NNE Spring Thread

[powderfreak]

53 minutes ago, klw said:

FWIW I went up Jay Peak on Thursday evening and there was no sign of any remaining snow anywhere there.

Still some drifts up high and on the hiking trails.  Several large patches on the Cliff Trail hiking trail from the Gondola top to the ridge and there's still some on the Long Trail from what I've heard.  

Surprising as Jay had 8 more feet of snowfall last winter than here ;).  

[powderfreak]

As usual there's some cool meso-scale stuff going on from the local topography.

I'm not sure I've seen this so pronounced but the stiff easterly flow today seemed to create a standing wave type pattern where the precipitation enhancement and heaviest rainfall actually occurred downwind of the Mansfield-Bolton stretch of the Spine.  I'm not sure exactly what would create the thin almost convective line on the edge of the downslope drying? 

So you've got easterly flow going up over the mountains, then downslope drying on the west slope (some stations are as low as 0.35-0.45" today on the west slope), then the air must've been rather abruptly lifted as the edge of the downslope drying had some torrential rainfall at times today. 

What ends up happening is a strong couplet of mix/max rainfall totals over only a couple miles.  Its rare to see the edge of the downslope as the local precipitation maximum but that pencil thin line of steady moderate to heavy rain just sat over the same area for hours today while a mile east was seeing brighter skies and -RN. 

Lower rainfall along the west slopes and even the Spine itself, but some of the usual downslope spots had only 0.4" today.  However the standing wave then produced an axis of 1.0-1.8" type rainfall parallel to the mountains, but west of the ridges by several miles.  Then as you proceed west the totals fall again heading west towards BTV area.  Odd to see an easterly flow produce that band of enhanced precipitation about 5-10 miles west of the terrain axis.

[mreaves]

1 hour ago, powderfreak said:

As usual there's some cool meso-scale stuff going on from the local topography.

I'm not sure I've seen this so pronounced but the stiff easterly flow today seemed to create a standing wave type pattern where the precipitation enhancement and heaviest rainfall actually occurred downwind of the Mansfield-Bolton stretch of the Spine.  I'm not sure exactly what would create the thin almost convective line on the edge of the downslope drying? 

So you've got easterly flow going up over the mountains, then downslope drying on the west slope (some stations are as low as 0.35-0.45" today on the west slope), then the air must've been rather abruptly lifted as the edge of the downslope drying had some torrential rainfall at times today. 

What ends up happening is a strong couplet of mix/max rainfall totals over only a couple miles.  Its rare to see the edge of the downslope as the local precipitation maximum but that pencil thin line of steady moderate to heavy rain just sat over the same area for hours today while a mile east was seeing brighter skies and -RN. 

Lower rainfall along the west slopes and even the Spine itself, but some of the usual downslope spots had only 0.4" today.  However the standing wave then produced an axis of 1.2-1.8" type rainfall parallel to the mountains, but west of the ridges by several miles.  Then as you proceed west the totals fall again heading west towards BTV area.  Odd to see an easterly flow produce that band of enhanced precipitation about 5-10 miles west of the terrain axis.

Look at the prolonged yellow and orange blob along 89 through the Barre/Montpelier area. I can vouch for that, it's been nasty all day. 

[backedgeapproaching]

Interesting stuff PF.  Over 1" here today and around 2" the past few days, but defintley some downsloping here. The east slope high terrain was just crushed around here, got to be some 3" totals, the radar looked ridiclous all day with some nice echoes  just rotting over the same areas. 

[OceanStWx]

2 hours ago, powderfreak said:

As usual there's some cool meso-scale stuff going on from the local topography.

I'm not sure I've seen this so pronounced but the stiff easterly flow today seemed to create a standing wave type pattern where the precipitation enhancement and heaviest rainfall actually occurred downwind of the Mansfield-Bolton stretch of the Spine.  I'm not sure exactly what would create the thin almost convective line on the edge of the downslope drying? 

So you've got easterly flow going up over the mountains, then downslope drying on the west slope (some stations are as low as 0.35-0.45" today on the west slope), then the air must've been rather abruptly lifted as the edge of the downslope drying had some torrential rainfall at times today. 

What ends up happening is a strong couplet of mix/max rainfall totals over only a couple miles.  Its rare to see the edge of the downslope as the local precipitation maximum but that pencil thin line of steady moderate to heavy rain just sat over the same area for hours today while a mile east was seeing brighter skies and -RN.

