An intense low pressure system over eastern Canada has brought down the coldest and most extensive air mass of the late fall season. The map above (from the initial analysis for the NAM model) indicates the extent of the cold air as indicated by the blue dashed thickness lines (thickness is related to the mean temperature of the layer between the 1000 mb and 500 mb surface). The extent of the cold air is dramatic and extends from the tundras of the North Pole to the lower 48 states from the Pacific Northwest to the Mid-Atlantic. The solid lines are isobars that indicate lines of equal barometric pressure. The closer the spacing, the stronger the pressure gradient and the stronger the wind. Winds are blowing from the northwest across the Northeast at 20 to 30 mph with gusts to 50 mph. A Wind Advisory is in Effect for Long Island and NYC tonight through Friday morning. The wind chills will be in the single digits tonight. Light flurries and snow showers occurred in Manhattan around 8:15 to 8:30 pm this evening. The northwest is producing heavy snow squalls and blizzard lake effect snows on the leeward sides of Lake Ontario and Lake Erie. The next chance for some wet snow and rain will come here in NYC area Sunday evening and Monday morning.
George Wright is a Certified Consulting Meteorologist and President of Wright Weather Consulting, Inc. Our web site is WrightWeather.com.
