Saturday, August 29, 2009

Big Changes Headed This Way




The coolest air mass we have seen since Summer began will be moving into the Mid-Atlantic on Monday. The high temperature map from today is posted above, and gives a glimpse of what is to come. Highs across the Great Lakes were in the 50s and 60s today, while the desert southwest had temperatures nearing 120 degrees. This large spread in temperatures is due to a meridional (north-south) upper-level flow, indicated by the top graphic (forecast for Sunday night). Hot tempertures are found under the ridge (SW US) and cool temperatures are found under the trough (Great Lakes). The strong trough will dig into the eastern US, bringing highs in the upper 60s and low to mid 70s to central Virginia on Monday and Tuesday.