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NNE Warm Season Thread 2021


wxeyeNH
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7 minutes ago, Patriot21 said:

I'm at 42° at 10:30 according to my thermometer. Can easily see your breath

Nice dude!  Crisp evening.  49F here, but MVL is 55F.  Temperatures are all over the place on the mesonet. Calm and clear is key, the lower (relatively to background geography) spots are cooling efficiently but any breeze causes a spike.

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6 hours ago, powderfreak said:

Nice dude!  Crisp evening.  49F here, but MVL is 55F.  Temperatures are all over the place on the mesonet. Calm and clear is key, the lower (relatively to background geography) spots are cooling efficiently but any breeze causes a spike.

Yes it was a nice evening. It was calm and clear here like you said. The hills directly behind my house top out around 1800 so maybe that helps with my cooling. I am about 500' lower than them.

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3 hours ago, Patriot21 said:

Yes it was a nice evening. It was calm and clear here like you said. The hills directly behind my house top out around 1800 so maybe that helps with my cooling. I am about 500' lower than them.

What did you end up with for a low?  41.7F down this way along the West Branch.

Felt real nice.  And yeah if you sit in a relatively lower spot (but still good elevation) that’s the best for night cooling.  A bowl/field at like 1300ft seems ideal with higher hills around.

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2 hours ago, powderfreak said:

What did you end up with for a low?  41.7F down this way along the West Branch.

Felt real nice.  And yeah if you sit in a relatively lower spot (but still good elevation) that’s the best for night cooling.  A bowl/field at like 1300ft seems ideal with higher hills around.

I'm not sure the final low, I leave for work at 3am and my thermometer is back by my garden shed, so I don't walk right by it as I leave in the morning and I drive an older vehicle with no thermometer built in lol. I need to invest in a digital station for more accuracy. I have noticed I have gotten frosts before where the higher and lower elevations around me did not. I'm set-up basically like you described as a bowl, but a 3 sided bowl. West, east and north are higher up and due south is lower elevation. The trees are also cleared out around the house so that may help some.

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14 minutes ago, Patriot21 said:

I'm not sure the final low, I leave for work at 3am and my thermometer is back by my garden shed, so I don't walk right by it as I leave in the morning and I drive an older vehicle with no thermometer built in lol. I need to invest in a digital station for more accuracy. I have noticed I have gotten frosts before where the higher and lower elevations around me did not. I'm set-up basically like you described as a bowl, but a 3 sided bowl. West, east and north are higher up and due south is lower elevation. The trees are also cleared out around the house so that may help some.

My wife got me this one for Christmas.  Ambient WS-7078  It was easy to set up and seems to be pretty accurate. I like the console and the app. I've linked it to Wunderground

The only issue I've had is that there was a random 2" of rain recorded one night a few weeks ago.  I know it didn't rain that much, if at all.  It's almost like a bird or squirrel took a big leak over the rain gauge.  I've kept an eye on it and haven't noticed any other anomalies like that.

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April is another one of those months with a lot of snowfall variability, and it came in a bit on the plus side this winter.  Nothing has come close that the snowfall we had in April 2007, but it’s interesting to note that the past several years have shown much more consistent snowfall totals relative to the period before that really exhibited that April variability.  I think of April as the spring equivalent of November when it comes to the frequency, amount, and overall tenor of snow.  But as I look at the numbers and summary plots now, it’s obvious that November is much snowier; our site averages more than twice the amount of snow in November compared to April, and the number of storms is nearly double as well.

17JUN21A.jpg

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8 hours ago, mreaves said:

My wife got me this one for Christmas.  Ambient WS-7078  It was easy to set up and seems to be pretty accurate. I like the console and the app. I've linked it to Wunderground

The only issue I've had is that there was a random 2" of rain recorded one night a few weeks ago.  I know it didn't rain that much, if at all.  It's almost like a bird or squirrel took a big leak over the rain gauge.  I've kept an eye on it and haven't noticed any other anomalies like that.

Thank you so much for the link. Exactly what I need.  That's funny about the random 2". Was there actually any liquid in the gauge in the morning? 

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6 hours ago, J.Spin said:

April is another one of those months with a lot of snowfall variability, and it came in a bit on the plus side this winter.  Nothing has come close that the snowfall we had in April 2007, but it’s interesting to note that the past several years have shown much more consistent snowfall totals relative to the period before that really exhibited that April variability.  I think of April as the spring equivalent of November when it comes to the frequency, amount, and overall tenor of snow.  But as I look at the numbers and summary plots now, it’s obvious that November is much snowier; our site averages more than twice the amount of snow in November compared to April, and the number is storms is nearly double as well.

