Lorenzo is still at hurricane force in the eastern North Atlantic has now transitioned to an extra-tropical cyclone and has grown in size. The Global Precipitation Measurement mission or GPM core satellite provided a look at the rainfall occurring within this strong system. The Portuguese Institute for the Sea and the Atmosphere has discontinued all warnings for the Azores, and now Ireland and the United Kingdom are on watch for Lorenzo’s approach.
NASA Looks at Lorenzo’s Rainfall, Extra-Tropical Transition
The GPM’s core satellite passed over Lorenzo on Oct. 2 at 4:31 a.m. EDT (0831 UTC). GPM found the heaviest rainfall occurring north of the center, where it was falling at a rate of more than 1 inch (25 mm) per hour. Scattered light rain falling at less than 0.2 inches (less than 5 millimeters) per hour circled the rest of the storm. Forecasters at NOAA’s National Hurricane Center or NHC incorporate the NASA rainfall data into their forecasts.
Satellite data showed that Lorenzo had become extra-tropical. That means that a tropical cyclone has lost its “tropical” characteristics. NHC defines “extra-tropical” as a transition that implies both poleward displacement (meaning it moves toward the north or south pole) of the cyclone and the conversion of the cyclone’s primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones that become extratropical can still retain winds of hurricane or tropical storm force.
Read more at NASA / Goddard Space Flight Center
Image: The GPM’s core satellite passed over Lorenzo on Oct. 2 at 4:31 a.m. EDT (0831 UTC). GPM found the heaviest rainfall occurring north of the center, where it was falling at a rate of more than 1 inch (25 mm) per hour (red). Credit: NASA/JAXA/NRL