Pat Shingleton: "Overlord and Allison"
As we have endured eight days of daily rain, it doesn't compare to June 7, 2001 and Tropical Storm Allison that weakened to a depression and stalled over eastern Texas. On June 8, the remnants of the storm drifted south, re-forming over the northwestern Gulf of Mexico. The system lingered, spun and reorganized as a tropical cyclone before moving inland over Louisiana on the 11th. That morning, the winds increased to 45 m.p.h., as the center moved across southeastern Louisiana and southeastern Mississippi. On June 14 it became a sub-tropical depression and tracked east-northeast, stalling over eastern North Carolina. For three days it wandered around the mid-Atlantic coast, merged with a cold front and dissipated in Nova Scotia on the 19th. Allison was a tremendous rain machine dumping 36.99 inches on Houston and more than 20 inches in Baton Rouge. It caused $5 billion damage and 41 deaths and became the costliest and deadliest U.S. tropical storm on record. The invasion of Europe on June 6, 1944 was the greatest military operation in history. If the weather was unfavorable for Operation Overlord, it would have postponed the invasion for two weeks until tides were suitable for landing. Weatherwise Magazine reported that in 1944, there were no meteorological observations or the use of computer models. Years ago, predicting the weather over the English Channel was challenging. Weathermen depended on secretive ship and plane reports and from spies on the European mainland. These observations were coded, forwarded to England and tediously plotted to maps by hand. Numerous groups extrapolated the data including: a civilian group in Dunstable, England, The British Meteorological Service, U.S forecasters called “Widewing” and the British Navy. On May 31, 1944, a series of low pressure systems from Nova Scotia to Scotland displayed characteristics of a possible hurricane. The persistent Azores high could deflect the storms however with too much cloud cover, the advance bombers would be useless; too much wind and the landing craft couldn’t function. Dr. J.M. Stagg , Operational Meteorologist, coordinated all forecasts to produce a consensus that met the approval of General Eisenhower who attended the daily weather briefings. Initially, Stagg was not optimistic about the invasion and encouraged a postponement to the Supreme Commander on June 4. On June 5, he predicted that “tolerable” weather was expected on the Normandy Coast for the landing on June 6.