Milwaukee – Fall has been quite mild for most of the United States. In fact, September east of the Rockies was one of the warmest for many locations (Fig. 1). In the image below, the light orange to dark orange divisions east of the Rockies were above average to warmest on record. The mild weather has continued in October with many locations seeing a late frost, if it has even happened.
Fig. 1 September Temp Rankings
Not every fall is warm and mild. How quickly we can forget early blasts of cold and snow in October. Just five years ago the east coast was blasted by record setting snow. And, guess what? It was a very warm October with temperatures well above average for the first three weeks. I am not suggesting that we are going to see snow before the end of the month in major cities. However, the longer the mild weather lasts, the more likely we can expect an abrupt change. Winter eventually arrives and some years there isn’t a nice gradual change to adapt.
Getting back to late October, 2011… This storm was given a name – Snowtober. It was a major disruption for millions of people in the Mid-Atlantic and New England. The storm developed off the coast of North Carolina on October 29th and moved north. By the time the storm moved out to sea, millions were without power and record snow hit parts of Pennsylvania north to Maine.
Fig. 2 Snowtober Snowfall
On the wide view of the East Coast in figure 2, significant snow fell from the mountains of West Virginia and Virginia north into central and eastern Pennsylvania through northern New Jersey, southern New York and most locations in New England. Everywhere you see blue is snow in excess of 4”. Purple areas designate snowfall of 10”or more. A close up of the heaviest snow shows western Massachusetts and southwestern New Hampshire were the bulls-eyes.
Fig. 3 Southern New England Snowfall
Jaffrey, New Hampshire measured 31.4” of snow and Plainfield, Massachusetts measured 30.8” of snow. Other notable snow totals:
- Central Park = 2.9”
- Portland, ME = 5.2”
- Allentown, PA = 6.8”
- Wilkes Barre, PA = 9.1”
- Gray, ME = 12.9”
Not only were snow amounts significant, but this was a heavy wet snow. The weight of the snow brought down branches and trees causing power outages to over 3 million people. The National Weather Service reported that some communities in Connecticut were without power for over a week. Winds were also very strong with gusts to 69 mph along the Massachusetts coast. 39 people died from the storm.
Because the storm impacted areas adjacent to the major cities of the east coast, it only rated 1.8 on the Regional Snowfall Index (RSI). RSI is used by the National Weather Service to rank snowstorms by impact on population. It has a ranking system of 1 through 5. The same ranking scale Enhanced Fujita and Saffir-Simpson for tornadoes and hurricanes.
Fig. 4 Snowtober RSI Reports
In Figure 4, note how many of the snowfall reports are north and west of I-95 and the major population centers of Washington D.C., Baltimore, Philadelphia, New York City and Boston. A 1.8 on the RSI is a notable storm. For the 3 million without power it was more than notable. It was also a Halloween when many kids wore boots, mittens and hats while navigating snow piles between homes. It was only five years ago. Don’t be caught off guard because of our mild fall temperatures. Winter is coming. Are you going to be ready?
Meteorologist Mark McGinnis can be found on Facebook and on Twitter @fairskiesconsul