The overall objective of the Fronts and Atlantic Storm Tracks Experiment (FASTEX), conducted in the North Atlantic Ocean during January-February 1997, was to advance the scientific understanding necessary to enable detailed diagnosis and prediction of the life cycles of eastern oceanic storms and their associated cloud and precipitation systems. During FASTEX, four ships were located in the central North Atlantic Ocean to obtain measurements in developing frontal waves likely to impact northwestern Europe. Meteorological measurements on board these ships included 1.5-6 hourly rawinsondes and standard meteorological observations. Additional measurements were available on the NOAA-sponsored, Woods Hole Oceanographic Institute's R/V Knorr. The measurements on board the R/V Knorr included a 915 MHz wind profiler, an S-band vertically pointing Doppler cloud and precipitation radar, a surface flux measurement system, and a wave-height spectra recorder.

The first intensive observation period (IOP1) of FASTEX occurred on January 8-10. During IOP1, one decaying cyclone and three frontal waves were present in the North Atlantic Ocean. Each of the three waves, which were sampled by the mid-oceanic ship array, showed some development, with wave 1 developing into the strongest storm. Wave 2 was also sampled by the research aircraft near the coast of Ireland. The ship data revealed the boundary-layer structure of each wave, such as 15-20 m s-1 surface winds and 30-40 m s-1 low-level jets in the warm sectors of each wave. Surface stresses reached 1 N m-2 and surface latent heat fluxes reached 100-200 W m-2 in the warm sectors. Various aspects of an MM5 simulation were verified with the observations. These aspects included the development of the frontal waves, their tracks, the surface fluxes, and the boundary layer structure. Mesoscale validation of the precipitation and thermodynamic structure in the downwind research aircraft region will also be done. The sensitivity of these mesoscale aspects in the model simulations to the surface flux formulation and the boundary layer scheme will be shown. One surface flux scheme utilizes surface wave characteristics to produce surface fluxes in excellent agreement with those observed during FASTEX.