National Weather Service - Burlington, VT - St. Patrick's Day Nor'easter March 16-17, 2007

St. Patrick's Day Nor'easter

16-17 March 2007

Summary

Mother Nature on St. Patrick's Day, left no doubt that winter still had several more days to go before spring officially arrived Tuesday evening (March 20^th - 805 pm EDT). Snowfall totals from the St. Patrick's Day storm ranged from 4 to 6 inches within the Saint Lawrence River Valley (western edge of the storm) to a rather uniform 10 to 14 inches across the rest of Northern New York and Vermont.

This occurred, after a week that felt more like Spring, as temperatures climbed in the 40s to 60s on Tuesday (13^th) and Wednesday (14^th), which helped greatly reduce the snow pack (including some bare spots) across Vermont and Northern New York. In addition, several weak areas of low pressure moved along a boundary draped across the region and delivered an half to one inch of rainfall on Wednesday (14^th) and Thursday (15^th). This combination of snow melt and rainfall caused increased runoff into ice-covered rivers, that resulted in scattered ice jams and localized flooding on the 14^th and 15^th in both Vermont and northern New York.

This boundary pushed south of the region as a cold front on Thursday afternoon and delivered colder air and high pressure across the area Thursday night and Friday (16^th). The cold front continued to move south Thursday night, before it became stationary across the Carolinas on Friday morning (16^th), where low pressure developed along the boundary.

On Friday, a coupled jet stream dipped across the Mississippi River Valley and southeast United States and turned sharply up the East coast. This allowed the storm to intensify rapidly during Friday and move northeast along the eastern seaboard. Wintry weather occurred across interior portions of the Mid-Atlantic states, including Washington D.C. and Philadelphia on Friday morning and moved north into New York City and Southern New England by noon.

Snow entered southern Vermont by mid to late afternoon, reaching the Adirondacks and Central Vermont by early evening and overspreading the entire region by late evening. Heavy snow started in southern Vermont by late evening and reached the rest of the region by Midnight Saturday (17^th) with snowfall rates of 1 to 2 inches per hour at times. The snow mixed with sleet at times in the Connecticut River Valley early Saturday morning before gradually tapering off from south to north across Vermont and New York before sunrise and along the Canadian border by late morning.

However, there was a second part to this storm that developed late Saturday afternoon and continued Sunday morning (18^th)...called wrap-around and upslope. On Saturday morning, infra-red satellite clearly showed a dry slot (light green-aqua color) that developed and moved into Vermont, which quickly shutdown the steady snowfall. Meanwhile, deeper layered moisture in the wrap-around portion of the storm (light yellow) was producing snowfall across Ontario and the eastern Great Lakes.

During the course of late Saturday afternoon and Saturday night, as the surface low pulled further away from Vermont and Northern New York, the deeper layered wraparound snows moved into the region (yellow/tan). This snowfall became locally enhanced by favorable upslope flow (air moving up the slope of a mountain, lifting to a point of condensation, then falling as snow) along the northwest slopes of the Northern Adirondacks of New York and the Northern Green Mountains of Vermont. This snow continued until midday Sunday and then quickly dissipated.

An additional 2 to 5 inches of snowfall occurred across the northern Champlain Valley and other northern valleys in Vermont with 4 to 8 inches additional snowfall in communities along the favored upslope regions of the Northern Adirondacks and Northern Green Mountains. Therefore, some two-day snowfall totals exceeded 18 inches, with many northern ski areas reporting around 2 feet of snow.

Snowfall Map for Nor'easter ending Saturday

Storm Total Snowfall from the Nor'Easter

Snowfall Reports from the Nor'Easter ending Saturday 3/17 (text)

PUBLIC INFORMATION STATEMENT

SPOTTER REPORTS

NATIONAL WEATHER SERVICE BURLINGTON VT

245 PM EDT SAT MAR 17 2007

THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN DURING THE PAST 24

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...

 ROUSES POINT          13.0  1101 AM  3/17   MEDIA

 DANNEMORA             12.0  1123 AM  3/17   SPOTTER

 PLATTSBURGH           11.5   910 AM  3/17   TV STATION

 MOOERS                11.0   822 AM  3/17   HAM RADIO

 PERU                  10.7   710 AM  3/17   SPOTTER

 SCHUYLER FALLS         9.5   823 AM  3/17   HAM RADIO

 ELLENBURG DEPOT        8.0   600 AM  3/17   COOP

...ESSEX COUNTY...

