VARIATION OF THE LOW LEVEL WINDS DURING THE PASSAGE OF A THUNDERSTORM GUST FRONT.

THREE TIME HISTORIES OF WIND PROFILES IN THUNDERSTORM GUST FRONTS AT CAPE KENNEDY AND THREE AT OKLAHOMA CITY ARE ANALYZED.WIND PROFILES AT MAXIMUM WIND STRENGTH BELOW 100 M FOLLOW LOGARITHMIC LAWS, SO THAT WINDS ABOVE THE SURFACE LAYER CAN BE ESTIMATED FROM SURFACE WINDS ONCE THE ROUGHNESS LENGTH IS KNOWN.A STATISTICAL ANALYSIS OF 81 CASES OF SURFACE WINDS DURING THUNDERSTORMS AT TAMPA REVEALED NO PREDICTOR WITH SKILL TO PREDICT THE TIME OF MAXIMUM GUST.SOME 34PERCENT OF THE VARIANCE OF THE STRENGTH OF THE GUST IS ACCOUNTED FOR BY A STABILITY INDEX AND SURFACE WIND PRIOR TO THE GUST; THE REGRESSION EQUATIONS FOR THESE VARIABLES ARE GIVEN.THE COHERENCE BETWEEN MICROSCALE WIND SPEED VARIATIONS AT THE DIFFERENT LEVELS HAS THE SAME PROPORTIONS AS IN NON-THUNDERSTORM CASES.(A).(MICROFICHE).