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 linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net. This blog is for you, so I hope you enjoy it! -Matt Noyes
General Weather Summary:
12:40 PM Update: Have updated the accumulation map (below) just a touch. Minor changes from the previous version, mainly to bump up amounts ever so slightly in Northern Rhode Island hills and higher terrain of interior Southern MA.
Previous Discussion: The migration of arctic air has been intriguing to watch over the past couple of weeks, and will have an impact on our weather for weeks to come. For the first half of the winter, New England was exposed to cold air only in quick bursts - northwest wind carrying cold southward from Quebec and Ontario. But this cold air was well-established in Canada and now, after a period of a few weeks of repetitive cold, the source of cold air has settled south into Northern New England, where deep cold will remain present for the next couple of weeks, and will ensure that plenty of cold air is available for the remainder of New England, as well, which would serve important when more moisture becomes involved in our weather pattern.
For some time now, the very same weather pattern that's been frustrating New England snow lovers has also been responsible for churning our seas for mariners. That is, our prevailing jet stream pattern continues to deliver air that's just cold enough, and much more importantly, just dry enough to keep deep moisture to our south. This has meant one storm after the next passing south of New Englnad, with the counterclockwise flow of wind around each storm center hurling ocean swell coastward, while prevailing offshore winds closer to New England add chop. This has meant several ocean storms - and very few coastal storms - over the past few weeks. In the immediate future, there's no evidence this will change, though the next few weeks will bring a gradual shift toward a pattern favoring higher frequency of storms. Nonetheless, we're on the doorstep of a storm with potential for some of us slated for Tuesday night into Wednesday morning, while for others the upcoming event will be only a very light or even completely negligible event.
Daybreak Tuesday brought quiet and cold conditions, with some spots in Northern New England recording their coldest morning in the last few days. Though skies dawned mostly clear - with a few flurries found only in the Berkshires where westerly surface winds were pushing up against the mountainfaces - clouds were evident to our southwest on satellite imagery. These clouds are the outer effects of a slow-moving and weak storm crawling east out of the Great Lakes that will continue to spread thickening clouds over New England through the day on Tuesday from southwest to northeast. For those of you who are weather fanatics, I'd urge you to take a look at the satellite imagery linked to the left of this discussion, or the Northeast radar composite linked just above the local radars at right. What you'd find is a well-defined spiral in the atmosphere...pinwheeling bands of clouds and associated snow showers with heavier squalls that have been making the trip steadily east from Michigan to Pennsylvania and New York. These squalls have, at least in spots, been quite impressive given the lack of moisture with the approaching system. Instead, the snow bands are driven by ample energy aloft - evidenced by the swirling pattern of the clouds - and this alone has been sufficient to bring near white-out conditions to some parts of the Upper Ohio Valley! This is rather impressive for a moisture-starved system, and is nature's key that plenty of potential exists with this disturbance.
Ahead of the energy center, clouds will gradually increase and thicken over New England later Tuesday. In the mountains of Northern and Western New England, a few flurries are likely from time to time Tuesday afternoon, with scattered snow showers a better bet across Central and Western New England by Tuesday evening. Even still, there will continue to be a separation between energy and moisture - with energy diving in from the west and north, and deep moisture locked south of New England. For most of us, this will mean a period of snow that will blossom as it migrates eastward, squeezing out only an inch or two in the western half of Southern and parts of Central New England, but increasing in intensity as it reaches eastern areas. The reason for this intensification comes thanks to so much energy aloft, which aids in developing a closed center of circulation in the lowest several thousand feet of the atmosphere. A developing storm turns counter-clockwise, and this will result in a weak south and even easterly flow tugging Atlantic moisture into the coastline, providing the missing ingredient for this energy center to thrive. It makes sense, therefore, that areas closest to the moisture will see the greatest snowfall, and this appears to be on Cape Cod. One factor that will cut down on accumulations is the progressive nature of the storm, which will carry most of the snow offshore by mid-morning. Nonetheless, with snow expected to still be falling early Wednesday morning in Eastern Massachusetts, and fresh snow elsewhere, Wednesday morning's commute is likely to start out somewhat difficult.
Later Wednesday, as the storm pulls quickly away from New England, a few snow showers are likely to linger in the mountains while the remainder of New England finds breaks of sun and breezy, cool conditions. This break in the action will last into Thursday, before another disturbance moves toward New England Thursday night. Contrary to its predecessors, this storm will have plenty of moisture thanks to a track that will bring the storm near the Gulf of Mexico coastline before it prepares to wrap northward and redevelops off the Atlantic Seaboard. The most likely scenario is for snow to overspread New England Thursday night well in advance of the main storm center, then become heavier heading into Friday. At this point - given ocean water temperatures still running in the 40s in the open ocean south and east of New England - it's likely that at least some warm air will be carried northward with this storm that may result in a mix with and perhaps change to rain in far southeastern New England on Friday. I'm not sold on this warmth penetrating too far north, though, largely because of what I discussed at the start of this discussion, which is the cold airmass well in place across Northern New England. This is not only cold but also quite dense and stubborn and will not budge even with approach of warmth from the south. The result will likely be for easterly winds to become more northeasterly Thursday night into Friday, resulting in a very slow northward progression of any rain/snow line. Therefore, the potential exists for significant accumulation through much of New England Thursday night through Friday and this is a storm worth paying close attention to.
