Welcome to the weather blog - a regular Monday through Friday discussion of the weather! While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants. I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible. You'll find a quick weather synopsis and a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. My email is contact@mattnoyes.net. This blog is for you, so I hope you enjoy it! -Matt Noyes
For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net
Matt's Quick Weather Synopsis: Monday morning has brought a chill to all of New England, with many areas starting the day within 10 degrees of zero, and an active wind providing additional chill. Though the cold arctic air is also dry air, and will bring sunshine to most areas to start the new work week, a few clouds sliding south out of Canada will blot out the sun from time to time on a line from the Mount Washington Valley of New Hampshire to Portland, ME, points northeast. Otherwise, don't let the sunshine fool you! With winds gusting to 35 mph and frigid temperatures in place, wind chill values will hover in the single digits north and teens south at even the warmest time of the day. Monday night, a fast moving upper level disturbance slides through New England, providing widespread snow showers for a fresh dusting through particularly interior New England by early Tuesday morning. This system scoots east quickly on Tuesday morning, however, keeping breezy and chilly, but bright weather in place. Another weak disturbance may deliver a few more flurries Tuesday night, then once again sunshine returns for Wednesday. A more potent storm center moving east from the Western U.S. will cross New England on Thursday, bringing widespread snow and perhaps a mix with rain in extreme southern New England. Behind this storm, fresh winds will usher in another shot of chill for Friday...keeping the entirety of this week a cold a wintry feeling one for us all! Have a wonderful Monday. -Matt
General Weather Summary: After receiving amounts of snow varying from a dusting to a foot of accumulation this weekend across New England, a quieter weather pattern takes hold for the start of our new workweek. Incidentally, I receive lots of inquiries for snow amounts from folks after storms have passed, and for those of you who are interested, the National Weather Service issues all of their snow spotter reports, completely free of charge anytime snow amounts are greater than 2". If you find their network dense enough, there's no need to pay for this data elsewhere: http://www.erh.noaa.gov/box/pns.shtml is the address. I'll add this to my mattnoyes.net web page soon, too. In the meantime, the weather may be quiet, but quiet won't equate to comfortable as cold arctic air has a firm grip on New England and will team up with an active wind to bring very chilly conditions through Tuesday.
While most of New England can enjoy sunshine between disturbances today, satellite imagery shows an area of clouds drooping southward through Maine and northeastern New Hampshire, and trying to slide farther south along the eastern New England coastline. These clouds are actually the result of warmer air aloft - that's right, warmer air coming from the north - as storms to our east have become so tightly wound that the counter-clockwise flow of air around them has carried warmer and more moist air all the way around the north side of the storms and back around the back of them. The clash of this warmer and more moist air with our dry, arctic air, is causing for the clouds. In most areas under this shield of renegade clouds, sunshine will still be able to break through, and the rest of New England will enjoy blend of golden sunshine. "Enjoy" may be a rather tame word to use, however, given that temperatures will hold in the teens across Northern New England and in the lower to middle twenties through Southern New England with winds from the west-northwest gusting to 35 mph, creating wind chill values ("feels like" temperatures) in the teens region-wide!
A fast moving, energetic disturbance located across the Central Great Lakes Monday morning will swing overhead through New England overnight Monday night. This disturbance will bring with it scattered snow showers and flurries, and many residents of interior New England - especially north of the Massachusetts Turnpike - may awaken to a fresh and very light dusting of snow Tuesday morning, with a thicker coating of fluff possible in the higher terrain of Northern New England. Breezes will remain active Monday night, keeping wind chill values below zero in many communities.
While Tuesday may dawn with lingering clouds and perhaps even a lingering flurry in some areas, sunshine will return along with another day of brisk west-northwest winds, gusting to 25-30 mph at times. With arctic air slow to let go of New England, temperatures will only climb about 4 or 5 degrees higher than they did on Monday, even with the help of plenty of sunshine. Expect a virtual repeat Tuesday night into Wednesday - that is, flurries Tuesday night with a fast moving upper level disturbance, followed by sunny but brisk conditions Wednesday, though winds are likely to subside a bit.
Meanwhile, rains and several feet of snow will be falling up and down the West Coast Monday - even raining in Los Angeles - as a strong Pacific storm system barrels its way inland. This moisture-laden system will eject a piece of energy eastward across the U.S., and the associated surface storm center will move into New England on Thursday. As with this past weekend's disturbance, the exact track of the storm will make a large difference regarding where the heaviest precipitation falls. Regardless, as warmer and more moist air surges north in association with this approaching storm, snow is likely to develop for many areas on Thursday. If enough warm air comes into play, a mix or change to rain would be possible in especially far Southern New England, though right now I wouldn't count on a widespread mix or changeover.
Cold air sticks around through the first 7-10 days of March, as the atmospheric pattern features something special in the world of meteorology...a "Greenland Block." This is the term meteorologists use to describe a large and stationary area of high pressure that builds across Greenland - well to our east - and because high pressure is generally a fair-weather center, it blocks storms from moving quickly across the North Atlantic. The result is to keep storms curling north when they move just east of the Canadian Maritimes, and with counter-clockwise flow of air around storms, this keeps an average northerly wind blowing into New England for quite some time. The result of a pattern like this is for cold conditions to persist, with storms reaching their maximum intensity to our east, rather than over us, but that's not to say storms can't still affect New England - stronger disturbances can occasionally strengthen further as they move overhead and this can produce widespread snows. A few chances of disturbed weather will remain while this "Greenland Block" holds.
