The Socorro UFO incident of April 24, 1964, is one of the very best UFO cases on record, with an unshakable, credible witness, policeman Lonnie Zamora, and unexplainable physical evidence left behind on the ground (or lack thereof, such as evidence of hoaxers being responsible).
Despite this, various debunkers have tried to argue that Zamora saw some sort of balloon. This will only deal with the impossibility of it being balloon because the historical wind data (shown below) makes it impossible. Zamora's UFO would have had to fly almost directly into stiff winds. (This was reported by primary investigators in 1964, but stupid debunking arguments never seem to die.)
The wind data also confirms Lonnie Zamora's account of the winds at the time (~5:50 p.m. MST): "The wind was blowing hard... Wind was blowing against me, from about the south-southwest or maybe the southwest, 'cause I could tell the way dust [from spinning tires] flew off when I was trying to put the car up that first hill to where I had a view of the ravine and the object down in it."
Zamora also reported the egg-shaped object departing rapidly to the WSW, in the direction of a prominent mine 2 miles away at the base of the western mountains, again meaning that the object would have had to fly almost directly into the wind he reported. Zamora also mentioned three other landmarks for the departure direction, all to he WSW, so there is no ambiguity in the direction of departure that he reported.
This is indeed confirmed by the historical wind data and weather reports that show a low pressure storm system beginning to move through N.M. at the time of the sighting, around 5:50 p.m. MST, bringing winds out of the South to West, with Socorro most likely having winds out of the SSW. Zamora had it exactly correct.
Strong, gusty winds were predicted, kicking up dust at times throughout New Mexico. Gusts of winds in nearby Albuquerque were predicted to be 25-30 mph at noon, picking up to 40 mph or more at night. Average wind speeds in Albuquerque at 5:00 & 6:00 p.m. were around 20 mph (meaning gusts would have been at least 30 mph by weather bureau definition). Similarly in Truth and Consequences, even closer to and south of Socorro, winds at 5:00 & 6:00 p.m. were 23 mph. Stallion Station Army Air Field, at the north end of White Sands Missile Range and only about 20 miles from Socorro, had winds of about 14 mph at the time of the sighting.
Likewise Zamora reported strong gusty winds in Socorro at the time, sometimes kicking up dust. As shown below, Albuquerque was near the center of the LOW pressure storm system moving through, and winds increase as one approaches the center of the LOW. (Nearby Zuni, N.M., WSW of Albuquerque, and closer to the LOW's center, had reported wind gusts of 60 mph.)
Below is a plot of the historical wind direction data (red arrows), derived from the NOAA website (Surface Data, Global Hourly) and wunderground.com (Nov 2010: additional historical data for Roswell and Truth and Consequences, N.M., Aug. 2012; Clayton, Cliff, Farmington, Las Vegas, Raton, Santa Rosa, Silver City, Stallion AAF, Tucumcari, and Zuni N.M.; Flagstaff, AZ, Amarillo, TX, and Pueblo, CO added ). The range of reported wind directions between 5:00 and 7:00 p.m. is plotted at each reporting station. An idealized LOW pressure storm system (circular light blue arrows) has been plotted that closely matches the reported wind directions from widely scattered weather stations. (Note: In some locations, such as Farmington, Roswell, Las Vegas, and Pueblo, more than two directions have been plotted, the result of more than two reporting stations in the area and/or lack of agreement between NOAA and Weather Underground data.)
The Socorro UFO departure course reported by Zamora is shown in dark blue. As can be seen, the UFO would have been flying almost directly into the stiff winds blowing at the time, completely ruling out any sort of balloon.
LOW pressure systems circulate counterclockwise in the Northern hemisphere. The center of the LOW at the time of the sighting would have been north and west of Socorro near the Four Corners area of Utah, Colorado, Arizona and New Mexico. All areas east and south of the LOW center would have winds coming out of the South to West.
General wind direction follows the idealized circular CCW circulation pattern, but in real LOWs, the winds tend to cut somewhat across the idealized pattern and spiral into the center, like water circulating around and spiraling into a drain.
Winds at the time in nearby Albuquerque were out of the South to SSW. But as you go further south, the LOW pressure system circulation brings in more westerly winds, such as seen at Alamogordo, Truth or Consequences, and El Paso. Stallion AAF, 21 miles SE of Zamora, had winds out of the SSW. Therefore winds in Socorro at the time were probably out of the SSW or maybe SW, just like Zamora said. A best-guess SSW wind in Socorro has been plotted as a dotted red arrow, again emphasizing how the UFO (blue arrow) would have had to fly against the wind.