je.st
news
Tropical Storm Helene Forecast Discussion Number 32
2018-09-15 10:42:02| National Hurricane Center (Atlantic)
Issued at 500 AM AST Sat Sep 15 2018 247 WTNT43 KNHC 150841 TCDAT3 Tropical Storm Helene Discussion Number 32 NWS National Hurricane Center Miami FL AL082018 500 AM AST Sat Sep 15 2018 Helene appears to be maintaining its strength. Recent microwave images show that the storm has an eye feature, but the vortex is significantly tilted in the vertical due to southwesterly shear. Deep convection is most organized in bands to the north and west of the center. Based on the tropical storm's appearance in microwave images, the initial intensity is again held at 60 kt, near the high end of the satellite intensity estimates. Helene is expected to gradually weaken during the next few days due to the influences of southwesterly shear, drier air, and much cooler SSTs along the forecast track. These conditions should also cause Helene to lose tropical characteristics, and the storm is forecast become extratropical in 24 to 36 hours. The tropical storm is moving north-northeastward at a fairly fast pace, 19 kt. The center of Helene is expected to pass to the west of the Azores by tonight. However, Helene has a fairly large wind field, and tropical-storm-force winds are expected across the western Azores as the storm passes by. A shortwave trough to the northwest of the system is expected to approach Helene by tonight, and that should cause the cyclone to turn northeastward and then speed up in that direction as it heads toward Ireland and the United Kingdom late this weekend and early next week. The models are in fair agreement, and only small changes were made to the previous NHC track forecast. Helene is expected to be a post-tropical cyclone when it approaches Ireland and the United Kingdom in two to three days. Interests in those locations should consult products from their local meteorological service for information about potential impacts from Helene. Local forecasts and warnings for the UK can be found on the website of the UK Met Office at https://www.metoffice.gov.uk/. Local forecasts and warnings for Ireland can be found on the website of Met Eireann at https://www.met.ie/. FORECAST POSITIONS AND MAX WINDS INIT 15/0900Z 37.7N 34.8W 60 KT 70 MPH 12H 15/1800Z 39.7N 32.7W 60 KT 70 MPH 24H 16/0600Z 41.8N 29.2W 55 KT 65 MPH 36H 16/1800Z 44.1N 24.3W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 17/0600Z 46.7N 18.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 18/0600Z 55.8N 5.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 19/0600Z...DISSIPATED $$ Forecaster Cangialosi
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics