Dec 7-8 Ocean Effect Snow Potential

[CCPSUSuperstorm2010]

While Ocean Effect Snow events are rare they do occur during the coldest air masses of the season. It appears Monday night into Tuesday morning a new rush of colder air works into the region with westerly winds as a big ocean storm retrogrades back into Maine. Right now the 850mb circulation of this low does not move southwest enough to allow the surface to 850mb wind trajectory to change from west to southwest as currently modeled by the GFS model. EURO and the NAM both show favorable winds at 850mbs and cold 850mb temperatures reaching -12C to -14C over the Cape and Islands. Right now oceanic temperatures south of the South Coast of SNE are between 10-12C with cooler waters in Nantucket Sound and closer to the coastline. 700mb level moisture looks quite sufficient right now for precipiation to be produced. Also if winds align properly for this to occur, this will be happening during the evening into the early morning hours so surface temperatures should be cold enough to allow for mostly to all snow to fall. We need the winds to change for us to have any chances at snowfall from Monday evening into Tuesday around noon. Timing looks to be around 21z Monday into 15z Tuesday if this was to occur. Right now the 00z EURO favors southwesterly winds at 850mb, I do not have the surface and precip charts for the EURO so I don't know if it shows snow or not. NAM is just out of its range to show any precipitation falling across Cape Cod, MA. 18z GFS does not look favorable at this time. 15z SREF means look good for potential measurable precipitation to occur in this period. Still about 3 1/2 days of changing around for the models. We need to the 850mb circulation to head a little more southwest in this period as the ocean storm retrogrades into Maine and Quebec, CN. Still plenty of time for the models to get into better agreement. I will have more later on.

[NSwx]

Great post, Sure looks to be a strong LP, been looking for this all fall.

[Damage In Tolland]

[CoastalWx]

While Ocean Effect Snow events are rare they do occur during the coldest air masses of the season. It appears Monday night into Tuesday morning a new rush of colder air works into the region with westerly winds as a big ocean storm retrogrades back into Maine. Right now the 850mb circulation of this low does not move southwest enough to allow the surface to 850mb wind trajectory to change from west to southwest as currently modeled by the GFS model. EURO and the NAM both show favorable winds at 850mbs and cold 850mb temperatures reaching -12C to -14C over the Cape and Islands. Right now oceanic temperatures south of the South Coast of SNE are between 10-12C with cooler waters in Nantucket Sound and closer to the coastline. 700mb level moisture looks quite sufficient right now for precipiation to be produced. Also if winds align properly for this to occur, this will be happening during the evening into the early morning hours so surface temperatures should be cold enough to allow for mostly to all snow to fall. We need the winds to change for us to have any chances at snowfall from Monday evening into Tuesday around noon. Timing looks to be around 21z Monday into 15z Tuesday if this was to occur. Right now the 00z EURO favors southwesterly winds at 850mb, I do not have the surface and precip charts for the EURO so I don't know if it shows snow or not. NAM is just out of its range to show any precipitation falling across Cape Cod, MA. 18z GFS does not look favorable at this time. 15z SREF means look good for potential measurable precipitation to occur in this period. Still about 3 1/2 days of changing around for the models. We need to the 850mb circulation to head a little more southwest in this period as the ocean storm retrogrades into Maine and Quebec, CN. Still plenty of time for the models to get into better agreement. I will have more later on.

Actually, interesting post. The only thing that may be a problem, is that winds may be too much from a 270 type direction. You probably want more of a 250 type deal for the Islands and 230-240 for the Cape. It's pretty rare for this type of OES, but it could happen on the Islands, if the flow lines up properly. I wouldn't really expect too much right now.

[CCPSUSuperstorm2010]

Actually, interesting post. The only thing that may be a problem, is that winds may be too much from a 270 type direction. You probably want more of a 250 type deal for the Islands and 230-240 for the Cape. It's pretty rare for this type of OES, but it could happen on the Islands, if the flow lines up properly. I wouldn't really expect too much right now.

