Snowfall maps/discussion for 4/1/11

[weatherwiz]

Probably going to be some changes as we get closer, especially once it becomes more clear on the exact track.

Discussion:

An area of low pressure working up through the Gulf of Mexico into the state of FL will continue working up the coast over the next 36 hours, as it does so the system will begin to rapidly intensify as the Arctic jet phases with the subtropical jet and pieces of shortwave energy embedded in the Arctic jet work to interact with the low pressure system.

With some weak blocking upstream thanks to a slightly negative North Atlantic Oscillation (NAO) this storm will either ride up along the coastal plain or be just offshore. This is absolutely huge because a track like this usually means part of, if not all the region sees winter weather. Exactly how close to the coast the low tracks will determine who exactly sees snow and who turns over to rain. It is this that will make this forecast extremely difficult as a shift of 50-100 miles to the west or east will have a SIGNIFICANT impact on the outcome of the storm.

Latest computer weather models continue to indicate that this system will track somewhat close to the coast, this means that rain/snow line will be running right through our region and this means this will be a highly complex and complicated forecast. Given the expected track of the storm the rain/snow line should setup in a Northeast to Southwest line.

Despite the fact we are about 30-36 hours away from the onset of the storm there is still a littler bit of uncertainty here, mainly with regards to the exact track of the storm. While there aren't really many indications this storm will track any further west than what most model guidance is suggesting there remains a possibility that this storm could actually track a little further east in which case more areas would receive much more snow. This will continued to be watched very closely over the next 12-18 hours.

Forecast:

Due to the above mentioned questions as of this time this is a rather low confidence forecast. Until details become much more clear with the exact track of the storm it's going to be a little difficult to have much confidence within the forecast.

Based on the current projections for the track it appears as if everyone or mostly everyone will begin as a period of snow, and this snow could be very heavy at times and accumulate very quickly. This snow is expected to begin possibly as early as midnight Thursday night. This snow may quickly change over to rain, especially across the coastal plain of CT up through the rest of CT (with the exception of the higher elevations of Litchfield county) and then RI, and SE MA. THe question for these areas is how much snow accumulates before the changeover? It's also possible that the rain could once again flip back over to snow as colder air begins to work in aloft, depending on if and how quickly this occurs this could lead to several more inches of snowfall accumulation perhaps.

The areas that stay all snow or see mostly all snow will obviously receive the highest snowfall totals from this storm. In this area as much as 8-16'' of snow will be possible, with some isolated amounts even higher than that.

Both snowfall and rainfall rates will be extremely heavy at times, snowfall rates could be as high as 2-3'' per hour at times with rainfall rates as high as 1-2'' per hour. There will be some very strong lift involved within this system which will help lead to these heavy precipitation rates. Some thunder can't be ruled out as well, especially given how some models show a little bit of elevated instability working into the region and because of the very strong lift that will be over the region for a time.

As we get closer to the event and new model data continues to come in some revisions to this map are likely, especially once the details on where the storm tracks becomes much more clear.

[Cold Miser]

Nice - Wiz.

[weatherwiz]

Nice - Wiz.

Thank you.

I'm holding out hope we can get a somewhat further east track so we can get more snow but it's getting a bit late.

I was really hoping BDL could pull of 14.1''

[Quincy]

to make one note, the dotted line is not necessarily the 6" line. It means that 3-6" is likely (very high confidence) and that the higher terrain will likely see 6 to possibly 12".

my biggest concern is that most of the accumulating snow will be done shortly after daybreak Friday, except for those areas across the higher terrain and well inland.

[Mr Torchey]

Probably going to be some changes as we get closer, especially once it becomes more clear on the exact track.

Discussion:

An area of low pressure working up through the Gulf of Mexico into the state of FL will continue working up the coast over the next 36 hours, as it does so the system will begin to rapidly intensify as the Arctic jet phases with the subtropical jet and pieces of shortwave energy embedded in the Arctic jet work to interact with the low pressure system.

With some weak blocking upstream thanks to a slightly negative North Atlantic Oscillation (NAO) this storm will either ride up along the coastal plain or be just offshore. This is absolutely huge because a track like this usually means part of, if not all the region sees winter weather. Exactly how close to the coast the low tracks will determine who exactly sees snow and who turns over to rain. It is this that will make this forecast extremely difficult as a shift of 50-100 miles to the west or east will have a SIGNIFICANT impact on the outcome of the storm.

Latest computer weather models continue to indicate that this system will track somewhat close to the coast, this means that rain/snow line will be running right through our region and this means this will be a highly complex and complicated forecast. Given the expected track of the storm the rain/snow line should setup in a Northeast to Southwest line.

