Spring 2019 New England Banter and Disco

[dendrite]

34/5 30%

I wish those numbers were 10F higher for a combo of good melting and evaporation. It's just not warm enough to melt anything except snow adjacent to low albedo surfaces.

[powderfreak]

1 minute ago, dendrite said:

34/5 30%

I wish those numbers were 10F higher for a combo of good melting and evaporation. It's just not warm enough to melt anything except snow adjacent to low albedo surfaces.

25/2 with NW wind gusting up to 20mph.  

That sun is full on scam right now.  Looks so nice until you step outside.

[wxeyeNH]

Some of you know Josh Morgerman an avid Hurricane chaser and who is part of the AMWX community. I met him years ago at one of the AMWX get-togethers.  Really nice guy.  Last year he teamed up with a UK producer and created the new series Hurricane Man.  A crew traveled with Josh as he traveled the globe in pursuit of tropical cyclones.  The first episode aired on British cable last night.  I understand it is really good.  Lots of epic footage.  A US cable channel just picked it up but it's not 100% finalized so Josh can't say who they are but he did say it's one of the major channels most people get.  Should be a good show.  I think Josh has chased more tropical cyclones than anyone else in the world.  That is quite a feat!

[dendrite]

Just now, powderfreak said:

25/2 with NW wind gusting up to 20mph.  

That sun is full on scam right now.  Looks so nice until you step outside.

The dews definitely give it an arctic feel versus a 34/25 type airmass. There's another push of CAA overnight so it should be quite the chilly evening once the sun goes down. This airmass flies out of here starting Wednesday though. 'Tis the season when the sun sets with -12C 850s and by sunrise 850s are near 0C and still climbing. You get a low in the teens with rad cooling and then mix out through the following afternoon and pull off a high near 60F.

[HoarfrostHubb]

1 minute ago, wxeyeNH said:

Some of you know Josh Morgerman an avid Hurricane chaser and who is part of the AMWX community. I met him years ago at one of the AMWX get-togethers.  Really nice guy.  Last year he teamed up with a UK producer and created the new series Hurricane Man.  A crew traveled with Josh as he traveled the globe in pursuit of tropical cyclones.  The first episode aired on British cable last night.  I understand it is really good.  Lots of epic footage.  A US cable channel just picked it up but it's not 100% finalized so Josh can't say who they are but he did say it's one of the major channels most people get.  Should be a good show.  I think Josh has chased more tropical cyclones than anyone else in the world.  That is quite a feat!

He knows his stuff.  I worry whenever he chases some of the huge ones.   

[dendrite]

2 minutes ago, wxeyeNH said:

Some of you know Josh Morgerman an avid Hurricane chaser and who is part of the AMWX community. I met him years ago at one of the AMWX get-togethers.  Really nice guy.  Last year he teamed up with a UK producer and created the new series Hurricane Man.  A crew traveled with Josh as he traveled the globe in pursuit of tropical cyclones.  The first episode aired on British cable last night.  I understand it is really good.  Lots of epic footage.  A US cable channel just picked it up but it's not 100% finalized so Josh can't say who they are but he did say it's one of the major channels most people get.  Should be a good show.  I think Josh has chased more tropical cyclones than anyone else in the world.  That is quite a feat!

Lisa has showed me a few of the trailers. Josh is a science guy, but he definitely has a flair for the dramatic too.

[wxeyeNH]

3 minutes ago, dendrite said:

34/5 30%

I wish those numbers were 10F higher for a combo of good melting and evaporation. It's just not warm enough to melt anything except snow adjacent to low albedo surfaces.

31/4

Help me understand something Brian.  So a higher dew helps melt snow, right?  You've posted many times that high dews are snow eaters.  Yet when the air is very dry, say in my house laundry, plant soils etc dry out much quicker.  Wouldn't a low dew day quicken sublimation and help get rid of the pack?  I assume from your posts that all things being equal a 35/20F day would have more melt than a 35/5F day.  Thanks

[mreaves]

9 minutes ago, wxeyeNH said:

31/4

Help me understand something Brian.  So a higher dew helps melt snow, right?  You've posted many times that high dews are snow eaters.  Yet when the air is very dry, say in my house laundry, plant soils etc dry out much quicker.  Wouldn't a low dew day quicken sublimation and help get rid of the pack?  I assume from your posts that all things being equal a 35/20F day would have more melt than a 35/5F day.  Thanks

I think he is saying that with the current combo, only sublimation is going to work on the snow.  Like you said, given the same temp but with a higher dew point, snow would melt quicker.

