TEMPERATURES
PRECIPITATION
Long Range Forecast Discussion February 10-22 Models are in agreement with a strong positive height anomaly across northwestern North America to break down and slide to the southwest into the northeast Pacific. A trough over the nation is fore to spread westward as the polar vortex over northeast Canada retrogresses to the west. Uncertainty exits for the Feb. 10-14. The GFS and the GEFS form a low along the arctic boundary and track through the Northeast into Canada or form offshore of the East coast near the Gulf Stream and move northeast into the Atlantic. At this time, I am favoring the 12Z European because it is close to the 12Z Canadian. Models are in agreement on the 500-hpa circulation for Feb. 13-17 and are indicating a ridge over the northeast Pacific, a trough over the western U.S, and a ridge of the gulf. The ensembles differ with the strength of the western trough. The charts are forecasting below normal heights over the northeast Pacific and Alaska. Above normal heights are forecast over the eastern Pacific. Below normal heights are forecast over the western U.S. Above normal heights are forecast over the north Atlantic and the eastern U.S. The two long range models are in agreement for Feb. 18-22. The models forecast the western trough to shift eastward. The GFS is more amplified with the pattern. The change in this period is fore slightly lower heights in the East. The NAO index is positive and is forecast to trend briefly negative then positive by day 14. The PNA index is positive and is forecast to remain positive through day 14. The AO index is negative and is forecast to increase in value through day 14. Below normal temperatures are forecast for the West. Above normal temperatures are forecast for the Southeast. Below normal precipitation is forecast for the West and the western section of the central and northern Plains. Above normal precipitation is forecast for the Southeast and the lower mid-Atlantic.
530 PM EST Tue. Feb. 7, 2012
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