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:
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As for the weather, the trough, or dip, in the jet stream winds aloft that has left New England cool and at times unsettled over the past couple of days will gradually lift out over the coming days, though quite begrudgingly. Eventually, this pattern change will give way to deep summer warmth for the Memorial Day holiday, and while the transition may have a few bumps along the way, the forecast continues to hold promise for most - whether you prefer 60s, 70s or near 90, this seven day stretch from Monday to Monday will have provided something for us all.
The Wednesday morning scenario places a persistent area of low pressure east of New England, with a pool of cold air aloft. Cold air high in the sky contrasts greatly with warmer air near the ground in a setup like this, and the result will be building clouds through the day Wednesday, blotting out from time to time the warming sunshine. In Eastern New England, these clouds are likely to grow tall enough and heavy enough to drop a few rain showers late Wednesday morning through mid to late afternoon. These clouds will diminish quickly after sunset Wednesday evening as the cool pool of air aloft nudges east in response to the eastward retreating storm center.
Of course, this storm is moving east away from New England largely in response to yet another intense disturbance moving east, kicking the old out and ready to usher in new energy. Before the next system arrives, however, New England will see a quiet transition day on Thursday. Ahead of the approaching disturbance, the counter-clockwise flow of air around this system centered over the Great Lakes and of Pacific origin will help to usher warmer and more moist air into New England at all levels of the atmosphere. As is often the case with increasing warmth and humidity, plenty of clouds will grace the skies of New England on Thursday, though I expect them to be thin enough to allow for plenty of dim and milky sunshine that - combined with a developing then strengthening south and southwest wind - will help to boost temperatures into the 70s.
Meanwhile, a cold front will be settling southward through Canada, and this approaching front means business with a well of cold air behind it. The jet stream winds aloft will be critical in the role this front plays in our weather heading into the start of the holiday weekend - remember that this fast river of air aloft not only steers storms like the next one racing east out of the Great Lakes later this week, but also acts as a thermostat, separating cold air to the north from warm air to the south of the wind corridor. I'm quite certain the jet stream will NOT buckle enough to allow that powerful cold front to carry a cool airmass into New England this weekend, but that doesn't mean it won't have an impact. In fact, the frontal boundary will settle into Northern New England on Friday at the very same time the strong upper level disturbance moves into the Northeast from our west. The result will be widespread development of thunderstorms and downpours through Southern Canada and extreme Northern New England Thursday night, then developing through most of the remainder of the Northeast during the day Friday and especially Friday afternoon. Some of these thunderstorms are likely to bring torrential rain and frequent cloud to ground lightning.
With the energetic disturbance not likely to pass through New England until Saturday morning, I'm expecting areas of rain, downpours and thunder to continue through Friday night, dropping a couple of inches of rain in many parts of New England! This rain is likely to linger into Saturday morning, but the rate of strengthening of this storm is likely to salvage the later half of the day. What I mean by this is that the surface storm associated with the jet stream disturbance will actually be strengthening fairly quickly as it pulls off the Massachusetts coastline, and will be drawing air into its center. This *should* allow winds to shift from the northwest as Saturday wears on, allowing drying of the lower levels that will bring emerging sunshine. With such a mild airmass in place - the jet stream continues to rise northward after the passage of this system meaning the warm air just keeps coming - any sunshine would easily push temperatures well into the 70s across New England. It stands to figure that there is some degree of variability to the Saturday forecast dependent on the speed of the storm and the rate at which it strengthens - a slower storm or slightly farther south track would delay the wind shift and therefore delay drying later Saturday, but right now I think we're on track for emerging Saturday sunshine.
Regardless, the summer warmth that's been building from the Southwestern U.S. through the nation's midsection and even northward into Central Canada will be on the move and destined to move into New England. By Sunday, this warm and increasingly dry air will yield a gorgeous blend of sun and clouds, with the only lingering question being surface wind direction - which may turn onshore near the coastline to keep coastal areas cooler, but most of New England will warm to near 80 degrees!
By Memorial Day Monday, all signs point to a strengthening southwest wind, which is a warm wind direction for almost all of New England, except, of course, south-facing shorelines. With enough dry air in place for nearly full sunshine, the combination of sunshine and warm air should have no problem boosting temperatures well into the 80s - even at the coastline - with some spots hitting 90! This deep summer warmth will last through midweek, and even after the passage of a cold front that's likely to bring a round of strong thunderstorms, a warmer-than-normal pattern is likely to continue through the first half of June!
Matt
Matt's Technical Meteorological Discussion: Updated Wednesday, May 24 at 3:20 PM
Clouds and showers popping up this afternoon have been well progged by models in past several runs as upper level cool pool and increased sfc diurnally warmed airmass are at odds. Both convective showers and clouds will diminish gradually after dusk. Winds should go near calm overnight which will allow decent cooling for a time tho Ci clouds are likely to spread overhead at least in fragments late as warm advection begins aloft.
Surface weather map in immediate vicinity will be devoid of any major players on Thu as NewEng will be sandwiched between Great Lakes low - the reflection of Pacific-origin shortwave moving east on the south side of the Westerlies - and the anticyclone off the Mid-Atlantic coast. The result will be a strengthening SW flow and this coupled with dimmed sunshine will mix the atmosphere well and add enuf insolation to boost temps above normal into the 70s most areas. Not full sun effect given multiple cloud fragments that will ride overhead - perhaps not as any organized cloud mass, but with warm and moist advection at all levels of the atmosphere, this phenomenon will be difficult to avoid.
