Nicer And Drier Today

Hello everyone!

Tropical Storm Isaias is long gone this morning and we’ll enjoy nicer conditions along with drier air in its wake. That drier air will drift into the region on WSW flow later this afternoon. First, we’re still dealing with a bit of southerly flow which means the humidity isn’t quite gone. As the drier air arrives, a few clouds will pop up along the boundary between the two airmasses (it would be too generous to deem this a cold front). Up in the mountains, a few of these clouds will become tall enough to pop off a brief shower or maybe even a thunderstorm. For the rest of us, dry weather will prevail today.

Highs will range from 75 in the north to near 90 in far southern NH. Aside from those afternoon clouds, skies will be mostly sunny today (just a few upslope stratocumulus in the mountains this morning).

As a quick note, I’m taking the next few days off to enjoy some time offline in the beautiful northern woods of Maine. I’ll be back Monday morning as per usual. The weather for the rest of this week looks fabulous with lower temps, lower humidity, sunshine (at least tomorrow), and generally dry conditions. A few more clouds and maybe some showers arrive later Friday into Saturday but overall shouldn’t be impactful. Temps will spend most of their time bouncing between 50s/low 60s at night (!) and 70s or low 80s during the day. It’s gonna be a great few days to get outside!

-Jack

Tropical Storm Isaias To Bring Strong Winds And Heavy Rain To The Region Tonight

Hello everyone!

Today will feature the long-awaited arrival of Tropical Storm Isaias as it races up the East Coast ahead of an advancing trough over the Great Lakes. While the storm center is still located way down near the NC/VA border (as of 6 AM), moisture is streaming well north thanks to strong southerly flow aloft. The net result for us is that clouds are already thick across the region this morning, and will remain that way through the rest of the day.

Zooming out on the radar imagery this morning shows an impressive plume of heavy rain extending from the storm’s center (south of Richmond, not quite in the frame here) all the way up past Ottawa and Montreal. Note that the heaviest rain is focused away from the coastline in the Mid Atlantic and west of the Hudson River in New York. This general trend will continue as the storm races towards Quebec City today. If you’re to the west of the track, you’re mostly concerned about heavy rain. If you’re to the east of the track, you’re mostly concerned about strong winds. Because the storm is headed west of us, we’re mostly concerned about the wind. That’s not to say there won’t be heavy rain, it will just likely remain below the levels needed to cause major flash flooding concerns.

Forecast model guidance (this map valid 9 PM) suggests that as the storm moves through Vermont, we’ll see two areas at risk for particularly strong winds: western NH (closer to the actual circulation) and the coastline (less friction). Both of these areas will likely gust over 50 mph, resulting in tree damage and power interruptions. For spots in between or farther northeast, gusts should stay in the 35-45 mph range which could cause a few isolated issues, but likely won’t support widespread impacts.

The other threat we’ll have to think about is that of tornadoes. On the eastern side of the storm, we’ll have some instability (shaded in the peach-ish color on the map above), abundant wind shear (pretty much off the charts for our region), and a line of thunderstorms moving northeast associated with the outer bands of Isaias. This storm has already produced numerous tornadoes as it moved ashore in North Carolina last night, and all indications are that this will continue as the system moves up the coast. The SPC (Storm Prediction Center, like the National Hurricane Center but for severe storms) has outlined our area as having a significantly-above-normal chance to see a tornado this evening.

What does this mean for you? You should have a way of receiving NWS tornado warnings if they are issued for your location, and you should be ready to move to your basement or an interior room on the first floor with no windows. Tornadoes will develop and dissipate rapidly so despite the best efforts of our friends up at NWS Gray, you might not have much time to act once a warning is issued. Remember that statistically speaking, your odds of getting a tornado tonight are still quite small. The vast majority of us probably won’t even get a warning. But it’s good to be prepared in case that happens, especially on a day like today when the risk is much higher relative to normal.

As far as timing goes today, expect showers to continue through the rest of the morning and into this afternoon. Generally, coverage and intensity of rain will tend to decrease as we move towards the later afternoon hours. Then this evening, the main part of the storm will rotate through in the form of that outer band which will bring briefly heavy rain, strong winds, and the threat for tornadoes as it moves northeast between 7-8 PM (SW NH), 8-9 PM (central NH/SW ME), and 9-10 PM (points north/east). Gusty winds will continue overnight before calming down tomorrow.

Temps today will be a bit on the cooler side thanks to all the clouds and southeasterly flow off the (very warm but not yet hot) Gulf of Maine. Look for highs ranging from the upper 60s/low 70s north to upper 70s/low 80s south.