Lower rainfall along the west slopes and even the Spine itself, but some of the usual downslope spots had only 0.4" today.  However the standing wave then produced an axis of 1.2-1.8" type rainfall parallel to the mountains, but west of the ridges by several miles.  Then as you proceed west the totals fall again heading west towards BTV area.  Odd to see an easterly flow produce that band of enhanced precipitation about 5-10 miles west of the terrain axis.

Just spitballing a little bit here, but mid level lapse rates (especially out your way) were decent today. Stable low levels could create the standing wave, and the unstable mid levels could create the convective/added lift above that standing wave (versus say just some enhanced cloud cover).

[dendrite]

15 hours ago, OceanStWx said:

Just spitballing a little bit here, but mid level lapse rates (especially out your way) were decent today. Stable low levels could create the standing wave, and the unstable mid levels could create the convective/added lift above that standing wave (versus say just some enhanced cloud cover).

Different subject, but what goes into the MHT threadex climo data? I know they pulled a 104F 7/14/95, yet the record for that date is listed as 98F in 1952. They had a 100F in June of that year too, but it's not listed either. The station info does have that period supposedly covered.

Station Thread for Manchester Area, NH

	Name	Period in Thread
1	Manchester	02/01/1885 to 06/05/1948
2	Manchester Airport	06/06/1948 to 03/31/1967
3	Manchester	04/01/1967 to 03/31/1998
4	Manchester Airport	04/01/1998 to 12/31/2016

[wxeyeNH]

I drove over to Mount Washington today,  the Cog side.  Took the drone up over the base station.   Attached is the video.  I had some connection issues and it was quite breezy so the drone was being blown around a bit.  Not a great video.

Some snow remains in the ravines on the west side.  Much more snow on the east side looking at the mountain from Wildcat cam.  The greenup line is almost up to treeline in the high Whites but not quite.

Weatherwise,  I thought it was interesting that as I got up high the Cu was almost at drone elevation to the west but the Cu were higher than the summits on the range line.

 

 

[eekuasepinniW]

2 hours ago, wxeyeNH said:

I drove over to Mount Washington today,  the Cog side.  Took the drone up over the base station.   Attached is the video.  I had some connection issues and it was quite breezy so the drone was being blown around a bit.  Not a great video.

Some snow remains in the ravines on the west side.  Much more snow on the east side looking at the mountain from Wildcat cam.  The greenup line is almost up to treeline in the high Whites but not quite.

Weatherwise,  I thought it was interesting that as I got up high the Cu was almost at drone elevation to the west but the Cu were higher than the summits on the range line.

 

 

this is my favorite drone video that's been posted here.

 

[wxmanmitch]

On 6/6/2017 at 7:52 PM, powderfreak said:

As usual there's some cool meso-scale stuff going on from the local topography.

I'm not sure I've seen this so pronounced but the stiff easterly flow today seemed to create a standing wave type pattern where the precipitation enhancement and heaviest rainfall actually occurred downwind of the Mansfield-Bolton stretch of the Spine.  I'm not sure exactly what would create the thin almost convective line on the edge of the downslope drying? 

So you've got easterly flow going up over the mountains, then downslope drying on the west slope (some stations are as low as 0.35-0.45" today on the west slope), then the air must've been rather abruptly lifted as the edge of the downslope drying had some torrential rainfall at times today. 

What ends up happening is a strong couplet of mix/max rainfall totals over only a couple miles.  Its rare to see the edge of the downslope as the local precipitation maximum but that pencil thin line of steady moderate to heavy rain just sat over the same area for hours today while a mile east was seeing brighter skies and -RN. 

Lower rainfall along the west slopes and even the Spine itself, but some of the usual downslope spots had only 0.4" today.  However the standing wave then produced an axis of 1.0-1.8" type rainfall parallel to the mountains, but west of the ridges by several miles.  Then as you proceed west the totals fall again heading west towards BTV area.  Odd to see an easterly flow produce that band of enhanced precipitation about 5-10 miles west of the terrain axis.

Hydraulic jump? Faster downslope flow on the west slope runs into slower flow further west and causes a band of mesoscale convergence and lift. Then, as OceanStWx mentioned, midlevel instability could have resulted in convective enhancement. 

