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:
Lots going on behind the scenes besides just the storm, so late on the update - my apologies.
A major storm will cross New England today, to be remembered largely for the wind it will generate on the trip through. This storm will be the first in a series over the next couple of weeks, but more specifically, the first in a set of two storms that will usher in a new, cold weather pattern for next week.
Pertinent Maps (more below in discussion):
In the meantime, relatively warm air delivered a mild start to most of New England Friday morning. The advance of more warmth and moisture to New England - the result of a deep tropical moisture tap - brought one round of rain through most of the six-state region overnight Thursday night into Friday morning, while rains continued to fall on the warm side of a cool front settling toward Northern New England from Southern Canada. With a very strong impulse of moisture-loaded energy set to march over New England later Friday, periods of rain, heavy at times, will continue to migrate from southwest to northeast across the region. Though there will be breaks in the rain at times, the combination of strong energy, ample moisture, and the resultant surface storm will ensure rain fills in for most areas Friday afternoon, with the heaviest amounts falling where steady rains have been falling for quite some time - in Northern and Western New England - and it's in these areas where localized flooding of streams is possible, while we all may see localized flooding of streets in heavier downpours.
Additionally, the passage of the surface storm will bring a quickly falling barometric pressure - a sure sign of storminess - and this will help to transport more warmth and moisture into Southern New England...enough for thunderstorms to develop Friday afternoon and some of the storms will have the potential to tap strong winds aloft and cause locally damaging wind gusts. As the storm center moves through Eastern New England, barometric pressures will rise rapidly behind it as winds shift to the west, and this pressurized air will create widespread wind gusts to 60 mph Friday evening through the overnight. These winds will have the capability of bringing down trees, tree limbs and power lines through the overnight, and will help to make temperatures in the 30s feel like the 20s by dawn. Additionally, keep in mind that signs, banners, and lightweight objects like Halloween decorations will blow around in the overnight into Saturday. Finally, these winds will be transporting colder air into New England, and rain will turn to snow before ending in the mountains of Vermont, New Hampshire and extreme Northwestern Maine, where a dusting of snow will fall, with amounts to two inches in higher terrain. 
The drier and cool air moving in will bring a decent Saturday after any lingering snow showers in Northeastern Maine, with a blend of sun and clouds elsewhere, but winds will continue to be quite active, with a west-northwest wind gusting to 40 mph! This will make the coxswain's jobs (those who steer the boats) very challenging for the Head of the Charles, and will continue to mean signs and banners serve as sails in the winds, along with tents, so please be sure everything is well-secured. After a chilly Saturday night, expect dry conditions to begin Sunday - so...all in all...most of New England does enjoy a decent fall weekend. That said, the next blast of energy - two strong disturbances merging from the Pacific and from near the North Pole - will be gathering strength and moisture across the nation's midsection. Clouds will increase Sunday and showers will likely develop by evening from west to east. This will set the stage for what will likely be a powerful storm for New England Monday into Tuesday. With cold air prior to the storm, and more cold air on the backside of the circulation, the threat for more widespread snow is present across Northern New England at the beginning of next week. This is a potential that needs to be monitored carefully for a possible early-season snow on especially the Northern Mountains. The most likely scenario would be for precipitation to begin late Sunday as a mixture of rain and snow or perhaps all snow but light in intensity across Northern Maine later Sunday night. For a time, most areas will see rain on Monday, but with substantially colder air available immediately west and north of the storm, rain should transition to snow later Monday or Monday night across the North Country. With moisture present, a northwest wind pushing up against the mountain faces, and cold air streaming in, "upslope" snows are likely to be generated Monday night through Tuesday in the Greens, parts of the Whites and the mountains of Maine.
While this surge of cold air will bring the potential for an early-season accumulating snow to Northern New England early next week, we'll all feel the result, as next week should be marked by much-below normal temperatures - perhaps producing record cold around midweek from the Northeast to the Mid-Atlantic, though admitedly, our records are already quite cold for the middle of next week - some dating back to the late 1800's, and the Mid-Atlantic may see a better chance of realizing record values. None the less, it'll be plenty cold!
Have a wonderful weekend.
