powderfreak
New member
I wanted to get this out before BTV sent out this afternoon's forecast package for comparison reasons. If you just want a straight forecast, scroll down and read the last section.
This storm is a juicy looking one on radar and if one were to just look at the national radar and water vapor loop, you would think we're about to get absolutely nailed. The Great Lakes low is weaker than modeled and the Gulf low is stronger than modeled. I'm going to make a few modifications to the model output and see where it takes us. National maps make this storm look like a classic Miller A (Low pressure track out of the Gulf of Mexico straight up the east coast...the classic track) and one would think, hey, this is looking awesome. The 500mb pattern and Great Lakes low is going to be the problem as the upper level trough hangs back to the west. So a strong low moving out of the Gulf is actually going to get dismantled by the energy in the Great Lakes region instead of bombing out on its way up the coast. MM5 from SUNY and NAM/ETA track the east coast low inland straight through southern New England into Gulf of Maine. That's not going to happen. Its really cold across the northeast with strong cold air drainage. How cold is it? Atlanta's Hartsfield Airport reported several hours of freezing rain this morning and portions of SC,NC,VA are closing in on an inch of ice with trees and power lines starting to come down.
Up here in New England, moisture transport off the Atlantic will be coming in on a strong southeasterly wind aloft with low level cold air moving in on a northerly flow. The meso-scale models are indicating much stronger orographic enhancement with this system than I would've thought. SUNY MM5 and regional ETA (BTV's workstation 5km ETA hasn't updated since the 13th, I should email those guys to see whats up...so I'm left with the PSU regional ETA) have strong downsloping on the western side of the Berkshires, Green Mtns, and White Mountains with strong orographic lift on south and east facing slopes. The models actually seem to put a precip hole over VT which I cannot figure out.
The NAM has incredibly low precipitation across most of VT which has me worried. NAM/ETA has BTV with .39" QPF split 50-50 sleet and snow. It has MPV (Montpelier) even lower at .35" QPF. Meanwhile, its got Plattsburgh, NY at .65" with .5" of that snow...and similar values for most of the Adirondacks with a precip maximum over the south and east facing slopes. The NAM also has a lot of mixing with over half of the storm in VT consisting of mixed precipitation in the form of sleet and freezing rain. This has to due with its track further to the west which I'm going to throw out and follow the GFS for this forecast which indicates less mixing and a better looking precipitation field (spits out .5-.6" QPF with little mixing at MPV, BTV, PLB).
Low pressure track is not going through the cold air in southern New England and will be forced towards the coast. Baroclinic zone is right along the coast and that is the path of least resistence. It was thought that the Great Lakes low could pull the low through the cold air, but with that low being weaker than forecasted, the east coast low is swinging further east. This means less mixing of p-types across VT and nearly no mixing across the Adirondacks. There will likely be some sleet mixed in across most areas at some point but only very briefly northwest of a White River Junction-Rutland-Glens Falls line. In those areas, proximity to low pressure, ocean, and strong upper level SEly flow will cause a change over for 3-6hrs of the 12hr event.
Forecast by Region:
Catskills: Precip breaks out around midnight as snow, mixes with and changes to sleet/freezing rain then tapers off to snow showers or freezing drizzle around noon. Lower elevations might warm up enough to end as plain rain. 4-6" of snow, sleet, and a coating of ice on top. Precipitation will fall heavily at times.
Berkshires: Snow breaking out around 3am changing to sleet then freezing rain. 3-5" of snow and sleet with significant ice accumulations possible. Going to have to watch areas in the state of MA north of the Pike for tree dropping ice accumulations after a quick burst of snow. Precipitation will be heavy at times.
Vermont south of Killington: Snow beginning around 3am then changing to sleet and possibly freezing rain in the southern two counties of VT...then back to snow. 4-8" of snow and sleet with a coating of ice. All ends by 3pm Friday. Precipitation will be heavy at times.
Vermont north of Killington: Snow spreading northward and reaching most areas by sunrise. Might mix with sleet in the first few hours before becoming all snow by noon. Snow will come in bursts. 4-8" of snow accumulation by 6pm Friday. Additional mountain snow showers overnight could add up to 2" by Saturday morning bringing resorts 6-10" of new snow for Saturday morning skiers.
Adirondacks: Snow beginning between 3-6am...with bursts of heavier snow throughout the day. Accumulating 6-12 inches by 6pm Friday.
In New Hampshire and Maine...significant ice accumulation occurs just inland from the coast during the day on Friday with ice and snow in the mountains. Foothill communities could be looking at quite the accumulation of sleet and freezing rain. Ski resorts should expect 6-12" of snow and sleet accumulations by Saturday morning.
