powderfreak
New member
The NWS has a Snow Advisory out for the Green Mountain communities for 3-5"...and also in the Adirondacks. This is likely under-done for the ski resorts...possibly well under-done. I had checked this earlier before writing my Stowe post, and the models have significantly increased what was going to be scattered snow showers and maybe a squall line to a more synoptic type event between 4pm today and 1am tomorrow most areas but holding across the Green Mtn Spine possibly till daybreak. Have read the NWS discussion but am going off the very latest model data and intuition.
SNOW FORECAST (through 6-7am tomorrow on ski area Snow Reports):
Adirondacks: 4-7" for Whiteface and Gore...high end at Whiteface, low end at Gore. Lake effect snow will add to that on Saturday and Sunday.
Northern half of the Green Mountains: 4-7" on average from Killington to Sugarbush...though someone could report 6-8" in the morning and it wouldn't surprise me. Read discussions below for more info on N.VT.
Southern Green Mountains: 2-4" on average from Okemo to Mt. Snow.
Berkshires: 1-3" with very isolated 4" in northern Berks (hills around North Adams/RT 2 region).
Catskills: 1-3" with very isolated 4" in the high country of Delaware County because of its on the western side, but snow should come in a short burst late this afternoon into early evening.
White Mountains north of Loon: 4-7" with highest in Coos County but don't think there's any downhill areas up there.
White Mountains south of Loon: 1-4" with the lesser amounts the closer you get to the south and east.
Sunday River and Sugarloaf in Maine: 3-7" with uncertainty highest here as low pressure will be further north of the region and my general lack of knowledge of snow events in that region. Model precipitation is almost the same as N.NH, N.VT, and N.NY.
TIMING FOR N.NY and N.VT:
9z and 12z RUC and 12km grid (higher resolution NAM) brings light snow into the western half of the Adirondacks through 4pm. NAM then brings the snow to the Green Mountain Spine southward along the west slopes of the Berkshires after 4pm with little accumulation by 7pm in west slope communities from the Berkshires to Jay Peak. Its snowing moderately in the 'Dacks and western Catskills at this time. See potential for 1"/hr rates in the late this afternoon/early evening...especially along the southern and western perimeter. Moderate snow should be in the Green Mountains after 7pm with a steady snow through midnight. Will likely see 1"/hr on the ski terrain but most populated regions will likely average a half an inch per hour with the chance for a burst at the height of an inch in an hour. Given fast movement, 6 hours average bet for snow in Green Mtn communities yields 3-4" for the populations. Champlain Valley, thinking I'll have 2" of new snow tomorrow morning in my backyard.
SITUATION/DISCUSSION: Temps will be relatively mild compared to the past two weeks and with the NAM having a good handle on temps now, will go with it...bringing 32-35F for highs below 500ft in the Champlain Valley, Hudson River Valley, Mohawk Valley, and Connecticut River Valley...locations below 1,000ft will likely flirt with 32F but the ground temps are still very cold so it won't matter much. BUT, the warmer temperatures are good as more moisture will also come with it.
What we have is a low pressure system strengthening across southern Canada and lifting ENE...leaving NY and New England on the south side of the low. This is normally bad, but its on the Arctic Jet Stream and not the southern stream which has done us in many times so far this winter. A very impressive upper level jet streak is moving up from the Ohio River Valley back into the western Gulf Coast states...we will be in the left front quad of this jet streak which means upper level divergence of air (left front and right rear of streaks are the divergence points) that will cause low and mid level air to rise. The NAM and GFS have textbook upper level divergence crossing the north country this evening which will initiate strong lift. Since this strong wind field aloft is coming out of the western Gulf States region, warm air advection will be occurring and is very good in the upper levels. We also have a large area of potent energy/vorticity maximums pushing through the region this evening and night. Needless to say, the upper air dynamics are fairly impressive. Even if you have no idea what any of that means, its good as it'll allow for clouds that extend deeper up into the atmosphere and has a noticeable trigger for widespread precipitation to break out.
In the lower and middle levels of the atmosphere (4,500ft and 9,000ft) we will see warm air advection (WAA) before the cold front moves through and the WAA snows are some of the best *small* events during the winter. Our clippers are caused by WAA out in front of the low before a cold front swings through. They almost always produce big dendrites (and in this case, the best dendrite snow growth region of -12C to -18C in the atmosphere will be saturated between 5K and 9K feet) and that's what should happen here as everything lines up nicely. Ratios will likely average near 15 to 1. The WAA will be our main source of precipitation; once the cold air moves in, things will die down except for lake effect and very high elevation light snows. Temperatures drop for Saturday and its cold (but not *too* cold, till Sun/Mon) and breezy with lake effect and orographic snows. Can't pinpoint heaviest accumulations right now as it'll be a nowcast situation; one resort could have another 6" on Saturday while a dusting falls next door.
