Tuesday, November 27, 2012
Quick snowfall update
After looking at things this AM I probably should have stuck with my original snowfall call. Given that, here is the original snowfall map with some slight additions, mainly to add an area where some locally higher amounts may occur to due heavier banding.
Monday, November 26, 2012
Updated snowfall forecast for 11/27/12...looks like more snow
Yet another touch and complex snowfall forecast for our region as latest computer model guidance has trended stronger with the developing wave of low pressure tomorrow which will be sliding just to the south of our region. With computer forecast models now deepening and strengthening the system quicker and closer to the coast, this will allow for more in the way of moisture and stronger lift to at least work into a portion of the region. Given this it does appear some of the snowfall totals from the previous forecast will have to be bumped up a bit.
The highest uncertainty with this forecast will be out across eastern MA. Computer forecast models have have the combination of strongest lift and highest moisture over this area, however, signals of an inverted trough setting up across SE MA could actually allow for warmer marine air to contaminate the lowest 2000' of the atmosphere giving this area more in the way of rain or a mix of rain/snow, cutting down snowfall totals. On the western side of this boundary is where the highest snowfall totals are going to occur as on the western side these locations will still be under the strongest lift/highest moisture and will also be cold enough to support all or mainly all snow. The million dollar question (and is always the million dollar question) is where this boundary, known as the "coastal front" sets up.
Snowfall should begin breaking out in the early to mid morning hours and start off light in intensity. In fact, for much of the storm's duration the intensity will only range from light to moderate, with the exception being some areas from SE CT into RI and interior SE MA where stronger lift aloft will allow for more periods of higher intensity snows (possibly in the range of 1'' to 1.5'' per hour). Snow will be ongoing throughout much of the afternoon and overnight periods when the system will finally begin to wind down as it moves off to the north and east. Some leftover flurries are still possible on Wednesday, especially across eastern southern New England.
Areas along the RI/SE MA coast will also experience a mix of rain/snow, especially during the afternoon hours when temperatures in the lowest 1000-1500' of the atmosphere are a touch on the warm side and especially when the precip rates are very light. During bursts of heavier precipitation, any precip would be mainly snow.
Given the above this is what I would expect:
:
The highest uncertainty with this forecast will be out across eastern MA. Computer forecast models have have the combination of strongest lift and highest moisture over this area, however, signals of an inverted trough setting up across SE MA could actually allow for warmer marine air to contaminate the lowest 2000' of the atmosphere giving this area more in the way of rain or a mix of rain/snow, cutting down snowfall totals. On the western side of this boundary is where the highest snowfall totals are going to occur as on the western side these locations will still be under the strongest lift/highest moisture and will also be cold enough to support all or mainly all snow. The million dollar question (and is always the million dollar question) is where this boundary, known as the "coastal front" sets up.
Snowfall should begin breaking out in the early to mid morning hours and start off light in intensity. In fact, for much of the storm's duration the intensity will only range from light to moderate, with the exception being some areas from SE CT into RI and interior SE MA where stronger lift aloft will allow for more periods of higher intensity snows (possibly in the range of 1'' to 1.5'' per hour). Snow will be ongoing throughout much of the afternoon and overnight periods when the system will finally begin to wind down as it moves off to the north and east. Some leftover flurries are still possible on Wednesday, especially across eastern southern New England.
Areas along the RI/SE MA coast will also experience a mix of rain/snow, especially during the afternoon hours when temperatures in the lowest 1000-1500' of the atmosphere are a touch on the warm side and especially when the precip rates are very light. During bursts of heavier precipitation, any precip would be mainly snow.
Given the above this is what I would expect:
:
Tuesday, November 27th, 2012 light snowfall event
A weak wave or perhaps multiple weak waves of energy will ride along a boundary just to our south throughout the day on Tuesday extending into early Wednesday. While some computer models eventually develop these waves into a somewhat unorganized but juicy storm, the weather pattern for this "cyclogenesis" (development/deepening of a low pressure system) to occur close to the coast is not favorable, therefore, these waves will remain weak.
Several computer models are showing some decent moisture being associated with these waves (at least decent enough to lead to the production of snow) as well as lift just strong enough to lead to the development of precipitation, and given the thermal temperature profiles of the atmosphere we should be looking at mainly snow, though areas along the coast may have to deal with some mixing.
