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:
Heartbreaking! That's the best description for Southern New England snow lovers (and meteorologists) awakening to much less snow than was predicted to fall by Wednesday morning. Instead of bands of widespread snow with a developing storm tapping Atlantic moisture, localized bursts of snow were all we could muster, delivering an inch or two to some, a dusting to many, and nothing at all to others. For yours truly, I awakened extra-early to face the early-morning drive in, and ran to the window like a schoolboy, with my eager smile quickly wiped away to find barely a flake had fallen outside my window. On a brighter note, this extra time was handy when I realized halfway to work that I'd forgotten my suit jacket and tie, and had to go back home to get 'em! While the missed snow event is a blessing for some, it is undoubtely a curse for others whose livelihood depends on clearing snow, and while treatments were required for many areas, I'm aware of the headaches the LACK of snow has caused many folks. The cause of this forecast "bust" was the sluggish nature of the energy center to pick up Atlantic moisture as it passed south of New England, not picking up necessary moisture until it was south of Block Island - too late to deliver appreciable snow.
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, after a partly cloudy and cold Wednesday night with a noticeable increase in clouds late, before another disturbance moves toward New England later Thursday. 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 some of 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. That said, I'm also not completely sold on bringing gobs of precipitation into New England. Though we have a deep "trough," or dip in the jet stream, that keeps us cold, this also keeps storms rather flat. With a recent pattern of keeping storms to our south, it would take a significant deviation in the storm track to bring the snow shield deep into New England, and that's a tough sell to make when I'm still looking at a broad trough that would favor southward suppression of the storm. At this point, therefore, I'm willing to bring snow showers that will morph into a shield of snow Thursday night into early Friday, though I'm not sold on more than a few inches in the higher amounts, except perhaps in Southeastern New England, just on the cold side of the rain/snow line where locally higher amounts could occur. That's not a hard and fast forecast for the storm so much as my thoughts on how it should evolve, given the pattern. With New England riding so close to such deep moisture, it's still a bit early for any numbers to start flying around in forecasts.
This weekend will bring another disturbance Friday night - capable of a few renewed snow showers - then colder air gradually moving southward through New England on Saturday with an active wind, but mostly dry in many areas excepting snow showers in the Northern Mountains. Another disturbance Saturday night will move over New England and drag an associated reinforcing surge of cold air at the surface, perhaps bringing a few more snow showers for many overnight Saturday night, then locking in the cold for Sunday.
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 last 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!
Have a great hump day!
Matt
Matt's Technical Meteorological Discussion: Updated Wednesday, January 31 at 2:10 PM
What a bust! There are two sides to a busted forecast - one is the public side and the other is the technical. I am all about being willing to apologize on the public side, and acknowledge where a forecast went wrong, as long as it doesn't take away from your ability to adequately cover the weather that lay ahead. From a technical standpoint, this discussion was written briefly yesterday but with authority - that is, I felt quite certain of how the situation would unfold. Oddly enough, I was reminded by fellow meteorologist Jodie Frazee here at NECN of my comments at the end of the day..."Of course, you know, there is another possibility with this storm. This shows low potential of a center-jump that would nearly bypass New England entirely." With such a rushed discussion, this never made it in yesterday, but truth be told I would have dismissed the possibility as remote, anyway. That said, the reason for any concern at all was the channeled nature of the vorticity. Experience has shown that a fast moving and relatively channeled vort will only produce appreciable precipitation in bursts, or along the thin ribbon of PVA that precedes it. That was the case in this event, which meant the resultant low level center was also very compact, and therefore moisture entrainment was limited. An interesting question is: If we are going to give respect to the channeled nature of the vorticity, does that mean we should use the same caution for later this week? The answer is probably yes.