Matt
Matt's Technical Meteorological Discussion: Updated Friday, October 20 at 2:30 PM
Wind gust to 61 mph recorded at KMPO in Ern PA at 1739Z with line of low topped convection moving E that will be in Wrn Srn NewEng at 1530 EDT and will reach KBOS between 1800 and 1900 EDT with damaging wind burst behind wind shift and possibly svr thunder along the line. Warm sector has bled into Srn NewEng according to sfc pressure/theta-e composite and deepening storm has reached 993 mb already before even reaching Hudson Valley. Will continue strengthening as it moves over Srn NewEng with 4-5 mb pressure rise/fall couplet and strong isallobaric component to the wind.
Winds may die down for a couple of hours behind front after the big gusts as cold and dry advection is slightly delayed, but once CAA commences, winds will gust once again up to 60 mph and become more widespread with damage done thru the overnight, scattered power outages, trees down, lightweight objects blown around. Please stress importance in forecasts of securing objects like signs and banners that can act as sails. Area of heaviest rain to move E ahead of potent vort max and in area of greatest isentropic lift in WAA across Wrn/Nrn NewEng where flooding of streams and streets most likely. Snow reported in KELZ and KBFD earlier today in Srn NY/Nrn PA - both are elevated stations but KELZ lowered to 1/2 mile in SN and this is a sign of the dynamic and advective cooling that will take hold in Nrn NewEng this eve and tonight. If we could snow during diurnal max there...and just flipped from rain to snow at diurnal max in KART (Watertown, NY)...we will have no problem doing the same in elevated locales of VT/NH as soon as 00Z/03Z respectively. Most areas shouldn't see more than a half inch or so up the spine of the Greens, but higher terrain will see a couple of inches, esp near 1800 feet in elevation.
Likely lingering snow showers early Sat in NW ME - tho perhaps still too mild in wraparound warmth aloft for NE ME - but most of NewEng transitions to windy sun/cloud blend. Downsloping component present in Ern areas and dry enuf air to preclude upslope development in Wrn/Nrn areas, but winds should still gust to 40 mph first half of day with 850 winds still cranking.
As winds taper Sat Ngt, temps tumble. Tds in lower 30s put lows near the same, tho some breeze still present will prevent widespread decoupling. Sunday brings moderation and less wind but next shortwave already increasing clouds thru the day. Am still holding showers off until eve but model runs holding it off until night are too slow given vorticity advection quickly moving E. A dynamic situation again for Mon/Tue and I continue to hedge on the colder and stormier side of the solutions. With deepening upper low forecasted to shift directly overhead, we won't see worst case scenario of deep phasing, but still plenty of energy and thermodynamics at work. First, slug of warm and moist advection ahead of upper low will crank out rain Sun Ngt into early Mon for most of NewEng as upper low shifts SE from Hudson Bay to Lake Superior. For a lot of NewEng this is probably it and it's done early Mon with some clearing late and winds kicking up. This will not be the case in the North Country, however, where the upper low will catch the surface system as it tries to ride out north and east, and effectively stall it. The result is going to be low level cold advection, moisture wrapping around the low in the midlvls and dynamic cooling as the upper low shifts east, and this should result in significant bursts of convective snow in Nrn NewEng - esp the mountains of ME - on Mon, and esp later in the day. Then we have ample moisture to interact with upslope NW flow and CAA to setup accumulating upslope snows in Nrn VT, Nrn NH and NW ME Mon Ngt thru Tue. By Tue, I expect cold enuf air to keep Srn NewEng in 40s, Nrn NewEng in 30s. As for records, min temps are quite cold Tue and Wed, and with an active wind that will be difficult to challenge, but record low maximum temps are possible Tue or Wed. Records more likely to fall in the Mid-Atl.
That's all for today - enjoy the weekend.
Matt
Wednesday's Discussion:
3:05 PM: 'Tis the season for surges of winter amidst lingering tropical warmth and moisture, and NewEng shud see both in the coming week. Tropical airmass in place as of this writing thanks to delivery by former TS Norman who chugged over NewEng last night dropping rainfall amounts over an inch to some, and under a quarter inch to others. Nonetheless, the storm has left behind an appreciable chunk of tropical warmth directly from the Gulf of Mexico and areas with sun have seen corresponding quick temp rises.
