Mild and Unsettled Today Ahead of our Next Storm

Hello everyone!

Another storm is on the way for tomorrow and I’m delighted to say it should put on a pretty good show with heavy snow and gusty winds. The leadup to this storm will be a bit unconventional as southwesterly flow around a low pressure system over Quebec brings milder air into the region. Normally we look to see high pressure over Quebec feeding cold air into the region ahead of a potential snowstorm but alas. Maybe next time.

This map shows several different analysis and observation products but most relevant for most of are the temperature observations which are all the little numbers. Note that our area is embedded within the warm sector of a low over Hudson Bay which means temps are generally in the upper 30s to mid 40s. A cold front is noted over the Great Lakes and behind it, temps are much cooler (10s/20s).

Today, we’ll be mostly feeling the warm air moving north ahead of the northern upper-level disturbance on the map above. Any time warm air is trying to root out some pre-existing cold air, we have to look out for clouds and some light precipitation.

That’s exactly what forecast model guidance is expecting across the area today, with the best shot of some light rain/snow up in the mountains. Showers could expand towards the coastline this evening but overall precip will be spotty and light today as high temps rise towards the mid 30s up north and mid 40s along the coast.

By tomorrow, the disturbances mentioned above will join forces off the Virginia Capes and we’ll have ourselves a rapidly intensifying storm headed northeast. The loop below shows a model forecast for energy around 20,000 feet aloft.

For those with a meteorological background, this loop contains a treasure trove of information about the storm’s forecast. But even if it just looks like pretty colors to you, hopefully you’ll find it a satisfying rendition to illustrate the merging of the disturbance over the Great Lakes with the disturbance over Missouri into a big storm approaching Cape Cod.

Precipitation will begin moving into the area tomorrow morning in the form of a cold rain. However, as the storm intensifies, it will draw cold air down into the region from Quebec. Additionally, we’ll get to enjoy a process known as “dynamic cooling” where furious upward motion and heavy precipitation northwest of the storm’s center drives a chain reaction of thermodynamic processes from the expansion of air parcels to the transfer of latent heat that allows the storm to manufacture its own cold air locally.

Thus by tomorrow afternoon, almost everyone except for the immediate coast south of Portland (east of the Turnpike) and Midcoast (south of Rt 1 especially) will be enjoying heavy snow with temps right around or just above freezing.

via Tropical Tidbits

During the afternoon and evening, a process known as “frontogenesis” or the creation of a new frontal boundary will be helping to support very heavy precipitation. Where snow is falling, it will accumulate at a rate of 1-2″ per hour despite the relatively meager surface temperatures. Believe it or not, you can get rapid snowfall accumulations with surface temps above freezing! We last experienced this phenomenon on April 9th of this year when over a foot of snow fell across much of central Maine despite temps through most of the event sitting around 32-34F.

Because our storm will be driven by two disturbances joining forces, it will undergo bombogenesis which means its central pressure will drop by more than 24mb in 24 hours. What’s the upshot of that?

Not only will the snow fall heavily at times, but we’ll also have to deal with gusty winds. Winds will be sustained around 20-30 mph across the region tomorrow afternoon with gusts higher than that, especially along the midcoast. Normally this is a little below my threshold for talking power outages, but once you paste the trees and power infrastructure with heavy wet snow, it doesn’t take all that much wind to bring stuff to the ground. With that in mind, everyone should be ready for power outages tomorrow night that might drag on for a little while.

So how much snow do I expect? Here’s a look.

It’s always tough to tell where exactly the rain/snow line sets up and obviously that’s a pretty important part of the forecast. Right now, I’d draw it from the York County coast to Brunswick-Bath-Damariscotta-Belfast. Northwest of that line, snow totals will quickly ramp up to 8-12″ (or maybe a little more). But you won’t have to go very far southeast of that line to end up with bare ground. The big winner with this one will be the Sugarloaf area which could end up with as much as 18″. The snow up there won’t be the same cement that the coast will see but it won’t exactly be blower pow either. Honestly though, that’s good news. We want to build a dense base now so we’re not scraping rocks when the fluffier stuff hopefully shows up in January and February.

I’ll have an updated look at the storm forecast tomorrow morning.

-Jack

A Taste of Nicer Weather Today

Hello everyone!

After several days of stormy or at least unsettled conditions, tranquil weather will pay a brief visit to the region today before our next storm approaches starting tomorrow. Skies are clear across the region this morning and should remain at least mostly clear through sunset (best chance for clouds will be up north). Southwest breezes will push milder air into the region and temps will rise accordingly. Look for highs in the mid 30s up north and mid/upper 40s south. A few show showers are possible in the mountains later this afternoon but otherwise, we’ll stay dry.