In the short term, instability is combining with orographic lift and more importantly dynamic lift ahead of a shortwave straddling the Canada border Wed afternoon to create increasing convective snow showers along the Green and White Mountains. These will continue until evening passage of the shortwave, then diminish. Elsewhere, a quiet afternoon and evening - have gone with PC conditions overnight given diminishing low level clouds early but increasing middle and high altitude clouds later. With warm and moist advection at almost all levels of the atmosphere, and into a cold antecedent airmass, on Thursday, I'm expecting plenty of clouds at many levels. Some breaks of sun are likely to be found between these from time to time, but I don't think they will be the remembered feature of the day. Additionally, with a gradual and widespread warm and moist advection, overall weak isentropic lift will aid in scattered snow showers as the lower atmosphere moistens later in the day and Thu eve. Overnight Thu Ngt is when things turn a bit more interesting with the approach of the Srn stream shortwave. The assoc sfc cyclone will have interacted with Gulf moisture, and this will be a juicy storm and, of course, the question is whether this moisture streams northward into NewEng. To simply follow the QPF or RH fields of the models would be maddening over the course of the week, and instead we need to look at the synoptic pattern. We know, of course, that a strong upper low remains near Hudson Bay with a large trough over the Eastern 2/3 of the United States. The situation isn't just this simple, however. Upstream we find very strong positive height anomalies associated with the Alaskan ridge - the same ridge we looked at together several weeks ago that would be building and sending deep cold our way. Build it did, and today Alaska is sitting in what is record warmth at 850 mb, as the 850 mb temp soared to +8 C at Fairbanks when hurricane force winds blasted warmth deep into Alaska. In addition to setting up Chinook winds in Alaska in January (wow), this also is a sign of just how amplified our weather pattern is, especially when one considers that Fairbanks was in the depths of tremendous cold just three to four weeks ago.
So what does all of this mean for us? What it means is fast north to south flow around the east side of that Alaskan ridge, taking shortwaves and racing them from Western Canada to the Rockies and SW US quickly. But the broad nature of the trough extends from the SW US all the way to the Eastern Seaboard, and with negative height anomalies even over the Central Atlantic, it's very hard to turn anything significantly northward. In fact, if we were to forecast only by the 500 mb flow and vort maxes, we'd wonder how to get more than just the northern shield of a storm into NewEng, thanks largely to the relatively flat and fast flow from the Southern Rockies to the Nrn Mid-Atlantic coastline. In this fast flow with tight packing of isoheights, vorticity remains channeled, making it even more difficult to bring precip north.
This leaves us with a setup that brings enuf isentropic lift for at least light precip Thu Ngt, then by late Thu Ngt/early Fri the approach of the channeled vort should bring a period of slightly more significant precip, but does not extend very far northward and therefore will be difficult to pull much precip northwest. This is likely a big reason of why we're witnessing a southern trend in the guidance, and while a southward suppression does look good for the bulk of the moisture, this channeled vort should still be able to provide enuf lift to extend the precip shield into Srn NewEng - esp Ern areas - and I've held onto the potential for a few inches of snow in parts of Srn NewEng. Given the longwave pattern, however, I'm unable to bite on more than that at this point.
By Fri afternoon this first shot is likely gone as the storm remains progressive until slowing and bombing in Ern Canada, but another vort max will zip east from the Great Lakes Fri ngt and may bring another round of snow showers. In fact, the vorticity advection is actually better with the Fri ngt shortwave than it is Thu ngt into Fri! This serves as a reminder that we are, to some extent, making a mountain out of a molehill with the Thu Ngt/Fri event, giving credence to the moisture availability just south of us but having trouble acknowledging that there just aren't enough favorable dynamics over NewEng to make it work.
The combo of the Fri ngt vort max and the strengthening storm in Ern Canada will bring a steady wind and a steady flow of colder air into NewEng on Sat, though the more impressive arctic chill will lurk behind an arctic front that will be stationary north of NY and on the move east across the Great Lakes. This front should move thru with another vort Sat ngt, and will usher in colder air for Sun.
Another burst of deep cold appears en route for next Tue...but the question is whether we have anything hidden in the details to contend with as that arctic air works south. The longwave pattern appears favorable Sunday night for a wave to develop along or just ahead of the southward surge of arctic air, and this has peaked my interest for Sunday night/Monday. Right now, there's limited support from guidance, but the combination of a trof axis to our west, a shortwave rotating around the base of the trof, and the arctic front pressing south marks it as an alert for the synoptic pattern before the cold comes on strong for the middle of next week.
Have a great Wednesday.
Matt
Tuesday's Discussion:
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