While one of the more reliable computer models shows very little, if any precipitation making it into the region, several other computer models are in agreement that we will see a period of light snow spreading into the region. However, given the one more reliable computer model keeping everything offshore leads me to feel that I wouldn't not be surprised if many of us nothing more than flurries.
Given this, the best shot at "accumulating" snow will be well to the south and east of the MA Pike and any accumulations should generally remain around an inch or so with a few locations perhaps picking up 2-3'', especially if we see some heavier bands work in. Since this system will be occurring more in the daytime with the sun angle not quite at it's lowest yet, surface temperatures may warm up into the mid-30's. This should really help to prevent much in the way of accumulations of non-grassy surfaces, especially considering the snowfall intensity will not be all that heavy. If we were dealing with higher intensity snowfalls these mid-30's surface temps would not be an issue.
Snowfall should begin during the morning hours of Tuesday and virtually go on and off throughout the entire day and lasting into the overnight hours with perhaps a few flurries leftover very early Wednesday AM.
Below is the forecast map:
Several computer models are showing some decent moisture being associated with these waves (at least decent enough to lead to the production of snow) as well as lift just strong enough to lead to the development of precipitation, and given the thermal temperature profiles of the atmosphere we should be looking at mainly snow, though areas along the coast may have to deal with some mixing.
While one of the more reliable computer models shows very little, if any precipitation making it into the region, several other computer models are in agreement that we will see a period of light snow spreading into the region. However, given the one more reliable computer model keeping everything offshore leads me to feel that I wouldn't not be surprised if many of us nothing more than flurries.
Given this, the best shot at "accumulating" snow will be well to the south and east of the MA Pike and any accumulations should generally remain around an inch or so with a few locations perhaps picking up 2-3'', especially if we see some heavier bands work in. Since this system will be occurring more in the daytime with the sun angle not quite at it's lowest yet, surface temperatures may warm up into the mid-30's. This should really help to prevent much in the way of accumulations of non-grassy surfaces, especially considering the snowfall intensity will not be all that heavy. If we were dealing with higher intensity snowfalls these mid-30's surface temps would not be an issue.
Snowfall should begin during the morning hours of Tuesday and virtually go on and off throughout the entire day and lasting into the overnight hours with perhaps a few flurries leftover very early Wednesday AM.
Below is the forecast map:
Wednesday, November 7, 2012
Snowfall Total Update
What a winter storm...wow! The mesoscale features and processes involved with them storm have been incredible and when dealing with winter storms and snowfall forecasts it is these features which can absolutely kill snowfall forecasts b/c our computer models just aren't fine enough to pick up on these features in their entirety. Anyways, we have seen some VERY impressive banding set up from central NJ up through the NYC area and into SW CT along with another band (although a bit less impressive) across SE CT into RI. The banding from NJ to SW CT just does not want to move and models continue to indicate this band will sit over these areas for at least several more hours before rotating through the rest of the state. once it begins to rotate through the rest of the state the band will begin to run into some much drier air advecting in from the north resulting in weakening of the band and keeping the more impressive snowfall totals across the SW part of the state. It should also be noted isolated power outages are possible as well as winds continue to gust. Here is updated snowfall map.
Tuesday, November 6, 2012
Nor'easter to bring snow/sleet/rain/strong winds/coastal flooding 11/7-11/8
We are a little more than a week removed from the devastating impacts Hurricane Sandy left behind and unfortunately it appears much of the Northeast will be impacted by a strong coastal storm. Thankfully, this system will be nothing similar to that of Sandy, however, this storm will present issues, especially along the coastal plain from NJ up through SNE where strong/damaging winds will occur along with more coastal flooding and for the areas that were severely impacted from Sandy this is the last thing they need.
This will be a very challenging forecast as this system will not only be presenting us with rain but with snowfall/sleet and perhaps even some freezing rain as well and pining down who exactly sees snow and how much will be real difficult. There were be alot of impacts from this storm so let's get right to it and break it all down!
Snowfall
Over the past few days computer forecast models have trended colder, and colder with the airmass preceding the storm and for a duration of the storm and with this much of the region with the exception of the coastal plain will receive minor accumulations of snowfall with the highest totals occurring across the Northwest Hills of CT into the Berkshires of MA. It's also possible many locations within the snow zone will mix with sleet or even completely change over to sleet at some point during the storm and there could be some pockets of freezing rain as well. The snow will be very wet and heavy meaning it will cling to trees/power lines. While accumulations are expected to be on the lower side, we will still deal with some pockets of tree damage and power outages, especially when combined with the potential for strong winds...more on this below.