 WILMINGTON            12.0   820 AM  3/17   SPOTTER

 CROWN POINT           11.5   756 AM  3/17   SPOTTER

 JAY                   10.0   812 AM  3/17   HAM RADIO

...FRANKLIN COUNTY...

 TUPPER LAKE            9.0   709 AM  3/17   COOP

 TUPPER LAKE            8.0   848 AM  3/17   PUBLIC

 SARANAC LAKE           6.0   819 AM  3/17   HAM RADIO

 MALONE                 5.5   732 AM  3/17   COOP

 DUANE                  4.0   821 AM  3/17   HAM RADIO

...ST. LAWRENCE COUNTY...

 EDWARDS               �6.0   738 AM  3/17   HAM RADIO

 NORFOLK                6.0   816 AM  3/17   HAM RADIO

 CANTON                 5.0   947 AM  3/17   COOP

 OGDENSBURG             4.0   742 AM  3/17   HAM RADIO

VERMONT

...ADDISON COUNTY...

 MONKTON              �12.0  1231 PM  3/17   SPOTTER

 NEW HAVEN             12.0   827 AM  3/17   COOP

 BRIDPORT              11.0   735 AM  3/17   SPOTTER

 SOUTH LINCOLN         11.0   849 AM  3/17   COOP

 CORNWALL              10.0   805 AM  3/17   COOP

...CALEDONIA COUNTY...

 WALDEN                16.0   917 AM  3/17   SPOTTER

 WHEELOCK              12.0  1044 AM  3/17   SPOTTER

 STANNARD              11.5  1100 AM  3/17   SPOTTER

 SUTTON                10.0   826 AM  3/17   COOP

 LYNDONVILLE            8.8  1125 AM  3/17   SPOTTER

 EAST BURKE             8.0 � 920 AM  3/17   SPOTTER

...CHITTENDEN COUNTY...

 HANKSVILLE            12.2   947 AM  3/17   COOP

 SOUTH BURLINGTON      11.0   821 AM  3/17   HAM RADIO

 WESTFORD              11.0  1200 PM  3/17   NWS EMPLOYEE

 SOUTH BURLINGTON      10.6  1000 AM  3/17   NWS OFFICE

 ESSEX CENTER          10.0   925 AM  3/17   SPOTTER

 NORTH UNDERHILL        9.7   747 AM  3/17   NWS EMPLOYEE

 COLCHESTER             9.5  1004 AM  3/17   NWS EMPLOYEE

 JERICHO CENTER         9.4  1231 PM  3/17   NWS EMPLOYEE

 ESSEX                  9.0   710 AM  3/17   NWS EMPLOYEE

 ESSEX JUNCTION         9.0   823 AM  3/17   HAM RADIO

 ESSEX JUNCTION         8.0   748 AM  3/17   HAM RADIO

 SHELBURNE              8.0  1027 AM  3/17   PUBLIC

...ESSEX COUNTY...

 EAST HAVEN             9.5   932 AM  3/17   COOP

 CANAAN                 9.0   850 AM  3/17   COOP

 ISLAND POND            9.0  1004 AM  3/17   COOP

...FRANKLIN COUNTY...

 HIGHGATE CENTER       16.0   819 AM  3/17   HAM RADIO

 ENOSBURG FALLS        11.0   849 AM  3/17   COOP

 SWANTON               11.0   927 AM  3/17   SPOTTER

 SAINT ALBANS           9.8   916 AM  3/17   NWS EMPLOYEE

...GRAND ISLE COUNTY...

 NORTH HERO            12.0  1125 AM  3/17   SPOTTER

 SOUTH HERO             9.0  1124 AM  3/17   SPOTTER

...LAMOILLE COUNTY...

 STOWE                 12.5  1252 PM  3/17   SPOTTER

 JEFFERSONVILLE        10.2   700 AM  3/17   COOP

 JEFFERSONVILLE        10.0   749 AM  3/17   SPOTTER

 EDEN                   9.7   850 AM  3/17   COOP

 MORRISVILLE            9.0   825 AM  3/17   COOP

...ORANGE COUNTY...

