A Look Ahead…

400pm

I’d like to write a little bit about the next significant storm threat, which seems to be lining up for the middle of next week. For much of this winter we have been in a blocking pattern, resulting from a strong high pressure system over or near Greenland, which has been forcing the jet stream to drop from Canada into the US, with a trough of low pressure in the eastern US often resulting in cold air and snowstorms from the South to the Midwest to the Northeast. We’ve seen plenty of that since Christmas.

The overal l pattern does not appear to be changing that much, however there are some signs that the blocking pattern may relax to coincide with the next storm threat. What does this mean? Well, the most reliable longer range computer model this winter, the ECMWF (or, the Euro as I & others affectionately call it), is responding to this possible break in the blocking pattern by indicating the storm next week may take a track further west than many of the recent ones have. This would allow warmer air to move up the East Coast and bring a better chance of rain versus snow. However, one of the other longer range models does not relax the blocking as much, and therefore keeps it colder, showing a storm track more to the east, resulting in a colder and snowier result for much of New England. So early on, you can see what kinds of issues a meteorologist faces when thinking about upcoming weather.

Logic says it should be the Euro model that will have this handled better, because it’s done well most of the winter. But just because a model has done well doesn’t mean it will hit everything. So you have to look for clues that may tip you off that the model may be making an error.  Just the simple fact we’ve been so cold and have such a deep snowcover can mean that computer models can make errors, and forecast warmer conditions than will occur. So that will be one factor to consider. Also, the model that is giving the colder solution was one that did a fairly decent job predicting the details of the most recent big storm, so there is some pull to want to buy what it says. Confused yet? So am I…

But, having seen these conflicts before, I will wait a while before I start to come up with solid ideas. But a very early guess is that the truth lies somewhere in between. And we may see a storm that tries to stay further west, only to redevelop on the coast. If pressed to a forecast of rain vs. snow right now for next week, I’d have a slight leaning of white versus wet. Time will tell. And for me, this will be fun to follow, especially since I’m looking to break out of a forecasting slump!

2 Clippers & More Cold

700am

So maybe the storm threw me a curveball, but one thing I’m not misunderstanding is that we have no changes in the overall pattern for the near future… We will see a break from major storms, however, for several days. Two much weaker systems, “Alberta Clippers”, will move rapidly eastward through the area. The first one will cross the area late Friday with scattered mainly light snow showers. Little accumulation is expected from this feature. The second clipper will traverse our area on Saturday afternoon & evening. This one, being slightly stronger, may produce localized coating to 1 inch snow amounts.

Sunday will be mostly dry but a cold front crossing the region may produce a few isolated snow showers or snow squalls. This front will bring another very cold airmass into the region for the last day of January on Monday, though it still does not look as cold as the one from a week before.

Looking ahead to the first few days of February, more cold seems a certainty, with another snow threat as well. More about this in the next blog…

Snow Update

1010pm

Mother Nature is having fun messing with me on this one. Frustrating. But I still love weather and trying to forecast it.

So, part 1 of storm came in earlier than expected and gave a bit more than I thought. Granted, it was only up to about an inch, but I didn’t think we’d see more than flakes in the air around Boston from that part.

So now in comes part 2. It is a powerful upper level system (thunderstorms in the Mid Atlantic indicate the power of this system). As it tracks east northeast, passing south of New England overnight, it will toss its precipitation shield into southern New England (this is happening now).  With the entire area colder than originally forecast, mixing/rain has been limited to mainly Cape Cod and this will all go back to snow as colder air gets drawn into the system. So most of the region from southern NH through MA/CT/RI will see snow overnight. The heaviest bands of snow are expected to be along and south of the Mass Pike for the most part, though a few will sneak up to the nort as well.

When it’s all done expect updated snowfall totals to come in this way: 1-3 inches in southern NH, 3-6 inches with spotty 7 to 8 inch amounts in northern MA, though lighter well to the northwest, and 6-12 inches in a wide swath of CT/RI, and southeastern MA up to about Boston, including to near the cape Cod Canal. Slighty lesser amounts will occur further east on Cape Cod.

So it’s more snow than I forecast originally, though not a tremendous amount more. Still, the timing is just right, or wrong depending on your perspective, to cause alot of delays and cancellations for schools.

This system is still expected to move right along and the snow will be over in most places near or shortly after sunrise, with fairly rapid clearing from west to east following. Most of the region should have the sun out by mid morning, and rest of the day Thursday will be bright & chilly.