That makes sense based on our mountain climo.  November seems to feature a baroclinic zone starting to move into and through the area.  And I think we do better on the general climo NW to SE (sinking south) period than when the jet stream mean rises north in the spring.  The northern Greens like to live on those cold frontal passages, with dynamics or strong thermal changes going from warm/moist to cold/dry... found more in November than April.  On average April is probably more warm air advection and November more cold air advection.  On a very simplistic level with a lot of seasonal variability, I think that bolded stat can be explained as simply as cold air advection and warm air advection in the large aggregate. 

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9 hours ago, Patriot21 said:

I'm not sure the final low, I leave for work at 3am and my thermometer is back by my garden shed, so I don't walk right by it as I leave in the morning and I drive an older vehicle with no thermometer built in lol. I need to invest in a digital station for more accuracy. I have noticed I have gotten frosts before where the higher and lower elevations around me did not. I'm set-up basically like you described as a bowl, but a 3 sided bowl. West, east and north are higher up and due south is lower elevation. The trees are also cleared out around the house so that may help some.

I don't have a station online, there are several very close by. I just have a basic one for the garden.  My climate seems to very closely resemble MVL ASOS on the whole, we drop faster in the evening as the shadow from Mansfield hits first.  Gives it a head start over MVL.  But by morning, the two spots seem very close in low temps.  Afternoon highs seem pretty similar too on sunny days.

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19 hours ago, J.Spin said:

April is another one of those months with a lot of snowfall variability, and it came in a bit on the plus side this winter.  Nothing has come close that the snowfall we had in April 2007, but it’s interesting to note that the past several years have shown much more consistent snowfall totals relative to the period before that really exhibited that April variability.  I think of April as the spring equivalent of November when it comes to the frequency, amount, and overall tenor of snow.  But as I look at the numbers and summary plots now, it’s obvious that November is much snowier; our site averages more than twice the amount of snow in November compared to April, and the number of storms is nearly double as well.

17JUN21A.jpg

April here averages 5.1" which is 0.2" more than November, but 3 Aprils have had only traces while all 23 Novembers have recorded some measurable snow.  After never having more than 2 of the 15-year periods with more snow here than there, April did that 5 times, led by 37.2" in 2007.  The Farmington co-op recorded 36.1"; their closest to that in 129 Aprils is 24.0" - the 50% gap is impressive even for a high-variability month.  We squeaked past you in 2008 with 2.0" but the April Fool's storm in 2011 didn't do much out year way while dumping 15.1" here.  We had 7.7" in 2019 and the 8.5" storm in April 2020 cut our power for 30 hours and (along with multiple shorter outages Oct-March) pushed us to buy an on-demand generator.

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Today the dog said goodbye to winter with a final roll in the snow.  This is the last patch of frozen water on Mansfield and likely to melt out in the next 24 hours.  It goes very fast once it gets this small. 

I also love that you can see the footprint of it, with the green vegetation all around the dead, flattened grasses.  It's crazy to think the brown grass, recently melted off, is going through the same process that our lawns go through when they melt out in April, ha.

203566987_10104565040259590_201377368190

202009987_10104565235488350_548910689112

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On 6/17/2021 at 9:32 PM, powderfreak said:

That makes sense based on our mountain climo.  November seems to feature a baroclinic zone starting to move into and through the area.  And I think we do better on the general climo NW to SE (sinking south) period than when the jet stream mean rises north in the spring.  The northern Greens like to live on those cold frontal passages, with dynamics or strong thermal changes going from warm/moist to cold/dry... found more in November than April.  On average April is probably more warm air advection and November more cold air advection.  On a very simplistic level with a lot of seasonal variability, I think that bolded stat can be explained as simply as cold air advection and warm air advection in the large aggregate. 

Great inferences PF; that makes a lot of sense.  In addition, when I think about it, it fits the typical weather experiences for many of us who live along the spine of the Northern Greens.  As with the November/April dyad, I’d say the trend is there even for the October/May dyad despite the fact that those months are the very fringe of the snow season and exhibit high snowfall variability.  I’ll have the May snowfall plot next as the final in that series of analyses.

FactsAboutSnow.jpg

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I’ve never recorded snow in June at our site, so I consider May the final month of our snow season.  The variability in the plot of snowfall by season speaks for itself, with accumulating May snowfall being quite inconsistent and only happening every few seasons or so.

Similar to November and April, I consider October the counterpart to May on the front end of the season.  Although there can be a lot of variability in both months with respect to whether or not we get any accumulating snow at all in a given season, I think a comparison of the plots for the two months is informative in the context of PF’s recent comments.  Although both months have surprisingly similar mean snowfall values, the October snowfall mean comes from a much more consistent distribution of snowfall among the seasons.  Those October snows often come as autumnal cold fronts push through and the mountains help wring out some moisture as the cold air arrives, which is certainly in line with PF’s idea about the types of setups that work well to produce snow here.