Rainfall
While much of the coastal Plain will be mostly rain some mixing or brief periods of snow is possible across some of these locations. Rainfall amounts should generally be in the 0.50'' to 1.50'' range and with this the threat for flash flooding will be on the lower side, however, the normal typical flood prone areas could see pockets of flooding.
Damaging Winds
Winds will be the biggest issue right along the coastal plain from NJ up through southern CT/southern RI and right into far SE MA. Across these areas winds will be sustained anywhere from 25-35 mph with wind gusts as high as 60 mph. Across far inland areas winds aren't expected to be this strong but they may gust as high as 30-40 mph. With the forecast for strong winds this will lead to pockets of tree damage/power outages, especially across the coastal Plain..more on this below.
Power Outages:
Across inland locations where minor accumulations of wet snow are expected along with gusty winds there will be pockets of tree damages and power outage but nowhere near to the degree that we experienced with Sandy. Across the coastal Plain where winds are expected to be much stronger power outages will be more on the scattered side than isolated side and this is certainly not good news at all for the restoration process in areas still experiencing outages and issues from Sandy.
Coastal Flooding
Coastal flooding is once again expected from NJ up through coastal CT/RI/SE MA as higher than normal tides will coincide with the height of the storm leading to high storm surge...storm surge in spots can be anywhere from 4-6' which is terrible for the areas that were heavily damaged/destroyed by Sandy.
Precip will begin across NJ/NYC area overnight tonight and slowly spread northward into southern New England by early to mid afternoon. The heaviest of the precip is expected to occur within a window of about 6-8 hours then the system is expected to weaken which will decrease precipitation rates. While the storm will be a slow mover and stall this will allow precip to occur on and off into much of Thursday. Below is a map with snowfall amounts as well as other impacts expected with the storm:
This will be a very challenging forecast as this system will not only be presenting us with rain but with snowfall/sleet and perhaps even some freezing rain as well and pining down who exactly sees snow and how much will be real difficult. There were be alot of impacts from this storm so let's get right to it and break it all down!
Snowfall
Over the past few days computer forecast models have trended colder, and colder with the airmass preceding the storm and for a duration of the storm and with this much of the region with the exception of the coastal plain will receive minor accumulations of snowfall with the highest totals occurring across the Northwest Hills of CT into the Berkshires of MA. It's also possible many locations within the snow zone will mix with sleet or even completely change over to sleet at some point during the storm and there could be some pockets of freezing rain as well. The snow will be very wet and heavy meaning it will cling to trees/power lines. While accumulations are expected to be on the lower side, we will still deal with some pockets of tree damage and power outages, especially when combined with the potential for strong winds...more on this below.
Rainfall
While much of the coastal Plain will be mostly rain some mixing or brief periods of snow is possible across some of these locations. Rainfall amounts should generally be in the 0.50'' to 1.50'' range and with this the threat for flash flooding will be on the lower side, however, the normal typical flood prone areas could see pockets of flooding.
Damaging Winds
Winds will be the biggest issue right along the coastal plain from NJ up through southern CT/southern RI and right into far SE MA. Across these areas winds will be sustained anywhere from 25-35 mph with wind gusts as high as 60 mph. Across far inland areas winds aren't expected to be this strong but they may gust as high as 30-40 mph. With the forecast for strong winds this will lead to pockets of tree damage/power outages, especially across the coastal Plain..more on this below.
Power Outages:
Across inland locations where minor accumulations of wet snow are expected along with gusty winds there will be pockets of tree damages and power outage but nowhere near to the degree that we experienced with Sandy. Across the coastal Plain where winds are expected to be much stronger power outages will be more on the scattered side than isolated side and this is certainly not good news at all for the restoration process in areas still experiencing outages and issues from Sandy.
Coastal Flooding
Coastal flooding is once again expected from NJ up through coastal CT/RI/SE MA as higher than normal tides will coincide with the height of the storm leading to high storm surge...storm surge in spots can be anywhere from 4-6' which is terrible for the areas that were heavily damaged/destroyed by Sandy.
Precip will begin across NJ/NYC area overnight tonight and slowly spread northward into southern New England by early to mid afternoon. The heaviest of the precip is expected to occur within a window of about 6-8 hours then the system is expected to weaken which will decrease precipitation rates. While the storm will be a slow mover and stall this will allow precip to occur on and off into much of Thursday. Below is a map with snowfall amounts as well as other impacts expected with the storm:
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