Total Precipitation for this evening through early tomorrow morning...GFS is showing .25-.5", while the high-res NAM has three maximums along the spine, .30" over the Rutland/Addison County border (likely trying to indicate Killington-Sugarbush region of the spine), .36" in the vicinity of Stowe/Smuggs and Mt Belvidere north of there, and .32" near Jay Peak. It all fits rather well if we assume .25-.35" from 1,500ft to 4,000ft from Killington to Jay Peak. Knowing the orographics and likely higher ratios I feel confident calling for 4-7" at those resorts with locally higher amounts. Killington, SB, and MRG can do well with a good surge of WAA out of the SW, while north of there air is traveling over the 'Dacks first but with good upper level dynamics here, I don't think we'll see much shadowing. This should fall after lifts close and before they open on Saturday...if you know what I mean.
Will address Saturday and Sunday later.
-Scott
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE BURLINGTON VT
444 AM EST FRI FEB 2 2007
...ACCUMULATING SNOW LATER TODAY AND TONIGHT IN ADVANCE OF MORE
ARCTIC AIR FOR THE NORTH COUNTRY...
.AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE NORTHERN GREAT
LAKES TODAY AND ACROSS SOUTHERN ONTARIO AND QUEBEC TONIGHT WITH
ACCOMPANYING LOW PRESSURE AND COLD FRONT. THIS WILL BRING A LARGE
SWATH OF SNOW TO THE REGION LATER TODAY THAT WILL CONTINUE THIS
EVENING AND THEN EXIT FROM WEST TO EAST AFTER MIDNIGHT.
THEREAFTER...COLDER AIR RETURNS TO THE REGION SATURDAY AND
CONTINUES THROUGH EARLY TO MID NEXT WEEK.
IN ADDITION...BRISK WEST TO SOUTHWEST WINDS FLOWING ACROSS LAKE
ONTARIO WILL CREATE A MAJOR LAKE EFFECT SNOWFALL EVENT. ALTHOUGH
THE MAIN EVENT IS LIKELY TO REMAIN SOUTH OF SAINT LAWRENCE AND
FRANKLIN COUNTIES...PORTIONS OF THE ADIRONDACKS WILL WITNESS SNOW
SHOWERS AND HEAVIER SNOW SQUALLS AT TIMES SATURDAY NIGHT AND
SUNDAY. PLEASE STAY TUNED TO LATER FORECASTS ON THIS DEVELOPING
WEATHER SITUATION.
VTZ003-004-006>008-010-016>018-022200-
/O.NEW.KBTV.SN.Y.0001.070202T2100Z-070203T0900Z/
ORLEANS-ESSEX-LAMOILLE-CALEDONIA-WASHINGTON-ORANGE-
EASTERN FRANKLIN-EASTERN CHITTENDEN-EASTERN ADDISON-
INCLUDING THE CITIES OF...NEWPORT...ISLAND POND...JOHNSON...
STOWE...ST. JOHNSBURY...MONTPELIER...BRADFORD...RANDOLPH...
ENOSBURG FALLS...RICHFORD...UNDERHILL...BRISTOL...RIPTON
444 AM EST FRI FEB 2 2007
...SNOW ADVISORY IN EFFECT FROM 4 PM THIS AFTERNOON TO 4 AM EST
SATURDAY...
THE NATIONAL WEATHER SERVICE IN BURLINGTON HAS ISSUED A SNOW
ADVISORY...WHICH IS IN EFFECT FROM 4 PM THIS AFTERNOON TO 4 AM
EST SATURDAY FOR NORTH CENTRAL...NORTHEAST VERMONT AND THE WESTERN
SLOPES OF THE GREEN MOUNTAINS FROM ADDISON COUNTY NORTHWARD.
SNOWFALL ACCUMULATIONS OF 3 TO 5 INCHES ARE EXPECTED BY SATURDAY
MORNING.
SNOW WILL DEVELOP AND MOVE INTO WESTERN VERMONT BY MID TO LATE
AFTERNOON AND OVERSPREAD THE REST OF VERMONT BY EVENING. THE SNOW
WILL BEGIN TO TAPER OFF TO SCATTERED SNOW SHOWERS FROM SOUTHWEST
TO NORTHEAST BY MIDNIGHT...BUT LIKELY LINGER IN NORTHEAST VERMONT
AND THE NORTHERN GREEN MOUNTAINS THROUGH EARLY SATURDAY MORNING.