I wish I had a better way of making all the regions fit together into a more fluid forecast, but with so many mesoscale features its hard to forecast for each region. With so many people on this board spread across the northeast, I want to hit each area as well. It might've been a bit rushed but I've got a final exam in a couple hours and wanted to beat the afternoon NWS forecast packages. Weather is much more interesting than Labor Economics anyway
-Scott
This storm is a juicy looking one on radar and if one were to just look at the national radar and water vapor loop, you would think we're about to get absolutely nailed. The Great Lakes low is weaker than modeled and the Gulf low is stronger than modeled. I'm going to make a few modifications to the model output and see where it takes us. National maps make this storm look like a classic Miller A (Low pressure track out of the Gulf of Mexico straight up the east coast...the classic track) and one would think, hey, this is looking awesome. The 500mb pattern and Great Lakes low is going to be the problem as the upper level trough hangs back to the west. So a strong low moving out of the Gulf is actually going to get dismantled by the energy in the Great Lakes region instead of bombing out on its way up the coast. MM5 from SUNY and NAM/ETA track the east coast low inland straight through southern New England into Gulf of Maine. That's not going to happen. Its really cold across the northeast with strong cold air drainage. How cold is it? Atlanta's Hartsfield Airport reported several hours of freezing rain this morning and portions of SC,NC,VA are closing in on an inch of ice with trees and power lines starting to come down.
Up here in New England, moisture transport off the Atlantic will be coming in on a strong southeasterly wind aloft with low level cold air moving in on a northerly flow. The meso-scale models are indicating much stronger orographic enhancement with this system than I would've thought. SUNY MM5 and regional ETA (BTV's workstation 5km ETA hasn't updated since the 13th, I should email those guys to see whats up...so I'm left with the PSU regional ETA) have strong downsloping on the western side of the Berkshires, Green Mtns, and White Mountains with strong orographic lift on south and east facing slopes. The models actually seem to put a precip hole over VT which I cannot figure out.
The NAM has incredibly low precipitation across most of VT which has me worried. NAM/ETA has BTV with .39" QPF split 50-50 sleet and snow. It has MPV (Montpelier) even lower at .35" QPF. Meanwhile, its got Plattsburgh, NY at .65" with .5" of that snow...and similar values for most of the Adirondacks with a precip maximum over the south and east facing slopes. The NAM also has a lot of mixing with over half of the storm in VT consisting of mixed precipitation in the form of sleet and freezing rain. This has to due with its track further to the west which I'm going to throw out and follow the GFS for this forecast which indicates less mixing and a better looking precipitation field (spits out .5-.6" QPF with little mixing at MPV, BTV, PLB).
Low pressure track is not going through the cold air in southern New England and will be forced towards the coast. Baroclinic zone is right along the coast and that is the path of least resistence. It was thought that the Great Lakes low could pull the low through the cold air, but with that low being weaker than forecasted, the east coast low is swinging further east. This means less mixing of p-types across VT and nearly no mixing across the Adirondacks. There will likely be some sleet mixed in across most areas at some point but only very briefly northwest of a White River Junction-Rutland-Glens Falls line. In those areas, proximity to low pressure, ocean, and strong upper level SEly flow will cause a change over for 3-6hrs of the 12hr event.
Forecast by Region:
Catskills: Precip breaks out around midnight as snow, mixes with and changes to sleet/freezing rain then tapers off to snow showers or freezing drizzle around noon. Lower elevations might warm up enough to end as plain rain. 4-6" of snow, sleet, and a coating of ice on top. Precipitation will fall heavily at times.
Berkshires: Snow breaking out around 3am changing to sleet then freezing rain. 3-5" of snow and sleet with significant ice accumulations possible. Going to have to watch areas in the state of MA north of the Pike for tree dropping ice accumulations after a quick burst of snow. Precipitation will be heavy at times.
Vermont south of Killington: Snow beginning around 3am then changing to sleet and possibly freezing rain in the southern two counties of VT...then back to snow. 4-8" of snow and sleet with a coating of ice. All ends by 3pm Friday. Precipitation will be heavy at times.
Vermont north of Killington: Snow spreading northward and reaching most areas by sunrise. Might mix with sleet in the first few hours before becoming all snow by noon. Snow will come in bursts. 4-8" of snow accumulation by 6pm Friday. Additional mountain snow showers overnight could add up to 2" by Saturday morning bringing resorts 6-10" of new snow for Saturday morning skiers.
Adirondacks: Snow beginning between 3-6am...with bursts of heavier snow throughout the day. Accumulating 6-12 inches by 6pm Friday.
In New Hampshire and Maine...significant ice accumulation occurs just inland from the coast during the day on Friday with ice and snow in the mountains. Foothill communities could be looking at quite the accumulation of sleet and freezing rain. Ski resorts should expect 6-12" of snow and sleet accumulations by Saturday morning.
I wish I had a better way of making all the regions fit together into a more fluid forecast, but with so many mesoscale features its hard to forecast for each region. With so many people on this board spread across the northeast, I want to hit each area as well. It might've been a bit rushed but I've got a final exam in a couple hours and wanted to beat the afternoon NWS forecast packages. Weather is much more interesting than Labor Economics anyway
-Scott