 BROOKFIELD            10.0   755 AM  3/17   COOP

 CHELSEA               10.0   749 AM  3/17   COOP

 RANDOLPH CENTER        9.5  1012 AM  3/17   SPOTTER

 SOUTH STRAFFORD        9.0   834 AM  3/17   SPOTTER

...ORLEANS COUNTY...

 JAY                   12.0  1130 PM  3/17   TOWN OFFICIAL

 NEWPORT               11.8   700 AM  3/17   COOP

 EAST ALBANY           11.0   831 AM  3/17   COOP

 BROWNINGTON            8.5   511 AM  3/17   SPOTTER

...RUTLAND COUNTY...

 RUTLAND               10.8  1005 AM  3/17   COOP

 PAWLET                10.5   636 AM  3/17   SPOTTER

 DANBY FOUR CORNERS     8.0  1005 AM  3/17   COOP

 CLARENDON              6.0  1231 AM  3/17   VT AOT

...WASHINGTON COUNTY...

 MORETOWN              11.0   718 AM  3/17   PUBLIC

 WAITSFIELD            11.0   810 AM  3/17   COOP

 WATERBURY CENTER      11.0   727 AM  3/17   SPOTTER

 NORTHFIELD            10.2   245 PM  3/17   NWS EMPLOYEE

 WAITSFIELD            10.0   634 AM  3/17   PUBLIC

 MARSHFIELD             9.0   854 AM  3/17   SPOTTER

 MONTPELIER             9.0   947 AM  3/17   COOP

 NORTHFIELD             9.0   811 AM  3/17   COOP

 PLAINFIELD             9.0   924 AM  3/17   COOP

 WORCESTER              8.2   829 AM  3/17   COOP

 NORTH CALAIS           8.0  1009 AM  3/17   SPOTTER

...WINDSOR COUNTY...

 SPRINGFIELD           14.5   508 AM  3/17   SPOTTER

 CHESTER               12.0  1125 AM  3/17   SPOTTER

 HARTLAND              12.0   921 AM  3/17   SPOTTER

 BETHEL                11.5   636 AM  3/17   SPOTTER

 ROCHESTER             11.5   753 AM  3/17   COOP

 SOUTH WOODSTOCK       10.0   826 AM  3/17   COOP

 NORWICH                9.0  1041 AM  3/17   PUBLIC

 WHITE RIVER JUNCTION   9.0  1123 AM  3/17   SPOTTER

 ANDOVER                8.0   820 AM  3/17   HAM RADIO

$$

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Surface Maps for Thursday (15^th), Friday (16^th) and Saturday (17^th) Mornings

US Surface Chart, Thursday Morning (3/15/2007), 1200UTC (8am EDT) Back to Text

US Surface Chart, Friday Morning (3/16/2007), 1200UTC (8am EDT) Back to Text

US Surface Chart, Saturday Morning (3/17/2007), 1200UTC (8am EDT) Back to Text

Upper Air Charts showing Deepening and Sharpening Coupled Upper Jet

Friday Morning (16^th) through Saturday Morning (17^th)

US Upper Air Chart (250HPa), Friday Morning (3/16/2007), 1200UTC (8am EDT)

US Upper Air Chart (250HPa), Friday Evening (3/17/2007), 0000UTC (8pm EDT - 3/16/2007)

US Upper Air Chart (250HPa), Saturday Morning (3/17/2007), 1200UTC (8am EDT) Back to Text

Surface Low Track along the Eastern Seaboard Friday Afternoon into Saturday

Surface Chart, Friday Afternoon (3/16/2007), 1800UTC (2pm EDT)

Surface Chart, Friday Evening, 0000UTC 3/17/2007 (8pm EDT - 3/16/2007) Back to Text

Surface Chart, Saturday Morning (3/17/2007), 0600UTC (2am EDT)

Surface Chart, Saturday Morning (3/17/2007), 1200UTC (8am EDT) Back to Text

Satellite and Radar on Friday Evening (16^th)

Infra-red Satellite and Surface Chart, Friday Evening, 0000UTC 3/17/2007 (8pm EDT - 3/16/2007)

Composite Radar and Surface Chart, Friday Evening, 0000UTC 3/17/2007 (8pm EDT - 3/16/2007) Back to Text

Satellite and Radar on Saturday Morning (17^th)

Infra-red Satellite and Surface Chart, Saturday Morning (3/17/2007), 1200UTC (8am EDT)      Back to Text