Looking ahead, a weak disturbance will bring lots of clouds and perhaps a few snow flurries Friday. Another low pressure area will cross southern New England late Saturday with some light snow. Clearing is expected Sunday with dry weather lasting through Monday as January comes to a close. Colder weather is expected at the end of the weekend and the start of next week, but it does not look as cold as the past very cold airmass early this week.

January’s End

1250am

Once we get by the storm system of Wednesday night, what can we expected Thursday through Monday, the last 5 days of the month?

High pressure will rapidly build across the region on Thursday, during the day, with plenty of sunshine, a few clouds, and a high temperature around 30. Colder air will move in Thursday night, and high temps on Friday will probably stay in the 20s. There will also be more clouds on Friday as a disturbance travels from the Great Lakes eastward across New England. This disturbance may produce a few snow showers but should not produce any significant snow.

Over the weekend, another, slightly stronger, low pressure area will come across the Great Lakes and head across New England. Latest indications are that this area of low pressure will pass over far southern New England or just south of New England, setting the stage for a period of snow sometime Saturday or Saturday night. It’s early, but some minor accumulations seem possible with this. Clearing should move in during Sunday as this low moves away.

Another Arctic airmass is expected to head into the region from Canada later Sunday & Monday, and the last day of January may be a bright but very cold day, with high temperatures not reaching 20. At this early stage it does not look like as cold an airmass as what went through here during the last couple days, but should be significantly cold regardless.

Update On Wednesday Night Storm

11:00pm

Hi all!

This blog will be short, because I don’t need to go over the technical aspects of the upcoming storm. My reasoning has not changed, so it would just be a re-run. 😉

I’ll just get to the time frame and the snow amounts, and here it is…

Snow starts in Boston between 6pm & 9pm, a bit earlier to the south, later to the north. The reason for the 3  hour window of start time is that the air above us will be very dry and it will take some time for the snow, which will be falling above us for several hours, to stop evaporating into the dry air and start reaching the ground. The heaviest snow will occur sometime between midnight & 6am Thursday. After this we should see a rapid ending to the snow from southwest to northeast during the morning commute Thursday.

Snow amounts should be 2-5 inches from southern NH southward to the northern part of the 128 belt (just north of Boston), and 5-9 inches from Boston southward into Plymouth County. I still think that amounts of 8 or 9 inches will not be that common, but are certainly possible, in those areas. Further south, except 4-7 inches near the Cape Cod Canal and dropping off to 2-4 inches over the Cape except 1-3 inches on the outer Cape, which will mix with and probably change to rain for a time for the first half of the precipitation event.

Another blog will be posted in a while with an outlook for the last 5 days of January. This includes a snow threat Saturday and a potentially very cold Monday.

Mini Storm, Bigger Storm?

150am

The extreme cold of Monday is now easing, and even though some readings were still near zero Monday evening, temperatures have started to rise as clouds have moved in. These clouds are associated with a weak storm system that will bring a period of light snow to MA & southern NH from the early morning to midday hours of Tuesday. Accumulations will range from 1/2 to 1 1/2 inch, with a spot 2 inch amount possible, especially in the hilly terrain. Once this system departs Tuesday afternoon, we may see breaks in the clouds and even a little sun before the day is through. Temperatures will continue to moderate and may approach 30 in some areas Tuesday afternoon.

Partly cloudy skies are expected Tuesday night with low temperatures falling back to around 20. Clouds will return and thicken during the day Wednesday ahead of the next storm system, which is currently developing near the Gulf of Mexico. This system will have plenty of moisture with it, and one might be tempted to think it’s set to unload all of it over New England since it is forecast to move up the East Coast by most of the computer models. But I still feel that this may not quite be how it plays out. If you read recent blogs you see that I have been concered about a boundary southeast of New England causing the Gulf of Mexico storm to start getting pulled further east, rather than coming north. I still think this scenario will play out. However, the moisture from the storm should still get far enough north to make it into much of southern and parts of central New England.

A last punch of energy coming along will cross CT & RI as well as south central to eastern MA. This area will be responsible for most of the snow that falls, which will occur early Thursday morning. I don’t think any snow will make it into Boston from the south until after sunset on  Wednesday.

Somewhat warmer air aloft and at the surface may result in mixing and a possible change to rain over Cape Cod & the Islands and a portion of southeastern MA. But I think the immediate Boston area & points north and west will see snow from this system. The question then becomes, how much snow?

