EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 136 AM EDT SUN AUG 03 2014 VALID 12Z WED AUG 06 2014 - 12Z SUN AUG 10 2014 TROPICAL STORM BERTHA WAS LOCATED NEAR THE DOMINICAN REPUBLIC AT 19.5N 69.7W AT 03 UTC. THE NATIONAL HURRICANE CENTER TRACKS BERTHA JUST EAST OF THE BAHAMAS...WELL OFF THE ERN US COAST...AND FURTHER OUT TO SEA OVER THE NEXT FEW DAYS INTO MIDWEEK IN RESPONCE TO AMPLE ERN US MID-UPPER LEVEL TROUGHING. THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF NOW A BIT MORE REASONABLY COMPATABLE MID-LARGER SCALE DETERMINISTIC MODEL GUIDANCE FROM THE 12 UTC GFS/ECMWF/CANADIAN/UKMET DAYS 3-5. ADDED TO THIS ONLY A SMALL ENSEMBLE COMPONENT TO ADDITIONALLY SMOOTH LESS PREDICTABLE SMALLER SCALE COMPONENTS. MARGINALLY INCREASED ENSEMBLE INPUT IN THIS BLEND DAYS 6/7 NEXT WEEKEND CONSISTENT WITH INCREASING FORECAST SPREAD. THIS FILLS THE VOID FROM THE UKMET THAT WELL...DOES PROVIDE FORECAST OUTPUT BEYOND FRI. IN THIS ACTIVE PATTERN...THE IMPINGEMENT OF THE TROUGH OFF THE WEST COAST OF CANADA ON THE WESTERN NORTH AMERICA RIDGE WILL SEND MUCH MONSOONAL MOISTURE OFF TO THE NORTH AND EAST THIS PERIOD. THE NORTHERN ROCKIES SHOULD BEAR THE BRUNT OF RAINFALL EVEN WITH SOME ENERGY LINGERING BACK ON THE WRN PERIPHERY OF THE MEAN RIDGE. TO THE EAST OF THE ROCKIES...SHORTWAVE ENERGY IS FORECAST TO CONTINUE SPLITTING INTO A WEAKNESS ALOFT THAT HAS BEEN LOOSELY CENTERED NEAR THE CENTRAL MISSISSIPPI VALLEY...WITH QUITE A BIT OF RAINFALL POSSIBLE OVER A LARGE PORTION OF THE MIDWEST AND VICINITY. ACTIVITY SPILLS FURTHER SEWD AS MOISTURE AND ENERGY INTERACT AND EMANATE FROM A WAVY FRONTAL ZONE SET IN THE WAKE OF COOLING AND LEAD PCPN FOCUSING GRADUAL EJECTION OF AN AMPLIFIED NERN US MID-UPPER LEVEL LOW/TROUGH TOWARD THE CANADIAN MARITIMES. SCHICHTEL