[powderfreak]

32 minutes ago, dendrite said:

The dews definitely give it an arctic feel versus a 34/25 type airmass. There's another push of CAA overnight so it should be quite the chilly evening once the sun goes down. This airmass flies out of here starting Wednesday though. 'Tis the season when the sun sets with -12C 850s and by sunrise 850s are near 0C and still climbing. You get a low in the teens with rad cooling and then mix out through the following afternoon and pull off a high near 60F.

Yeah...especially with the cold snowpack in the mountain valleys, we should be primed for some big diurnal ranges here soon.  Tis that season.  Low of 5F and a high of 50F like you said, while temps at 1,500ft warm through the night the fields on the valley floor here just continue to drop.  Good fake cold set-ups coming.

[dendrite]

33 minutes ago, wxeyeNH said:

31/4

Help me understand something Brian.  So a higher dew helps melt snow, right?  You've posted many times that high dews are snow eaters.  Yet when the air is very dry, say in my house laundry, plant soils etc dry out much quicker.  Wouldn't a low dew day quicken sublimation and help get rid of the pack?  I assume from your posts that all things being equal a 35/20F day would have more melt than a 35/5F day.  Thanks

Evaporation and sublimation are cooling processes. Snow sublimates and water evaporates more quickly with lower relative humidities and wind. So one of two things happens during the day when it's something like 34/5. Some of the snow is melting due to adjacent warmer surfaces and that moisture will readily want to evaporate. The snow/ice not melting will be primed to sublimate as well if the temp is close to enough to freezing or lower. So any evaporation and/or sublimation will create latent cooling on the snow surface. The wetbulbs tell the story. That's the temp the air would have if it was completely saturated. In this case, the snow surface temp can approach the 2m wetbulb since the surface is continuously cooling due to the sublimation and evaporation. My wetbulb is 25F...not exactly conducive for big snow melt. Of course the sun is getting high enough to do damage on snow and ice adjacent to darker surfaces. So even with the low wetbulbs, snow banks go down pretty quickly. A leaf in the middle of the pack may sink down through it a few inches simply from heating up so much from the sun.

Higher RH slows the evaporation rate. So those 53/53 airmasses we get in December annihilate the pack. At near 100% RH there's no evaporation to cool the snow surface to limit the melting. So with our wetbulb in the low 20s today the snow surface temp is probably leaning below freezing due to the melting/freezing processes.

Also, at temps going above +4C, the water molecules start losing their hexagonal structure. So at wetbulbs around 39F the snow melt really starts to accelerate.

[ORH_wxman]

36 minutes ago, dendrite said:

Lisa has showed me a few of the trailers. Josh is a science guy, but he definitely has a flair for the dramatic too.

Oh yeah he loves it. Josh knows his shit too...he is probably exactly how you would want to model yourself as a chaser if you intend to chase high-end damaging winds. He meticulously researches every angle going into a storm. I helped him plan a few back in the day over a decade ago...he would seek opinions on everything from the actual storm to who has been near the chase zone for staging...so that definitely helps in minimizing risk. 

[Ginx snewx]

Great back story by Joshs support crew and camera folks on what it took to follow him into hell and back. 