Despite the fact we are about 30-36 hours away from the onset of the storm there is still a littler bit of uncertainty here, mainly with regards to the exact track of the storm. While there aren't really many indications this storm will track any further west than what most model guidance is suggesting there remains a possibility that this storm could actually track a little further east in which case more areas would receive much more snow. This will continued to be watched very closely over the next 12-18 hours.

Forecast:

Due to the above mentioned questions as of this time this is a rather low confidence forecast. Until details become much more clear with the exact track of the storm it's going to be a little difficult to have much confidence within the forecast.

Based on the current projections for the track it appears as if everyone or mostly everyone will begin as a period of snow, and this snow could be very heavy at times and accumulate very quickly. This snow is expected to begin possibly as early as midnight Thursday night. This snow may quickly change over to rain, especially across the coastal plain of CT up through the rest of CT (with the exception of the higher elevations of Litchfield county) and then RI, and SE MA. THe question for these areas is how much snow accumulates before the changeover? It's also possible that the rain could once again flip back over to snow as colder air begins to work in aloft, depending on if and how quickly this occurs this could lead to several more inches of snowfall accumulation perhaps.

The areas that stay all snow or see mostly all snow will obviously receive the highest snowfall totals from this storm. In this area as much as 8-16'' of snow will be possible, with some isolated amounts even higher than that.

Both snowfall and rainfall rates will be extremely heavy at times, snowfall rates could be as high as 2-3'' per hour at times with rainfall rates as high as 1-2'' per hour. There will be some very strong lift involved within this system which will help lead to these heavy precipitation rates. Some thunder can't be ruled out as well, especially given how some models show a little bit of elevated instability working into the region and because of the very strong lift that will be over the region for a time.

As we get closer to the event and new model data continues to come in some revisions to this map are likely, especially once the details on where the storm tracks becomes much more clear.

Thats a damn good map Paul, good luck!

[weatherwiz]

Thats a damn good map Paul, good luck!

Thanks!

I'm sure I'll have to change it.

[weatherwiz]

Discussion:

A strong coastal storm is set to impact the region beginning later tonight, although there are some areas of snow/rain showers across parts of the region now this is more associated with the first wave and could actually slightly have an impact on the overall storm as this could actually help to keep the storm a bit further off the coast which means more in the way of cold air over the region and more snow.

Over the past 24 hours computer models have started becoming a bit more consistent and a bit more clear with the overall track of the storm. The storm track should be right off the mid-Atlantic coast and just to the southeast of CT and and going across parts of RI and then over far SE MA. This track is very close to the region meaning there will be a good deal of warm air both at the surface and into the lower levels of the atmosphere for locations very close to the center of the low track. Further away from the center of the storm the temperature profile should remian cold enough for either all snow or mostly snow.

Given how surface temperatures will be on the warmer side and temperatures aloft will be on the warmer side the snow is expected to be very wet and heavy. This type of snow can easily stick to tree limbs and power outages. With potential for some strong wind gusts as well the potential will exist for pockets of tree damage and there could also be some isolated power outages as well.

Along the coastal plain where the precipitation will be mostly rain the potential will exist for some coastal flooding as very heavy rain is likely. Rainfall rates could be as high as 1'' per hour and as much as 1-3'' of rainfall will be possible. The ground is still somewhat saturated which may also lead to some pockets of isolated flooding further inland for the locations that also receive rain.

While becoming less unlikely there is still an outside chance this system ends up tracking a bit further off the coast, considering many locations are really right on the line between receiving several plus inches of heavy snow this will have to be closely watched through the rest of the evening.

Forecast:

While there will be on and off snow/rain showers the rest of the afternoon and into the evening (some of which could be heavy at times) the bulk of the storm really won't begin until early in the overnight hours, likely between 12-2 AM. Just about everyone should begin as snow, with the coastal areas of CT/RI/MA quickly changing over to rain. THese areas should receive little accumulation.

What could really help some locations with accumulation is the fact snowfall rates will be fairly heavy meaning the snow could start to accumulate rather quickly. This will definitely hold true for interior locations in MA where it will take a bit longer for the snow to changeover to rain.

The storm should start winding down late Friday morning and should be out of the region by mid to late afternoon.

[free_man]

BOS 0-2"

BED 2-4"

ORH 5-10"

LWM 3-6"

MHT 4-8"

EEN 6-12"

HFD 2-4"

My call from 24 hours ago looking pretty solid. A couple obvious misses..