-Jack

A Bit Cooler Today

Hello everyone!

Today will feature cooler weather as the storm that has been impacting the region for the past few days weakens to our north. Look for high temps ranging from the low 30s up in the mountains to the mid 40s near the coast. SW winds will remain gusty throughout the day, ironically bringing colder air into the region from NY/PA. A disturbance embedded within this SW flow pattern will cross the region late this afternoon into the early evening hours. Its primary impact will be providing a focal point for cloud/shower development in the mountains/foothills. Most of these showers will fall as snow though they won’t linger long enough in any given spot to drop more than a coating. A few flakes may even try to stray towards the coastline later in the evening. Before that front arrives, skies will be partly to mostly sunny.

-Jack

Wind and Rain Linger Today

Hello everyone!

The storm that brought heavy rain to the region yesterday evening and knocked power out for nearly 100,000 of us last night is still producing unsettled weather across the area this morning. Winds are still gusty from the southeast, though not nearly as strong as last night. Rain is still falling, especially away from the coastline but is not nearly as heavy as yesterday afternoon. Temperatures this morning are anomalously warm, ranging from the upper 50s in much of Maine to the low 60s in NH. As an interesting footnote, this makes us the second-warmest part of the nation this morning, narrowly beating out southern California (low 50s) and coming in just behind the Florida Keys (upper 60s).

Radar imagery this morning shows light showers in progress over our area while a batch of steadier/heavier rain lurks east of Cape Cod. This rain will be pulled north this morning and may even try to retrograde back to the west a bit thanks to some interesting dynamics aloft.

This forecast map does a pretty good job sketching out who will see the heaviest rain late this morning into early this afternoon. Points northeast of Brunswick/Augusta will get the steadiest and heaviest rain which will add up to another 0.5-1.5″. This is where the strongest winds will be found too, though gusts around 40-45 mph will do a lot less damage than last night’s 55-65 mph gusts. As you move farther west, winds will be considerably lighter and rain will take the form of more scattered showers rather than a steady soaking.

High temps today are pretty much happening right now, though temps might jump another couple degrees over the next couple hours before colder air arrives from the southwest. By 7 PM, temps will be falling into the mid 30s over NH, mid 40s over western Maine, and low 50s over eastern Maine. Much of the western half of the area will dip below freezing by tomorrow morning which could produce some slick spots on the roads as leftover moisture freezes up.

-Jack

Classic November Gale Arrives Today

Hello everyone!

A storm is on the way this afternoon and it’ll run the New England November Gale playbook to a tee.

Low pressure will pass to our west which means we’re on the warm side of the storm and winds will be picking up out of the southeast later this morning.

We had a beautiful sunrise here in Boothbay Harbor but mid/high clouds are quickly obscuring any early glimpses of the sun and overcast skies will be the rule for the rest of the day.

This forecast map shows expected conditions at noon today, by which point rain will be falling in southern NH as well as along the southeast-facing slopes of the mountains where upsloping will be at work with developing southeasterly flow. Temps will be considerably cooler inland (mid/upper 30s) than near the coast (low to mid 50s).

Winds during the morning hours will remain light as we need to wait for the heavier rain to mix down strong winds from aloft.

By the time this forecast map is valid at 5 PM, that process will be underway south of Portland where winds will be gusting over 30 mph. Steady/heavy rain will be falling across the entire area with a few isolated pockets of sleet/snow in the highest terrain.

The storm will peak overnight tonight as bands of very heavy rain with embedded thunderstorms move up the coast from Massachusetts. These showers and storms will tap into the energy of a low-level jet stream just above the surface packing hurricane force winds. Not all of that energy will make it to the ground, but coastal spots especially northeast of Portland are likely looking at 50-60 mph gusts beginning around 7 PM today and continuing through midday tomorrow.

This animation shows forecasted wind speeds from 1 PM today to 1 PM tomorrow. Note the extended period of strong SE winds along the coast starting this evening and continuing into tomorrow before a cold front slowly pushes east and winds shift around to the southwest.

Power outages are likely especially in the usually-prone areas so make sure you prepare today for that possibility.

This forecast loop shows atmospheric moisture content and winds in that low-level jet I mentioned earlier. The strong southerly winds that we’re worried about causing power outages are also bringing a plume of moisture up from the deep tropics. It’s hard to overstate how unusual this airmass will be for our area for this time of year! That moisture will support very heavy rain tonight and tomorrow morning. The Midcoast and southeast-facing hills/mountains should expect 3-5″ of rain from this storm while most of the rest of Maine picks up 2-4″. New Hampshire won’t get the heavy rain for nearly as long tomorrow so will end up with a bit less (1-3″ outside the Whites).