[wxeyeNH]

22 minutes ago, dendrite said:

Evaporation and sublimation are cooling processes. Snow sublimates and water evaporates more quickly with lower relative humidities and wind. So one of two things happens during the day when it's something like 34/5. Some of the snow is melting due to adjacent warmer surfaces and that moisture will readily want to evaporate. The snow/ice not melting will be primed to sublimate as well if the temp is close to enough to freezing or lower. So any evaporation and/or sublimation will create latent cooling on the snow surface. The wetbulbs tell the story. That's the temp the air would have if it was completely saturated. In this case, the snow surface temp can approach the 2m wetbulb since the surface is continuously cooling due to the sublimation and evaporation. My wetbulb is 25F...not exactly conducive for big snow melt. Of course the sun is getting high enough to do damage on snow and ice adjacent to darker surfaces. So even with the low wetbulbs, snow banks go down pretty quickly. A leaf in the middle of the pack may sink down through it a few inches simply from heating up so much from the sun.

Higher RH slows the evaporation rate. So those 53/53 airmasses we get in December annihilate the pack. At near 100% RH there's no evaporation to cool the snow surface to limit the melting. So with our wetbulb in the low 20s today the snow surface temp is probably leaning below freezing due to the melting/freezing processes.

Also, at temps going above +4C, the water molecules start losing their hexagonal structure. So at wetbulbs around 39F the snow melt really starts to accelerate.

Thank so much for this detailed explanation.

[ORH_wxman]

8 minutes ago, wxeyeNH said:

Thank so much for this detailed explanation.

Dendrite's last sentence is one that a few of us have talked about before...powderfreak included....but it is good that he brings it up again because it's really important for fast snow melt. It's an important piece of information to have when we hear things like "rains to Maine, shut down the ski resorts".

 We often mention the magical upper 30s dew points during winter rain events or warm ups...and it because the snow just starts releasing once it hits that temp due to the change in ice crystal structure. Now, sometimes you won't get a lot of melting from a cutter if you only warm sector for a few hours and have been very cold preceding it simply because the interior of the snow pack hasn't had enough time to warm up to drastically affect the ice crystal structure. So you'll get a brief melt of the top few inches and that's it and we'll say "wow we didn't really lose that much pack". But if that same cutter occurs after several days of like 45-50 high temps with dew points in the 30s, then it will do a ton more damage to the pack since the interior temperature of the pack has risen significantly prior to the cutter. This is also why sometimes those radiational cooling spots can hold pack well even if they warm sector around the same time as a hilltop during a cutter...at night time leading up to the cutter, maybe they were radiating down to like 5F while the hilltops were only getting to 20-25F. So the temperature of the snow pack down in those basins is colder. We sometimes think of those areas as only holding pack longer due to not losing their inversion during a cutter, but I've seen scenarios where the inversion breaks at similar time but they hold on to better snow because of the interior temperature of their snowpack. I actually recall this happening leading up the to January 2008 torch and associated cutter. Nobody in SNE really CAD'd at all during that but leading up to the cutter was like 3 or 4 days of torch temps. Total furnace. I was driving eastward a day or two after it ended and all of the sudden came upon almost full snow cover still in large areas of Sudbury MA after seeing smaller regions with near full cover in Boylston and Shrewsbury...while my hill in N ORH was totally wiped out. I figured finally that these guys kept radiating to like 20F at night in the torch days leading up to the final cutter while I was struggling to get to freezing at night. 

 

Anyways, pretty cool stuff. 

[Typhoon Tip]

Three cycles and counting and I love the rendition illustrated by the operational GFS ... Parallel run not too dissimilar, as is the GGEM... though differ on details...  

Between 18z Saturday and 00z Sunday ... 70 to 74 F along the Pike while there's 1.5"/hr snow rates along the N side of the St L. Seaway... That's pretty neat to see - ... 

 

[tamarack]

1 hour ago, wxeyeNH said:

31/4

Help me understand something Brian.  So a higher dew helps melt snow, right?  You've posted many times that high dews are snow eaters.  Yet when the air is very dry, say in my house laundry, plant soils etc dry out much quicker.  Wouldn't a low dew day quicken sublimation and help get rid of the pack?  I assume from your posts that all things being equal a 35/20F day would have more melt than a 35/5F day.  Thanks

Others have hit the important reasons.  However, I don't think there's much difference between 35/20 and 35/5, at least not like the difference between 50/40 (w/o RA) and 50/20.  Once the dews climb above 32, melting accelerates.  As Will explained, the change in crystal structure steepens the melt rate.  Without being able to cite data, I think that change accompanies a drastic lowering of ratio, 5:1 pack becoming 2.5 and ripe.  I've read that hitting 40% water content is a rapid-melt trigger.

