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Hurricane Lorenzo Forecast Discussion Number 34
2019-09-30 22:32:32| National Hurricane Center (Atlantic)
Issued at 500 PM AST Mon Sep 30 2019 000 WTNT43 KNHC 302032 TCDAT3 Hurricane Lorenzo Discussion Number 34 NWS National Hurricane Center Miami FL AL132019 500 PM AST Mon Sep 30 2019 The wind field of Lorenzo continues to expand, with a trio of scatterometer overpasses showing that tropical-storm-force winds now extend up to 270 n mi from the center, while hurricane-force winds can be found up to 90 n mi from the center. A cloud-covered eye has been apparent throughout the day and cloud-top temperatures surrounding the eye have remained fairly consistent. The most recent Dvorak CI values from TAFB and SAB suggest Lorenzo is maintaining its strength at 90 kt, which will remain the initial intensity for this advisory. A drifting NOAA buoy near the eyewall of Lorenzo recently reported a pressure of 964.8 mb, supporting the minimum central pressure of 957 mb. Lorenzo continues moving north-northeastward at 13 kt, around the northwestern periphery of a subtropical ridge to its southeast. Over the next couple of days Lorenzo will be accelerated northeastward by increasing southwesterly flow ahead of a mid-latitude trough amplifying across the central Atlantic. This motion should take the core of Lorenzo near the western Azores late Tuesday and early Wednesday. The forecast track confidence remains high through 72 hours. After that time, global models have come into a little better agreement on the future track of Lorenzo, with a turn to the right toward Ireland or the U.K. as a weakening extratropical low. The official forecast track is just a little to the right of the previous one and lies near the consensus aids. The environment surrounding Lorenzo is not expected to change much through tonight, and therefore the intensity should remain fairly steady. On Tuesday, the hurricane should begin gradually weakening as drier air entrains into the circulation and the system moves over progressively cooler waters. By 48 hours, the interaction with the approaching trough, an associated cold front, and very strong southwesterly shear will help transition Lorenzo into an extratropical low. This transition is expected to be complete by 72 hours. The low is then expected to weaken and dissipate shortly after 96 hours. The official forecast was increased through the first 48 hours to reflect a more steady intensity in the near term, and then is blended close to the previous forecast after that time. Key Messages: 1. Lorenzo is expected to bring hurricane and tropical storm force winds to the Azores beginning Tuesday night, and these conditions will continue into Wednesday. Hurricane and Tropical Storm Warnings are now 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. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 30.9N 42.1W 90 KT 105 MPH 12H 01/0600Z 32.8N 40.5W 90 KT 105 MPH 24H 01/1800Z 36.1N 36.7W 85 KT 100 MPH 36H 02/0600Z 40.3N 31.4W 80 KT 90 MPH 48H 02/1800Z 45.9N 25.0W 75 KT 85 MPH 72H 03/1800Z 55.2N 14.8W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 04/1800Z 56.3N 10.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 05/1800Z...DISSIPATED $$ Forecaster Latto
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