EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1253 AM EDT TUE OCT 21 2014 VALID 12Z FRI OCT 24 2014 - 12Z TUE OCT 28 2014 THE ENSEMBLE MEANS OFFER THE BEST CONTINUITY THIS FORECAST PERIOD AND SIDESTEP SOME OF THE MORE PROBLEMATIC EXTREMES OFFERED BY THE OPERATIONAL MODELS. THE STAKES ARE HIGHEST ACROSS SOUTHERN FLORIDA WHERE THE INTERACTION BETWEEN THE POLAR WESTERLIES AND THE POTENTIAL TROPICAL CYCLONE EMERGING FROM THE BAY OF CAMPECHE AND NORTHWESTERN CARIBBEAN SEA REMAINS UNCLEAR. THE PERIOD BEGINS WITH A LARGE VORTEX NEAR CAPE COD AND A CLOSED SUBTROPICAL HIGH OVER ARIZONA AND NEW MEXICO. THE NEW ENGLAND LOW SHOULD KEEP CHILLY RAINS FEEDING INTO THE STATES THAT BORDER CANADA FOR THE FIRST COUPLE DAYS. THE SOUTHWESTERN RIDGE COULD PRODUCE ONE-HUNDRED-DEGREE READINGS ON THE LOW DESERTS OF CALIFORNIA AND ON THE OTHER SIDE OF THE COLORADO RIVER IN ARIZONA. BY MID PERIOD, A PROGRESSIVE LONGWAVE TROUGH SHOULD MOVE BODILY INTO THE WEST, URGING THE DOWNSTREAM FEATURES INTO NEW CONFIGURATIONS. THE DOWNSTREAM TROUGH OVER THE CENTRAL GULF STATES AT THE START OF THE FORECAST SEEMS DESTINED TO DIG INTO FLORIDA AND THE BAHAMAS, PERHAPS KEEPING THE TROPICAL LOW AT BAY SOUTH OF CUBA. THERE ARE STILL OPERATIONAL SOLUTIONS THAT PULL THE LOW TOWARD FLORIDA AND THE SOUTHEASTERN UNITED STATES COAST. BY THE END OF THE PERIOD, THE PROGRESSIVE FLOW SHOULD SEND HEIGHTS RISING OVER THE NORTHEAST, WITH A BROAD SWATH OF WESTERLIES FROM THE PACIFIC COAST TO THE GREAT PLAINS. THIS STRETCH OF FLOW LOOKS NOISY WITH SHORTWAVES, AND IS LIKELY TO BE HANDLED DISPARATELY BY THE MODELS IN UPCOMING DATA CYCLES. CISCO