'Tis the season when the sun sets with -12C 850s and by sunrise 850s are near 0C and still climbing. You get a low in the teens with rad cooling and then mix out through the following afternoon and pull off a high near 60F.

'Tis the season for 40+ diurnal ranges.  Unfortunately, also the season for 4° ranges in misery mist.

[dryslot]

2 minutes ago, tamarack said:

Others have hit the important reasons.  However, I don't think there's much difference between 35/20 and 35/5, at least not like the difference between 50/40 (w/o RA) and 50/20.  Once the dews climb above 32, melting accelerates.  As Will explained, the change in crystal structure steepens the melt rate.  Without being able to cite data, I think that change accompanies a drastic lowering of ratio, 5:1 pack becoming 2.5 and ripe.  I've read that hitting 40% water content is a rapid-melt trigger.

'Tis the season when the sun sets with -12C 850s and by sunrise 850s are near 0C and still climbing. You get a low in the teens with rad cooling and then mix out through the following afternoon and pull off a high near 60F.

'Tis the season for 40+ diurnal ranges.  Unfortunately, also the season for 4° ranges in misery mist.

Didn't take long for mud season to get underway.

[wxeyeNH]

42 minutes ago, ORH_wxman said:

Dendrite's last sentence is one that a few of us have talked about before...powderfreak included....but it is good that he brings it up again because it's really important for fast snow melt. It's an important piece of information to have when we hear things like "rains to Maine, shut down the ski resorts".

 We often mention the magical upper 30s dew points during winter rain events or warm ups...and it because the snow just starts releasing once it hits that temp due to the change in ice crystal structure. Now, sometimes you won't get a lot of melting from a cutter if you only warm sector for a few hours and have been very cold preceding it simply because the interior of the snow pack hasn't had enough time to warm up to drastically affect the ice crystal structure. So you'll get a brief melt of the top few inches and that's it and we'll say "wow we didn't really lose that much pack". But if that same cutter occurs after several days of like 45-50 high temps with dew points in the 30s, then it will do a ton more damage to the pack since the interior temperature of the pack has risen significantly prior to the cutter. This is also why sometimes those radiational cooling spots can hold pack well even if they warm sector around the same time as a hilltop during a cutter...at night time leading up to the cutter, maybe they were radiating down to like 5F while the hilltops were only getting to 20-25F. So the temperature of the snow pack down in those basins is colder. We sometimes think of those areas as only holding pack longer due to not losing their inversion during a cutter, but I've seen scenarios where the inversion breaks at similar time but they hold on to better snow because of the interior temperature of their snowpack. I actually recall this happening leading up the to January 2008 torch and associated cutter. Nobody in SNE really CAD'd at all during that but leading up to the cutter was like 3 or 4 days of torch temps. Total furnace. I was driving eastward a day or two after it ended and all of the sudden came upon almost full snow cover still in large areas of Sudbury MA after seeing smaller regions with near full cover in Boylston and Shrewsbury...while my hill in N ORH was totally wiped out. I figured finally that these guys kept radiating to like 20F at night in the torch days leading up to the final cutter while I was struggling to get to freezing at night. 

 

Anyways, pretty cool stuff. 

Great post too.  Thanks

[Typhoon Tip]

Kind of a napey day out there... Light wind and high-ish sun at 49 F ... gotta also admit, I wasn't thinking it was gonna be that 'mild' - relatively speaking... 

[weatherwiz]

weather.com and wunderground used to have a very user friendly data set where you could get daily max temp/min temp records all listed in a way where you just click the month and it gives the record high/low for each day. I guess though with all the site designs over the few years has changed. Does anyone know of any place where you can get them and where you can view easily? weather.com still had it, but you have to click on each day. 

[HoarfrostHubb]

1 hour ago, ORH_wxman said:

Dendrite's last sentence is one that a few of us have talked about before...powderfreak included....but it is good that he brings it up again because it's really important for fast snow melt. It's an important piece of information to have when we hear things like "rains to Maine, shut down the ski resorts".

