A Significant Near Blizzard Intensity Winter Storm, Drops Significant Amounts Of Snow On The Region...
OVERVIEW
Low pressure that stalled out near the Great Lakes region and slowly drifted northeast on February 21-22, spawned a Coastal low pressure system near Long Island on the 22nd. The low then moved Northeast, over Cape cod, into the Gulf of Maine, and eventually up into New Brunswick. It was a storm to remember that's for sure. It shall be remembered for a few things. To name some, the Champlain Valley was the splitting line of moderate snow amounts vs. very heavy snow amounts, Snowfall rates that reached nearly 4 inches per hour, prolonged Champlain Valley convergence, and the significant upslope snows.
THE CHAMPLAIN VALLEY SPLIT
The Champlain Valley was the splitting line of this storm. the New York side of the Champlain Valley received a general 4-8 inches, mainly on the lower end of things. The Vermont side, was the most interesting. Towns such as Swanton, Colchester, and Salisbury received anywhere from 2.5 - 5.5 inches of Snow, while anywhere from 2 - 5 miles inland from these locations, places revised upwards of 8 inches of snow. For instance, Swanton, VT received 5.3 inches, while Highgate Center received 8 inches, and just about 5 miles East of Highgate, in Sheldon Springs, they received over 12 inches of snow!! Now to further the craziness Colchester which only received 2.6 inches, was dominated by South Burlington's 8.4 inches. I would imagine some type of terrain shadowing had something to do with that. Although there was a small area of 2-4 inch snowfall from Colchester back to South Hero. In general you can see that the closer to the Lake you were, the less snow. (The Lake temperature of a nearly freezing 33 degrees had nothing to do with this, it was simply where the back edge of heaviest snow decided to cut off.)
HEAVY SNOWFALL RATES
While the coastal low was intensifying, it caused mesoscale bands to form, which are bands of extremely heavy snow. These bands of snow happened to set up from the Western slopes of the Green Mountains, and points east. This was the result of strong moisture inflow, lift, and rapid intensification of the low pressure system. Some reports out of Eastern Vermont, indicated snowfall rates reached a rate of 4 inches per hour. Then, on the 23rd, wrap around, and upslope snow developed. Where once again rates reached 2 inches per hour from time to time.
CHAMPLAIN VALLEY CONVERGENCE
While, the Champlain Valley Convergence did not drop an overly impressive amount of snow, and conditions were not 100% favorable for Champlain Valley convergence to push its full potential, it still occurred. Wrap around moisture that pushed over the Champlain Valley and into the Western slopes of the Greens was aided by a Northwest flow, which converged the moisture in the Valley as well, mainly the Central, and Northern portions of the Champlain Valley. The result was continued snow, for much of the day on the 23rd. Some of this snow was occasionally heavy. This helped add, from as little as 1 inch to as much as 5 inches of additional snow in the Champlain Valley of Vermont. Which helped push expected storm totals from the 4-8 inch range to the 8-12 inch range for a significant portion of the Northern, and Central Champlain Valley.
UPSLOPE SNOW
This is probably one of the most impressive parts to the storm. Due to a strong, and favorable moist Northwest flow on the back of the departing low pressure system, heavy snow developed along the Western Slopes of the Green mountains for the entire day of the 23rd. Some upslope snow actually lasted into the early afternoon hours on the 24th, although it was no where near as intense as it was on the 23rd. As mentioned in the "Heavy Snowfall Rates" section above. Snowfall rates reached 2 inches per hour at times on the 23rd. This helped boost totals significantly. The upslope snow produced an additional 5-10 inches of snow for the Western Slopes. This helped push widespread storm totals into the 12-18 inch range, with more isolated upslope areas experiencing 18-25 inches. The winner of the most significant upslope snows was eastern Franklin County Vermont, where numerous 18 or more inch amounts were witnessed and where the highest snow total reported from this entire storm occurred, which was Bakersfield, VT, at a total of 25.5 inches.
SUMMARY:
Overall this was a very significant storm. Another part of this storm that was not mentioned, was the winds. Towards the evening of the 22nd, and early morning of the 23rd winds increased into the 10-20MPH range in the Valleys with gusts to 30MPH, and for the higher elevations/ Western slopes winds were in the 15-25MPH range with gusts to 40MPH. This resulted in significant blowing, and drifting snow. If frequent gusts of 35MPH or higher, would have occurred for 3 consecutive hours, then this could have been classified of a Blizzard for much of the area. However winds fell just short of the criteria. Never-the-less Blizzard like conditions did occur. Below is 3 maps, the first one is the First official forecasted snowfall accumulation map issued by JRWeather on the 21st. The Second is the last official forecasted snowfall accumulation map issued by JRWeather, and the third map is of the actual recorded storm totals across the area.
CLICK ON IMAGES TO ENLARGE!
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