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December 16-17, 2007
Winter Storm |
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Summary
The first major snowstorm of the 2007-08 Winter season for Vermont and northern New York, actually occurred prior to the Winter Solstice (December 22nd 108 am EST). Snowfall totals from this pre-winter storm ranged from 6 to 12 inches in southern Vermont, where a prolonged period of sleet and/or freezing rain occurred, to a rather uniform 12 to 18 inches across the rest of Vermont and northern New York (detailed snow amounts available here).
On Saturday morning (15th), a strong and unseasonably cold high pressure system was located across northern New England and southeast Canada. Meanwhile, low pressure was developing across eastern Texas. This area of low pressure gradually strengthened and incorporated abundant moisture from the Gulf of Mexico, as it traveled to the Mississippi and western Ohio River Valleys by Saturday night. During Saturday night and early Sunday morning (16th), this primary low would continue to strengthen in the Ohio River Valley, while a coastal low would gradually develop along the mid-Atlantic coast, due to a strong, coupled upper-level jet stream as well as a deepening mid-atmospheric trough.
Snow began to overspread New York and Vermont early Sunday morning (16th) with snowfall rates rapidly increasing to over an inch per hour. The Ohio river valley storm maintained its strength during Sunday as it moved into the eastern Great Lakes, this allowed milder air aloft (4000-8000 feet) to move into the North Country, as well as drier air to be incorporated into the storm. These two factors caused precipitation to fall as a wintry mix (snow, sleet and freezing rain), as well as developed a lull in intensity of precipitation during the mid-late morning hours that lasted until mid-late afternoon. However, by late Sunday afternoon and continuing through Sunday evening, the secondary coastal storm intensified and this allowed the second part of this winter storm to wrap accumulating snow into northern New York and Vermont, as well as provided brisk winds that caused considerable blowing snow.
Although each winter storm is different in many ways...the same general characteristics are often very similar for major snowstorms in the North Country (Vermont and northern New York) and this storm exhibited these characteristics;
- A strong and sometimes "coupled" upper atmospheric jet stream
- A deepening long wave trough along with a strengthening, negatively-tilted short wave
- A strong temperature gradient from south to north and coastal vs. inland (Surface, 850mb, 700 mb)
- An abundant moisture supply (Gulf of Mexico or Atlantic)
- Surface low pressure track between Boston and outer Cape Cod, Massachusetts
Snowfall Map
Click on image to enlarge
Storm total snowfall map depicts a wide swath of 12 to 18 inches across northern New York and the northern half of Vermont. This is where the precipitation mainly fell as snow, although there were some reports of sleet. Snowfall amounts of 6 to 12 inches occurred across southern Vermont, where milder and drier air accounted for a period of sleet and freezing rain as well as a longer lull in precipitation.
Snowfall Reports
PUBLIC INFORMATION STATEMENT
SPOTTER REPORTS
NATIONAL WEATHER SERVICE BURLINGTON VT
1005 AM EST MON DEC 17 2007
THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE PAST 10
HOURS FOR THE STORM THAT HAS BEEN AFFECTING OUR REGION.
APPRECIATION IS EXTENDED TO HIGHWAY DEPARTMENTS...COOPERATIVE
OBSERVERS...SKYWARN SPOTTERS AND MEDIA FOR THESE REPORTS. THIS
SUMMARY IS ALSO AVAILABLE ON OUR HOME PAGE AT WEATHER.GOV/BURLINGTON
********************STORM TOTAL SNOWFALL********************
LOCATION STORM TOTAL TIME/DATE COMMENTS
SNOWFALL OF
(INCHES) MEASUREMENT
NEW YORK
...CLINTON COUNTY...
PERU 19.2 555 AM 12/17
ELLENBURG DEPOT 17.0 912 AM 12/17 COOP
AUSABLE CHASM 12.0 741 AM 12/17 HAM OPERATOR
PERU 12.0 756 AM 12/17 HAM OPERATOR
PLATTSBURGH 12.0 700 PM 12/16 RACES
PLATTSBURGH 12.0 745 AM 12/17 HAM OPERATOR
PERU 6.5 941 AM 12/17
...FRANKLIN COUNTY...
WHIPPLEVILLE 14.0 804 AM 12/17 COOP
MALONE 12.0 700 AM 12/17 COOP
SARANAC LAKE 12.0 750 AM 12/17 HAM OPERATOR
TUPPER LAKE 10.0 708 AM 12/17 COOP
...ST. LAWRENCE COUNTY...
POTSDAM 15.5 843 AM 12/17
EDWARDS 12.0 740 AM 12/17 HAM OPERATOR
NORFOLK 12.0 755 AM 12/17 HAM OPERATOR
OGDENSBURG 12.0 758 AM 12/17 HAM OPERATOR
CANTON 9.0 700 AM 12/17 COOP
VERMONT
...ADDISON COUNTY...
VERGENNES 17.8 800 AM 12/17
NEW HAVEN 13.0 700 AM 12/17 COOP
SOUTH LINCOLN 13.0 700 AM 12/17 COOP
BRIDPORT 11.0 735 AM 12/17
SHOREHAM 10.5 748 AM 12/17 HAM OPERATOR
...CALEDONIA COUNTY...
WHEELOCK 17.0 805 AM 12/17 1900 FT
SUTTON 15.7 700 AM 12/17 COOP
WEST BARNET 13.5 830 AM 12/17
SAINT JOHNSBURY 12.9 903 AM 12/17 COOP
...CHITTENDEN COUNTY...