PLEASE STAY TUNED TO NOAA WEATHER RADIO...YOUR LOCAL MEDIA...OR
GO TO http://WWW.WEATHER.GOV/BURLINGTON FOR FURTHER UPDATES ON THIS
WEATHER SITUATION.
SNOW FORECAST (through 6-7am tomorrow on ski area Snow Reports):
Adirondacks: 4-7" for Whiteface and Gore...high end at Whiteface, low end at Gore. Lake effect snow will add to that on Saturday and Sunday.
Northern half of the Green Mountains: 4-7" on average from Killington to Sugarbush...though someone could report 6-8" in the morning and it wouldn't surprise me. Read discussions below for more info on N.VT.
Southern Green Mountains: 2-4" on average from Okemo to Mt. Snow.
Berkshires: 1-3" with very isolated 4" in northern Berks (hills around North Adams/RT 2 region).
Catskills: 1-3" with very isolated 4" in the high country of Delaware County because of its on the western side, but snow should come in a short burst late this afternoon into early evening.
White Mountains north of Loon: 4-7" with highest in Coos County but don't think there's any downhill areas up there.
White Mountains south of Loon: 1-4" with the lesser amounts the closer you get to the south and east.
Sunday River and Sugarloaf in Maine: 3-7" with uncertainty highest here as low pressure will be further north of the region and my general lack of knowledge of snow events in that region. Model precipitation is almost the same as N.NH, N.VT, and N.NY.
TIMING FOR N.NY and N.VT:
9z and 12z RUC and 12km grid (higher resolution NAM) brings light snow into the western half of the Adirondacks through 4pm. NAM then brings the snow to the Green Mountain Spine southward along the west slopes of the Berkshires after 4pm with little accumulation by 7pm in west slope communities from the Berkshires to Jay Peak. Its snowing moderately in the 'Dacks and western Catskills at this time. See potential for 1"/hr rates in the late this afternoon/early evening...especially along the southern and western perimeter. Moderate snow should be in the Green Mountains after 7pm with a steady snow through midnight. Will likely see 1"/hr on the ski terrain but most populated regions will likely average a half an inch per hour with the chance for a burst at the height of an inch in an hour. Given fast movement, 6 hours average bet for snow in Green Mtn communities yields 3-4" for the populations. Champlain Valley, thinking I'll have 2" of new snow tomorrow morning in my backyard.
SITUATION/DISCUSSION: Temps will be relatively mild compared to the past two weeks and with the NAM having a good handle on temps now, will go with it...bringing 32-35F for highs below 500ft in the Champlain Valley, Hudson River Valley, Mohawk Valley, and Connecticut River Valley...locations below 1,000ft will likely flirt with 32F but the ground temps are still very cold so it won't matter much. BUT, the warmer temperatures are good as more moisture will also come with it.
What we have is a low pressure system strengthening across southern Canada and lifting ENE...leaving NY and New England on the south side of the low. This is normally bad, but its on the Arctic Jet Stream and not the southern stream which has done us in many times so far this winter. A very impressive upper level jet streak is moving up from the Ohio River Valley back into the western Gulf Coast states...we will be in the left front quad of this jet streak which means upper level divergence of air (left front and right rear of streaks are the divergence points) that will cause low and mid level air to rise. The NAM and GFS have textbook upper level divergence crossing the north country this evening which will initiate strong lift. Since this strong wind field aloft is coming out of the western Gulf States region, warm air advection will be occurring and is very good in the upper levels. We also have a large area of potent energy/vorticity maximums pushing through the region this evening and night. Needless to say, the upper air dynamics are fairly impressive. Even if you have no idea what any of that means, its good as it'll allow for clouds that extend deeper up into the atmosphere and has a noticeable trigger for widespread precipitation to break out.
In the lower and middle levels of the atmosphere (4,500ft and 9,000ft) we will see warm air advection (WAA) before the cold front moves through and the WAA snows are some of the best *small* events during the winter. Our clippers are caused by WAA out in front of the low before a cold front swings through. They almost always produce big dendrites (and in this case, the best dendrite snow growth region of -12C to -18C in the atmosphere will be saturated between 5K and 9K feet) and that's what should happen here as everything lines up nicely. Ratios will likely average near 15 to 1. The WAA will be our main source of precipitation; once the cold air moves in, things will die down except for lake effect and very high elevation light snows. Temperatures drop for Saturday and its cold (but not *too* cold, till Sun/Mon) and breezy with lake effect and orographic snows. Can't pinpoint heaviest accumulations right now as it'll be a nowcast situation; one resort could have another 6" on Saturday while a dusting falls next door.