18JUN21A.jpg

09JUN21A.jpg

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3 minutes ago, DavisStraight said:

What's your earliest date of fall snow Jspin. We get October snow down south, do you get Sept snow?

The CO-OP near me here in SVT at 1700' has never had measurable snow in 60 years. Only 1 year had a trace. 

Doubt Jspin would have ay at 500', even with him being in NVT.  Im sure he will have the graph ready in the AM though :).  Would think you would have to be pretty high up for Sept snow more than a trace. 

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6 minutes ago, backedgeapproaching said:

The CO-OP near me here in SVT at 1700' has never had measurable snow in 60 years. Only 1 year had a trace. 

Doubt Jspin would have ay at 500', even with him being in NVT.  Im sure he will have the graph ready in the AM though :).  Would think you would have to be pretty high up for Sept snow more than a trace. 

Yeah it’s something that happens rarely at the picnic tables.  I’ve seen freezing mist/drizzle with clear ice over snow in September.  It’s very hard to get a deep layer sub-freezing column.  The summits have been known to get sub-0C on upslope flow but with super cooled water droplets.  Not a cold enough atmosphere to support ice crystals.

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9 hours ago, DavisStraight said:

What's your earliest date of fall snow Jspin. We get October snow down south, do you get Sept snow?

We had slushy flakes on 9/14/77 at 535' in Fort Kent during a cold coastal (47/35; 1.62").  The old Casey Brook Road, logging road heading south from the SE Public Lot in Allagash, was blocked by hundreds of saplings bent across the road by 1-2" paste at 1000-1200'.  We also saw slushy flakes at 970' in the back settlement on a sun&shower day, 8/28/82 (54/35; T/T).

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9 hours ago, DavisStraight said:

What's your earliest date of fall snow Jspin. We get October snow down south, do you get Sept snow?

 

9 hours ago, backedgeapproaching said:

The CO-OP near me here in SVT at 1700' has never had measurable snow in 60 years. Only 1 year had a trace. 

Doubt Jspin would have ay at 500', even with him being in NVT.  Im sure he will have the graph ready in the AM though :).  Would think you would have to be pretty high up for Sept snow more than a trace. 

 

9 hours ago, powderfreak said:

Yeah it’s something that happens rarely at the picnic tables.  I’ve seen freezing mist/drizzle with clear ice over snow in September.  It’s very hard to get a deep layer sub-freezing column.  The summits have been known to get sub-0C on upslope flow but with super cooled water droplets.  Not a cold enough atmosphere to support ice crystals.

I’d actually been thinking about putting together plots of earliest snowfall dates (First Frozen, First Accumulating Snow, First 1” Storm, First 2” Storm, etc.) because I have all those data, but figuring out a presentation format that I felt was effective has been tough.  This inquiry got me working on it some more though.  I wanted the dates to be on the horizontal axis in a plot because I like that format for chronological data.  In addition, what I really wanted to do was have each season as a row in the plot, and stack all the first occurrence dates for each threshold of snow in the row as different colored dots/points for each category.  Excel hasn’t quite been able to hit what I want, and I really haven’t felt like dealing with export to another graphing application just to achieve that result, but I think I’ve settled on a format I like.  I’m putting just one category on a plot at a time, and it’s much less busy, so I can actually display the data points as the dates themselves.  The date text markers aren’t placed perfectly with respect to the date axis (they’re on the left side of the desired position) because I’m sort of adapting a horizontal bar graph to get my result, but I still think effectively shows the distribution of dates by season.

So to get to DS’s question about September snow, I’ve never seen it at our site, consistent with what backedge suspected. Below I’ve added the plot of earliest frozen precipitation at our site, which is the lowest threshold I record for early season occurrences of frozen precipitation.  This first frozen precipitation observation doesn’t need to be specifically snow (although it often is), so it can be graupel or sleet, etc., as long as it’s frozen.  It also doesn’t need to accumulate, just be observed as falling frozen precipitation.  I record first accumulating snow as its own category, so I’ll do a separate plot for that.

Anyway, as the plot below indicates, the earliest frozen precipitation in the records we have for out site is October 11th.  That really doesn’t seem all that far from September, but it’s probably an eternity at that time of year.  Even Mt. Mansfield struggles to get snow in September as PF noted, but I’ve got a plot of those data that I made for a post a couple of seasons back, so I’ll grab that for a separate post.

