Welcome to the weather blog - a regular Monday through Friday discussion of the weather! You'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net. While the discussions usually will only come on days I'm working, I'll occasionally issue special updates when the weather warrants. 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 Weather Summary:
** SATURDAY MORNING UPDATE: I am updating from home since I'm off today. I can't change the maps at the bottom of this discussion from home, but it looks like the event will be pretty close to what was laid out last time I was at work on Thursday...a general 3" snowfall with locally higher amounts, especially from the turnpike southward. Some areas on the northern extent of the 3" area I drew on the map into Central NH will not get the full 3", and instead will fall closer to 2", which will make a difference as to how far north the "plowable snow" extends. But, in general, my thinking continues the same as before. This will be my final post on the event, so from this point forward, please reference my homepage, www.mattnoyes.net, for current radar imagery. Happy New Year!
Techie Sat AM Disc: Precip amounts of .15 Merrimack Valley to .25 South of the Turnpike. This will not be a 10:1 ratio storm...greatest upward vertical motion is centered either side of 600 mb through heart of dendritic crystal growth layer. Low level temps are a few degrees below freezing and perfect for "sticky" flakes, which means dendritic crstyals will coalesce in the lower layers. This combo is the best one we can get for ratios - should be close to 22:1 snow to water ratio today, and hence my reasoning for keeping amounts up. Happy New Year! -Matt **
Thursday's Complete Discussion:
A quick note here: I'll be off Friday, December 30, so this will be the final comlete post of 2005. I may issue an update from home sometime Friday, but because there's an impending snow event for the weekend, I've tried to be as complete as possible in today's discussion, and have included maps for both tonight's snow in Northern New England, and the snow expected New Year's Eve in Central and Southern New England. The latter is not as specific as I normally am, but that's because we're still 60 hours away from the event as of this writing.
Today's Summary: While New England has been settled into a mild weather pattern the last couple of weeks - along with most of the nation - cold air has been building in Canada and will dislodge in our direction for the start of 2006. This pattern change not only will bring temperatures down, but also is likely to result in a snowy pattern for the first 5-7 days of January.
In the meantime, rain rules the roost today with one to two inches of liquid expected in Central and Southern New England, and through Maine - and lesser amounts in Northern VT. Areas of interior Central and Northern New England that started with slick spots this morning will see a transition to plain rain as temperatures nudge above freezing in advance of the main slug of rain pushing northward. As an area of low pressure moves from the Delaware coastline, directly over Southern New England, and to a position along the Maine coastline by Friday morning, heavy rain with occasional embedded thunderstorms will move through Southern New England from mid-morning until evening on Thursday. Farther north and east, the period of heaviest rainfall comes from afternoon through evening. Most of New England is shrouded in fog through the day Thursday - especially across the interior where the clash of cold snowpack and warm air has established. Finally, with the low pressure center crossing directly over New England, winds along our coastlines will gust over 35 mph at times, though inland winds will be much lighter. These winds along the coast will be warm winds, and portions of Eastern and Southeastern MA will warm into the 50's.
Meanwhile, a significant ice storm is still shaping up for Northern Maine, where Northern Aroostook County will see freezing rain falling through most of Thursday afternoon and the first half of Thursday night. While Presque Isle has pushed above freezing during the day...and Caribou may come just barely above the 32 degree mark, areas north and west of Caribou through the St. John Valley and into Fort Kent will stay cold enough for 1/2 to 3/4 of an inch of ice accumulation which will bring down powerlines, resulting in several days without power for some locales. Additionally, snowmobiles in these Northern Aroostook areas should be ready to go, as downed trees and lines may make some roads impassable. Finally, even in Presque Isle where rain falls, the snow has been fluffy and will absorb the rain, rather than melting. This means the snowpack will become heavy, and will put significant stress on roofs, and where snow has not been cleared off flat roofs and barns, building collapses will be possible in structures that cannot support the weight.
