NNE Autumn 2013 Thread

[OceanStWx]

Just a word of precaution on the Estimated Froude. That's based off the Mount Mansfield wind sensor, so if that freezes up or has faulty data, it's also going to be faulty. I'm gonna bet that the wind on Mansfield is much stronger than 10 knots right now as its reporting.

Now available on there is:

http://www.erh.noaa.gov/btv/mountain/profile/greens.txt

 

This is model based and also offers a prediction. The flow today is very unblocked as shown by the model, and confirmed by the soundings this afternoon and reports that the snow is making it well across the mountains. Also the precip is quite cellular and convective as noted by the graupel reports, also a signature of unblocked flow.

 

I want this for the Whites!

 

I feel too often we blindly subscribe to SHSN for north facing slopes and leave it at that. You guys have done great work with this in the Greens.

[dendrite]

Can hear some pretty high wind gusts from bed now. Just saw a 25mph on the Davis. 35/19

[J.Spin]

Nice, JSpin...finished up with 0.3" here at home which is currently only visible on mulch and dirt surfaces. The graupel just seems to fall through the grass blades and melt...or at least it would take a lot of graupel to cover grass, lol. You really need to get up near Topnotch/Nordic Barn area to see more consistent white on the ground and it looks like there was more like a solid half inch or more accumulating up at that 900ft elevation.

Anyway, second accumulating snow here...though the mini-event last week also put down 0.3" but that stuck to the grass and was much more visibly white.

 

We’re right in line with you, finishing up with 0.3” of snow here on 0.02” of liquid.  This has been the second round of accumulating snow that I’ve been able to record for this location, although that first one was back in that event we had in October.  The point forecast here certainly suggests the potential for more accumulation coming up…

 

• Tonight Snow showers likely, mainly after 2am. Cloudy, with a low around 33. Calm wind becoming south around 5 mph after midnight. Chance of precipitation is 60%. New snow accumulation of around an inch possible.
• Sunday Rain and snow showers likely, becoming all rain after 8am. Cloudy, with a high near 47. Southwest wind 5 to 9 mph. Chance of precipitation is 60%. New snow accumulation of less than a half inch possible.

 

…but it seems like we’ll be marginal down here in terms of temperatures based on the NWS discussion.  They’ve got a round number of 1,500’ for the snow line in the synopsis, and as low as 1,000’ in the short term section, so it will be something to watch based on the way this area can sometimes get the snow levels to lower a bit with the topography.  Checking on our NWS point forecast hourly weather graph, it comes in with 0.35” of liquid for this next system, and averaging the ranges from the 00Z ECMWF, 00Z GFS, and 06Z GFS for this location produces 0.39” of liquid, so there’s some decent potential by the liquid numbers.

 

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE BURLINGTON VT

353 AM EST SAT NOV 9 2013

 

.SYNOPSIS...

WITH A BRIEF RIDGE OF HIGH PRESSURE OVER THE REGION...PARTLY SUNNY AND DRY CONDITIONS START THE WEEKEND OFF THIS MORNING...BUT CLOUDS WILL BE ON THE INCREASE THROUGH THE DAY AS LOW PRESSURE APPROACHES FROM THE GREAT LAKES. THIS SYSTEM WILL BRING A MIX OF RAIN AND SNOW SHOWERS TO THE AREA SATURDAY NIGHT THROUGH SUNDAY NIGHT...WITH SOME MINOR SNOW ACCUMULATIONS POSSIBLE...MAINLY ABOVE 1500 FEET.

 

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...

AS OF 352 AM EST SATURDAY...CLIPPER SYSTEM STILL ON TRACK TO MOVE ACROSS THE NORTH COUNTRY SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH THE BEST DEEP LAYER MOISTURE AND LIFT PRODUCING THE MOST WIDESPREAD PRECIPITATION DURING THE DAY SUNDAY. THERMAL PROFILES SUPPORT PRECIP STARTING AS MAINLY SNOW SATURDAY NIGHT...TRANSITIONING TO RAIN BELOW 3000 FEET DURING THE DAY SUNDAY...BEFORE TURNING BACK TO SNOW AND DISSIPATING SUNDAY NIGHT. INITIAL SOUTH TO SOUTHWESTERLY FLOW WILL KEEP PRECIP CHANCES LOWER IN THE CHAMPLAIN VALLEY DUE TO DOWNSLOPING OFF THE ADIRONDACKS SUNDAY MORNING...BUT SHOULD FILL IN DURING THE AFTERNOON AS WINDS TURN WESTERLY. AS FAR AS SNOW ACCUMULATIONS GO...VALLEYS ARE LIKELY TO SEE NOTHING WITH A DUSTING TO 2" POSSIBLE FROM 1000-2500 FEET...AND UP TO 6" POSSIBLE ACROSS THE HIGHEST ELEVATIONS ABOVE 3000 FEET THROUGH SUNDAY NIGHT.

