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Nor'easter update: Was the forecast a bust?

From FOX 25 Chief Meteorologist Kevin Lemanowicz:

10 a.m. update -- The nor'easter is still churning offshore as I write this at 10am, producing strong winds and pushing milder air inland. The accumulating snow is done, and except for an occasional bit of sleet mixing in, everyone getting cold rain or nothing now. This storm happened as we said it would, but just received a tweet saying that we "dropped the ball" on this one. Going with the theory that if one says it, there must be others thinking it, I thought I'd write a forecast wrap-up.

This storm has been thought about since last week. Sandy was still spinning in the northeast when we had a storm in our 7day forecast that could be a nor'easter and produce some snow. It was too early to make specific forecasts, but it was on the 7day. (See Exhibit A)

I wasn't comfortable putting snow totals on a map until yesterday… or at least as comfortable as I could be. I was looking at several computer models, which are much talked about by everyone in this day of Twitter. The ECMWF (Euro) did so well with Sandy, that I thought it might have the right idea with this nor'easter. The GFS model was close to it. Both were showing a more western track. That would mean warmer air farther inland, pushing the heavier snow bands farther west as well. I modified that a bit and brought some snow into Worcester, but agreed more would fall farther west.

(See Exhibit B) That was my forecast starting Wednesday morning. The storm didn't roll onshore here until late morning. Temperatures were well in to the 40s out to metrowest. Sure seemed like the warm air was coming in and the more western track would work out. However, there was heavy snow falling in western and southern CT, so it seemed clear the snowbands would likely have to shift east somewhat. Those models (EURO and GFS) were both still keeping heavy band to the west, but another model (RPM) was bringing the heavy snow into central MA, particularly southern Worcester county! It had it nailed, but I didn't buy into it. The RPM had been up and down and all over the place in the day leading up to the storm, so my confidence in it was not high. One other model, the NAM, skewed the snow closer to Boston and a little higher without going as aggressive as the RPM. This is the one I went with and came up with this at noon Wednesday…

(See Exhibit C) Closer, but still didn't work out. The storm pulled even farther southeast. That brought the cold air farther east, too, allowing for more snow farther east. It also allowed that heavier band to correspondingly be farther southeast. Temperatures that were in the 40s to metro west dropped right through the 30s. Amazing cold air takeover! It also allowed for northerly winds on the back side of the storm to bring very dry air into the mix. Doppler radar showed snow falling all day through western MA, NH, and VT, but it was never reaching the ground in the dry air. That's called "virga." That was happening Wednesday evening, so the forecast changed accordingly to this… (See Exhibit D)

This is pretty close to what one model, the RPM, had said. Had it been more consistent leading up to the storm, perhaps I'd have given it more credence.

Forecast Final Analysis- Strong winds- check… Coastal flooding- check… Power outages- check… Heavy rain southeast MA- check, Snow to the west- check, Impacts on evening and morning commutes- check

There was plenty of warning of a strong storm, and I am happy that those most impacted by winds and flooding were ready.

I think everyone was prepared for most of the storm, however the higher snow totals and farther east storm track were NOT well forecast. I can blame it on the models, but in reality it was my thinking that the blocking pattern that drove Sandy to the west dramatically would keep this storm farther west as well, so I went with a model that was closest to what I was thinking. I am happy I adapted at noon Wednesday with the new forecast of higher amounts farther east, but I did not, clearly, go aggressive enough with the farther east track or snow totals.

There will be people in southeast MA that believe this forecast was right on. Likewise for Worcester county areas that had 2-4". Others in southern NH, especially southwest NH, southern VT, and western MA are all rightfully thinking this was a bust. Same with those having higher amounts closer in to Boston and south of Worcester. If you measure a forecast based solely on snow totals, then this forecast was, indeed, a bust for you.

6 a.m. update -- The nor'easter continues to wind up off of Nantucket this morning. It is an intense storm with strong winds. There have been gusts as high as 76 mph measured. That is hurricane strength! Gusts continue over 50mph at times. That can still bring down some trees and line. Power outages have been scattered, but could still occur.