This will provide a very helpful nail in the coffin of our drought, which should prevent substantial river flooding issues. That said, small streams will make a run at their banks tonight/tomorrow morning and the usual poor drainage spots will fill up with water. Keep an eye on that if you’re headed out and about tonight.

Heavy rain and wind will continue tomorrow morning before gradually tapering off from west to east tomorrow midday/afternoon.

-Jack

Nicer Weather Today

Hello everyone!

After several cloudy and showery days, we’re finally looking for some sun to arrive today as high pressure crosses the region ahead of our next storm system. Upslope clouds are still hanging on in the usual spots up north and a few clouds are lingering along the midcoast but otherwise, sunshine is the rule this morning. Most spots should be partly/mostly sunny until high clouds begin arriving from the west this evening. Sunshine and relatively mild air aloft will push temps into the upper 30s north and upper 40s south. Enjoy the nice weather today, the storm moving in tomorrow looks to be a fairly impressive one with high winds and torrential rain. It will linger through most of Tuesday too.

-Jack

Another Round Of Scattered Showers Today

Hello everyone!

A weak cold front will cross the region today and as it does, it will push ongoing upslope showers off the mountains and into the foothills/coastal plain. Expect showers to be most numerous around 1-4 PM. Outside the mountains, temps will rise into the 40s today so precipitation will fall as rain though some graupel (“soft hail” or “snow pellets”) wouldn’t surprise me given the cooler temps aloft. Abundant low-level moisture has blanketed the area with a thick cloud layer this morning, but we’ll see some breaks of sun develop this afternoon as westerly winds pick up and downsloping becomes a stronger influence on the weather along the foothills/coastal plain. The drier air associated with those winds will also bring a few sunny moments to the mountains, though they will generally be short-lived.

-Jack

Quiet But Cloudy Today

Hello everyone!

Today will feature generally quiet weather albeit with some fairly cloudy skies. Low/mid clouds are fairly widespread across the area this morning though slight downsloping has opened a corridor of clearing just southeast of the higher terrain. As the day goes on, some of the low cloudiness should try to lift along the coast but clouds will hang tough in the mountains. A weak front will approach from the west later today which will bring renewed overcast to the entire area. A few showers are possible as that front passes through after sunset. The best chance for a shower will be up in the mountains though I wouldn’t be surprised to see sprinkles drifting into the foothills too. Temps today will be on the milder side, ranging from 40 up north to 55 in southern NH.

-Jack

Cool and Unsettled Today

Hello everyone!

Cool temps and unsettled weather will be the story of today as warm air begins the process of dislodging the Canadian airmass that moved in yesterday. The first consequence of that process is abundant cloud cover which is already in place across the area. The second consequence is light precipitation which has begun to fall over northern parts of the area this morning. The robust cold airmass in place across the region currently is supportive of snow which will be the dominant precipitation type this morning.

This forecast map gives a pretty good idea of who will see the most persistent snow this morning: areas north of a Fryeburg-Richmond-Camden line. South of that, there’s just not enough upper-level support. The steadiest and heaviest (moderate vs light) snow will be found up in the mountains where upper-level support is maximized.

Morning snow will taper off and change to rain south of Route 2 by this afternoon as winds shift around to the south and warm air continues pushing into the region.

Up in the mountains, this renewed push of warm air will keep the snow going as cold air remains better-entrenched near the high terrain.

The colder temps and longer duration of precipitation/snow mean that parts of the mountains could pick up 2-4″ of snow today. 1-3″ is more likely in the foothills with a coating-2″ along the coastal plain north of Portland. York County and southern NH may not even see a single flake as low-level dry air evaporates whatever flurries are forming aloft.

High temps today will range from 30 up in the mountains to 40 near Portsmouth NH and perhaps also Rockland ME.

For those planning ahead to potential outdoor gatherings tomorrow, the forecast sadly isn’t looking great. A storm currently moving through Missouri will provide steady cold rain along the coast and a messy mix of cold rain and freezing rain inland.

-Jack

Classic Post-Cold Front Weather Today

Hello everyone!

Today will feature classic post-cold front weather as we welcome Canadian high pressure moving in behind yesterday’s storm. Northwesterly breezes are pushing cooler and drier air into the region this morning and though winds will slacken throughout the day, the upslope/downslope pattern they produce will remain more or less intact. Cooler temps (mid 20s) will be found up in the mountains under thick low clouds while sunshine and downsloping will boost temps into the low 40s along the coastal plain.

Our next opportunity for precip will arrive tomorrow in the form of light snow, and unfortunately Thanksgiving looks cold and wet with a mix of freezing rain and rain as another weak storm moves through.

-Jack

Reliably hype-free weather info for Western Maine and New Hampshire from amateur forecaster Jack Sillin

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