I think it will break down this way in terms of snow amounts: A general 2 to 5 inches over most of eastern MA, and I’m leaning toward the lower half of that range (2 or 3) being the rule. The first burst of snow after dark on Wednesday evening should be responsible for a coating to 1 inch, with some mixing possible well SE of Boston. There should then be a lull in the precipitation toward midnight, with a second area of snow moving through and peaking during the 2am to 8am timeframe. This would be when most of the remaining accumulation would take place. Mixing to the southeast should go back to snow as colder air works southeastward across the region. As you head to the northwest, snow amounts may drop off very quickly, so that by the time you get to northern Worcester County you may see very little snow. Places like Springfield may sit on the fence as well but should be in on the Thursday morning snow enough to pick up a few inches.

Keep in mind, there is still a chance that this system is surpressed even further south, and much of the area misses out on precipitation.

By Thursday night, partial clearing & colder weather can be expected, and Friday should be a brighter, chilly, but dry day.

Looking ahead briefly, a couple of weak weather systems may bring a few periods of snow showers or light snow to the region over the weekend. We may see another shot of very cold air by later Sunday or Monday, as we close out the month of January.

The next blog update will be about 4pm Tuesday.

Update on Extreme Cold & Storm Threat

1045pm

Hi everyone! Just a couple quick updates.

First, the most recent 3 runs of the NAM (short range model) are supporting my idea of a storm track further offshore and less of a chance of a major impact. I still feel that it will be close enough to bring some threat of snow/mix to part of southeastern New England, but we’ll fine tune that as soon as possible.

More importantly, an extremely cold night is underway and will lead to a very cold Monday. The NWS Boston has issued wind chill warnings & advisories for the area. Bottom line is, if you plan on spending any time outside through Monday evening, bundle up, because the risk of frostbite is real, and can occur in as little as 10 minutes if you are not properly protected! So be safe out there!

Extreme Cold / The Week Ahead

400pm

Hi everyone! Thanks for visiting!

It’s time for a look at the week ahead, highlighted by an extremely cold start to the week and a midweek storm threat. The weather this week will be determined by the interaction, or lack of interaction, of a split jet stream (a northern one over southern Canada and the northern US, and a southern one over the central and southern US).

It’s been a cold & dry weekend across the region, and it’s about to get even colder. An Arctic cold front has been moving southeastward across New England today and will push south of the area tonight. This has opened the door for some slightly modified arctic air to move into the area. Boston may fall below zero tonight for the first time since 2005. I’m forecasting a -1F low temperature tonight. Most of the areas outside the city and away from the immediate coast will see low temperatures of -2 to -10. A few isolated colder readings are possible in valley areas where winds could be a little lighter. Winds will be strong enough from the northwest, gusting around 25 mph at times, to produce wind chills of lower than -20 at times tonight into Monday! Under bright sunshine, temperatures will barely recover back to near 10 in most locations.

By Monday night, clouds will be moving in ahead of a weak weather system approaching from the west. This, along with the fact the core of the coldest air will be exiting, will mean that we will not see a repeat of the extreme cold of tonight. Low temperatures in most areas should remain slightly above zero, still very cold certainly, since we will already be nearly at those levels by the end of the day Monday.

On Tuesday, expect clouds to dominate the day. There may be some light snow showers or even a period of light snow as a weak low pressure area with the northern jet stream moves through the region. This is not associated with the potential storm for midweek.

Once this system gets by us, attention will be on the storm threat during the Wednesday-Thursday timeframe. There are alot of factors to consider when forecasting the development and movement of this storm. I have been in great disagreement with the approach taken by many of the media outlets regarding this potential system, and you can see I use the word “potential” for a good reason. We’re talking about computer forecasts of a storm that has yet to develop and is largely going to be made up of energy that JUST entered the northwestern US from the Pacific during the past 12 to 24 hours. Hearing people talking about 1 to 2 feet of snow Wednesday is disturbing to me, because it plants seeds for overreaction of the public, preparing for yet another “storm of the century” as well as anger, if the advertised storm does not deliver. Regardless of how major I think this system has the potential to be, I would never start throwing those kinds of numbers out so far in advance. It’s irresponsible.