>>IMAGES: Mass. hit by first nor'easter of 2012

The precipitation has been diminishing inland. Snow is transitioning to rain as warm air works in up above, melting the flakes on the way down. Problem is if your temperature is below freezing, that rain will cause ice to form on just about any outside surface. You have to be careful of slippery conditions. Eventually the warm air will work its way down so that this ends as some light rain or drizzle inland. Heavy rain continues closer to the storm on the south shore, Cape Cod, Nantucket, and Martha's Vineyard.

Snow totals have been mostly 2-4" from 128 out to Worcester county. That's closer in than I expected yesterday, but the amounts have been ok. Then there is that heavy band in western Norfolk county, western Bristol county, and southern Worcester county. Amounts have been from 4 up to 8" (Southbridge) in that band. That is something I did not see happening. The cause has been a storm track more to the southeast. That track has kept northerly winds blowing, in turn keeping the cold air locked in. That cold air was able to stay in place closer to the storm and the heavier precipitation. The result has been more snow. It is a matter of inches on a weather map, but that is why we talk so much about the track.

I have the latest all morning long on the FOX 25 Morning News. Follow me on Twitter, @klemanowicz, or "like" me on Facebook to get more updates and ask questions.

From Fox 25 meteorologist Sarah Wroblewski:

We're in it now. The center of an area of low pressure well to the south has been delivering huge waves, strong winds and a mixed bag of precip to the Mid-Atlantic to Northeast. Interestingly enough this is a time when a lot of nowcasting takes place and things can easily change throughout the period. One of the first things is the rain snow line. The evening commute was a mess… and we're likely going to see not the smoothest commute again Thursday morning.

The previous Winter Weather Advisory for western MA has been expanded into portions of metro west, western Norfolk county and northern Bristol County and the Providence metro area for that matter. This is in place for accumulating snow and some light icing until 7AM Thursday morning. As precipitation was advancing into the area today, despite temps above freezing, dewpoints were much lower than the temperature. As precipitation falls, evaporational cooling takes place and that is why we have seen snow in many areas today and accumulating snow for that matter. The snow engine just didn't shut off and especially near the rain/snow line. It's not uncommon to see heavy snow on the colder side. Places near the 495/95 interchange such as Mansfield, Plainville, Foxboro to name a few has continued to see steady snow through the afternoon and this evening, piling up the snow to a few inches already.

Interesting fact, although the precipitation shield looks impressive on radar and extends into northern New England… some of that snow is not hitting the ground! Dew points are so low (single digits and teens) in northern MA, that when the precip is falling… it is drying up before it makes it to the ground. Some parts of northern MA into NH have seen no snow so far… just clouds and wind.  Tonight we'll continue to see snow for areas that are already seeing snow, and rain for the Cape and Islands. As warmer air aloft tries to work in… we may see some freezing rain develop and allow for icy conditions. This may also compact the snow totals, but I'm shifting the totals a bit to accommodate for the drier trend to the north and snow engine SW of Boston.

This Nor'easter also continues to bring very strong NE winds. Winds will continue to be gusting to near 50 along the east coast and 60 for the south coast, Cape and Islands, but improvement will come tomorrow. We'll continue to monitor the next high tide cycle (5:30 AM Thursday) for those winds to continue to churn up the seas, and allow for a pounding surf and possible storm surge which could bring another round of minor coastal flooding and beach erosion to the coast.

Sarah's update from 6 p.m. Wednesday:

A bit surprising for many to see the first few flakes today… and those flakes are adding up fast in some locations. In fact, parts of CT have already picked up nearly 5" of snow.  However, not everyone is enjoying this taste of winter… in fact… some areas are still reporting no precipitation despite the radar showing a shield of precipitation into NH. That's because the air is so dry… dew points are ranging in the teens and 20s north and west of Worcester in NH. This basically means as the snow falls…it dries up before it makes it to the ground. Closer to the MA Pike, 495 into 128… we are getting reports of lower visibilities and some grassy surfaces and tops of cars covered. Closer to Boston a few snowflakes mixing in, but roads are wet. Across southeastern areas… just rain… and wind!

