EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1200 PM EDT MON MAR 28 2016 VALID 12Z THU MAR 31 2016 - 12Z MON APR 04 2016 ...GUIDANCE AND UNCERTAINTY ASSESSMENT... MODELS AND ENSEMBLES OVERALL OFFER BELOW NORMAL FORECAST SPREAD AND UNCERTAINTY WITH THE FLOW PATTERN EVOLUTION DAYS 3-5 THU-SAT. A GENERAL MODEL COMPOSITE SEEMS REASONABLE FOR THIS PERIOD. FORECAST SPREAD AND RUN TO RUN CONTINUITY ARE NOT QUITE AS GOOD DAYS 6/7 SUN/NEXT MON...BUT PREDICTABILITY SEEMS AT LEAST AVERAGE OVERALL. ACCORDINGLY...THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A BLEND OF THE QUITE COMPATABLE 06 UTC GFS AND 00 UTC ECMWF/UKMET/CANADIAN DAYS 3-5 BEFORE SWITCHING TO THE 06 UTC GEFS MEAN AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS FOR DAYS 6/7. ...FLOW PATTERN AND WEATHER HIGHLIGHTS/THREATS... SIGNIFICANT MID-UPPER LEVEL TROUGHING AND DEEPENED SURFACE LOW/FRONTAL SYSTEM WILL PROGRESS WITH SOME PUNCH ACROSS THE E-CENTRAL US THEN ERN NOAM THU/FRI. A SWEEPING FRONT WITH A WIDESPREAD ENHANCED MOISTURE AND PCPN THREAT IS EXPECTED WITH THIS SYSTEM. THIS INCLUDES SOME MODEST SNOWS POTENTIAL ON THE FAR NRN PERIPHERY OF THE OVERALL PCPN SHIELD. SYSTEM PASSAGE WILL LEAVE A TRAILING FRONT DOWN ACROSS THE GULF OF MEXICO/FL. MID-UPPER LEVEL TROUGHING AND PCPN SHOULD LINGER OVER THE SWRN US/NRN MEXICO THU/FRI IN A SEPARATED SRN STREAM DUG TO THE LEE OF QUITE AMPLIFIED NOAM WEST COAST RIDGING ALOFT. SRN STREAM IMPULSE ENERGY IS SLATED TO EJECT ACROSS THE SRN/SERN US SAT-MON TO FOCUS MOISTURE AND RAINFALL INTO/OVER THE WAVY LEAD FRONT...WITH HEAVIEST RAIN POTENTIAL OVER FL WITH DEEPER MOISTURE POOLING/CONVERGENCE. FARTHER NORTH...AMPLE SECONDARY IMPULSES DIGGING TO THE LEE OF THE AMPLIFIED NOAM WEST COAST RIDGE ALOFT IN THE WAKE OF THE MAIN LEAD SYSTEM SHOULD ALLOW FOR ADDITIONAL COOLING SURGES FROM CANADA INTO THE US...WITH MODEST CLIPPER LOW SPRING SNOW POTENTIAL FOR THE US NRN TIER ACROSS THE UPPER MIDWEST/GREAT LAKES/NORTHEAST. THE 00 UTC ECMWF/ECMWF ENSEMBLE MEAN OFFER MORE RADICAL RUN TO RUN CONTINUITY IN THIS FLOW IN OFFERING A MORE DEVELOPED UPPER MIDWEST/GREAT LAKES SURFACE LOW THAT IS DISCOUNTED DAYS 6/7 IN LUE OF BETTER CLUSTERED GUIDANCE FROM THE OLDER 12 UTC ECMWF AND RECENT GFS/GEFS RUNS. SCHICHTEL