 

It’s interesting to see the NWS mentioning a half foot of snow up high, as they tend to take a respectably conservative tack with the numbers they throw out.  That seems right in line with the hourly point forecast graph though, with no concerns about any mixing up there on Mansfield:

 

[Hitman]

I don't know that I recall seeing this before, but there has been talk in the media of a storm for Thursday (I saw it mentioned on tv yesterday morning and in an article in the Atlanticwire), and there isn't even a storm thread on this board. Guess it proves the old maxim, dont believe what you read in the papers. But it is unusual for it to be hyped to the public when it's not even worthy of its own thread.

[dendrite]

I don't know that I recall seeing this before, but there has been talk in the media of a storm for Thursday (I saw it mentioned on tv yesterday morning and in an article in the Atlanticwire), and there isn't even a storm thread on this board. Guess it proves the old maxim, dont believe what you read in the papers. But it is unusual for it to be hyped to the public when it's not even worthy of its own thread.

It got a lot of talk in the SNE thread, but the media took off on it once the Euro showed a bomb for a few runs in a row. It was d7 though and we all know the caveats with that here.

[Nittany88]

Well the column is below freezing except for maybe the lowest 500ft...but I can't see how a melting snowflake turns into a graupel pellet...unless we are just melting the arms off it and the core of the snowflake is graupel in nature?

I just think they are formed aloft in two different ways, so I can't figure out why elevation at the surface would matter, as sometimes we do get the graupel on the mountain. But these early season events seem more real flakes higher up and GS lower down pretty consistently.

Graupel is formed by convective processes...a convective updraft sends the snowflakes back up into the supercooled droplets in the cloud (much like hail), where the supercooled droplets freeze/rime onto the snowflakes before finally falling to the ground.

[Hitman]

It got a lot of talk in the SNE thread, but the media took off on it once the Euro showed a bomb for a few runs in a row. It was d7 though and we all know the caveats with that here.

Oh yeah, I read the discussion, but my point was that it, the potential storm, didn't even warrant it's own thread while being talked about in the general media. Usually there is 10 pages of a storm thread before hearing mention of it on tv.

[Nittany88]

I want this for the Whites!

 

I feel too often we blindly subscribe to SHSN for north facing slopes and leave it at that. You guys have done great work with this in the Greens.

Thanks! It works out well here because of the barrier-like structure the Greens have to westerly flow. I'm sure it could be done for the Whites, especially for the stretch from Mt Washington down to Franconia Notch as I imagine it is quite barrier-like on NW flow. The rest however might be difficult because they are much more spread out like our Adirondacks.

[eyewall]

The froude estimate didn't seem too far off yesterday as initially it was well below 1 and the radar trends seemed reasonably consistent with that. As it climbed above 1 you saw much more progressive eastward movement off the spine (as you would expect). I understand that wind instrument issue would certainly throw a wrench in. I guess it is also best to make sure it is reporting reasonably well first.

[wxeyeNH]

The 12Z GFS and NAM seem to be a bit juicer in tonights system. Perhaps a couple of inches of snow down to the Lakes Region of NH?

[powderfreak]

The froude estimate didn't seem too far off yesterday as initially it was well below 1 and the radar trends seemed reasonably consistent with that. As it climbed above 1 you saw much more progressive eastward movement off the spine (as you would expect). I understand that wind instrument issue would certainly throw a wrench in. I guess it is also best to make sure it is reporting reasonably well first.

 

I'm not sure what time you are talking about, so maybe it was earlier in the morning, but yesterday to me was a classic FN of 1 or higher.  MVL and MPV both reporting a lot of -SN obs and I could just tell by how steadily it was trying to snow/graupel in town that there wasn't much blocking going on. 

 

If anything, I think the Froude number came down a bit yesterday after sundown.