-Jack

Temps Rise And Humidity Briefly Falls Today, Isaias Still Expected To Bring Heavy Rain And Strong Winds Tomorrow

Hello everyone!

A “cold front” is struggling to push east across the region this morning as a storm moving through Quebec tries to push drier air in our direction while tropical moisture begins streaming north ahead of Isaias. Dew points currently in the upper 60s to low 70s should fall off into the lower 60s or even upper 50s in western parts of the region by this afternoon. The humidity will linger a bit more along the coastline. Winds behind the boundary this afternoon will be from the west-southwest which is favorable for warm temps, especially along the coastline. With that in mind, expect highs ranging from the mid 70s up north to the low 90s along the coastal plain.

Skies will feature a mix of sun and clouds today as various disturbances drift overhead and leftover low-level moisture clears out. The best chance for cloud-cover will be up in the mountains while the coastal plain will see more sunshine. No precipitation is expected until late tonight in advance of Isaias.

Speaking of Isaias, the system is still expected to impact our area as a tropical storm tomorrow. The track has shifted a bit to the west since yesterday’s update which means that more of us will be on the windy side of the storm rather than the rainy side.

Flash flooding will still be possible in the mountains where the heaviest rain (2-5″ localized 6-8″) will fall. Most of us though will end up with a brief round of showers and storms that could drop an inch or two of rain. That will be welcome news for parched lawns and gardens, but generally isn’t much of a flooding concern (except for the usual poor drainage spots that flood every time we get a thunderstorm).

The bigger story for most of us will be the strong winds. As the storm passes to the west, we’ll see southeasterly winds pick up during the day tomorrow. Currently, most coastal spots should expect gusts to 45-55 mph with a few 60 mph readings not impossible in embedded stronger thunderstorm cells. Inland, winds should top out around 35-45 mph. This is enough to knock down trees and powerlines, especially given that these gusts will be from the southeast. As we learned in October 2017, our area is particularly vulnerable to tree damage from southeasterly winds because they don’t happen very often (but when they do, they’re usually quite strong). So be prepared for a bit of time without power tomorrow night and Wednesday. Unless the storm really pulls itself together today, I’m not expecting widespread major issues. This is about as strong as one of the stronger non-tropical storms we might get in late fall.

One last note is that the environment will be favorable for tornadoes as Isaias passes just west of the region probably tomorrow night (this storm has been really frustrating to figure out timing). By virtue of tornadoes being spatially confined phenomena, the odds of one striking your house is extraordinarily small. That said, you should have a way to get warning information from our friends up at NWS Gray if they issue a tornado warning for your area. Remember that the best place to be during a tornado is in your basement or an interior room on the first floor with no windows. We very rarely have to worry about tornadoes up here, but tropical cyclones are one good way to produce them. The last time we had a tropical cyclone pass to our west (Fay earlier in July), we also had a tornado (EF0 near Sebago Lake).

Here’s a timelapse I took of that storm looking WSW from Hackers Hill in Casco.

I’ll have another update on Isaias tomorrow morning at the usual time, or perhaps this evening if there are significant changes to report.

-Jack

Humidity Returns Today, Isaias Looking Like Less Of An Issue For US

Hello everyone!

Today will feature continued warmth and increasing humidity as southerly winds continue ahead of a storm developing in the Great Lakes. A bit of weak lifting ahead of that storm will team up with our warm and humid airmass to produce a few showers this afternoon/evening. As per usual, the best shot at some rain will be in the mountains. High temps will range from the upper 70s up in the mountains to the upper 80s in southern NH.

Skies are sunny for most of us as I write this a little before 6 AM, but clouds are rapidly increasing from the west ahead of the aforementioned storm system. I’d expect mostly cloudy skies for the rest of the day once these clouds arrive, though a few sunnier patches are possible especially farther east.

In news relating to Isaias, the storm has been plagued by dry air and wind shear as it has been drifting through the Bahamas over the past couple days. The upshot for us is that the storm is unlikely to approach the Carolinas as a strong hurricane, which means it won’t make it up to Maine as a weaker (but still intact) hurricane.

As a result, the threat for widespread damaging winds and destructive storm surge is now quite low. This is especially good because we haven’t had a hurricane since Bob back in 1991, and therefore there are plenty of folks in Maine and New Hampshire who have never seen what a hurricane can do up here (and Bob wasn’t all that bad of a hurricane in our area all things considered).

We will still get some impacts from Isaias, but they will be more in the form of breezy conditions, higher humidity, and heavy rain. The heavy rain may actually cause some flooding issues, especially if the storm tracks along the coast (putting the mountains on the western/rainy flank of the system). For most of us though, Isaias will pass with little impact outside of some grateful gardens. Remember, most of our region is still experiencing drought conditions, so a widespread soaking rain is welcome news!

