TAMDAR Discussion Board

TAMDAR lends support to upper air report

Posted By: Lyle Alexander
Date: 1-December-05 0106Z

On the morning of November 29th, a deep low pressure trough over the Upper Mississippi Valley produced a very tight low level pressure gradient in the Ohio Valley. At Wilmington, OH (ILN), a raob at 12Z reported 104 knots of wind from 200 degrees at 700 millibars. It is rare to have a wind of 100 knots that low and no other RAOB report at that time or at the adjacent 00Z runs were within 15 knots of it. I investigated and found that TAMDAR provided good support for these winds. A cluster of reports in the Detroit and Cleveland area were in the 100 to 110 knot range from 10 to 12 thousand foot range. Without TAMDAR, aircraft reports were rather sparse at this altitude and I could only find 92 knots of wind below 12 thousand feet. Lyle Alexander