Have a wonderful Monday!
Matt
Matt's Technical Meteorological Discussion: Updated Monday, February 27 at 3:20 PM
Warm advection clouds across ME/NH/parts of NE MA today are the result of warm air wrapped all the way around the north side of storm circulation to our northeast and another burst of these is possible later Tuesday as polar vortex throws warmer air southward aloft. A strange reality, I know, but this is what happens when you get a wound up storm bombing northeast of NewEng during a strong Greenland block and developing strong negative NAO.
I'm going to broadbrush the short-term in favor of focusing on the medium range and longer range forecasts today...and the broad strokes paint an eastward moving shortwave moving over NewEng Mon Ngt and bringing snow showers with it - esp Nrn MA point N - with a dusting of accum possible given a couple of hundreths that output on esp SUNYSB MM5 and WRF.
Good mixing Tuesday will team with downslope flow and sunshine for at least most of the day away from warm advection clouds from the north to bring temps into the 20's most areas Central and South. Wed features a westward retrogression of the polar vortex and this is an important shift as it dictates where the storm currently slamming the west coast with copious amounts of rain and snow will be steered.
In fact, using this pattern shift, we could determine that the NAM solution for the track of Thursday's shortwave - our first stopping point in the medium range - was initially likely much too far north as it took the shortwave over Central and Northern NewEng, but the new 12Z position is more in line with the remainder of the operational models and likely more on target. There are a few things to keep in mind with this shortwave: 1) It is the composite of northern and southern stream energy, but really is a reincarnation of the storm over the West Coast Monday afternoon, which splits north and south and then comes together again over the Western Great Lakes, 2) When the new merged vorticity maximum moves through the northeast on Thu, remember its origin - it has come from moisture-laden beginnings bringing rain from SEA to LAX on Monday, and feet of snow to the CA mountains, 3) It is cresting a thermal ridge of tremendous warmth - some 20 to 25 C at 850 mb over the Central and Southern Plains, and this sets up a tremendous baroclinic zone with the cold air shoved south of the polar vortex, 4) The surface low will be strengthening as it moves in a path that...according to progged 500 mb and 700 mb flow...should take it immediately south of NewEng as it races E.
Once again this leaves us with a storm that we wonder whether it will be able to generate a closed circulation and add ocean moisture, but this time it's not nearly as important to do this as it was with the weekend system. Remember that in this discussion you and I considered the importance of this ocean inflow for the past weekend storm, and we knew that where an easterly flow could establish, the higher snowfall and QPF would be, and that was likely to set up on the northern side of the circulation. We needed that moisture this weekend to offset what was otherwise a bone-dry atmosphere. Though the air is dry currently, by Thursday the situation will be quite different, as this storm comes of Pacific origin - carrying its own moisture. For snow lovers, that's a good thing because indications right now are somewhat iffy on whether it could get its act together quickly enough to incorporate Atlantic moisture, largely owing to its very fast progression eastward. Nonetheless, this system of moist origins will carry a southerly llvl jet east into NewEng late Wed Ngt into Thu, and this will again result in a band of snow, heavy at times, into Thu across most of Southern and Central NewEng, and likely spreading into Nrn NewEng as well, esp given lingering trough and SE sfc flow in place. Remember that with this past weekend's event, there was a fairly well-defined southern cutoff to the plowable snowfall amounts - that is the nature of a system that is relying heavily upon a surge of warmth and moisture colliding with a cold airmass - south of the collision there will be a sharp drop in precip amounts. This will be the case again with the upcoming storm, but indications are that most areas should end up under this enhanced baroclinicity. So, once again a shot of plowable snows appears en route for NewEng late Wed Ngt into Thu.
Thereafter, with northwest flow the weather may quiet down for a few days, but this is likely to only be the calm before the storm that will break the back of the deep cold for a time, if not for the rest of winter. Consistent indications for several days have been coming back for a few things to happen around March 6-7. The first is that the polar vortex lets go of Eastern Canada and shifts north and northeast, diminishing the confluent flow that has kept disturbances moving so quickly across us. The second is that...in response to this shift and a weakening of the Greenland Block, the NAO approaches neutral. Historically, when we see the NAO shift from strongly negative to near-neutral or slightly positive, this can signal a large storm development near the Northeastern US. Add to this the fact that a strong Pacific shortwave will be traversing the country - the leftover heart of the Aleutian low spinning south of Alaska today - into a less confluent flow over the Northeastern US but still confluent enough over Nova Scotia to hold cold high pressure to our NE, and we have a recipe for a strong storm. Additionally, the operational models continue to key in on this time period for storm development, which can add further confidence to a forecast of a large storm in this time period. Behind the storm, it does appear heights rise dramatically, which tells me two things: 1) The storm will likely be a strong one, as this is evidence of the amount of warmth and moisture available to it from the southern stream and the resultant baroclinicity, and 2) This strong storm will lead the northeast into a spring-like pattern for what is likely to be at least a week, taking us to around March 13-14. Thereafter, while the deep cold will be exhausted, cold locked in Siberia that will have been cut off from migrating eastward (truly it's this bridge to Siberian cold that's been feeding our current cold streak) will be able to slide east into Western and Central Canada again, and renewed cold appears possible sometime after March 14, though not as deep and not for as long a period, it still will be watched carefully as baroclinicity would be a big factor at that point, owing to a significantly higher sun angle.
Needless to say, plenty watch for one and all. That's all for today.
Matt