Total Precipitation for this evening through early tomorrow morning...GFS is showing .25-.5", while the high-res NAM has three maximums along the spine, .30" over the Rutland/Addison County border (likely trying to indicate Killington-Sugarbush region of the spine), .36" in the vicinity of Stowe/Smuggs and Mt Belvidere north of there, and .32" near Jay Peak. It all fits rather well if we assume .25-.35" from 1,500ft to 4,000ft from Killington to Jay Peak. Knowing the orographics and likely higher ratios I feel confident calling for 4-7" at those resorts with locally higher amounts. Killington, SB, and MRG can do well with a good surge of WAA out of the SW, while north of there air is traveling over the 'Dacks first but with good upper level dynamics here, I don't think we'll see much shadowing. This should fall after lifts close and before they open on Saturday...if you know what I mean.
Will address Saturday and Sunday later.
-Scott
URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE BURLINGTON VT
444 AM EST FRI FEB 2 2007
...ACCUMULATING SNOW LATER TODAY AND TONIGHT IN ADVANCE OF MORE
ARCTIC AIR FOR THE NORTH COUNTRY...
.AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE NORTHERN GREAT
LAKES TODAY AND ACROSS SOUTHERN ONTARIO AND QUEBEC TONIGHT WITH
ACCOMPANYING LOW PRESSURE AND COLD FRONT. THIS WILL BRING A LARGE
SWATH OF SNOW TO THE REGION LATER TODAY THAT WILL CONTINUE THIS
EVENING AND THEN EXIT FROM WEST TO EAST AFTER MIDNIGHT.
THEREAFTER...COLDER AIR RETURNS TO THE REGION SATURDAY AND
CONTINUES THROUGH EARLY TO MID NEXT WEEK.
IN ADDITION...BRISK WEST TO SOUTHWEST WINDS FLOWING ACROSS LAKE
ONTARIO WILL CREATE A MAJOR LAKE EFFECT SNOWFALL EVENT. ALTHOUGH
THE MAIN EVENT IS LIKELY TO REMAIN SOUTH OF SAINT LAWRENCE AND
FRANKLIN COUNTIES...PORTIONS OF THE ADIRONDACKS WILL WITNESS SNOW
SHOWERS AND HEAVIER SNOW SQUALLS AT TIMES SATURDAY NIGHT AND
SUNDAY. PLEASE STAY TUNED TO LATER FORECASTS ON THIS DEVELOPING
WEATHER SITUATION.
VTZ003-004-006>008-010-016>018-022200-
/O.NEW.KBTV.SN.Y.0001.070202T2100Z-070203T0900Z/
ORLEANS-ESSEX-LAMOILLE-CALEDONIA-WASHINGTON-ORANGE-
EASTERN FRANKLIN-EASTERN CHITTENDEN-EASTERN ADDISON-
INCLUDING THE CITIES OF...NEWPORT...ISLAND POND...JOHNSON...
STOWE...ST. JOHNSBURY...MONTPELIER...BRADFORD...RANDOLPH...
ENOSBURG FALLS...RICHFORD...UNDERHILL...BRISTOL...RIPTON
444 AM EST FRI FEB 2 2007
...SNOW ADVISORY IN EFFECT FROM 4 PM THIS AFTERNOON TO 4 AM EST
SATURDAY...
THE NATIONAL WEATHER SERVICE IN BURLINGTON HAS ISSUED A SNOW
ADVISORY...WHICH IS IN EFFECT FROM 4 PM THIS AFTERNOON TO 4 AM
EST SATURDAY FOR NORTH CENTRAL...NORTHEAST VERMONT AND THE WESTERN
SLOPES OF THE GREEN MOUNTAINS FROM ADDISON COUNTY NORTHWARD.
SNOWFALL ACCUMULATIONS OF 3 TO 5 INCHES ARE EXPECTED BY SATURDAY
MORNING.
SNOW WILL DEVELOP AND MOVE INTO WESTERN VERMONT BY MID TO LATE
AFTERNOON AND OVERSPREAD THE REST OF VERMONT BY EVENING. THE SNOW
WILL BEGIN TO TAPER OFF TO SCATTERED SNOW SHOWERS FROM SOUTHWEST
TO NORTHEAST BY MIDNIGHT...BUT LIKELY LINGER IN NORTHEAST VERMONT
AND THE NORTHERN GREEN MOUNTAINS THROUGH EARLY SATURDAY MORNING.
PLEASE STAY TUNED TO NOAA WEATHER RADIO...YOUR LOCAL MEDIA...OR
GO TO http://WWW.WEATHER.GOV/BURLINGTON FOR FURTHER UPDATES ON THIS
WEATHER SITUATION.