That said, I have reason to believe that the impact from this potential storm may range from minimal to moderate, and that we will be spared a direct hit from another monster storm. My favorite and what I feel to be the most reliable computer guidance has been advertising to me that the northern and southern jet streams are going to have a difficult time phasing, or getting together, which is something we usually need to produce a big storm and give it an avenue to come up this way. In this case, I feel that Tuesday’s weaker northern stream system will be well offshore and out of the way, as the southern stream system tries to develop over the southeastern US. There is a boundary forecast to be located off the East Coast on Wednesday. It is my expectation that the new low pressure area developing with the southern jet stream, not being influenced by energy to the north, will tend to develop along this boundary and try to follow it. And since this boundary is not forecast to move a great deal, that will tend to steer the southern stream storm on a more northeastward course, rather than turning it straight north up the coast. A track like this would put southern New England on the northwest flank of the storm, with results being anywhere from a light to borderline moderate snowfall (except mix/rain over far southeastern MA & Cape Cod due to warmer air aloft), or even just a brushing and a lower probability of a complete miss. My leaning at this point is for the first scenario mentioned just above. There is plenty that can go wrong with this forecast, so of course I will be watching and upating as we get closer, as has been needed over and over lately with these storms. For now, I wouldn’t be too worried about getting belted with a massive storm at midweek. And timing-wise, whatever we do get would likely occur mainly Wednesday night.

Later this week, expect a continued cold weather pattern, with the next chance of any storminess coming around Saturday. At this stage, that does not look like a major storm, but could produce quite a bit of wind as it is forecast by most guidance to be a pretty strong northern jet stream system. Looking way ahead, there are signs of another visit from very cold Arctic air behind that system, to end January & start February.

Harsh Winter 2010-2011

410pm

Well now that I’ve accepted the fact that I blew the winter forecast this year, it’s just time to enjoy trying to forecast what the rest of the winter has in store. Pardon my absence for a couple of days. I was feeling under the weather (no pun intended… ok, pun intended..sorry). 🙂

A quick word on the storm that was. This storm turned out pretty much as expected. I missed the high end of the snow but a little bit, but the snow to water ratio ended up at nearly 20 to 1, which is even drier and fluffier snow than I expected in the Boston area. 7.5 inches fell here. You’ll see that along with snowfall reports from across southern New England here (from my friends at the National Weather Service in Taunton MA):

http://forecast.weather.gov/product.php?site=NWS&format=CI&version=1&glossary=0&highlight=off&issuedby=BOX&product=PNS

So, now the snow is done, though there is still blowing snow around as NW winds pick up a little behind the storm. Cold air is rushing in, and temperatures tonight across the Boston area will fall to the lower to middle teens, recovering only slightly to near 20 tomorrow under a sunny to partly cloudy sky.

Saturday night, some clouds will roll across the sky from the northwest as an arctic cold front approaches. This front will cross the region overnight or first thing Sunday morning, and may produce a brief burst or 2 of snow. Any of these bursts could be briefly heavy with gusty winds, otherwise known as a snow squall (fairly common occurrance with Arctic cold fronts). If you do see one, it will not last very long.

This front will usher in the coldest air that most of the region has seen in about 6 years. Temperatures should spend Sunday in the teens, but will fall to near or a little below zero in Boston Sunday night, and possibly as cold as -10 across some suburban and certainly rural locations in eastern and central MA, as well as southern NH. If the wind is light enough, some valley locations could see even colder temperatures. On Monday, under bright but ineffective sunshine, the temperature may never make it to 10 degrees in much of the region.

The cold will ease slightly as it makes it back to the 20s Tuesday, feeling relatively mild compared to Sunday & Monday.

The next storm threat seems to be coming along for the middle of next week. And though based on medium range computer models this storm has some significant potential to produce alot of precipitation, it is far too early to be sure in any detail how this system will impact this area.  Something to follow for sure, but in the shorter term be ready for very cold weather!

Cold & a bit more snow…

225am

The next 4 days…

 Dry & chilly weather will dominate today, with clouds & sunshine. The most clouds will be early in the day as the system that brought rain & snow Wednesday departs & again late in the day as the next storm system approaches from the southwest. This storm will pass through the region on Friday, with about a 12-hour period of snow, starting between 1am & 3am, ending between 1pm & 3pm, and depositing a general 2 to 5 inches of light, dry, fluffy snow. Somewhat less snow can be expected to the northwest of Route 495, and a few spotty amounts over 5 inches may occur over southeastern MA. Amounts should be on the light side in southern NH & west of Worcester MA, that is, under 2 inches.

This weekend, expect dry & very cold weather, with lots of sun but also windy conditions Saturday. There may be some more clouds on Sunday, especially across far southern New England, with even a few snow showers developing, but most of the region will remain dry. Low temperatures of 0-10 will be common and high temperatures of 15-25 can be expected both Saturday & Sunday.

Your no-hype southeastern New England weather blog!