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Author Topic: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs  (Read 42702 times)

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #300 on: February 27, 2019, 09:51:22 AM »
Tonight's CCIN is out. Another big gain. Looks like we are at about 1,550KM^3 vs 1,375KM^3 at same time in 2018.

If 2018's maximum of 1,625KM^3 serves as a proxy, we could expect 1,830KM^3 or more in 2019 at maximum in early-mid April. If our current momentum lasts any longer than 2018's first un-absolute maximum (~3/8), we could add additionally atop the existing lead vs. last year.


bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #301 on: March 02, 2019, 05:53:51 AM »
Seems like the suspicious link between nearly ice-free Bering by 3/1 and crazy SWE and cold in North America has more support after 2/2019. I'm sure there are more factors behind the SWE / cold but this has to be a big one.

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #302 on: March 02, 2019, 08:15:11 AM »
D10 forecasts are becoming quite aggressive with impending snowfall. 00z CMC shows deep falls across very wide areas.



Therefore I think it is unlikely we see a SWE max until at least D10+ although there is probably one coming soon thereafter (within a week or two?). Last year we saw four maximums with the highest occurring in early April for North America.

We are about 150KM^3 ahead of 2018 at the moment as well -- about 11%.



Last year saw a slight overall gain in March (with maxes intermixed). It would be quite interesting if this year added substantially more mass as it would indicate that this "reaction" can indeed be sustained much later into spring if sufficient momentum is built up. Maybe the near complete melt-out of the Bering and its potential non-recovery (unlike 2018) could be the push needed for that to occur (+blocking, +water vapor, +northerly winds sweeping down from Greenland into North America).

Niall Dollard

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #303 on: March 02, 2019, 09:33:46 PM »
Checking in on the Nome webcam from time to time and noticed that they have had a lot of snow of late.

Feb just passed has been the snowiest since 1920. All that mild air SE winds has been poor for Bering ice but great for snow.

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #304 on: March 06, 2019, 01:21:20 AM »
With the latest cold outbreak into the USA, North American Snow Extent is back to over two standard deviations above the long term mean. The time is running out to get a low albedo spring for an early sea ice melt.

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #305 on: March 06, 2019, 09:42:20 AM »
North America is about to break the SWE graph again! 1,600KM^3 is just shy of Lake Ontario's volume, and about a Lake Erie's worth above normal for this time of year in the recent satellite record. We won't come close to Lake Huron's 3,500KM^3 but we could do half that at the max. The least amount of flux to substantially perturb AMOC during Agassiz outflows was guesstimated at 2,500KM^3. We are not far from that, and it could soon be happening 1X/each year.

oren

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #306 on: March 06, 2019, 11:47:46 AM »
Best to post a source in support of the 2500 km3 figure, which seems like a serious underestimate.
But in any case, what percentage of NA SWE do you believe can pour into the North Atlantic ocean over the span of a few days? Considering the parts that will melt early or late, sublimate, evaporate or seep underground, or flow in another direction (Arctic, Pacific, south)?
« Last Edit: March 06, 2019, 11:55:44 AM by oren »

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #307 on: March 06, 2019, 01:02:37 PM »
There are signs of the cold in North America reducing over the next week or 10 days.
The next USA storm looks like dumping rain on Chicago, not snow.

https://www.wunderground.com/news/storms/winter/news/2019-03-05-snow-wind-midwest-plains-severe-thunderstorms-south-weekend

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oren

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #308 on: March 06, 2019, 01:07:44 PM »
Where will all the snowmelt go?


gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #309 on: March 08, 2019, 10:25:51 AM »
https://ccin.ca/ccw/snow/current as at 7 march

Here are SCE and SWE for North America (NA) and Eurasia (EU)

Eurasia continues to follow the climate models, i.e. more snow at high latitudes but below average SCE as the snowline heads north as the years go by and now steeply declining as the spring approaches. Also maybe  SWE has peaked.

