Using The Mega-Cluster Ensemble To Track Snow Risk In The East U.S.

Discussion: Forecast models have shown (at times) a trail of snow storms across the East U.S. in recent days. Each model run varies, sometimes widely. How do you make an assessment for planning purposes given the variability of operational models? The mega-cluster ensemble accounts for ALL models including their prevailing skill level to put-together a daily “most likely” projection of the weather. The model also assigns a confidence level and identifies which operational model was used most influentially.

Fig. 1: The mega-cluster ensemble precipitation amount profile for tomorrow’s storm in the East.

Tomorrow’s storm in the East (Fig. 1) and most influential (heaviest amount) over North Carolina. The model indicates this system will move east-northeast rather than northeast (along the coast). The easterly trajectory of the storm should leave only southern Virginia in the precipitation shield with some snowfall risk involved.

Fig. 2: The mega-cluster ensemble precipitation amount profile for next TUE/WED storm on the East Coast.

Next week a coastal storm is in the forecast. Forecast confidence is LOW (29%). The projection indicates moderate snows (3-6 in.) for the Interior Mid-Atlantic and southern New England (Fig. 2).

Fig. 3: The mega-cluster ensemble precipitation amount profile for late next week in the East.

Late next week a potent cold front triggers possible significant precipitation rather than a coastal storm (Fig. 3). Temperatures are mild enough for mostly rain near the coast while significant cold and wind turn precipitation to snow for the Interior Northeast States. In the snow area a plowable snow occurs.

Fig. 4: The mega-cluster ensemble precipitation amount profile for Jan. 17-18 in the East.

Likely triggered by another strong cold front rather than a coastal storm are large area of snow shower activity is projected for a Jan. 17-18 event across the length of the Appalachians and northeast Corridor (Fig. 4). In the snow area a plowable snow occurs.

Fig. 5: The mega-cluster ensemble precipitation amount profile for Jan. 20-21 in the East.

A fifth event is forecast with reasonable confidence in 13 days for the East/Southeast (Fig. 5). This event has more precipitation and hefty snows are possible away from the coast.