HANKSVILLE 18.3 859 AM 12/17 COOP
MILTON 18.0 700 AM 12/17 NWS EMPLOYEE
ESSEX JUNCTION 17.6 901 AM 12/17 COOP
SOUTH BURLINGTON 15.5 730 AM 12/17 NWS EMPLOYEE
SOUTH BURLINGTON 15.5 841 AM 12/17
SOUTH BURLINGTON 14.4 930 AM 12/17 AIRPORT
WESTFORD 13.0 715 AM 12/17 NWS EMPLOYEE
UNDERHILL CENTER 12.8 800 AM 12/17 NWS EMPLOYEE
JERICHO 11.4 745 AM 12/17 NWS EMPLOYEE
COLCHESTER 11.0 740 AM 12/17 NWS EMPLOYEE
...ESSEX COUNTY...
EAST HAVEN 12.0 1003 AM 12/17 COOP
...FRANKLIN COUNTY...
SAINT ALBANS 11.3 610 AM 12/17 COOP
HIGHGATE CENTER 9.0 739 AM 12/17 HAM OPERATOR
...LAMOILLE COUNTY...
STOWE 15.0 1000 AM 12/17 2 MI SOUTH
CAMBRIDGE 15.0 842 AM 12/17
EDEN 13.3 844 AM 12/17 COOP
JEFFERSONVILLE 12.5 859 AM 12/17 COOP
STOWE 11.0 326 AM 12/17 SPOTTER
...ORANGE COUNTY...
BROOKFIELD 17.5 700 AM 12/17 COOP
CORINTH 12.1 700 AM 12/17 COOP
RANDOLPH CENTER 10.5 322 AM 12/17 SPOTTER
CHELSEA 10.0 324 AM 12/17 COOP
CHELSEA 10.0 712 AM 12/17 COOP
...ORLEANS COUNTY...
NEWPORT 12.0 700 AM 12/17 COOP
EAST ALBANY 8.0 847 AM 12/17 COOP
...RUTLAND COUNTY...
CHITTENDEN 15.0 959 AM 12/17 1000 FT COOP
BRANDON 10.0 958 AM 12/17 POST OFFICE
RUTLAND 7.5 800 AM 12/17 COOP
WALLINGFORD 7.0 1003 AM 12/17
...WASHINGTON COUNTY...
MARSHFIELD 14.0 824 AM 12/17
WATERBURY CENTER 12.5 839 AM 12/17
PLAINFIELD 9.5 848 AM 12/17 COOP
MONTPELIER 9.0 854 AM 12/17 COOP
WAITSFIELD 8.0 800 AM 12/17 COOP
...WINDSOR COUNTY...
SPRINGFIELD 14.0 843 AM 12/17
BETHEL 13.0 700 AM 12/17 COOP
ROCHESTER 10.0 700 AM 12/17 COOP
CAVENDISH 9.5 720 AM 12/17 COOP
WOODSTOCK 7.0 822 AM 12/17 COOP
Surface Map on Saturday December 15th at 7am
Click on image to enlarge
Saturday morning minimum temperatures were around Zero and Saturday afternoon maximum temperatures were in the upper single numbers and teens.
Evolution of Surface Low Track
7am EST Saturday 12/15 to 7am EST Monday 12/16
Click on image to enlarge
Surface low across Texas and Louisiana on Saturday morning strengthens as it moves into the Ohio River Valley Saturday night and Sunday. Meanwhile, a secondary coastal low slowly develops off the Mid-Atlantic coast Sunday, becoming the main system Sunday night.
Track of 850mb Low, Thermal Gradient and Moisture
Saturday Morning at 7am EST (12/15) to Sunday Night at 7pm EST (12/16)
Click on image to enlarge
850mb closed low across southern Plains/Mississippi River Valley on Saturday morning lifts northeast and rapidly intensifies across Ohio River Valley before moving across New England on Sunday. The tight gradient of isotherms (blue and red dashed lines) shows the "clash in air masses" and potential low-level energy available. Abundant moisture from the Gulf of Mexico (solid green lines) on Saturday lifts up the east coast on Sunday.
Upper Level Jet Stream (300mb)
Saturday Morning at 7am EST (12/15) to Sunday Night at 7pm EST (12/16)
Click on image to enlarge
Upper level jet stream (300 mb) with double-jet structure, including an 140kt jet streak progresses eastward. This double-jet structure creates upper-level divergence which promotes strong upward vertical motion and accounts for storm intensification.
Mid-Atmospheric Trough (500mb)
Saturday Morning at 7am EST (12/15) to Sunday Night at 7pm EST (12/16)
Click on image to enlarge
Short wave within long wave trough axis across central US on Saturday morning proceeds to strengthen, eventually becoming cut-off as it lifts northeast in negatively tilted trough axis across the northeast on Sunday.
Infrared Satellite and Surface Time Lapse
Saturday Morning at 7am EST (12/15) to Sunday Night at 7pm EST (12/16)
Click on image to enlarge
Abundant moisture is being tapped from the Gulf of Mexico and being transported northeast into New England as the storm approaches the region.
Radar and Surface Time Lapse
Saturday Morning at 7am EST (12/15) to Sunday Night at 7pm EST (12/16)
Click on image to enlarge
Snow overspreads the Northeast after Midnight (EST) on Sunday (12/16), followed by a lull in precipitation across much of New England and New York during the late morning through early afternoon hours. Meanwhile, steadier snow continues across western New York and Ontario before shifting east across the North Country later in the day.
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