North America still showing both SCE and SWE increased high variation from the average. Signs that Snow Cover Extent has peaked as precipitation gradually falling as rain in higher latitudes towards the 49th parallel. Definite signs of above zero celsius temperatures heading north, though patchy and intermittent, over the next days. Snow Water Equivalent may have peaked (or may not).
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Niall Dollard

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #310 on: March 10, 2019, 02:04:21 PM »
Rutgers northern hemisphere extent for Feb 2019 was 46.03 million km2.

A small positive anomaly of +0.44, like last year.

Above normal extent through USA and much of China (except NE)

Below normal extent in Europe and NE China.

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #311 on: March 10, 2019, 02:20:29 PM »
Wunderground.com says the USA is going to get a classic slow-moving March storm next week.

https://www.wunderground.com/news/storms/winter/news/2019-03-08-march-system-severe-flooding-snow-wind-west-plains-south

The balance between rain and snow is going to be interesting. The first image from Wunderground shows a lot of area with rain and less with snow. The 2nd image GFS shows more or less the same. The last image shows that warmth in North America is moving North as does the sun.

So my little prediction that belongs to me for North America (NA) is that by next weekend
- a goodly part of the current thin snow cover in the more southerly latitudes of the USA will be gone, i.e. SCE will be heading South (see image 4.png),
- NA-SWE (snow mass) will either be dithering around the max or will show a loss.
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gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #312 on: March 13, 2019, 03:17:10 PM »
Images at equinox attached.

Spring is coming to North America (and Europe), the snow will melt.

Asia still looking somewhat cold.
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Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #313 on: March 15, 2019, 11:38:40 PM »
All hail HTML, CSS, Javascript and the W3.CSS template creators.

I managed to combine a beautiful slider with an image slideshow. Now I have the tools to easily compare years against each other. The images are updated in the same place to a new year for easy comparison instead of putting all images into a huge grid like on my old website.

These news are posted here due to the first content using this are the Snow Covered Days maps.

https://cryospherecomputing.tk/Snow-Cover

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #314 on: March 16, 2019, 01:04:56 AM »
That is AMAZING and thank you! One question. Could you make a map comparing 2018 minus 1998 in terms of anomalies? (or a year - year comp tool)? This would be very helpful for comparing yearly shifts vs normals. I am comparing 1998 and 2018 and the 20 year change is astonishing in many regions -- parts of Canada have two to three months of extra snowcover vs. 20 years ago, while parts of the Arctic have become almost entirely ice free!

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #315 on: March 16, 2019, 10:11:01 AM »
https://ccin.ca/ccw/snow/current as at 15 march

Here are SCE and SWE for North America (NA) and Eurasia (EU)

Eurasia continues to be a poster child for the climate models, i.e. more snow at high latitudes but below average SCE as the snowline heads north as the years go by and now steeply declining as the spring approaches. Also SWE has probably peaked.

From my post on March 10 re Storm Ulmer in North America
Quote
Wunderground.com says the USA is going to get a classic slow-moving March storm next week.

The balance between rain and snow is going to be interesting.... ... my little prediction that belongs to me for North America (NA) is that by next weekend
- a goodly part of the current thin snow cover in the more southerly latitudes of the USA will be gone, i.e. SCE will be heading South
- NA-SWE (snow mass) will either be dithering around the max or will show a loss.

And to my relief and surprise, snow cover extent down by a lot, and snow water equivalent has reduced.

It looks like North America will be a bit dryer and warmth will be heading North and heading East especially from the Pacific Coast over the next 10 days, with some really warm days. So the only question is how quickly SCE and SWE will reduce in North America from now on?
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #316 on: March 16, 2019, 10:21:28 AM »
It looks like we may have seen the absolute maximum about a month earlier than 2018. The decline in North America today was quite dramatic and the forecast does not bode well for any additional gains, although this could still change as it isn't April quite yet. But barring a major surprise, we are probably post-SWE max, and despite still being much above average, this may be a bad sign for the sea ice adjacent to Canada this summer (IMO), at least in Beaufort, which is upstream of where major melt should continue occurring.

