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Hurricane Lorenzo Forecast Discussion Number 36
2019-10-01 10:41:42| National Hurricane Center (Atlantic)
Issued at 500 AM AST Tue Oct 01 2019 000 WTNT43 KNHC 010841 TCDAT3 Hurricane Lorenzo Discussion Number 36 NWS National Hurricane Center Miami FL AL132019 500 AM AST Tue Oct 01 2019 Lorenzo's eye has become less distinct on satellite images over the past several hours, but the system remains very well organized with tightly curved convective bands. The upper-level outflow remains quite well-defined. The advisory intensity, 85 kt, is a blend of subjective Dvorak estimates from TAFB and SAB along with ADT values from UW-CIMSS. Sea-surface temperatures beneath the cyclone are likely to fall below 20 deg C within 36 hours, along with a large increase in vertical shear. Since Lorenzo has such a large circulation, it will probably be slow to weaken, however. In 48 hours or less, the global models show the system merging with a frontal zone, indicating the transition to an extratropical cyclone. The NHC intensity forecast is on the high side of the numerical guidance but still weakens the cyclone below hurricane strength when it nears Ireland and Great Britain. By 96 hours, the cyclone should dissipate over Europe. The hurricane continues to accelerate, and is now moving northeastward near 19 kt. Continued acceleration on the southeast and east side of a large mid-tropospheric trough over the central north Atlantic should occur over the next day or two. In 72 hours or so, the cyclone is expected to turn east-northeastward while moving in the westerly flow ahead of the north Atlantic trough. There is still significant track model divergence around this time, and the official 3-day forecast is somewhat southeast of the model consensus. This leans toward the latest ECMWF solution, which continues to be on the southeast side of the track guidance envelope. Lorenzo is producing huge seas over the north Atlantic. Full information on the High Seas Forecasts can be found at the Ocean Prediction Center under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php. The UK Met Office also has information in High Seas Forecasts issued by under WMO header FQNT21 EGRR and on the web at http://www.metoffice.gov.uk/public/weather/marine-high-seas/ Key Messages: 1. Lorenzo is expected to bring hurricane and tropical storm force winds to the Azores beginning tonight, and these conditions will continue into Wednesday. Hurricane and Tropical Storm Warnings are in effect for the Azores. 2. Large swells generated by Lorenzo will continue to spread across much of the north Atlantic basin during the next few days. These swells will produce life-threatening surf and rip currents, especially across the Azores. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 33.4N 39.7W 85 KT 100 MPH 12H 01/1800Z 35.9N 36.7W 85 KT 100 MPH 24H 02/0600Z 40.2N 31.3W 80 KT 90 MPH 36H 02/1800Z 45.5N 24.5W 75 KT 85 MPH 48H 03/0600Z 51.0N 18.5W 70 KT 80 MPH...POST-TROP/EXTRATROP 72H 04/0600Z 56.5N 8.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 05/0600Z...DISSIPATED $$ Forecaster Pasch
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