A surprise snowstorm may cast a ghostly white across the landscape in the Northeastern U.S. late Friday and into the day on Saturday. The exact outcome of the storm will hinge on many factors, but most of the short-range weather forecasting models are indicating some type of precipitation from the Carolinas through Maine this weekend. Many areas will likely start out with precipitation in the form of rain with a change-over to wet snow. While locations directly along the coast may miss out on the snow as warmer ocean waters influence temperatures there, locations closer to and just to the west of the I-95 corridor from Baltimore up through New England will have the best chances of seeing the first snow of the season. Baltimore, Philadelphia, New York City, and Boston all could see a change from rain to snow. Snowfall totals will generally be a few inches to as much as 6’’ in the mountains; accumulations should be reserved to grassy surfaces as temperatures stay above or just near the freezing mark, however, any heavy bursts of snow could cover roadways. Higher elevations have the greatest chance of seeing a slushy accumulation on the roads. As is typical of coastal storms, a deviation in the forecasted track of the storm east or west by just 50 miles or more will greatly alter the outcome of the storm. A Winter Storm Watch has been posted by the National Weather Service for northeastern Pennsylvania and northwestern New Jersey.

The forecast isn’t as scary as it seems since the snow will be favorable for cold weather categories like comfort foods, snow removal products, and heavy outerwear. Cold weather apparel will do well as consumers rush to find extra layers of clothing to wear and keep them warm because this will be a “Chiller Night(s)” for Halloween festivities (Yes, that was a lame attempt at a reference to Michael Jackson’s Thriller and I apologize). Temperatures in the Northeast will trend the coldest in 9 years for the period of October 28th to the 31st. Fortunately, store traffic should not be impacted too severely as the snow is expected to stick only on grassy surfaces.

With the release of Britain’s Office for National Statistics (ONS) September 2011 Retail Sales Report last week there has been a lot of talk about the weather’s role in influencing sales. It’s true, there are many factors that influence retail sales, but weather, unlike the global economy and consumer sentiment, is one factor that retailers can actually leverage and use to their advantage.  Had stores like John Lewis known that September 2011 was going to be warmer than normal, they may have planned to reduce inventory on autumn ranges, or Tesco may have opted to order more bottled water and barbeque foods than comfort foods like stews and hot beverages. A single decision based off of the weather can lead to millions in increased sales for retailers even during times plagued with a plethora of economic headwinds.

So, what did our forecast for September 2011 in the United Kingdom say a year ago? For the United Kingdom as a whole our forecast was for a warmer, above normal September with less precipitation than last year and that’s not too far off from what actually happened (see graphs above).  Not too shabby for a forecast made a year ago. In last year’s report we even called out week 2 as being the only week in September that would trend cooler than last year and that the 1st and 3rd retail weeks of the month would be the only weeks to trend wetter than last year. What actually happened is depicted in the chart below where blue blocks represent cooler temperatures than last year and green blocks represent weeks that were wetter than the comparable week of last year.  Using these year-on-year comparisons, retailers are able to leverage the weather and make more informed inventory and marketing decisions as just a -1 degree C difference in weekly year-on-year temperatures can greatly impact the amount of product sold, for example, for every -1C in weekly year-on-year temperatures there is typically a +2% increase in hot soup category sales during the cold weather season.

The British Retail Consortium’s (BRC) September 2011 Retail Sales Monitor Report places heavy blame on the weather for less than stellar retail sales results, especially for clothing. According to the ONS, clothing and footwear sales volumes were down -2.1% from last year. Meanwhile, the warmer weather, especially late in the month was cited as a boost for food and drink categories. Many of the same conclusions were drawn from our report issued a year ago, the following are some comparisons between our report and the BRC’s report:

Similarly, the forecast for the United States played out rather nicely as shown in the graphs below. We forecasted an above normal, but slightly cooler than last year September and that’s what happened. In fact, our forecast pinned September 2011 as the 5th warmest in 19+ years, it was actually the 4th warmest.

With this year-ahead guidance, retailers were able to anticipate that, for the country overall, sales of seasonal Autumn categories will have changed slightly over last year as temperatures were projected to be slightly cooler than last year (cooler is better for Autumn categories). Seeing that temperatures were projected to be above normal in September 2011, retailers would have been wise to be lean on inventories of cool weather products like sweaters, long-sleeved shirts, boots, and heaters. Analysis of 30 years of retail same-store-sales data shows that a -1F change in temperature for September overall can have a +1.1% impact on U.S. retail sales, which is huge when considering the volume of retail trade.

When the world is filled with so many uncertainties, why leave the weather to chance when there’s something that can be proactively done to prepare for what’s ahead? The technology to forecast weather a year-ahead is here and the forecast has proven skill. Although year-ahead weather forecasting may seem like “hocus pocus” to some (as a Meteorologist, I’ve been accused of witchcraft on almost a daily basis), but our forecasts have given hundreds of clients advanced insight and placed them in a position to leverage the weather rather than be a victim.