Fog sticks around through most of Southern New England Thursday night under cloudy skies and areas of drizzle are likely, while winds swinging around to the northwest across Northern New England will usher enough cold air into the mountains for 3"-6" in the higher terrain, and a couple of inches in lower elevations of Northern New England.
Northwest winds penetrate farther south through all of New England on Friday morning with gusts of 30 mph, and this clears the fog for all areas. While these winds will usher in a colder airmass through Southern New England during the day on Friday, deep moisture will have already departed, and after just a few lingering early morning showers, expect mostly cloudy skies giving way to a few breaks of sunshine and a brisk and breezy day. Across the North Country, morning snow will taper, and cloudy, cool conditions will prevail.
Meanwhile, a new energetic disturbance will be sweeping east across the Upper Midwestern U.S., driven by the jet stream winds aloft. With this next storm not as eager to dip southward and ride up the coastline, there will be less moisture involved, but that also means we'll hold onto more cold air across New England. After morning sunshine on Saturday, clouds will thicken quickly during the afternoon, with a blend of rain and snow showers likely to develop in Southern New England by New Year's Eve, and snow showers developing through the remainder of New England except Central and Eastern Maine. It now appears likely that this disturbance will travel far enough south to bring accumulating snow to most of New England - with highest amounts expected in Southern New England. Any mixed rain/snow showers Saturday evening should transition to mostly snow Saturday night, and this will make for a wintry mess later on New Year's Eve. While pre-midnight events should simply be graced by some snow showers, after midnight is when roads will begin turning slick...at least that's the way it looks at this early stage, so if it's snowing, keep yourself in good enough shape to make it home through snow New Year's Eve, my friends!
Sunday begins with snow in Eastern parts of Central and Southern New England, then gives way to a chilly afternoon. Yet another storm will be heading east by Monday - this one more likely to transition to a coastal storm - and enough cold air may very well be in place for another accumulating snow event Monday night into Tuesday.
Again, I'm off Friday - so aside from a possible quick update on Friday, this will be the final post of 2005. Thanks to you, my viewers, it's been a fantastic year, which included the start of this blog, that so many of you have visited regularly. Here's wishing you a happy and healthy 2006.
All My Best,
Matt
Matt's Technical Meteorological Discussion: Updated Thursday, December 29 at 1:20 PM
Thunder started early Thursday morning with numerous CG strikes CC/Islands around 0600 hrs. Most of that forcing shifted E across the Atlantic before pushing into Maine with a well defined surface wave riding along northward progressing warm front. Result has been to keep cool NE wind locked in Western ME/NH and CT valley while bringing warmth up to Southern Aroostook County, ME. This will not be enough to mitigate problems with icing in that area...more on that below. Main sfc wave of low pres heading toward Long Island and will cross Srn NewEng Thu eve before chugging to the ME coastline, and heaviest rain will be in the moist and warm conveyor belt ahead of the circulation. Widespread 1-2" of rain many areas by the time all is done, though less in Nrn VT removed from low level baroclinic - or more importantly, theta-e gradient - zone a bit, tho we will make up for that in the wraparound overnight Thu night.
Not much change to the going forecast thoughts from yesterday in lots of areas for today's event. Deepening low pressure turns surface flow ageostrophic in many areas and that will be a problem in Northern NewEng. Even though CAR and PQI have both warmed above freezing, the St. John Valley stays below freezing and across these areas of Northern ME the heaviest precip arrives overnight tonight, after ageostrophic northerly wind has kicked in and cold air comes draining back down south. This still puts .5 to .75" of ice in St. John Valley, and nearly .5" in Caribou/Presque Isle even though you're seeing plain rain during the day. The cold air at 850 mb isn't far behind but south and east progress will be retarded until the mid-level center can move sufficiently northeast. This means the cold air comes pouring into the northern and western Mountains of NewEng Thu ngt and then puts the brakes on, so we accumlate snow in the mountains (see map above) assisted by upslope flow, and in Northern ME once the cold air comes in aloft. Elsewhere, wind flow is light in Southern and Eastern NewEng until cold advection begins - not until Fri AM - and downward momentum assoc with this advection carries wind to the surface. So, expect fog and drizzle to hang tough most of the night in these locales.
