Forecast Philosophy Unchanged

Tropical Storm Danny continues to be hindered by strong southwest shear. For that reason, Danny remains assymetrical with most convection northeast of the exposed circulation. Furthermore, additional center relocations are expected. One relocation already transpired overnight. The National Hurricane Center had to reposition their coordinates 80-90 nautical miles to the north-northeast between the 11PM and 5AM advisories.

The following is a summary as to how this atmospheric process works: Organized convection is essentially a large mass if rising air evacuating from the surface. This causes surface low pressure to form. Air from surrounding areas begins to fill the void left at the surface, hence the formation of a new circulation.

Afternoon visible imagery for a 2nd day in a row shows the beginning stages of center relocation to the northeast. Any additional repositioning to the northeast will further diminish the direct landfall threat to the USA. Forecast guidance has a better handle on the steering mechanisms than the exact position of the tropical cyclone, meaning that subtle changes in storm location will most alter the forecast path from this point onward. There's still an even number of models that take Danny into the Mid-Atlantic States and New England as there are models that recurve Danny into Nova Scotia. The expectation of more center relocations continues to make Nova Scotia landfall the more likely solution.

The intensity forecast guidance that strengthens Danny into a hurricane are still believed to be suspect. Water vapor imagery shows multiple upper lows in the western Atlantic and southeast US. The presence of these features do not bode well for that much strengthening. Conditions may become somewhat favorable for slow development into a modest 55-65mph storm once between 35N and Nova Scotia. Danny will also be acquiring extratropical characteristics by this time. It should be noted, however, that the official forecast still calls for Danny to become a Category 1 hurricane.

If the center of Danny remains just east of the US (current thinking), then effects in the Mid-Atlantic and New England would be minimal. Keep in mind that the strongest winds and rain should be confined to the eastern semicircle of the storm (offshore).

Elsewhere, the NHC has given a tropical wave in the central Atlantic a 30-50% chance of development within 48 hours. Some slow development is possible, but only one model is overly agressive at this time. The wave is still at least a week away from any landmasses.