 96.5W 45 KT 50 MPH 24H 14/0000Z 27.0N 96.5W 50 KT 60 MPH 36H 14/1200Z 28.6N 96.1W 55 KT 65 MPH...NEAR THE COAST 48H 15/0000Z 29.9N 95.4W 45 KT 50 MPH...INLAND 60H 15/1200Z 30.4N 94.8W 40 KT 45 MPH...INLAND 72H 16/0000Z 31.0N 94.0W 30 KT 35 MPH...INLAND 96H 17/0000Z 31.7N 92.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 18/0000Z...DISSIPATED $$ Forecaster Pasch
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics