EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1143 AM EDT MON MAR 09 2015 VALID 12Z THU MAR 12 2015 - 12Z MON MAR 16 2015 THE WPC MEDIUM-RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A BLEND OF THE 06 UTC GEFS MEAN AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS IN AN EFFORT TO MITIGATE SMALL-MEDIUM SCALE EMBEDDED SYSTEM VARIANCE THAT GROWS RAPIDLY DURING THIS FORECAST PERIOD...ESPECIALLY BUT NOT EXCLUSIVELY OVER THE ERN US. THIS SOLUTION MAINTAINS GOOD WPC CONTINUITY. IN AN ACTIVE SRN STREAM...AN AMPLIFIED LEAD MID-UPPER LEVEL TROUGH EJECTS/SHEARS NEWD FROM MEXICO OVER THE S-CENTRAL TO ERN US THU-SAT AS A KICKER SYSTEM DIGS AND SPREADS MODEST ORGANIZED PCPN OVER THE S-CENTRAL GREAT BASIN/ROCKIES THEN NWRN MEXICO. FRONTAL SYSTEM CONVERGENCE WITH THE LEAD SYSTEM SHOULD PROVE A MUCH MORE EFFICIENT HEAVIER RAIN PRODUCER NEWD FROM THE CENTRAL GULF COAST STATES ACROSS THE SERN/ERN US. ENERGY AND ASSOCIATED INLAND GULF MOISTURE SURGE INTERACTION WITH MORE UNCERTAIN NRN STREAM ENERGY DIGGING INTO THE N-CENTRAL TO NERN US HEADING INTO THIS WEEKEND. THE EXTENT OF ERODING OF AMBIENT SURFACE COLD AIR ACROSS THE MIDWEST AND DAMMED TO THE EAST OF THE APPALACHIANS REMAINS TRICKY IN THIS LATE WINTER/EARLY SPRING CROSSOVER PATTERN. THE DETERMINISTIC MODELS ARE SHOWING OPPOSITE RUN-RUN TRENDS AND EMPHASIS WITHOUT OFFERING A WELL SUPPORTED CHAMPION...ONLY AN ENVELOPE OF SOLUTION SPECIFICS. THE WPC BLEND DEPICTS A COMPOSITE OFFERING FOR NOW BUT MAINTAINS NOT ONLY THE AFOREMENTIONED HEAVIER RAINFALL PATTERN...BUT ALSO SOME POTENTIAL FOR WINTERY PCPN ON THE NRN EDGE OF THE OVERALL PCPN SHIELD INTO THE MIDWEST/GREAT LAKES AND NRN MID-ATLC/NERN US. WELL UPSTREAM...MODELS AND ENSEMBLES ARE SENDING A SIMILAR SIGNAL TO BRING INCREASING AMOUNTS OF TROUGH ENERGY/HEIGHT FALLS THROUGH THE ERN PACIFIC AND ACROSS THE NWRN US BY THE WEEKEND...SPREADING MODERATE TO TERRAIN ENHANCED SWATHS OF PCPN...BUT WITH ONLY ENOUGH COLD AIR FOR HIGH ELEVATION SNOWS. THIS SYSTEM AND LIGHTER PCPN POTENTIAL MAY DIG SEWD ACROSS THE N-CENTRAL US INTO EARLY NEXT WEEK AS A RIDGE BUILDS ALOFT UPSTREAM ACROSS THE WRN US IN RESPONSE TO AMPLE POTENITAL SYSTEM ACTIVITY BACK OVER THE E-CENTRAL PACIFIC. SCHICHTEL