Winds have been gusting over 50 mph on the Cape and Islands. No surprise we will continue to have a high wind warning in effect through Thursday morning for the south coast, Cape and Islands for gusts up to 60mph which could lead to power outages. A high wind watch in effect for the eastern coast of MA back towards Worcester County for gusts up to 50mph.

Western MA, Worcester County, northwestern Middlesex County and into southern NH there is a Winter Weather Advisory through 7am Thursday. Accumulating snow will make the roads pretty slick and as warmer air aloft in the storm works in, that may create a period of freezing rain to only further coat the roadways with some ice. It will be tricky commuting not only this evening, but through the overnight period into tomorrow morning. This storm looks to head to the northeast a bit faster than my previous thought yesterday so we should find some improvement starting tomorrow afternoon. Nonetheless, I think we'll see a coating to a slushy inch outside of Boston along the 128 to 95 Corridor. Closer towards 495 and west, areas may pick up 2-4" with higher totals possible across the higher terrain and out towards southwest NH, VT and western MA into northwest CT.

Update from Wednesday afternoon:

Snow has begun to fall from the Nor'easter making its way over Massachusetts.

In Dedham, a slushy, wet mix had begun falling in the early afternoon but was not accumulating.

Fox 25 meteorologist Sarah Wroblewski said the storm will dump two to four inches of snow on areas north and west of Interstate 495 through Wednesday evening into the overnight hours Thursday.

The speed on the Massachusetts Turnpike had been reduced to 40 mph because of the storm.

Rain is expected for areas near the coast.

The storm is currently also impacting Sandy-devastated areas of New Jersey and New York.

From FOX 25 Chief Meteorologist Kevin Lemanowicz:

Temperatures.

A heavy snow band has been rotating through southern New England. The reports out of CT have been impressive and the latest model runs seem to pull the storm a little more to the east. So, I've made slight modifications to snowfall totals.

Please note, one cable outlet has "named" this storm. It is not our policy to go along with that. We will NOT be using a storm name for this, or any, nor'easter until there is coordination with the National Weather Service (NWS).

The NWS has told their meteorologists to not use the name given today. This is going to make for a confusing situation and it is a careless attempt to get publicity, in my opinion. This is the only nor'easter happening right now, so there is no need for a name anyway.

>>TIMELINE: Track storms moving through Mass.

A nor'easter is rolling in this morning. Wind gusts have already topped 50 mph on Nantucket, 40 mph in southeast MA. There have already been, and will continue to be, trees down. I'd expect power outages as well. The winds will be strong throughout the night.

>>Upload your storm photos to pix.myfoxboston.com

Rain has been moving north slowly into our dry air. Cold air over the interior means even if it starts as rain, there will be a quick transition to snow, particularly in Worcester county and points north and west. There will be a period of accumulating snow today and tonight. Later tonight, as the precipitation becomes lighter, the snow will become rain. Problem is that the ground temperature in those snowy areas will stay at or below freezing. An icy glaze will form on top of that snow and on other surfaces. It will make for a slick Thursday morning in those areas, mainly outside I495. This storm will be rain in most of southeastern MA throughout, though some wet snow may mix in.

A High Wind Warning is in place for Cape Cod, Nantucket, and Martha's Vineyard, as well as the south coast of MA and RI. Winds could gust as high as 60 mph. That could bring down more trees, especially those weakened by Sandy last week. Power outages are likely tonight. A Wind Advisory is in place for strong winds elsewhere.

A Coastal Flood Advisory is in place for east facing shorelines. Minor to moderate flooding could occur during the evening high tides from 4-7pm. Waves will be big and erode the beaches again.

The snow and ice inland has prompted a Winter Weather Advisory.