In the longer range, the second and third weeks of February will bring a shift in the pattern that will result in shrinking the overall coverage of deep cold over the Lower 48, but will also help to nudge the axis of coldest air west just a bit, over the Great Lakes and Ohio Valley, which would allow moisture to stream northward over the Eastern Seaboard. In essence, this should theoretically allow for the storms that have been blasting off just off the coastline the past few weeks to begin taking off near or over the coastline as we round the corner into February. This is something worth watching.
For what it's worth, I was skiing this weekend in New Hampshire and the conditions were fantastic, and reports from ALL New England states are just as stellar. Anyone considering not skiing because of fear of conditions is worried for no reason - the man-made conditions are amazing and worth the trip. No, I'm not being paid by the ski areas to say it - just a long-time New England skier who loves to share the news!
Enjoy a bit of snow!
Matt
Matt's Technical Meteorological Discussion: Updated Tuesday, January 30 at 1:10 PM
Literally on my way out the door for an appearance but wanted to get a few thoughts down. For tonight's event, the great satellite presentation speaks for itself as buzzsaw vort max spins east and has great signature - even a super radar presentation right at the center of the vortex for a time this morning. Amazing! There should be no doubt of the integrity of this circulation as it moves east, and I'm quite comfortable with it developing healthy bands of snow. Ratios should be just under 20:1 on average with omega on the cold end of the dendritic crystal growth spectrum, tho cold thru the lower atmosphere, too, which reduces potential for aggregation, thereby cutting back on ratios from what they could be, which would have been even higher. I like the NMM representation given weak to moderate frontogenic forcing that should keep a rather contiguous west to east band of precip out of Upstate NY and across NewEng. Amounts will obviously be increased as Atlantic moisture is finally tapped by this vortex - it's already shown response to Great Lake moisture today. 850-500 mb lapse rates are strong and steep late tonight, tho this passes over most of Ern MA just prior to a llvl easterly flow developing. Over Cape Cod, the two come dangerously close to being in the same place at the same time which would mean a burst of heavy convective snows early tomorrow morning. Have adlibbed a 6" CHH or ACK, but concern is there for all of SE MA if this instabillity is tapped sooner. System will be progressive, but worth noting that in-house mesoscale model is really harping on mesolow development on north end of inverted trof along coast of ME - a Norlun feature of sorts. I can find no additional support for that feature at this time and have not included it in the forecast, but you can bet I'll be glued to sat and radar for any signature first thing in the morning. Otherwise, progressive nature brings breaks in clouds by mid-morning most spots. I know the models have been trending south on the Thu Ngt/Fri storm in 12Z runs - I also know I wanted to have more time to look at that storm today and that's not going to happen except to say that I would NOT flip and flop with the models on this one. Yes, the southward trend should be somewhat correct given the history of carrying storms to our south, but Southern New England still looks like a good bet at getting into some of this snow shield.
Matt
Monday's Discussion:
1:30 PM: Cape Cod squalls began as Eastern MA snow showers along trof - showing some weak evidence of Norlun characteristics earlier today with instabililty above trof, though losing those characteristics now - and primary mechanism now appears to be ocean enhancement. Most accumulation is done with this band after some localized rates around Chatham approaching 1"/hr early Mon AM. Drier air evidenced across remainder of NewEng is coupling with downsloping flow for decent sun.
Though I don't expect all clouds to dissipate Monday night with one vort max pivoting across the Canadian border and another sliding east-northeast out of Upstate NY. Ci deck likely to come in ahead of latter vort from midnight onward, though at the sfc winds will slacken. NMM coming on board in its 12Z run with the outlier 00Z WRF solution of blossoming precip field last-minute over far Srn NewEng Tue eve and overnight Tue ngt. It truly is a remarkable and challenging pattern we remain in, as frequent vort maxes need only moisture to thrive, but have by and large been devoid of that moisture, as is the case with today's impressive looking storm that sails southeast of NewEng and into the Canadian Maritimes. This certainly can leave one feeling gunshy, which is probably a very good idea in the medium range period, though in the short range the details become a bit easier to distinguish. This was the case with the Sun Ngt/Mon disturbance - appearing to have decent potential on Fri AM, but quickly becoming apparent it would be of little sensible consequence by Sat's guidance products. In this case - for Tue ngt's disturbance - the setup is one that actually is favorable for "surprise" snow in Southern NewEng, though I suppose that's a bit of a misnomer for me to use considering we're examining the potential together here. Nonetheless, we have a southern stream disturbance that, by itself, would sail south of NewEng once again. The delicate twist here is a very weak northern stream disturbance riding parallel and coming E out of NY State by Tue eve that will provide dynamic lift over Southern NewEng, and looks as though it will induce just enough sfc cyclogenesis to develop good boundary layer positive theta-e advection Tue eve into Tue ngt. Farther aloft there is less indication of this cyclone, but with an ocean sitting to our south and east, all we really need to do is get some sort of a south or east component around even a weak center to pull in enuf moisture to interact with the expanding dynamic lift. These were the reasons I kept a chance of snow in for Tue Ngt in the AM forecast today, tho it's interesting to see that the NMM/GFS/GGEM/RGEM/WRF are all now on-board with measurable precip for the time period. This is truly, yet again, another very delicate scenario as just a bit less development jeopardizes the moisture influx in the boundary layer, but for now it's certainly trending in a more moist - and therefore whiter - direction. Total accums would likely not be significant, but in a snow-starved winter, even a few inches can go a long way.
Later down the line, another vort slides thru Thu Ngt, and then another Fri Ngt, it would appear, and either of these hold potential, with the latter of more interest. Perhaps we will delve into this tomorrow or Wednesday. For today, I'm out of time.
Matt
