Experiments on the parameterization of the flux of sensible heat and moisture from the sea surface into the LFM boundary layer

"It has frequently been noted that LFM forecasts of boundary layer relative humidity are too low at oceanic locations. It is not unusual for a significant number of gridpoints to drop from a relative humidity of seventy percent or higher to a value less than forty percent within the first six hours of the forecast. By twelve hours or more after initial time, a large number of oceanic points may be found to have a boundary layer relative humidity of thirty percent, which is the minimum value allowed by the model at locations over the sea. This characteristic of the LFM is disturbing because it is so unrealistic. Another weakness of the model is its slowness in forecasting the onset of precipitation in the strong southerly flow from the Gulf of Mexico or in the easterly flow from the Atlantic. Even when it does forecast precipitation in these cases, it is frequently deficient in the predicted amount. This characteristic of the model has been thought to be related to the lack of a flux of moisture from the ocean into the boundary layer of the LFM"--Introduction. John E. Newell. "June 1981." "This is an unreviewed manuscript, primarily intended for informal exchange of information among NMC staff members." System requirements: Adobe Acrobat Reader. Includes bibliographical references (page 9). 1981 NWS (National Weather Service) NCEP (National Centers for Environmental Prediction) Library Public Domain 2285