Tropical Storm Andrea formed yesterday after a new center developed closer to the convective mass on her eastern side. This kind of a center jump was expected behavior for such a system. Recon data confirmed a closed circulation, and Andrea was born. Since then, despite wind shear still affecting the system, organization has improved, likely due to the shear changing from mainly westerly to mainly southerly, allowing a band of thunderstorms to wrap around the northern side of the center. Overnight, a second recon aircraft investigated Andrea, and found a central pressure down to 997mb with 60mph winds. Andrea has thus strengthened more than expected, and is now a moderate tropical storm. Andrea has about 12 hours until landfall in the big bend area of Florida, and some additional strengthening is possible given that her own intensity is modifying the environment to be slightly more favorable than it would have been, by expanding upper outflow on her northern side. Andrea may be a 65-70mph tropical storm at landfall. The structure and low wind shear necessary to become a hurricane do not appear to be present, and Andrea is not expected to become a hurricane. However, strong tropical storm force winds are now expected to accompany the heavy rain along the entire state of Florida east of Panama City and north of Naples. Isolated tornadoes are also possible in the bands on her eastern side. Some tornadoes have already been reported south of Tampa and near Miami.
The track of Andrea may be altered slightly to the west due to her newfound strength. A mid-latitude trough moving into the Mississippi Valley will start accelerating her northeastward tonight over Florida and just inland over Georgia, South Carolina, and North Carolina tomorrow, and close to New England and southeastern Canada on Saturday, though Andrea will be extratropical by that point. Heavy rains will be the main threat beyond Florida, though lighter amounts are expected due to a much faster forward speed. The trough will begin acting baroclinically on Andrea tomorrow, and she should lose her tropical characteristics shortly after moving through the Carolinas. I am in decent agreement with the 8am EDT NHC forecast. I will have a more detailed post tonight after work. Check my facebook page for periodic updates while I’m at work.
8am EDT NHC forecast track and warnings:
Andrea Satellite (click for loop):