On Monday we looked at the strong cold front that would be pressing southward thru Canada this week, and remarked that the cold airmass behind it should stay out of NewEng thanks to rising heights. The problematic feature for the end of the week and the weekend was the Pacific shortwave that was over Srn CA on Mon and continues to move E, transported by the southern perimeter of the westerlies. Our thinking from Monday still looks to be on track with this - keeping convective threat in the forecast for Fri...tho now looking like a late Fri Eve or early Fri Ngt onset with the daytime action over NY State, and NewEng rains thru the overnight Fri. One of the big factors discussed here Monday was the interaction between the Srn Canada front and the incoming vort, and that's still taking center-stage for this event - because while I may still foresee the cooler airmass staying put in Canada thanks to heights that won't fall enough to allow the new air to settle southward, there is good agreement on the surface convergent zone with this boundary dropping southward thru Nrn NewEng Thu Ngt into Fri, and this will help to focus the llvl moisture convergence in advance of the main vort. The result should be Srn Canada convection along the front settling southward into extreme Nrn NewEng Thu Ngt, then convection blossoming in the increasingly warm and humid airmass ahead of the incoming vort across NY State. This vort will clearly be dampening as it moves thru NewEng and maintains a positive tilt, and this will be reflected in the lower levels by an opening mid and low level circulation and a slightly weakening surface low pressure center. Nonetheless, the air will be increasingly moist with precipitable water values over 1.50" thanks to earlier advection during the day on a 30 kt SW llvl jet, trough axis will be well defined at all levels, and pockets of CAPE nearing 1000 J/kg will be present along with helicity values of over 150 m2/s2 in parts of Southern NewEng, while mid-level front will be settling southward into Northern NewEng. This will set up a continuing upglide heavy rain event across the Northern half of NewEng, with a more convective event for Southern NewEng, but heavy overnight rainfall over over 1" in many areas with a couple of inches not out of the question across the North depending on how this all plays out.
I'm staying relatively optimistic about Sat as morning lingering showers and clouds seem unavoidable but the progressive nature of this feature lends support to the NAM solution of a wind shift during the day Sat that would set up a downsloping NW sfc flow that would bring out sunshine Sat afternoon. Remember that with such a warm airmass and high heights settling in (deepening warmth) any sunshine can go a long way and I do expect that to be the case later Sat. In fact, the warming may be significant enuf for a slightly amplifying follow-up shortwave Sat afternoon to interact with lingering 850 thermal boundary and pocket of lingering cool air aloft for new convection to fire Sat afternoon.
Building heights and plenty of warm air continue to bode well for Sun thru Tue with increasing heat thru the period. Strengthening and expanding anticylcone E of NewEng on Sun may be just enuf to leave a coastal component at the beaches while interior keeps light land breeze. Beyond Sunday, I would caution one and all that statistical guidance is likely way too low on this for Mon-Wed in particular thanks to climatological anomaly coupled with what will be a good downslope component and very warm boundary layer air. I still think touching 90 is a good bet for the best downsloped spots Mon-Tue!
The longer range and the tropics thoughts really go hand in hand for now, as they both focus on one of the same features, and that's a decent cold front that cuts thru NewEng on Thu of next week. This puts a temporary break in the swelter, and is likely to bring significant convection given a good tap of Gulf and Atlantic moisture northward into NewEng prior to frontal passage. Behind the front, warm air from Canada will be quick to wrap back east into NewEng - and truly while I say from Canada, the origin of this air comes from the desert Southwestern U.S. Then again, why stop there, because to follow the origin of the dry air you'd find two contributors - one is Eastern Asia and the other is Australia. On Monday I'd mentioned that we are likely looking at what will be an extended period (several weeks at least) of hot and dry weather for the Southwestern quarter of the U.S., and this includes the four corners region. And how could it not be when we can trace dry source regions from the other side of the world in both the Northern and Southern hemisphere? One does have to wonder if this will have growing implications later in the summer as this hot and dry pattern in that part of the nation continues to feed warm and dry air north and east with warmer than normal temperatures prevailing thru at least the first half of June even here in the northeast. The result will be a warm start to meteorological summer with occasional taps from the tropics - as I'm expecting to see toward the end of next week - and if the ridge continues to pump across the SW quarter of the US (going to be tough to reverse that anytime soon given the season) then we will continue to favor broad troughing over the Northeast, though given the shear amount of available warmth, it may be an instance where troffing doesn't mean cool as much as it means unsettled and it means we'll keep an eye to the tropics. Speaking of...
Tropics: And speaking of the tropics, though we haven't officially opened the season yet, I mentioned earlier this week I wanted to add clarity to some thoughts I threw out to you regarding the Gulf for the first week of June. By June 6-8, indications from Ensemble means continue to be for a tropical wave to migrate west thru the Western Caribbean and into the Eastern Gulf. Here it would encounter the remnants of our cold front - slated to come thru the Northeast next Thu - and a stream of moisture screaming in from the Equator and across Central America. The confluence of a dying cold front, an incoming easterly tropical wave, and abundant moisture feed from the equator spells a good recipe at this early point in the season for development over the Gulf, and I think we're going to have to continue watching this carefully for that time frame.
Have a great Wednesday.
Matt