I'll have the latest all morning on the FOX 25 Morning News and post an update here when the latest data comes in around 11am.

Follow me on Twitter, @klemanowicz, or "like" me on Facebook to get more updates and ask questions.

10 a.m. update - Little has changed with this storm as it has developed this morning. I've made slight modifications to this morning's blog. Please note, one cable outlet has "named" this storm. It is not our policy to go along with that. We will NOT be using a storm name for this, or any, nor'easter until there is coordination with the National Weather Service (NWS). The NWS has told their meteorologists to not use the name given today. This is going to make for a confusing situation and it is a careless attempt to get publicity, in my opinion. This is the only nor'easter happening right now, so there is no need for a name anyway.

A nor'easter is rolling in this morning. Wind gusts have already topped 50 mph on Nantucket, 40 mph in southeast MA. There have already been, and will continue to be, trees down. I'd expect power outages as well. The winds will be strong throughout the night.

Rain has been moving north slowly into our dry air. It will be arriving in the Boston area and to the Mass Pike around noon. Cold air over the interior means even if it starts as rain, there will be a quick transition to snow, particularly in Worcester county and points north and west. There will be a period of accumulating snow today and tonight. A secondary storm will form off this nor'easter, taking the heaviest precipitation offshore. That will keep snow totals down, but as the precipitation becomes lighter, the snow will become rain. Problem is that the ground temperature in those snowy areas will stay at or below freezing. An icy glaze will form on top of that snow and on other surfaces. It will make for a slick Thursday morning in those areas, mainly outside I495. This storm will be rain in most of southeastern MA throughout, though some wet snow may mix in.

A High Wind Warning is in place for Cape Cod, Nantucket, and Martha's Vineyard, as well as the south coast of MA and RI. Winds could gust as high as 60 mph. That could bring down more trees, especially those weakened by Sandy last week. Power outages are likely tonight. A Wind Advisory is in place for strong winds elsewhere.

A Coastal Flood Advisory is in place for east facing shorelines. Minor to moderate flooding could occur during the evening high tides from 4-7pm. Waves will be big and erode the beaches again.

The snow and ice inland has prompted a Winter Weather Advisory.

I'll have the latest all morning on the FOX 25 Morning News and post an update here when the latest data comes in around 11am.

Follow me on Twitter, @klemanowicz, or "like" me on Facebook to get more updates and ask questions.

4a.m. update - A storm coming up the coast will become our latest nor'easter, bringing everything from damaging winds to an icy glaze.

Rain will be moving on to the islands this morning and move northward through the day, arriving in the Boston area and to the Mass Pike around lunchtime. Cold air over the interior means even if it starts as rain, there will be a quick transition to snow, particularly in Worcester county and points north and west.

There will be a period of accumulating snow tonight. A secondary storm will form off this nor'easter, taking the heaviest precipitation offshore. That will keep snow totals down, but as the precipitation becomes lighter, the snow will become rain. Problem is that the ground temperature in those snowy areas will stay at or below freezing. An icy glaze will form on top of that snow and on other surfaces. It will make for a slick Thursday morning in those areas, mainly outside I495. This storm will be rain in most of southeastern MA throughout, though some wet snow may mix in.

A High Wind Warning is in place for Cape Cod, Nantucket, and Martha's Vineyard, as well as the south coast of MA and RI. Winds could gust as high as 60 mph. That could bring down more trees, especially those weakened by Sandy last week.

Power outages are likely tonight. A Wind Advisory is in place for strong winds elsewhere.

A Coastal Flood Advisory is in place for east facing shorelines. Minor to moderate flooding could occur during the evening high tides from 4-7pm. Waves will be big and erode the beaches again.

The snow and ice inland has prompted a Winter Weather Advisory.

I'll have the latest all morning on the FOX 25 Morning News and post an update here when the latest data comes in around 11am.

Follow me on Twitter, @klemanowicz, or "like" me on Facebook to get more updates and ask questions.