U.S. SEPTEMBER 2011 SUMMARY: Warmer than normal conditions were prominent at the start and end of the month, while the middle of the month brought a taste of Fall to the North Central and East. The West, however, managed to stay warm and dry through most of the month with more Summer-like weather in many areas that were cool during the Summer months. The Northwest was unusually dry as well as the South Central states where severe drought conditions are ongoing. The Northeast was the complete opposite as the rain was seemingly endless. The 1^st day of the retail September was marked by Hurricane Irene making landfall in New Jersey and near New York City before accelerating to the north. Widespread power outages and flooding were reported from NJ to ME in Irene’s wake as +6” of rain fell over a vast area. As residents and businesses were finishing clean-up from Irene, another pesky tropical disturbance, Tropical Storm Lee, formed in the Gulf of Mexico. Lee dumped flooding rain from Louisiana northward along the Appalachian Mountains into the Northeast. For some in the Northeast Lee was the straw that broke the camel’s back as additional +6” of rain caused swollen rivers to spill over their banks resulting in some of the worst flooding since Hurricane Agnes in 1972. Following Lee, the faucet could not be shut off in the Northeast as a parade of stalled frontal boundaries kept the region shrouded in clouds and showers for a majority of the time.

Hurricane Irene resulted in at least 1 day of lost retail trade at the very start of the month as many businesses shut their doors as she made landfall in the Northeast. Home centers and discounters gained the most from Irene as clean-up supplies, portable generators and bottled water were in high demand. Mall-based stores and discounters will have had a negative impact from Irene as consumers shifted their focus from apparel shopping to storm necessities. Clean-up categories like wet/dry vacuums, tarps, and paint will have continued to be strong through at least the middle of September as remnants from Tropical Storm Lee caused more flooding. Warm, moist air in the East was abruptly replaced with much colder, Fall-like weather during Week 3 which was a huge positive for Fall seasonal categories. The cold weather extended into part of Week 4 helping to drive demand for items like fire logs, hot soups, and mouse traps in the North Central states. Fall categories were a hard sell in the West where warm and dry weather favored Summer consumables like ice cream, cold beverages, sun care, car wash/wax, and other outdoor categories.

U.K. SEPTEMBER 2011 SUMMARY: Following an abnormally cool Summer, temperatures finally turned warmer than normal in the U.K. The 1^st and 2^nd weeks trended warmer than normal, but the biggest story was the very mild weather during the final week of the month which sent people flocking to the beaches to soak up the warm and dry weather. More Autumn-like weather could be found during the 3^rd and 4^th weeks of the month when temperatures were closer to normal. While much of England and Wales trended drier than last year, areas to the north saw more unsettled weather including a few tropical disturbances. Remnants from Hurricane Irene brought heavy rain and wind to Scotland during the 1^st week of September. During the middle of the month, Post-Tropical Storm Katia brought more heavy rain and severe gales to Scotland, Northern England and Ireland. Katia caused localized flooding in central Scotland and some power outages.

Unfortunately the arrival of more Summer-like weather in late September is a negative for retail sales as this time of year is focused on Autumn categories and drier weather in September is a negative for footfall as consumers spend more time outdoors instead of shopping. Luckily, there was pent-up demand for many warm weather categories like ice cream, cold beverages, and sun care following a cool, dreary Summer. The final week of the month will have seen double to even triple digit surges in demand for Summer consumables. More seasonable weather during weeks 3 and 4 provided opportunities for Autumn categories, although demand will have been softer during week 3 as temperatures were warmer than last year. Flooding and damage from the various tropical disturbances in the North of the U.K. will have increased footfall at home centers and demand for clean-up categories.

G-20 SEPTEMBER 2011 SUMMARY: G-20 temperatures trended +1.1C warmer than last year with a majority of the warmer weather in Europe, Russia and Canada. Europe was warm and dry for much of September with Summer-like conditions prevailing. Despite the abnormally warm weather, parts of the Alps recorded their earliest snowfall on record around mid-month. Cooler weather presided over eastern China, Mongolia, South Aftrica, and parts of the Middle East.  Typhoon Talas struck Japan early in the month and was the deadliest cyclone to hit the country since 2004. Hong Kong’s stock market and businesses shut down as Typhoon Nesat brought threatening weather late in September. Monsoon rains across Pakistan and Thailand caused flooding and destroyed millions of acres of cropland.

Very warm and settled weather in Europe favored Summer consumables over more seasonal Autumn categories. Milder weather in Canada delayed the start of the season for Autumn categories. Seasonal categories were more favorable in places like eastern China and Mongolia where temperatures trended cooler than last year. Businesses in Japan and parts of China, including Hong Kong, experienced at least 1 day of disruption as Typhoon’s Talas and Nesat, respectively, brought flooding rain and damaging winds. Clean-up supplies will have seen a rise in demand in the cyclones’ wake.