 

This was 10am yesterday morning and this is easily 1< when its all barrier and east.  In fact there was a little while there when the best precip was east of the ridgelines too. 

 

[moneypitmike]

The 12Z GFS and NAM seem to be a bit juicer in tonights system. Perhaps a couple of inches of snow down to the Lakes Region of NH?

 

Yeah--you might need to brush the snow off your windshield.  The NAM suggests that even down here I might be able to measure a 1/2" if were to be snow.  My guess is I'll just have a few flakes in the air after a bit of rain showers with not much to show for it.

 

36.7/23

[powderfreak]

The 12Z GFS and NAM seem to be a bit juicer in tonights system. Perhaps a couple of inches of snow down to the Lakes Region of NH?

 

This may over-perform, especially 1,000ft up.  Good time of day for accums though as it wouldn't take much to get a burst of snow everywhere.

 

NAM is really juicy late tonight.  Might have to go skiing tomorrow.

 

 

 

By the time the upslope is done on Sunday night/Monday morning though, the NW facing slopes have gotten crushed.  NAM now with 0.9" spot in the northern Spine.  If you add in the Monday night FROPA snows the Spine is over 1" QPF in the next 72 hours.  That looks solid.

 

[powderfreak]

And man, average areal QPF now up near 1" now... the first half of that will be marginal but that backside WNW flow with Froude Numbers starting over 1 and then slowly lowering through the day on Monday, should make for a similar day to yesterday.

 

 

 

And as an aside, I honestly can't tell you how awesome the tools are that BTV has for mountain weather.  The mountains around here are part of living up here and in the 10 years I've lived between here and Burlington, the NWS has increased their mountain forecasts and information by like 10-fold.  Given that the heaviest traveled stretch of interstate in Vermont (I-89 between Burlington and Montpelier) travels through the upslope region, it makes sense to try to improve these forecasts.  Add in a fairly dense population living in these areas (relatively speaking to VT, of course) that act as bedroom communities for Chittenden County, and then the ski towns on the east side of the spine, there are plenty of reports to judge events by.  That's probably GYX's main problem is the lack of reports and lower number of people affected.  In VT there's a good number of folks living around the Spine and its visible clearly from BTV which makes it seem more local.  There's also the fact that it can have big impacts even in BTV proper like Jan 2010's record snowstorm. 

 

The increase in backcountry travel (hiking, skiing, snowboarding, snowshoeing, mountain biking, etc) has also exploded around here in the last 10 years, and those folks are often very weather savvy looking for the best information.  Smart phones and technology also makes it so you can access this stuff all in real-time even from the trail-head.  Its very cool to have a NWS that continues to work and improve these things...because I do think the mountain-loving community really appreciates it and probably utilizes the NWS a lot more than your average public. 

 

There's also this trend I've found in outside recreation across the U.S. that those folks utilize the NWS offices a lot more than any other source.  Whether its Salt Lake City for skiing in the Wasatch or the Denver/Grand Junction offices in Colorado... the NWS offices always have much more specific information than any sort of weather.com or accuweather.com website will.  Joe Public likes those sites because they are easy and bright and flashy.  The outdoor recreation segment seems to be the one sifting through the pages of the SLC office looking at SNOWTEL info in the mountains. 

 

Anyway, its great to see this stuff at BTV, as these added links for the text data with Froude Numbers are excellent:

http://www.erh.noaa.gov/btv/mountain/profile/greens.txt

http://www.erh.noaa.gov/btv/mountain/profile/Northern_Greens.txt

http://www.erh.noaa.gov/btv/mountain/profile/Central_Greens.txt

[eyewall]

I'm not sure what time you are talking about, so maybe it was earlier in the morning, but yesterday to me was a classic FN of 1 or higher.  MVL and MPV both reporting a lot of -SN obs and I could just tell by how steadily it was trying to snow/graupel in town that there wasn't much blocking going on. 

 

If anything, I think the Froude number came down a bit yesterday after sundown.

 

This was 10am yesterday morning and this is easily 1< when its all barrier and east.  In fact there was a little while there when the best precip was east of the ridgelines too. 

 

 

I suppose I was wrong then, but I was looking at the 1.45 degree angle tilt and at the onset it seemed to be moving more north to south along the spine before becoming more progressive with west to east motion. I didn't follow the numbers yesterday evening. Obviously I still have a lot to learn about the area, which is why I am hesitant so far to chime in with my own forecasts. I am kind of holding back and observing this winter more than anything else.