I’ll continue to keep an eye on the forecast for Isaias, especially if it were to change and become more impactful.

-Jack

Warm Temps Return Today, Isaias Expected To Bring Heavy Rain Early This Week

Hello everyone!

Today will feature another day of mostly sunny skies and mild temps, though with winds shifting around to the south, we’ll tack on a few degrees to our high temps today over yesterday. Dew points will also start to creep upwards especially this evening. Expect highs to range from the mid/upper 70s in the far north and right along the Midcoast to low 90s in southern NH. Skies will be mostly sunny today after some very patchy fog burns off in the next couple hours.

Just like the past couple days, afternoon cumulus will pop up in response to daytime heating. At the moment, there’s no indication that more than one or two of these will be able to produce a couple raindrops. As always, the best chance for a very brief shower is up in the mountains.

As I’ve been mentioning for a few days now, Hurricane Isaias remains worth watching closely as it moves through the Bahamas. Thankfully for the entire East Coast, the storm has continued to struggle over the last 24 hours due to some dry air and strong winds about 25,000 feet above the ocean south of Florida. This means that as the storm recurves up the coast, it will do so as a strong tropical storm rather than a strong hurricane. What’s the upshot for us here in Maine? If current forecasts hold, Isaias has a good shot at smashing the last of our drought. The setup here favors persistent rounds of heavy rain starting Tuesday morning and ending midday Wednesday (roughly). When all is said and done, we could be looking at a widespread 3-6″ rain event with locally higher totals possible. If your location is susceptible to flooding, you should start thinking about what you’d need to do to prepare for high water. If you’re high and dry, this storm is likely to feel like just another rainstorm.

If you want to dig deeper into the forecast for Isaias, I suggest reading over my recent blog posts for weather.us. Yesterday morning’s covered some of the meteorological nuances of the storm’s forecast while yesterday evening’s discussed the expected impacts in more detail. If you have friends and/or family down in Florida or North Carolina, make sure they’re up-to-date on the latest forecast info as impacts down there from wind and storm surge will be much more significant than they are up here.

-Jack

Mild Weather Continues Today

Hello everyone!

Today will feature continued warm temps and moderate humidity as we remain stuck in between a few weather features without any individual entity strong enough or close enough to dominate our weather. As a result, skies are mostly sunny (except for a few clouds/showers drifting through southern NH) and will generally remain that way through the rest of the day. Some clouds will pop up this afternoon in response to some instability generated by our semi-humid airmass and warm temps.

A few of those clouds will become tall enough to produce showers and even a brief thunderstorm this afternoon. Without a strong frontal boundary to focus activity, most towns probably won’t see rain, but the few that do could see quite a bit of it over a relatively short time. One or two of the stronger cells could produce some gusty winds too. Overall, impacts from storms this afternoon are likely to be minimal.

High temps will range from the mid 70s up north to near 90 in southern NH.

-Jack

N.B.

I don’t usually do medium-range (3-7 day) forecasts on this blog, but I wanted to drop a quick note here about Tropical Storm Isaias which has formed near Puerto Rico this morning. Most model guidance suggests this storm will become a strong tropical storm or hurricane east of Florida tomorrow or Saturday before turning north in our general direction.

It’s way too early to hone in on exactly what this means for our forecast. We could see the system weaken and be little more than a source of moisture for thunderstorms along an approaching cold front. We could also see it remain strong and produce more significant rain/wind/storm surge impacts. I suspect we’ll have a much better idea by Saturday.

I mention this not because I think Isaias is a serious threat to northern New England, but so that you’re aware that it could be at some point early next week. There’s still too much uncertainty at the moment to warrant immediate action of any kind. That said, if you have a few spare minutes today, I’d suggest thinking about what your plan would be if a strong tropical storm or hurricane were to approach our area. What supplies you’d need, if you would need to evacuate and if so to where, and so on. It’s entirely possible (even likely) that you won’t need to implement that plan next week. But it’s good to have in the back of your head for when a storm does arrive (and one will, eventually whether it’s next week, next month, next year, or next decade).

Still Warm But Less Humid Today

Hello everyone!

Today will feature warm but thankfully less humid weather as yesterday’s “cold front” continues drifting offshore and another boundary drifts in our direction from the west. Skies across the region this morning are sunny and aside from a few daytime cumulus, that will generally continue through this afternoon/evening. One or two of those cumulus might grow tall enough to produce a brief shower in the mountains this afternoon, but other than that, dry weather will continue. High temps will range from the upper 70s up north to the low 90s in southern NH and adjacent interior SW ME.

