EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 134 AM EDT MON OCT 20 2014 VALID 12Z THU OCT 23 2014 - 12Z MON OCT 27 2014 ...HEAVY RAIN THREAT CONTINUES FOR EXTREME SOUTHERN FLORIDA... RELIED ON THE EUROPEAN CENTRE ENSEMBLE MEAN FOR THIS FORECAST PACKAGE--PRIMARILY BECAUSE OF ITS REASONABLE DEPICTION OF THE RECURVATURE OF THE LOW EMERGING FROM THE NORTHWESTERN CARIBBEAN ACROSS WESTERN CUBA. THIS LOW--WHICH COULD WELL BE TROPICAL IN NATURE--ALONG WITH THE POLAR FRONT LYING ZONALLY TO ITS NORTH ARE KEY FEATURES FOR WHAT IS SHAPING UP TO BE THE MOST SIGNIFICANT SENSIBLE WEATHER THREAT AT THE MEDIUM RANGE. THE SPRAWLING VORTEX SLOWLY DISENGAGING FROM THE NORTHEASTERN UNITED STATES WILL KEEP THE COLD RAINS FALLING OVER NEW ENGLAND THROUGH THE END OF WEEK--WITH THE ATTENDANT POLAR FRONT BOTTOMING OUT ACROSS THE FLORIDA STRAITS. THAT FRONT WILL AFFORD AN EFFICIENT OVERRUNNING SURFACE FOR THE TROPICAL MOISTURE STREAMING NORTHWARD FROM THE CARIBBEAN SEA, WITH SOUTHERN FLORIDA--PARTICULARLY THE KEYS--LIKELY TO RECEIVE SEVERAL INCHES OF RAINFALL. THE OTHER AREA OF FOCUS FOR SIGNIFICANT WEATHER IS THE PACIFIC NORTHWEST, WHERE THE MODELS CONTINUE TO INDICATE SOAKING RAINS FROM THE CASCADES TO THE COAST ON THE EASTERN SIDE OF THE OFFSHORE LONGWAVE TROUGH. CISCO