Cold advection becomes more widespread on Fri, tho aside from upslope mountain locales where snow lingers early, enuf dry air and downsloping flow not to worry about precip after a leftover AM drizzle/shower of rain in Eastern areas. Winds will gust to or just over 30 mph at times as fast low level winds mix down, esp during afternoon. Airmass is cooling thru the day, tho diurnal effects will help, so temps may drop during the morning as advection and mixing begins, then should hold steady.
Next system to pay attention to is, of course, our Saturday vort max. This well defined and energetic disturbance looks quite impressive on satellite imagery Thu as it spins across the Rockies and toward the Plains. Yesterday we scratched the surface on the accumulating snow this system will likely create for Central and Southern NewEng, and the bottom line on the storm is that we have a strong vort max that will leave behind a dying primary low over the Niagara Frontier of NY, while spawning secondary development in the area of best vorticity, warmth and moisture advection over NJ later Saturday. In the area of broad warm and moist advection over NewEng late Sat afternoon, expect scattered showers to develop. In most areas, temps will be cold enough just off ground level for predominantly snow showers, though rain should mix in along and south of roughly the MA Turnpike. But through the evening, cold air comes in associated with the shortwave, and is locked in with the surface low developing to our south and the antecedent airmass not really needing much cooling to support snow anyway. The challenge with this storm will continue to be - with the guidance and meteorologists alike - how quickly the mid and low level centers can get their acts together to turn winds easterly and pull in Atlantic moisture is the key. While the models have been jumping around from run to run, the general consensus is for a .25" QPF line to run from Southern Maine to Rutland, VT, the .10" line from Penobscot Bay to Somerset County, ME, and the .50" line centered somewhere around Eastern CT to Cape Cod. Given the probablility of a warmer boundary layer allowing for some mixing in these far Southern locales...and a vorticity track that would argue for slightly farther north placement of max frontogenetic forcing at 850 mb, I've put max amounts in the climatologically favored areas for an event like this - and the synoptically favored area, for that matter - from interior SE MA west to NE CT (again, map provided above).
This has only strengthened my thinking of going cold for Sunday and I'm holding with the temps I've had going. Looks like another shot on Monday night into Tuesday, and while the GFS is begging for a warm solution, let's not get too focused on that solution right now...I'm not willing to buy it, at least not an all rain solution, for a couple of reasons. 1) Most other guidance, including the GFS ensemble means, are splitting the high pressure center to our northeast and east, rather than bridging them. This is important because it allows cold air to be held in on a northeast flow. 2) Most other models also agree on the southern stream energy outrunning a northern stream shortwave, but eventually interacting with it as a storm that stalls - or perhaps even retrogrades - on Tuesday. This would mean a shot of warm advection snow later Monday or Monday night, which mixes with or changes to rain in parts of (but perhaps not all) Southern New England, then goes back to snow with rather intense wraparound snows. Today's storm marks the second storm that will have sent significant wraparound moisture pinwheeling back across Northern NewEng - to find a storm farther south and east, and sending wraparound moisture into Southern NewEng, is not a ridiculous conjecture given the combination of model agreement and pattern continuation. We'll see how this shakes out, but I think the potential is certainly there for a winter weather event - certainly more moisture packed and more potent than this weekend's.
Personally, I'd love to get a third storm in before my first 5-7 day January window I set forth a few days ago runs out...and that's not impossible around Thursday of next week with yet another strong southern stream wave heading our way.
Have a wonderful New Year - no techie discussion tomorrow...next one on Monday. Thanks for all of your support this year - looking forward to a great 2006.
Matt
