AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
315 PM CST FRI DEC 25 2010

THE AO HAS BEEN NEGATIVE SINCE 17 NOVEMBER WITH A BRIEF NEUTRAL
PERIOD AT THE BEGINNING OF DECEMBER. THE NAO HAS BEEN NEGATIVE SINCE
17 OCTOBER WITH PERIODS OF NEUTRAL AT THE BEGINNING AND MIDDLE OF
NOVEMBER. GLOBAL SST ANOMALIES SHOW STRONG POSITIVES ACROSS THE
NORTH PACIFIC ALONG/WEST OF THE INTERNATIONAL DATE LINE AND IN THE
NORTH ATLANTIC WITH VERY STRONG POSITIVES IN THE LABRADOR SEA. GIVEN
THE STRENGTHS OF EACH ANOMALY AREA...THE NEGATIVE PHASES OF THE AO
AND NAO SHOULD BE THE FAVORED MODE FOR JANUARY.

THE EXPECTED PATTERN CHANGE IS WELL UNDERWAY WITH HEIGHTS COLLAPSING
ACROSS THE NORTH ATLANTIC AND WEST OF THE INTERNATIONAL DATE LINE.
THE FOUR WAVE PATTERN WILL BREAK DOWN TO WHAT APPEARS TO BE A LOW
AMPLITUDE THREE WAVE PATTERN BY THE MIDDLE OF NEXT WEEK. HOWEVER...
THERE IS A BROAD AREA OF NEAR ZONAL FLOW ACROSS MOST OF ASIA AND
INTO THE WESTERN PACIFIC. THUS THE LOW AMPLITUDE THREE WAVE PATTERN
WILL QUICKLY BREAK DOWN INTO A LOW AMPLITUDE FOUR WAVE PATTERN BY
LATE NEXT WEEK WITH A TROF OVER THE WESTERN CONUS. THE POLAR VORTEX
IS DISPLACED TO NEAR THE BEARING SEA BY NEXT WEEKEND WITH HEIGHTS
BUILDING AGAIN OVER THE UK. A TRANSITION INTO A LOW TO MODERATE
AMPLITUDE FIVE WAVE PATTERN LOOKS TO BE IN THE OFFERING AS HEIGHTS
ALSO BUILD ACROSS THE EASTERN PACIFIC. IF A FIVE WAVE PATTERN
OCCURS...IT WILL QUICKLY BREAK DOWN TO A MORE STABLE THREE WAVE
PATTERN CHANGE PRIOR TO THE MIDDLE OF JANUARY.