[powderfreak]

On 6/6/2017 at 10:06 PM, OceanStWx said:

Just spitballing a little bit here, but mid level lapse rates (especially out your way) were decent today. Stable low levels could create the standing wave, and the unstable mid levels could create the convective/added lift above that standing wave (versus say just some enhanced cloud cover).

Fascinating that makes sense.  

[eyewall]

Still plenty of turns to be had at 12,000ft in Colorado. I took this at Summit Lake (unfortunately the rangers wouldn't let me fly there):

From where I could fly (around 10,000ft):

[J.Spin]

On ‎6‎/‎6‎/‎2017 at 11:15 AM, tamarack said:

Great breakdown.  Adding some comparable data to what's in my sig:

 

Nice tamarack, next up on my list is updating the summary table I have on my website.  There were two colored areas of note in this year’s row.  The first was Winter Storm Stella taking the top spot for largest storm thus far in my records.  The second, which was rather surprising with the cool weather we’ve had over the past couple months, was the quick ending to the snowfall season – the last accumulating snowfall for us was on April 8^th, tying the earliest ending in 2009.

 

What I also find striking is that aberration of the previous season’s total snowfall.  It stands out so ridiculously from the rest of the data, but actually, the other red values in that row are pretty out of whack as well.  I don’t want to meet the season that comes anywhere near those numbers, but hopefully we won’t see something like that for a long, long time.

 

[tamarack]

43 minutes ago, J.Spin said:

 

Nice tamarack, next up on my list is updating the summary table I have on my website.  There were two colored areas of note in this year’s row.  The first was Winter Storm Stella taking the top spot for largest storm thus far in my records.  The second, which was rather surprising with the cool weather we’ve had over the past couple months, was the quick ending to the snowfall season – the last accumulating snowfall for us was on April 8^th, tying the earliest ending in 2009.

 

What I also find striking is that aberration of the previous season’s total snowfall.  It stands out so ridiculously from the rest of the data, but actually, the other red values in that row are pretty out of whack as well.  I don’t want to meet the season that comes anywhere near those numbers, but hopefully we won’t see something like that for a long, long time.

 

My only winter of 19 that's even close to last year's 48.2" is 2005-06 with 52.8", only 7.8" coming after Jan 31.  3rd place is 2009-10 with 64.8".  (And I need to change my sig to the warm-season version, listing each winter's total rather than the 16-17 details.)

[powderfreak]

Still running into some patchy snow in the high country...this was today on the Cliff Trail (hiking trail up to the ridge behind the Gondola) above 3,600ft.

I'd bet some of these areas see snow depths over 15 feet of wind-loading and stuff, which is why you don't measure snow in these areas, but its still fun to come across natural snow as we are in the second week of June now.  You can see one of the blue blazes of the hiking trail painted on the rock at the bottom of the first image.

I would expect all of the natural snow to be gone with the heat early next week...but this stuff even though on its last legs, takes some decent energy to melt.

Green-up and growing season is just starting to reach this elevation of 3,500ft+. 

 

[OceanStWx]

On 6/7/2017 at 1:13 PM, dendrite said:

Different subject, but what goes into the MHT threadex climo data? I know they pulled a 104F 7/14/95, yet the record for that date is listed as 98F in 1952. They had a 100F in June of that year too, but it's not listed either. The station info does have that period supposedly covered.

Station Thread for Manchester Area, NH

	Name	Period in Thread
1	Manchester	02/01/1885 to 06/05/1948
2	Manchester Airport	06/06/1948 to 03/31/1967
3	Manchester	04/01/1967 to 03/31/1998
4	Manchester Airport	04/01/1998 to 12/31/2016

When I look in xmACIS I see we have a broken period of record.

1885-1893, 1929-1949, 1951-1955, 1962, 1966-1972, and 1998-current.

[dendrite]

4 minutes ago, OceanStWx said:

When I look in xmACIS I see we have a broken period of record.

1885-1893, 1929-1949, 1951-1955, 1962, 1966-1972, and 1998-current.

I think 98 was about the time they went from manned to ASOS. So I assume since they didn't report 24hr max/mins back in the 80s/90s that the data from those years got excluded? Maybe the hourly readings miss the extremes by 1-2F, but I'd think it'd still be nice to have as much as possible included.

[OceanStWx]

2 minutes ago, dendrite said:

I think 98 was about the time they went from manned to ASOS. So I assume since they didn't report 24hr max/mins back in the 80s/90s that the data from those years got excluded? Maybe the hourly readings miss the extremes by 1-2F, but I'd think it'd still be nice to have as much as possible included.