This is more of a 6-7th event, not 7-8th event, I need to change the dates, but I agree. The EURO and ensembles are pretty cold for this period. We do need the SW winds to shape up, but given that the models have been pretty consistent with the track of the surface low into Quebec, CN this seems like another missed event. We don't need this, but it certaintly would be pretty cool to witness before I head to San Antonio, TX for two months of USAF basic training on January 18th.

[New England Storm]

This is more of a 6-7th event, not 7-8th event, I need to change the dates, but I agree. The EURO and ensembles are pretty cold for this period. We do need the SW winds to shape up, but given that the models have been pretty consistent with the track of the surface low into Quebec, CN this seems like another missed event. We don't need this, but it certaintly would be pretty cool to witness before I head to San Antonio, TX for two months of USAF basic training on January 18th.

It would be nice to see infact I cant remember the last time we had a good ocean effect snow potential. I think maybe 2007? any who it was in a time when just everything came together and it was very local event. Good luck at basic training.

[cpickett79]

lookin like a no go?

[Tropopause_Fold]

lookin like a no go?

flow is almost due west. will be very hard to make it bend north of the islands (if it can even get to ACK). there's a really small window near dawn on tuesday when the flow at 8h becomes more like 240, but i don't think that's enough to cut it.

best bet for getting OES on a S/SW flow is actually in advance of a warm-up. it doesn't happen all that often (for obvious reasons i suppose) but sometimes if we have a nice cold air mass in place and we get a clipper passing a bit north of the region and the low and mid-level flow veers around for a time but the WAA isn't too strong we can get some.

getting the OES stuff on a WSW wind does happen from time to time but more often than not it's just stray flurries and the "bulk" of the activity stays south.

[NorthShoreWx]

flow is almost due west. will be very hard to make it bend north of the islands (if it can even get to ACK). there's a really small window near dawn on tuesday when the flow at 8h becomes more like 240, but i don't think that's enough to cut it.

best bet for getting OES on a S/SW flow is actually in advance of a warm-up. it doesn't happen all that often (for obvious reasons i suppose) but sometimes if we have a nice cold air mass in place and we get a clipper passing a bit north of the region and the low and mid-level flow veers around for a time but the WAA isn't too strong we can get some.

Its rare. Here is the last one here; its probably the last one to affect the cape / islands as well:

http://www.northshorewx.com/oes20050119.asp

[CCPSUSuperstorm2010]

Looks like a no go right now.

[ackwaves]

Looks like a no go right now.

couple of flurries right now. bulk is just to our south as per radar. very close.

[CCPSUSuperstorm2010]

Close call for Nantucket and Martha's Vineyard, MA. Also the 12z EURO is showing some possible OES after the large early week storm next week.

[ConvectiveSolutions]

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

LATEST STREAMLINE ANALYSIS INDICATES LAKE EFFECT STREAMERS/PLUMES

WILL CONTINUE TO ALIGN THEMSELVES WNW ACROSS WESTERN MA AND

NORTHERN CT...THEN REGENERATING OVER THE SOUTH COASTAL WATERS IN

RESPONSE TO RELATIVELY WARM OCEAN TEMPS. THEREFORE EXPECT ANY SNOW

SHOWER/FLURRY ACTIVITY TO BE FOCUSED ACROSS THIS REGION WITH

LITTLE IF ANY SNOW ACCUMULATION CONFINED TO NARROW SNOW BANDS. AS

A RESULT HAVE MODIFIED THE FORECAST ACROSS THIS REGION TO REFLECT

THIS THINKING.

[CCPSUSuperstorm2010]

Potential exists for a secondary offshore storm to develop after the 12-13th storm moves through. H5 position is too far north to get the low to retrograde into the region. I really dislike these patterns in terms of the H5 low right over head. We need it around 40n or south of there for anything decent to develop after the front moves through.