The problem with passaging the East Coast in March (and November) is the arrival of the equinoctial gales ... or the change between summer and winter weather patterns, and the 'violence of the gales' between these two 'undulating zones'.
These changes between seasons although regularly occurring cant really be predicted nor forecasted for more than a few days out; nor, the intensity or 'mildness' of the equinoctial changes. Its a 'crap shoot'.
You can 'better your chances' by becoming a technical student of the weather and then make your own personal forecasts. An example of such tech textbooks:
http://www.amazon.com/Mariners-Weather-Handbook-Steve-Dashew/dp/0965802825 ... VERY expensive.
and then using NOAA, etc. weather charting websites to fill in 'your own' blanks to make your own personal forecasts:
NOAA National Weather Service
Ocean Prediction Center - Atlantic
Sailing Weather - Marine Weather Forecasts for Sailors and Adventurers - PassageWeather
For your own predictions of 'equinoctial / jet stream position and changes:
etc. .. 'high altitude' weather - jet streams / storm tracks, etc.
The BEST weather predictions .... When 'lower down' along the SE coast / south of Hatteras, better to contact (monetary subscription) with a pro 'weather router' such as Chris Parker (Marine Weather Center - Bahamas & Caribbean Marine Weather Services
) on Single Sideband HF radio .... 4.045 mHz upper side band starting at ~7:00 AM .... VASTLY better than 'NOAA" which is seemingly VERY conservative in its predictions (probably so because of litigation risk).
NOAA is 'ok', but you'll miss a lot of good sailing if you exclusively use NOAA (and all the websites that are based on NOAA data/forecasts) as your 'weather source', especially during the equinoctial changes during March and November.
You can listen to CarribWx (Mon—Sat) by using a good portable SW radio receiver(w/USB-LSB-AM function) and a good external antenna wire aligned to receive from central FL or 'vertically straight up'. The transmission times and frequencies are on the MarinHF/AMe Weather Center - Bahamas & Caribbean Marine Weather Services
Hint: most boats making passage from the Caribbean to 'back north' at this time ... usually wait until at least the beginning of April through the 2nd week of April when the majority of 'equinoctials' are very far north.