[powderfreak]

I suppose I was wrong then, but I was looking at the 1.45 degree angle tilt and at the onset it seemed to be moving more north to south along the spine before becoming more progressive with west to east motion. I didn't follow the numbers yesterday evening. Obviously I still have a lot to learn about the area, which is why I am hesitant so far to chime in with my own forecasts. I am kind of holding back and observing this winter more than anything else.

 

I wasn't really looking at the numbers either, just looking at radar and observations.  The big signal is if precip is reaching MVL and especially MPV, that the froude is over 1. 

 

Anyway, go up to Bolton on Monday morning

 

 

 

Its like this was run out of my basement and I isolated the ski area on the east side to receive the heaviest precip, lol.  Froude forecast numbers are generally 1 or higher until they start to drop during the day on Monday.  This is all QPF prior to the FROPA on Monday night.  Overdone most likely, but could be a surprising amount of snow at elevation...

 

[eyewall]

I wasn't really looking at the numbers either, just looking at radar and observations.  The big signal is if precip is reaching MVL and especially MPV, that the froude is over 1. 

 

Anyway, go up to Bolton on Monday morning

 

Upslope.jpg

 

 

Its like this was run out of my basement and I isolated the ski area on the east side to receive the heaviest precip, lol.  Froude forecast numbers are generally 1 or higher until they start to drop during the day on Monday.  This is all QPF prior to the FROPA on Monday night.  Overdone most likely, but could be a surprising amount of snow at elevation...

 

Upslope2.jpg

 

I will get up there on Monday morning if we don't have to do anything on Haiyan for a client in Vietnam (the company I work for handles weather domestic and abroad). As for MVL and MPV that makes sense. I will make it a point to compare the estimated froude to obs at those locations to see that correlation.

[Nittany88]

And man, average areal QPF now up near 1" now... the first half of that will be marginal but that backside WNW flow with Froude Numbers starting over 1 and then slowly lowering through the day on Monday, should make for a similar day to yesterday.

 

froude.jpg

 

 

And as an aside, I honestly can't tell you how awesome the tools are that BTV has for mountain weather.  The mountains around here are part of living up here and in the 10 years I've lived between here and Burlington, the NWS has increased their mountain forecasts and information by like 10-fold.  Given that the heaviest traveled stretch of interstate in Vermont (I-89 between Burlington and Montpelier) travels through the upslope region, it makes sense to try to improve these forecasts.  Add in a fairly dense population living in these areas (relatively speaking to VT, of course) that act as bedroom communities for Chittenden County, and then the ski towns on the east side of the spine, there are plenty of reports to judge events by.  That's probably GYX's main problem is the lack of reports and lower number of people affected.  In VT there's a good number of folks living around the Spine and its visible clearly from BTV which makes it seem more local.  There's also the fact that it can have big impacts even in BTV proper like Jan 2010's record snowstorm. 

 

The increase in backcountry travel (hiking, skiing, snowboarding, snowshoeing, mountain biking, etc) has also exploded around here in the last 10 years, and those folks are often very weather savvy looking for the best information.  Smart phones and technology also makes it so you can access this stuff all in real-time even from the trail-head.  Its very cool to have a NWS that continues to work and improve these things...because I do think the mountain-loving community really appreciates it and probably utilizes the NWS a lot more than your average public. 

 

There's also this trend I've found in outside recreation across the U.S. that those folks utilize the NWS offices a lot more than any other source.  Whether its Salt Lake City for skiing in the Wasatch or the Denver/Grand Junction offices in Colorado... the NWS offices always have much more specific information than any sort of weather.com or accuweather.com website will.  Joe Public likes those sites because they are easy and bright and flashy.  The outdoor recreation segment seems to be the one sifting through the pages of the SLC office looking at SNOWTEL info in the mountains. 

 

Anyway, its great to see this stuff at BTV, as these added links for the text data with Froude Numbers are excellent:

http://www.erh.noaa.gov/btv/mountain/profile/greens.txt

http://www.erh.noaa.gov/btv/mountain/profile/Northern_Greens.txt

http://www.erh.noaa.gov/btv/mountain/profile/Central_Greens.txt

It's looking pretty nice late tomorrow evening and tomorrow night for the spine and just east. Stowe to Jay Peak look to do very well. Limiting factor though is that its pretty short-lived.