Shortwave embedded in the flow to cross between 18Z and 00Z this afternoon and have adlibbed isolated shra/tsra with warmth and low level moisture in Srn NewEng, tho cov'g should be limited. Enuf dry air aloft for breaks to remain in clouds overnight tho fog will be dense in many areas with relatively light wind and high dewpoints.
Fog and sun starts Thu before clouds advance along midlvl baroclinic zone stretched across Nrn NewEng. Approach of shortwave energy to interact with this zone in generation of showers for Nrn NewEng by early afternoon, expanding S as cool front approaches from NW and baroclinic zone tightens. Leading s/w ejects NE from base of Central US trof on Thu and fills showers and period of rain in across Srn NewEng Thu eve into the ngt. Thereafter, attention turns to strong shortwave migrating rapidly E in Westerlies. Tho this s/w will be strong, it will also be progressive until it reaches NE NewEng later Fri, where it interacts with colder air aloft and deepens/closes off NE of ME. There has been some issue as to the path of assoc sfc low pressure center(s) with this vort max, more so with the secondary low than the primary, which will cut north of NewEng. The secondary has been progged from NYS to offshore NewEng as a nor'easter (ECMWF) but consensus likely to be best, not to mention the solution of the GFS Ensemble mean - which places triple point low over Ern NewEng - inland - perhaps getting Cape Cod into warm air as it swings thru but bringing gale SE gusts to the mid and downeast ME coast and perhaps gale force SW gusts under the belly of the strengthening sfc low to SE NewEng.
As this storm wraps up while moving NE Fri Ngt into Sat, still feel there is enuf basis to include potential of snow in the fcst for Nrn/NE ME with wraparound precip early Sat. While operational models have varied greatly for this time period, GFS Ensemble mean has stuck to its guns of keeping high chc pops in NE ME at the same time cold air in Srn Canada is ingested into storm center. Additionally, with upper level low closing off, moisture wraps around back of circulation and will maintain chc snow showers in Nrn ME for Sat AM. Precip also may end as a few flakes in Nrn mountains of NE VT/NH where upslope flow can generate enuf lift, but dry air quickly moving in behind storm by that point. Ridging is quick to move back in aloft and this will mean cool but dry most of NewEng Sat into Sun. Next s/w in line is one that recently ejected from the Aleutian low and will drop into Central US trof, ejecting NE into NewEng like its predecessor, but with enuf airmass modification for rain in all locales except perhaps in Nrn ME where warm and moist advection will ride overhead before llvl flow can swing out of the N and this means a brief pd of light WAA snow would be possible in Nrn ME later Sun ahead of the s/w. Warm advection should win out Sun Ngt, however, with all areas going to liquid.
The real meteorological fun only grows more intense early next week, as a strong shortwave dropping south from the polar vortex near the North Pole will merge with a Pacific counterpart and amplify handily at the base of the trof to our west on Monday. The trick here is that the storm Sun into Mon will have already yanked down a hearty chunk of cold air from Canada, and the motherload of cold will be heading east across the Midwest. This will be another chunk of record cold in Iowa, and will end up spelling record cold for the Mid-Atlantic and at least some of the Northeast by the middle of next week. But the transition to this cold will likely come with an intense cyclone as the upper low deepens and generates its own cold air through continued dynamic cooling over Southeastern Canada, and drives sfc cyclone development over or very near to NewEng on Monday. This storm will already have picked up plenty of Gulf moisture during its amplification, and with the cold air to the north and west of the storm, sufficient baroclinicity will meet sufficient vorticity to generate a powerful storm whose circulation will tap the cold to our west and northwest. The result should be enuf cold air meeting up with a wound up storm that will wrap significant mositure around its west side to generate snows from Nrn ME thru the North Country where upslope flow will play a significant role. In fact, the situation looks quite favorable for accumulating upslope flow snows in esp the Green Mountains as cold advection meets with moisture on a strong NW flow. While this will not spell snow for Srn NewEng, it will spell a great pattern for cold air - a prolonged NW flow at the sfc meeting up with an airmass to the tune of 12 C below normal, creating record low temperatures, especially by midweek when winds will weaken but WAA will not have begun yet, and overnight lows should plummet.
What could change this outlook? Obviously storm track and timing of cyclogenesis is crucial. Slightly farther east...or west...upsets how the cold air and the storm can interact and the wind direction. This won't change the cold - that's coming - what it would effect is the potential for accumulating snow. But at this point, I'd say it's certainly the best chance of snow the North Country has had since spring.