Tealight

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #317 on: March 17, 2019, 01:17:39 AM »
That is AMAZING and thank you! One question. Could you make a map comparing 2018 minus 1998 in terms of anomalies? (or a year - year comp tool)? This would be very helpful for comparing yearly shifts vs normals. I am comparing 1998 and 2018 and the 20 year change is astonishing in many regions -- parts of Canada have two to three months of extra snowcover vs. 20 years ago, while parts of the Arctic have become almost entirely ice free!

A year to year comparison tool would be nice, but it isn't something I can create easily. All the calculations would need to be done in javascript of which I have almost zero knowledge of. The current year comparison with the slider is just template code added together. It took maybe a reasonable 2-3 hour to create the site, far below the required few days to learn the basics of javascript.

I attached your requested 2018 - 1998 map.

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #318 on: March 17, 2019, 02:01:28 AM »
That is AMAZING and thank you! One question. Could you make a map comparing 2018 minus 1998 in terms of anomalies? (or a year - year comp tool)? This would be very helpful for comparing yearly shifts vs normals. I am comparing 1998 and 2018 and the 20 year change is astonishing in many regions -- parts of Canada have two to three months of extra snowcover vs. 20 years ago, while parts of the Arctic have become almost entirely ice free!

A year to year comparison tool would be nice, but it isn't something I can create easily. All the calculations would need to be done in javascript of which I have almost zero knowledge of. The current year comparison with the slider is just template code added together. It took maybe a reasonable 2-3 hour to create the site, far below the required few days to learn the basics of javascript.

I attached your requested 2018 - 1998 map.

Thank you!!! That is absolutely incredible.

bbr2314

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #319 on: March 18, 2019, 02:18:09 PM »
Plunging!



We shall see if it continues but at the moment it looks like it will for at least a few more days.

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #320 on: March 18, 2019, 03:11:18 PM »
Plunging!

We shall see if it continues but at the moment it looks like it will for at least a few more days.
NA temperatures say yes, but with little rain so wunderground.com suggest an orderly snow melt after the floods.
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SimonF92

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #321 on: March 18, 2019, 05:45:00 PM »
Whats the consensus? Is a high snow mass overlaying sea ice a good or a bad thing?

I know that melt-ponding that in turn was partially responsible for the June cliff of 2012, but then again there's an inference for increased protection from top-melt?

Shared Humanity

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #322 on: March 18, 2019, 06:25:16 PM »
Whats the consensus? Is a high snow mass overlaying sea ice a good or a bad thing?

I know that melt-ponding that in turn was partially responsible for the June cliff of 2012, but then again there's an inference for increased protection from top-melt?

I think it depends. If the heavy snow falls early in the freeze season, it will insulate the ice from the cold, preventing it from thickening. If it falls just before the melt season, it may serve to delay the onset of melt.

oren

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #323 on: March 18, 2019, 10:50:56 PM »
What SH said.

gerontocrat

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Re: Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs
« Reply #324 on: March 19, 2019, 11:46:49 AM »
https://ccin.ca/ccw/snow/current as at 18 March

Here are SCE and SWE for North America (NA) and Eurasia (EU)

Eurasia continues to be a poster child for the climate models,  below average SCE as the snowline heads north as the years go by and now steeply declining as the spring approaches. Also SWE has peaked.

The rain and warmth last week shattered the snow season in North America. SCE and SWE still heading strongly downwards. It looks like North America will be a bit dryer and warmth will be heading North and heading East especially from the Pacific Coast over the next 10 days, with some really warm days.

So the only question is how quickly SCE and SWE will reduce in North America from now on? The last image shows average temps for the next 10 days. But daytime temperatures will be much higher than the average shown, so melt will reach to much higher latitudes than the average 32 degrees Fahrenheit isotherm shown on that image. Also it looks like snowfall will be sparse during this period.

So my prediction that belongs to me is that SWE and SCE will continue to reduce strongly, though perhaps at a lower rate than in recent days.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)