[powderfreak]

BTV snow map...

[J.Spin]

BTV snow map...

 

I actually thought that this would be something to check on in the morning since the BTV NWS discussion and our point forecast don’t really get into timing, but I had just looked at the radar and the precipitation is practically on the doorstep – Saranac Lake is already reporting light snow:

 

 

[ctsnowstorm628]

I like 1-3" below 1,500 feet, and 3-6" above 1,500 feet. Wouldn't be surprised if Jay picks up 8-10"...same with Stowe.

[ctsnowstorm628]

Also, I am currently working for WeatherWorks Inc in NJ, and with that I am doing Certified Snowfall totals for VT. If possible, it'd be awesome if you guys could give me your snowfall numbers post storm.

 

Thanks!

[eyewall]

CPV: Trace jk I will let you know.

[powderfreak]

BTV upped the forecast overnight here from D-2" to 2-4" now....

Tonight...Occasional snow. Snow accumulation of 2 to 4 inches. Near steady temperature in the lower 30s. Light and variable winds. Chance of snow 90 percent.

Sunday....Snow likely in the morning. Rain likely. Additional snow accumulation a dusting to 2 inches. Highs in the lower 40s. Southwest winds around 10 mph. Chance of precipitation 70 percent.

Sunday Night....Cloudy. Rain or snow showers likely until midnight... then a chance of snow showers after midnight. Total snow accumulation of 2 to 4 inches possible. Lows around 30. Northwest winds 10 to 15 mph. Chance of precipitation 70 percent.

New AFD:

&& Near term /until 7 am Sunday morning/... as of 624 PM EST Saturday...skies have become overcast across the north country ahead of the surface warm front extending from Lake Ontario east-southeastward across central New York into the lower Hudson Valley. 850-700mb warm advection increases from SW-NE across the north country late this evening as front lifts northeastward. This will allow for periods of stratiform precipitation across the area...generally starting around 03z with quantitative precipitation forecast generally 0.10-0.25". The main challenge overnight is p-type and distribution of quantitative precipitation forecast. Planetary boundary layer is dry initially and will allow for some diabatic/wet-bulb cooling to take place and perhaps significantly counteract the affects of warm advection. At the same time...models are in agreement with overall upward vertical velocity/dynamic forcing will be increasing across our area...which could enhance these affects. With the exception of southwestern St. Lawrence County...it appears snow will be the main p-type 03-09z as primary band of low-level warm air advection moves through. That said...the near-surface temperatures will be 33-36f warmest across the Champlain Valley into western Rutland County and should generally limit snow accumulation on roadways. Such may not be the case however on as yet untreated roads from the Green Mountains eastward...and locally across the northern Adirondacks. Have adjusted the forecast slightly...calling for a slushy d-1" in the Champlain Valley overnight mainly on the grassy surfaces. The immediate Champlain Valley will also be subject to some shadowing affects that should limit precipitation amts compared to adjacent mountains looks like 2-3" of snow across central/eastern Vermont...especially at or above 800-1000 feet...with a few isolated 4" reports possible through 12z across the northern Green Mountains with this being the first accumulating snow event of the year...we/ll likely highlight some slick travel in the mountains and N-central/eastern Vermont overnight with forthcoming Special Weather Statement. Best forcing exits after 09z and should leave some intermittent light rain in the valleys near/after daybreak as thermal profiles warm. &&

[mreaves]

Also, I am currently working for WeatherWorks Inc in NJ, and with that I am doing Certified Snowfall totals for VT. If possible, it'd be awesome if you guys could give me your snowfall numbers post storm.

Thanks!

Is just a ruler in the snow ok or do you need more details?

[Lava Rock]

First flakes for us. Bought time.

[powderfreak]

First flurries a few minutes ago is now a more steady light snow...but flakes are so small from dry air here at onset visibility is still probably 5sm or more.

[klw]

It was a race to get some last outside chores done his afternoon before the snow and frozen ground really sets in. I had to wait for yesterday's snow to melt first. Got the last of the leaves up or mowed, some more wood in, the peonies cut back, and switched the snow shovels to the front of the tool stack.

[hvysnow79]

33 with -SN, been falling for about an hour.  Just starting to get an accumulation on the car and other surfaces.

[dryslot]

33 with -SN, been falling for about an hour.  Just starting to get an accumulation on the car and other surfaces.

 

Same, But at 32.5F here