I'm pretty sure we have the data, but we have to send it to NCEI (NCDC), and it can get bogged down there. But we are trying to piece the record together in order to produce RERs and the like.

[alex]

Hi All! Haven't posted much lately... busy starting a new company, Bretton Woods Rentals (www.brettonwoodsrentals.com); but was an interesting day  today, woke up to a nice frozen windshield. PWS reports a low of 34.3, but Gene got me a thermometer to put down at ground level, and that was down to 32.3. Hopefully the last frost of the season...

[CoastalWx]

That's great. 

[IrishRob17]

16 hours ago, alex said:

Hi All! Haven't posted much lately... busy starting a new company, Bretton Woods Rentals (www.brettonwoodsrentals.com)

Is there a weather weenie discount code? ;-)

[wxeyeNH]

16 hours ago, alex said:

Hi All! Haven't posted much lately... busy starting a new company, Bretton Woods Rentals (www.brettonwoodsrentals.com); but was an interesting day  today, woke up to a nice frozen windshield. PWS reports a low of 34.3, but Gene got me a thermometer to put down at ground level, and that was down to 32.3. Hopefully the last frost of the season...

I've become friends with Alex.  He's a great guy.  He wanted to move from Metro Boston to a snowy place and sure got that.  About 155-165"  (right Alex?) for the past season.  I have watched his webcam and weather station with interest this past year and have learned a lot about weather in the high Whites..  Not many reporting sites in the Whites...

1)  He does very good with upslope.  Not as well as the Greens but still good.  A due north wind is best for him as the Green's steal moisture with a more west component.  Also it's interesting that upslope snow showers/squalls seem to increase after dark.  Not sure why that is?  Upslope snow is so dry.  Unlike my synoptic type snow the upslope snow rapidly compacts.  Although he got 160" the snow stake seldom got above 2 feet.  Part of that was drifting as snow pictures he sent me from other parts of the house showed very deep snow.

2) Being in an upslope area leads to days and days of cloudiness.   If its not precipitating many times its cloudy.  South of the Whites get so much more sun than the north slopes.  

3)  Downslope with a south wind works just the opposite.  Several times this winter with nor'easter type storms I am precipitating hard but I look at his cam and its much lighter precip or even breaks in the clouds.  He is at the north base of the Whites so I assume that even though the surface may have a northeast or east flow the winds just above are from the south which creates the precip shadow.  I have seen this just north of Franconia Notch too.  So during a synoptic storm his snowfall is less than other areas but as the storm departs and I clear out the upslope sets in up there and he makes up for the QPF deficit.  Downslope really warms him up too.  In synoptic situations many times I am colder  with cold air damning while the BWoods area is much warmer with downsloping. 

Alex had a light frost yesterday morning.  June 15th.  I would guess he could start experiencing frosts by the 3rd week of August so a very short growing season!  

 

[J.Spin]

Working my way through the winter’s data, I’ve created the 2016-2017 monthly snowfall plot for our site, and added it below.  The visual representation certainly reveals quite the asymmetrical distribution with a heavy February/March emphasis.  As mentioned earlier, those were the only months notably above average, with everything else at or below average, and January well below average.

 

[wxeyeNH]

Batch of rain finally through.    .50"

[OceanStWx]

11 hours ago, wxeyeNH said:

I've become friends with Alex.  He's a great guy.  He wanted to move from Metro Boston to a snowy place and sure got that.  About 155-165"  (right Alex?) for the past season.  I have watched his webcam and weather station with interest this past year and have learned a lot about weather in the high Whites..  Not many reporting sites in the Whites...

1)  He does very good with upslope.  Not as well as the Greens but still good.  A due north wind is best for him as the Green's steal moisture with a more west component.  Also it's interesting that upslope snow showers/squalls seem to increase after dark.  Not sure why that is?  Upslope snow is so dry.  Unlike my synoptic type snow the upslope snow rapidly compacts.  Although he got 160" the snow stake seldom got above 2 feet.  Part of that was drifting as snow pictures he sent me from other parts of the house showed very deep snow.

2) Being in an upslope area leads to days and days of cloudiness.   If its not precipitating many times its cloudy.  South of the Whites get so much more sun than the north slopes.  

