Tuesday, May 1, 2007

Long Range Summer Forecast

The first one I've seen thus far is from meteorologist Larry Cosgrove. His forecast is attention grabbing, especially point number-3:

"The spring of 2007 in North America has been marked by a pattern of vigorous polar westerlies, strong storms, and occasional incidences of impressive high-latitude blocking (as was seen in the record-breaking cold spell in early-mid April). But an overlooked feature has been the persistent presence of a flat heat ridge straddling the Greater Antilles and Caribbean Sea. When this subtropical high has percolated, unseasonably warm and dry conditions have enveloped in the Old South. And due to the very existence of the anticyclone, deep moisture fetches have fed storms advancing into the Great Plains and Midwest.

Since the ridging will expand north and west with the coming of summer, it is speculated that:

1) Hot, dry conditions will begin to win out through the Dixie states beginning in May

2) The eventual peak of the heat ridge will be over and to the west of the lower Appalachian mountains, with occasional northward expansion. Fitting the "Great Smokies" variant of the Bermuda High, this system should establish long periods of heat, drought, and air stagnation across the Corn Belt, Mid-South and Mid-Atlantic regions during the upcoming summer months.

3) When all three heat ridges (Sonoran, Bermudan, Azores) interconnect, deep mean easterlies will increase the threat of tropical cyclone landfalls in the Florida Peninsula and along the Gulf Coast (most likely strike: Texas) in late summer and early autumn.

4) Best potential for lower temperatures and heavy precipitation will be along the northern tier of the U.S, and adjacent Canadian provinces. "

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