Composite Radar and Surface Chart, Saturday Morning (3/17/2007), 1200UTC (8am EDT) Back to Text

Surface Maps and Satellite for Saturday Night (17^th) and Early Sunday Morning (18^th)

Surface Chart, Saturday Evening, 0000UTC 3/18/2007 (8pm EDT - 3/17/2007) Back to Text

Surface Chart, Early Sunday Morning (3/18/2007), 0600UTC (2am EDT) Back to Text

Infra-red Satellite, Early Sunday Morning (3/18/2007), 0600UTC (2am EDT) Back to Text

Snowfall Reports from the Nor'Easter ending Saturday (3/17) and the

Wrap-around/Upslope Event of Saturday evening into Sunday (3/18) morning

PUBLIC INFORMATION STATEMENT

SPOTTER REPORTS

NATIONAL WEATHER SERVICE BURLINGTON VT

1014 AM EDT SUN MAR 18 2007

THE FOLLOWING ARE UNOFFICIAL OBSERVATIONS TAKEN OVER THE PAST 36

HOURS WHICH INCLUDES SNOWFALL FROM THE ST PATRICKS DAY NOR'EASTER

AND FROM UPSLOPE SNOW WHICH OCCURRED LAST NIGHT INTO THIS MORNING.

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...

 ELLENBURG DEPOT       20.0   700 AM  3/18   COOP

...ESSEX COUNTY...

 NEWCOMB               10.5   942 AM  3/18   COOP

...FRANKLIN COUNTY...

 TUPPER LAKE           12.0   700 AM  3/18   COOP

 MALONE                10.5   700 AM  3/18   COOP

...ST. LAWRENCE COUNTY...

 CANTON                 6.5   900 AM  3/18   COOP

VERMONT

...ADDISON COUNTY...

 SOUTH LINCOLN         18.8   700 AM  3/18   COOP

 NEW HAVEN             18.0   630 AM  3/18   COOP

 MONKTON               16.0   913 AM  3/18   SPOTTER

...CALEDONIA COUNTY...

 SUTTON                13.0   730 AM  3/18   COOP

...CHITTENDEN COUNTY...

 HANKSVILLE            20.5   700 AM  3/18   COOP

 NORTH UNDERHILL       17.6   741 AM  3/18   NWS EMPLOYEE

 JERICHO CENTER        15.9   600 AM  3/18   NWS EMPLOYEE

 SOUTH BURLINGTON      14.6   729 AM  3/18   NWS OFFICE

 ESSEX                 13.0   700 AM  3/18   NWS EMPLOYEE

...ESSEX COUNTY...

 CANAAN                12.5   800 AM  3/18   COOP

 ISLAND POND           12.0   900 AM  3/18   COOP

...FRANKLIN COUNTY...

 ENOSBURG FALLS        16.0   700 AM  3/18   COOP

 SAINT ALBANS          12.2   927 AM  3/18   COOP

...LAMOILLE COUNTY...

 JEFFERSONVILLE        15.4   855 AM  3/18   COOP

 PLEASANT VALLEY       15.3   100 AM  3/18   SPOTTER

 EDEN                  14.7   700 AM  3/18   COOP

 MORRISVILLE           11.5   700 AM  3/18   COOP

...ORANGE COUNTY...

 CORINTH               13.5   710 AM  3/18   SPOTTER

 BROOKFIELD            12.0   800 AM  3/18   COOP

 CHELSEA               11.2   700 AM  3/18   COOP

...ORLEANS COUNTY...

 NEWPORT               14.3   700 AM  3/18   COOP

 EAST ALBANY           11.3   700 AM  3/18   COOP

...RUTLAND COUNTY...

 RUTLAND               12.9   700 AM  3/18   COOP

 DANBY FOUR CORNERS    10.8   944 AM  3/18   COOP

...WASHINGTON COUNTY...

 WAITSFIELD            16.0   800 AM  3/18   COOP

 NORTHFIELD            11.5   950 AM  3/18   COOP

 MARSHFIELD            11.0   855 AM  3/18   SPOTTER

 WORCESTER             10.7   700 AM  3/18   COOP

 PLAINFIELD             9.9   944 AM  3/18   COOP

...WINDSOR COUNTY...

 BETHEL                12.0   700 AM  3/18   COOP

$$

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