Winter '12 / '13 - January 2013: Week One Outlook

From today/s PSD GFS ensembles...Week 2 anomaly forecasts (VT centered on 05-JAN-13).

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Area 1 depicts the Pacific/s polar jet at 250 mb riding up and over PNA ridge.

Area 2 is the sub-tropical jet (STJ) phasing with the polar jet over the upper MIssissippi river valley.

Area 3 is the negative height anomaly at 500 mb located over New Foundland...CN

Area 4 shows the 850 mb temperature anomaly drawing high-latitude cold air into the NE on the backside of the Newfoundland LOW and the warm advection onto the Greenland ice sheet which in turn would induce or strengthen a blocking HIGH and negative northern annular oscillation indexes (AO; NAO).

Area 5 highlights precipitation anomalies from Mexico to the mid-Atlantic states aligned with the STJ axis.  Note the northern edge of the anomaly coincides with negative 850 mb temperature anomalies.

Amplified flow + short wave energy + cold air + moisture = forecast for snow