3)  Downslope with a south wind works just the opposite.  Several times this winter with nor'easter type storms I am precipitating hard but I look at his cam and its much lighter precip or even breaks in the clouds.  He is at the north base of the Whites so I assume that even though the surface may have a northeast or east flow the winds just above are from the south which creates the precip shadow.  I have seen this just north of Franconia Notch too.  So during a synoptic storm his snowfall is less than other areas but as the storm departs and I clear out the upslope sets in up there and he makes up for the QPF deficit.  Downslope really warms him up too.  In synoptic situations many times I am colder  with cold air damning while the BWoods area is much warmer with downsloping. 

Alex had a light frost yesterday morning.  June 15th.  I would guess he could start experiencing frosts by the 3rd week of August so a very short growing season!  

 

With the Froude number you're talking mainly about flow (wind flow in meteorology). That flow can change with stability changes and boundary layer contraction.

[wxeyeNH]

Looks like some interesting weather coming up.   Storm Prediction Center already has us in slight to enhanced on the 3 day convective outlook.  I think that is pretty rare for day 3.

A friend of mine is also a photographer.  He rented a plane earlier this week and took a great picture of Newfound Lake looking north.  Can even see my 15 acre clearing.  It's just above the yellow dot.  In the distance above my house is the cliffs of Cannon and Franconia Notch.  The Groton Wind farm sure changes the scenery around here.  I'm all for renewable energy but question placing large wind farms on high ridges around the White Mountains.  That's a whole other topic....

[powderfreak]

14 hours ago, OceanStWx said:

With the Froude number you're talking mainly about flow (wind flow in meteorology). That flow can change with stability changes and boundary layer contraction.

Yeah the nocturnal inversion that sets up seems to help out a lot. 

That's often when we get those diesel upslope band going up and down the Spine with 30-40dbz just rippling over the mountains like a deform band in a nor'easter stuck over the same areas.  Daytime stuff often seems more squally and cellular, but when you see the band get its act together at like 4-8pm you know it's going to be a good night.  

Then the sun comes up the next day and it often breaks down in the like 8-10am range or at least lightens up.  

[wxeyeNH]

1 hour ago, powderfreak said:

Yeah the nocturnal inversion that sets up seems to help out a lot. 

That's often when we get those diesel upslope band going up and down the Spine with 30-40dbz just rippling over the mountains like a deform band in a nor'easter stuck over the same areas.  Daytime stuff often seems more squally and cellular, but when you see the band get its act together at like 4-8pm you know it's going to be a good night.  

Then the sun comes up the next day and it often breaks down in the like 8-10am range or at least lightens up.  

.....and at 10am you measure a foot.  Then by 5pm it's down to 6".   You and Alex and the other Vermont spine guys live in that constant snow globe but it just sublimates/settles so fast.  I don't know what I would enjoy more, the upslope fluff or my 10" of 31F heavy stuff that lingers for weeks.  I think I would trade for upslope verses retention.  Of course in the right areas you get both.

[mreaves]

Flash Flood Watch up for all of VT for Monday. Of course I'm sure the VT guys don't need some guy sitting in England to tell them that. 

[backedgeapproaching]

Some decent totals along the NH/VT (Putney) state line where the training setup. Also RUT area with some 3"+

Ended with 1.03" here.

6/20/2017	7:00 AM	VT-WH-12	Putney 2.0 WNW	3.75	NA	NA	VT	Windham		Classic | New
6/20/2017	6:00 AM	VT-RT-14	Rutland 2.0 E	3.27	NA	NA	VT	Rutland		Classic | New

[J.Spin]

Next up in my data analysis is the chronological plot of storm snowfall totals for this past season.  Moving from left to right, one area of visual note is that spike representing Winter Storm Argos around mid-November, marking the first substantial storm of the season after a run of those early season storms that often drop lesser amounts when cold air and appropriate moisture briefly meet in the proximity of our mountainous terrain.  A stretch that really stands out is that period from late February into mid-March with absolutely paltry (<1”) storm totals.  Average snowfall at that time of year is in the range of 1 to 2 inches per day, so that’s quite a run of poorly-producing storms.  It stands out even more however by the way it’s bracketed by some of the most substantial storms of the season – Winter Storm Orson and Winter Storm Pluto on the left, and massive Winter Storm Stella on the right.  With the data plotted in this manner, it really gives one the sense of how Mother Nature “loves her averages”, oscillating between big storms and a lengthy period of almost nothing in that timeframe.  A period like that stands out around here because our snowfall climatology is often more even-keeled than that.