0836 EDT 24 MAY
We are rapidly approaching the first big weekend of the summer months that being a long memorial day holiday weekend. Like so many things that are important and significant in this country the holiday of Memorial Day was founded the cause of the trauma of the civil war…. As was baseball the Red Cross and Rapid mass movement of armies by railroad.
The pattern going into this week will feature a strong ridge/ dome over the Midwest which will bring about several warm/ hot days for that portion of the nation. However the warmth will not really get into the Middle Atlantic states this week as the ridge is actually retrograde– moving WEST towards the Plains and not towards the East coast.
Of some concern is the development of a low pressure area in the southwest Atlantic which has been showing up on the various global weather models for the last several days. There’s been some talk from private weather services– such as Joe Bastardi up in accu weather land — at this system could become a significant tropical feature but that in fact it really is fantasy and not likely to happen.
There is a small chance this feature could become a subtropical low but even when you are always dealing with the the “extreme” scenario that JB loves to do… Reality has to be a factor. In this case the reality has to do with amazingly cold water which continues to exist over the southwest Atlantic Ocean. This large pool of cold water in the southwest Atlantic Ocean can be seen here.
If you think that this system has a chance to develop with of SSTA that are running anywhere from 1-3° below normal in the southwest Atlantic in late May… You probably need to slow down and rethink that.
Assuming this sort of sub tropical Low does in fact stay off the middle Atlantic Coast this weekend the long Holiday weekend should be OK for the Middle Atlantic region. There will be a weak cold front moving through PA NH MD DE VA traveling from north to south that will bring a few passing showers to the area Friday afternoon and evening. Parenthetically it is THIS cold front on Friday that will ensure the Low over the southwest Atlantic Ocean will be driven out to sea.
The rest of the holiday weekend looks to be pretty decent with warm temperatures but no serious heat and no significant rain threats on either Saturday Sunday or Monday. In summary at this point looks to be ideal.
The retrogression of the ridge will continue as we move into early June 2010 and will eventually reach the West coast. This would generally support some sort of trough position being located over some portion of the eastern Conus. This is strongly indicated by the European ensemble mean position…. Which shows are significant positive height anomaly over central and Southern California and other one over Eastern Canada.
The 0z GFS ensemble mean is mcuh more scattered and all over the Place. Some other individual members have a pretty significant trough over the Midwest and the northeast… while other members show a flat wide ridge over CA and the sw states and a strong Pacific jet coming into the Pacific NW and sw Canada. The jet then spreads as it moves into the Plains and Midwest—- the flow becomes more diffluent aloft– which could set up a fairly strongly pattern for the Midwest and the Middle Atlantic states.