Climate Signals Chart
Climate signals discussion: In the 8-14/11-15-day period +NAO signals a warm bias in the East. The cold bias at this time is supported by -WPO in Western Canada and -EPO for Central Canada. The -PNA pattern supports cold in the West U.S. and warmth in the East. In summary, the cold bias in the 8-14/11-15-day period is across the western half of North America and the warm bias is across the eastern third. Snow cover (and snow cover trend) can over-rule climate signals at times. However, the forecasts indicated are particularly strong signatures in the extended-range.
Medium-range 6-10 Day Forecast Valid February 8-12, 2022
Medium-range 11-15 Day Forecast Valid February 13-17, 2022
Discussion: Using the mega-cluster ensemble output which is best-supported by climate signals, the 6-10-day forecast reveals lingering cold in the South U.S. while California and the Continental Divide are mild. The 11-15-day forecast is bold cold in Central Canada leaning toward the Northwest U.S. as supported by a combination of -EPO/-WPO/-PNA forecasts. The East warm bias with these climate signals is negated by snow cover.
Mega-cluster Ensemble Percent of Normal Precipitation Medium-range Forecast for the U.S.
Discussion: The best supported by climate signals precipitation forecast for days 6-10 reveals a nationally dry pattern with storms just-off the East Coast. In the 11-15-day period a snowy pattern develops in the Interior West
Mega-cluster Ensemble 1st and 2nd Most Likely Upper Air Patterns Day-15
Discussion: Mega-cluster ensemble indicates the most likely upper air forecast for day-15 is an established polar vortex over North Canada with an upper ridge off the U.S. West Coast and coastal New England. The second-most likely solution – and best supported forecast by climate signals – is the cold upper trough dipping into the Northwest U.S. while the ridge pattern is off the U.S. East Coast. Bottom line: Colder West, warmer East.