So in terms of this past season, first frozen precipitation came on October 26th, which is a little on the late side (mean occurrence date is October 21st), but certainly right in that typical period where we see it.  In this case, that was also the date for the higher threshold of first accumulating snow, which is very typical for that parameter with a mean occurrence date of October 27th.

19JUN21A.jpg

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3 minutes ago, tamarack said:

We had slushy flakes on 9/14/77 at 535' in Fort Kent during a cold coastal (47/35; 1.62").  The old Casey Brook Road, logging road heading south from the SE Public Lot in Allagash, was blocked by hundreds of saplings bent across the road by 1-2" paste at 1000-1200'.  We also saw slushy flakes at 970' in the back settlement on a sun&shower day, 8/28/82 (54/35; T/T).

That’s really cool Tamarack; those observations certainly demonstrate the effect of that extra latitude up there.

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10 hours ago, backedgeapproaching said:

The CO-OP near me here in SVT at 1700' has never had measurable snow in 60 years. Only 1 year had a trace. 

Doubt Jspin would have ay at 500', even with him being in NVT.  Im sure he will have the graph ready in the AM though :).  Would think you would have to be pretty high up for Sept snow more than a trace. 

 

9 hours ago, powderfreak said:

Yeah it’s something that happens rarely at the picnic tables.  I’ve seen freezing mist/drizzle with clear ice over snow in September.  It’s very hard to get a deep layer sub-freezing column.  The summits have been known to get sub-0C on upslope flow but with super cooled water droplets.  Not a cold enough atmosphere to support ice crystals.

Here’s the Mt. Mansfield analysis I referred to in my post above – I just copied the text from the initial post below.  The return rate on August snow seems to be 50+ years, but for September snow it’s about once every 6 years, and for October it’s almost a lock.

“A comment in the main discussion thread had me pull up some of the first snowfall of the season data for Mansfield, but I’m putting it here for archival/discussion purposes as well.

In a few more weeks and we’ll definitely be watching for those first dustings in the peaks around here in NNE.  The earliest recorded accumulations on Mt. Mansfield are actually only a week from today (see inset in the graph below), and of course on Mt. Washington it can happen at almost any time.  I ran the early snowfall numbers for Mt. Mansfield a few years back and found that first snows occurred in September at an average rate of about twice a decade, and only about once a decade do we not have that first snow by October.  I recently assembled the actual numbers though, and I’ve plotted those below.  The occurrence of first snow by October is actually a bit higher than 90% though, so the absence of snow by October is closer to once every 15 years vs. once a decade.  First snows are potentially a bit more frequent than the numbers indicate too, since there are some seasons with chunks of autumn data missing, and with the ephemeral nature of early season snow and the variability in personnel making those observations, some occurrences of snow could have easily been missed.”

21AUG19A.jpg

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20 minutes ago, tamarack said:

We had slushy flakes on 9/14/77 at 535' in Fort Kent during a cold coastal (47/35; 1.62").  The old Casey Brook Road, logging road heading south from the SE Public Lot in Allagash, was blocked by hundreds of saplings bent across the road by 1-2" paste at 1000-1200'.  We also saw slushy flakes at 970' in the back settlement on a sun&shower day, 8/28/82 (54/35; T/T).

Damn, 8/28 is crazy for flakes.  I know Allagash is way up in the far north, but still.  Not like its 4k.

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15 minutes ago, J.Spin said:

That’s really cool Tamarack; those observations certainly demonstrate the effect of that extra latitude up there.

 

Only July failed to have at least catpaws there, though 7/31/78 had a frost.  We were at Allagash Bible Camp at 625' along the St. John on July 3-4, 1982 and both days had highs in the 60s with destructive sunshine that produced very chilly afternoon showers, especially on the 4th when a heavier shower brought enough cool air to drop the temp well down the 40s, maybe even upper 30s.  Would not surprise me if there had been flakes above 1000' up in the woods, though no one reported any that I know of.

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Earliest flakes, earliest measurable:
98    11/3       11/17
99    10/4       11/10
00    10/9       10/29  (6.3" 29-30, high on 29: 31°)
01    10/31     11/1
02    11/1       11/1
03    10/22     10/23
04    11/21     11/21
05    10/23     10/25
06    10/23     12/7
07    11/8       11/20
08    10/29     11/25
09    10/13     11/5
10    10/22     10/31
11    10/29     10/29   (4.5" 29-30, Octobomb was forecast 12-16 here)
12    11/5       11/8
13    11/10     11/10
14    11/1       11/2   (0.5", forecast was 4-8)
15    10/18     11/23
16    10/25     11/21
17    11/10     11/16
18    10/13     10/27
19    10/25     11/8
20    10/26     11/3

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