nice discussion here... from HPC today 8/10/08

... A DEEP CYCLONE
DIGS SHARPLY FROM SW-CENTRAL CANADA INTO THE US TO THE LEE OF THE
RIDGE...LEADING TO A RETROGRESSION OF AN EARLY WEEK ERN NOAM
TROUGH BACK TO THE E-CENTRAL US. THE COOLING SYSTEM SHOULD ALSO
ACT TO FOCUS A LINGERING PERIOD OF POTENTIALLY LOCALLY HEAVY
RAINFALL AS DEEP GULF MOISTURE FEEDS/POOLS DOWNSTREAM. THE EXTENT
OF MID-UPPER LEVEL TROUGH/CLOSED LOW DIGGING DIFFERS BETWEEN
MODELS AND ENSEMBLES BUT THERE IS A CLEAR RECENT TREND TO FAVOR AN
INCREASINGLY AMPLIFIED SOLUTION. EVEN ACTING CONSERVATIVELY FOR
AUGUST...AN AMPLITUDE THAT DEVELOPS NEAR THE MIDDLE OF THE FULL
RANGE OF MODEL AND ENSEMBLE MEMBER SOLUTIONS WOULD STILL PRODUCE
QUITE A POTENT TROUGH WITH 500 MB HEIGHTS UPWARDS OF 3 STANDARD
DEVIATIONS BELOW NORMAL. THIS WOULD BE SIMILAR TO THE EARLY TO
MID AUGUST 2004 PATTERN. THIS SEEMS CONSISTENT AS PER EXPECTED
STRENGTH OF THE UPSTREAM RIDGE IN ALMOST ALL MODEL AND ENSEMBLE
RUNS. THIS TROUGH COULD EVEN PUMP UP DOWNSTREAM WESTERN ATLANTIC
RIDGING ENOUGH TO ALLOW FOR THE POSSIBILITY OF TROPICAL
DISTURBANCES NEAR THE GREATER ANTILLES/CARIBBEAN SEA. .......