PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS

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PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST THU NOV 03 2005

6-10 DAY OUTLOOK VALID FOR NOV 09 - 13 2005

TODAYS MODEL RUNS HAVE COME INTO BETTER AGREEMENT WITH EACH OTHER OVER THE NORTH AMERICAN CONTINENT AND ADJACENT OCEANIC AREAS FOR THE 6-10 DAY FORE- CAST PERIOD. THE BLOCK PREDICTED OVER KAMCHATKA IS FORECAST TO REMAIN VERY STRONG BY ALL MODELS...WHILE THERE IS ALSO GOOD AGREEMENT ON SIGNIFICANT WEAKENING OF THE BLOCK NEAR SCANDANAVIA. THE POSITIVE HEIGHT ANOMALY CENTER PREDICTED BY SOME OF THE MODEL RUNS YESTERDAY NEAR 40N/145W IS NOW SHOWN BY NEARLY ALL MODELS AND THEREFORE OVERALL CONFIDENCE IN THIS FORECAST IS ELE- VATED. WITH A MORE AMPLIFIED RIDGE AT THIS UPSTREAM LOCATION WE WOULD ANTI- CIPATE LOWERED 500-HPA HEIGHTS ACROSS THE WESTERN CONUS ASSOCIATED WITH A TROUGH. HOWEVER...IF THIS RIDGE TURNS OUT TO BE A FLAT RIDGE THEN STRONG WESTERLIES WOULD LIKELY DOMINATE THE FLOW PATTERN OVER MUCH OF THE CONUS. WE ARE LEANING TOWARD A LOW AMPLITUDE PATTERN...WITH WEAK TROUGHING EXPECTING OVER THE WESTERN CONUS. ANOTHER VERY IMPORTANT CLIMATE ANOMALY FEATURE WHICH WILL HAVE A SIGNIFICANT EFFECT ON UNITED STATES WEATHER IS A DEEP TROUGH OVER THE NORTHERN GULF OF ALASKA WITH ITS ASSOCIATED NEGATIVE HEIGHT ANOMALY CEN- TER PREDICTED OVER THE NORTHERN ALASKA PANHANDLE. THE OPERATIONAL ECMWF HAS THIS CENTER FURTHER BACK NEAR ANCHORAGE...WHICH IS WHERE MOST MODELS PLACED IT YESTERDAY. THE OPERATIONAL ECMWF ALSO HAS THE FLATTEST FLOW PATTERN ACROSS NORTH AMERICA...WITH FAST WESTERLY FLOW IMPLIED ACROSS THE U.S./CANADA BORDER. ACROSS THE EASTERN CONUS...MOST MODELS HAVE A MODERATE RIDGE WITH ITS ASSOCIATED POSITIVE HEIGHT ANOMALY CENTER OVER THE OHIO VALLEY...WITH A MUCH WEAKER RIDGE OVER THE HUDSON BAY REGION. THE EXCEPTION TO THIS IS TODAYS DAVA RUN WHICH HAS THE OPPOSITE SETUP...WITH THE STRONGER RIDGE OVER HUDSON BAY.

8-14 DAY OUTLOOK FOR NOV 11 - 17 2005:

DURING THE WEEK 2 PERIOD...THE GENERAL MODEL CONSENSUS (NAMELY THE GFS SUPERENSEMBLE MEAN - THE GFS ENSEMBLE MEANS INITIALIZED AT 00 UTC AND 06 UTC - AND THE OPERATIONAL GFS RUNS ALSO INITIALIZED AT 00 UTC AND 06 UTC) INDICATES REASONABLE CONTINUITY OF THE ATMOSPHERIC CIRCULATION FROM THE 6-10 DAY PERIOD. THE PRIMARY HEIGHT ANOMALY CENTERS OVER THE HIGH LATI- TUDES ARE PREDICTED TO BE IN APPROXIMATELY THE SAME LOCATIONS AS FOR DAYS 6-10...BUT THERE IS NOTICEABLE PROGRESSION OF ANOMALY FEATURES OVER THE MID-LATITUDES. THOUGH THERE ARE SOME DIFFERENCES IN THE DETAILS REGARDING THE TIMING AND AMPLITUDE OF SHORTWAVE DISTURBANCES EMBEDDED IN THE MEAN FLOW...FOR ALL PRACTICAL PURPOSES MUCH OF THE CONUS SHOULD EXPERIENCE RELA- TIVELY MILD TEMPERATURES...WHILE COLDER THAN NORMAL CONDITIONS PREVAIL OVER ALASKA. THE BEST CHANCE FOR PRECIPITATION IS ACROSS THE ALASKA PANHANDLE AND THE PACIFIC NW. THE RIDGE OVER THE EASTERN PACIFIC MAY MOVE SLIGHTLY TO THE EAST...WITH A CORRESPONDING RISE IN THE 500-HPA HEIGHTS OVER CALI- FORNIA AND NEVADA. THE MEAN RIDGE FORECAST OVER THE OHIO VALLEY DURING DAYS 6-10 IS PREDICTED TO BE LOCATED OVER NEW ENGLAND DURING WEEK 2.