 We often mention the magical upper 30s dew points during winter rain events or warm ups...and it because the snow just starts releasing once it hits that temp due to the change in ice crystal structure. Now, sometimes you won't get a lot of melting from a cutter if you only warm sector for a few hours and have been very cold preceding it simply because the interior of the snow pack hasn't had enough time to warm up to drastically affect the ice crystal structure. So you'll get a brief melt of the top few inches and that's it and we'll say "wow we didn't really lose that much pack". But if that same cutter occurs after several days of like 45-50 high temps with dew points in the 30s, then it will do a ton more damage to the pack since the interior temperature of the pack has risen significantly prior to the cutter. This is also why sometimes those radiational cooling spots can hold pack well even if they warm sector around the same time as a hilltop during a cutter...at night time leading up to the cutter, maybe they were radiating down to like 5F while the hilltops were only getting to 20-25F. So the temperature of the snow pack down in those basins is colder. We sometimes think of those areas as only holding pack longer due to not losing their inversion during a cutter, but I've seen scenarios where the inversion breaks at similar time but they hold on to better snow because of the interior temperature of their snowpack. I actually recall this happening leading up the to January 2008 torch and associated cutter. Nobody in SNE really CAD'd at all during that but leading up to the cutter was like 3 or 4 days of torch temps. Total furnace. I was driving eastward a day or two after it ended and all of the sudden came upon almost full snow cover still in large areas of Sudbury MA after seeing smaller regions with near full cover in Boylston and Shrewsbury...while my hill in N ORH was totally wiped out. I figured finally that these guys kept radiating to like 20F at night in the torch days leading up to the final cutter while I was struggling to get to freezing at night. 

 

Anyways, pretty cool stuff. 

I assume this is also what folks mean by the pack getting "ripe"...  The energy needed to change the structure has been absorbed and done it's work... it just takes a little more energy to then kick the melt into overdrive.

I think this can actually be seen by remote sensing?

[HoarfrostHubb]

30 minutes ago, Typhoon Tip said:

Kind of a napey day out there... Light wind and high-ish sun at 49 F ... gotta also admit, I wasn't thinking it was gonna be that 'mild' - relatively speaking... 

Pretty much zero cloud cover as well.  The sun is strong.  Def not a raw day at all.  

[HoarfrostHubb]

Edit... had not carefully read Tamarack's post about a ripe pack.

[HoarfrostHubb]

2 hours ago, ORH_wxman said:

Oh yeah he loves it. Josh knows his shit too...he is probably exactly how you would want to model yourself as a chaser if you intend to chase high-end damaging winds. He meticulously researches every angle going into a storm. I helped him plan a few back in the day over a decade ago...he would seek opinions on everything from the actual storm to who has been near the chase zone for staging...so that definitely helps in minimizing risk. 

He is one of the most knowledgeable folks in the chase business (if not the most) and def. sets himself up to get good data/footage while staying safe... but man...it just takes one stray piece of rusted out corugated roof to hit ya...

He is great on social media too

[CapturedNature]

39 minutes ago, weatherwiz said:

weather.com and wunderground used to have a very user friendly data set where you could get daily max temp/min temp records all listed in a way where you just click the month and it gives the record high/low for each day. I guess though with all the site designs over the few years has changed. Does anyone know of any place where you can get them and where you can view easily? weather.com still had it, but you have to click on each day. 

Try ThreadEx:

http://threadex.rcc-acis.org/

[weatherwiz]

3 minutes ago, MetHerb said:

Try ThreadEx:

http://threadex.rcc-acis.org/

This is perfect!  Thank you. That's the exact format I was looking for. I tried the regional climatic data center cites, CPC, and a few other places. 

[dendrite]

38/-3 17%

Nose bleed wx

[dendrite]

BAF with 49/-2 for 12%

[Lava Rock]

Melting away pretty quick

[HIPPYVALLEY]

48 minutes ago, dendrite said:

38/-3 17%

Nose bleed wx