We'll keep an eye on it together.
Matt
Monday's Discussion:
1:40 PM: Slow moving wx pattern has been northern stream dominated of late but that will change in the coming days as trof continues to dig in Wrn US and sends subtropical jet springing northward. This subtropical jet is active with the remnant of Norman, a former tropical storm who churned across the Eastern Pacific before crossing Mexico, then regaining an impressive satellite signature over the Western Gulf of Mexico this weekend before making landfall early Monday into the Eastern TX coastline, where winds gusted in excess of 40 mph. Torrential rain has been lifting north and will turn NE as it encounters the fast flow of the westerlies across the Midwest, and the vort max assoc with the remnant of Norman will charge NE and directly over Srn NewEng late Tue Ngt and Wed AM, bringing a shot of heavy rain with it.
In the meantime, high altitude Ci clouds will spill overhead in waves Mon Ngt as thicker moisture puts on the brakes crossing OH Valley, but dry air and light wind shud still allow for temps to fall quickly after sundown. If enuf Ci spill overhead, my fcstd low temps will be a bit too warm, tho with Tds in the upper 20s to around 30, I'd imagine most locales will see frost, and concern is for perhaps pockets of black ice where freezing fog may result in Pioneer Valley through Monadnock Region and Central NH. Any sun early Tue will quickly help to mix the atmosphere, tho Ci clouds will thicken and lower as midlvl moisture spreads NE across NewEng thru Tue.
Slug of moisture slated for Tue Ngt shud come in with progged vort max as referred to in first paragraph. 12Z GFS a bit drier than its preceding run, 12Z NAM not much more moist and still noticeably drier than GFS. Canadian Ensembles and GFS Ensembles both lean toward wetter solution, while most guidance insists on quick solution. Wet and quick both make the most sense with slug of isentropic lift intense thanks to tropical slug but quick moving embedded in the subtropical jet. The net result shud be a shot of 1" QPF for most of Srn NewEng with locally higher amounts, then lesser amounts Nrn half of NewEng. As warm and moist advection wanes Wed AM, rain will taper, tho quick progression of warmth and moisture aloft leaves behind the corridor of warm advection in the llvls, and this means plenty of moisture is left behind at 850 mb and below. Hence, clouds linger thru most of day Wed tho a few breaks not impossible Wrn areas as sfc inverted trof/weak warm front moves E and brings westerly flow, while drizzle immediately behind rain assoc with shift of winds to the N and llvl cool advection shud be found in ME coastline.
Still will have sfc low assoc with llvl remnant of Norman that will eject off MidAtl coastline and pass SE of NewEng, while new shortwave induces sfc low development in the Great Lakes and drags cold front with multiple waves across OH and TN valley. This front with waves will enter the I-95 corridor Thu Ngt and strengthening wave with tropical moisture will be rippling thru MidAtl Thu Ngt en route to NewEng for Fri. This happens at the same time Nrn stream wave moves E, carrying cool air behind it, and this is enuf to at least peak interest in how the incoming cold air will interact with northward rippling moisture-loaded wave. I say this because, at some point, these two features really should link up, but the question is how quickly does that happen? The 12Z GFS is one of the quickest to merge, and while I do think the GFS tends to handle waves of fronts better than most of the guidance, the key here is more in the handling of the Nrn stream shortwave, which takes on a neutral/negative tilt at the end of this week but does so just a bit too far west on Thu to let the cold come flooding in as quickly as the new GFS would paint. I think the end result is that the merger of cold and tropical occurs E of ME later Fri, and this means Nrn ME will be on-guard for wrap-around precip...and yes, perhaps snow...late Fri into early Sat. Certainly something to watch carefully.
Another watcher will be the beginning of next week, which the GFS Operational has not been nearly as bullish on as its Ensemble member counterparts, but bullish may be the way to go for next Mon/Tue as polar vortex deepens over SCentral Canada before nudging east and quite literally helps to create its own cold air that should be quite eager to move into NewEng, with strong energy aloft and sfc baroclinicity ready to encourage sfc low development over or near Ern NewEng, and once again raising eyebrows for those interested in snow prospects for the North.
We'll see...plenty to work out between now and then.
Matt