-Jack

Still Very Hot And Humid Today

Hello everyone!

If you somehow managed to enjoy yesterday’s steambath airmass, well I have good news for you. It’s gonna be just as boiling today.

Hyperlocal temperature data (a very neat new addition to weather.us) shows temps already approaching climatological highs for the day (as of 5 AM). That’s one easy way to tell that today’s going to be really lot. The Jetport has yet to drop below 80 degrees! More acceptable temps (<70) are found in the Midcoast and up in the mountains.

High temps today will once again soar above 90 for most of the area outside the Midcoast shorelines and the far northern mountains. Some spots in southern NH could make another run at 95.

The hyperlocal dew point map this morning shows widespread values within a few degrees of 70F. That’s actually down a tad from yesterday, and is consistent with the more moisture-rich air associated with the warm front we saw yesterday drifting north. Nevertheless, dew points near 70 still feel pretty terrible even if they’re marginally less so relative to dew points near 75.

This humidity, combined with the extreme heat discussed above, will push heat index values into dangerous territory (>95F) once again today. Limit outdoor activity during the heat of the day if you can and make sure to stay hydrated regardless.

Given all this heat and humidity, as well as an approaching cold front, we’ll have to think about showers and thunderstorms today. High-resolution guidance isn’t super impressed by this afternoon’s storm threat, but some of the cells that approach the coastline early in the afternoon could be quite strong given how much juice they have to work with. Threats from storms today include damaging winds, frequent lightning, and heavy rain.

Storms will develop in the mountains later this morning before moving towards the coastline during the early/mid afternoon. Storms should be all wrapped up by mid/late afternoon.

-Jack

Heat And Humidity Becomes Extreme Across Southern Parts Of The Area Today

Hello everyone!

Today will be about as hot and humid as it’s possible to get here in Maine and New Hampshire, at least in southern parts of the area. A warm front will be lifting north through our region today and will be responsible for the heat and humidity as well as some afternoon shower/storm activity.

The first round of showers associated with the warm front is drifting southeast towards Sebago Lake as I write this around 6:15 AM. These will generally tend to weaken as they drift towards Portland later this morning. I think we’ll see a bit of a lull in shower activity during the mid/late morning hours before storms begin popping up early this afternoon.

These storms will initially develop in the mountains around noon-1 PM before moving east-southeast towards the coastline. The combination of hot temperatures, high humidity, and some cooler mid-level air will support plenty of instability to fuel the storms. Gusty winds, heavy rain, and frequent lightning will be the main threats with these storms but any time we get a warm front setup like this, we can’t totally rule out a tornado or two. The best chance, as always, is in the Sebago Lake region.

High temps today will range from the upper 70s/low 80s in the far northern mountains to the mid/upper 90s in southern NH. Most of central/southern NH and coastal/foothills regions in Maine will see temps above 90 this afternoon. Dew points near or above 70 will send heat index values into the triple digits over southern NH and adjacent parts of SW ME. Use appropriate caution if you need to be outside this afternoon.

-Jack

Heat and Humidity Returns Today

Hello everyone!

Today will feature the return of extreme (for our area) heat and humidity as west-southwesterly flow develops ahead of a cold front way to our northwest in Quebec. To start off this morning, we’ll get to enjoy some cloud cover moving in from Quebec ahead of a cluster of thunderstorms that formed along that frontal boundary yesterday. Those thunderstorms are located south of Quebec City and may actually survive into the northern part of our region over the next couple hours, bringing a round of heavy rain and a few rumbles of thunder.

As we move into the middle part of the day, clouds should fade especially across southern parts of the region. This sunshine will team up with breezy WSW winds to send temps into the low/mid 90s across the entire coastal plain and foothills region from central NH all the way to Waterville/Augusta and points northeast. The only exception will be right along the Midcoast shoreline where temps will be held in check somewhat by the Gulf of Maine. Mid to upper 80s are expected there. Up in the north, temps will also be a little cooler thanks to cloud cover and thunderstorm activity during the morning. Points between Greenville and Jackman (and continuing WSW into far northern NH) can expect highs in the upper 70s to low 80s. Dew points near 70 will push heat index values close to “dangerous” levels (>95F as determined by NWS standards, what counts for you will depend on many individual factors) across southwestern ME and southern NH.

Another round of showers and storms will develop well to our north this afternoon. These could drift south into the mountains this afternoon, bringing gusty winds, heavy rain, and lightning. If you’re escaping the heat through ascent to the high peaks, be mindful of the potential for storms this afternoon/evening. Otherwise, dry weather will prevail especially across southern parts of the area.

Tomorrow’s heat will be even worse.

-Jack

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

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