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Memorial Day Weekend Coastal/Snow


Damage In Tolland

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any money this is melting flakes high reflectivity, damn wonder if cat paws are falling in SW CT elevation

 

I was thinking that some of the higher reflectivities are being caused by sleet/graupel. There was one also heavy batch of precip over LI that had a good graupel signature to it on CC.

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The Mt Wash auto road stations show 32F down to 4kft. 3300ft is 35F so probably rain with some catpaws mixed in down there.

Although I guess I should add that MWN is -FZRA right now so I guess that's the glazing line and not the snow line...yet.

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Saturday...very minor update to fine tune probability of precipitation/temperatures and winds based on current observation. Radar continues to show bands of light to moderate rain rotating across our County Warning Area...with some bright band signatures associated with the melting layer on kcxx radar. Water vapor shows a classic backside deformation zn developing across central Vermont into northern New York at this time. This will produce periods of rain...with some heavy at times through today. Quantitative precipitation forecast amounts look good. Just starting to see rises on local waterways and expect river flooding to become more of an issue by this afternoon. Flood Watch looks very good. Otherwise...temperatures will hold in the M/u 30s mountains to l/m40s valleys with some l/m50s possible in the slv today. Have discarded the lav guidance which shows btv dropping into the middle 30s by noon today...its late may and this seems highly unlikely. As for the snow...Pico web cam shows The Summit is white...with some mixing of snow and rain down to the Killington base area. Current accumulating snow levels are around 3500ft...expect them to drop between 2000 and 2500 feet by this evening...with some accumulation possible. Meanwhile...accumulating snow will continue across the eastern dacks above 3500 feet...as Whiteface Summit temperature is down to 27f. Overall forecast remains on track with expected quantitative precipitation forecast amounts and impacts across our County Warning Area.

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LOL

It will have to get a heck of a lot colder in the next 9 hours for that to happen at MVL.

Mansfield has been 31-32F now for 5 hours straight, yesterday's NAM runs had the summit in the 20s at like 12-15z.

Current profile is this:

3950ft....31F (summit station)

3600ft...32F (top of Stowe's Quad)

2700ft...35F

2100ft...38F (Bolton Valley Base)

730ft....43/40 at MVL

How this goes to that Nam sounding by 21z will be real interesting with no real CAA from anywhere.

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AFN flips to snow at about 0-3Z.

Gets interesting at MPV/MVL between 15-18Z.

MVL is going to have to plummet somehow for it to get interesting by 2pm.

A friend who lives at Bolton at 2200ft on Wentworth Rd just text me that its all rain up there. Bolton station is 38F on Wunderground, so even they will have to really start to drop for excitement this afternoon.

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MVL is going to have to plummet somehow for it to get interesting by 2pm.

A friend who lives at Bolton at 2200ft on Wentworth Rd just text me that its all rain up there. Bolton station is 38F on Wunderground, so even they will have to really start to drop for excitement this afternoon.

Well the NAM is definitely dropping it between 15Z and 18Z.

Date: 3 hour Eta valid 15Z SAT 25 MAY 13
Station: KMPV
Latitude:   44.20
Longitude: -72.57
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
  0 1000   121                                                                 
SFC  964   420   3.2   2.3  94  0.9   2.8 336  18 279.2 280.0 277.7 292.1  4.68
  2  950   538   1.9   1.5  98  0.3   1.7 340  24 279.1 279.9 277.4 291.5  4.50
  3  900   971  -0.9  -0.9 100  0.0  -0.9 355  39 280.6 281.3 277.5 291.7  3.97
  4  850  1426  -2.7  -3.0  98  0.3  -2.8  21  43 283.3 284.0 278.4 293.6  3.61


Date: 6 hour Eta valid 18Z SAT 25 MAY 13
Station: KMPV
Latitude:   44.20
Longitude: -72.57
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
  0 1000   112                                                                 
SFC  963   420   0.5   0.1  97  0.4   0.4 327  18 276.7 277.3 275.4 287.6  4.00
  2  950   529  -0.0  -0.1 100  0.0  -0.0 335  24 277.1 277.8 275.7 288.1  4.00
  3  900   959  -1.4  -1.5  99  0.1  -1.4 350  49 280.0 280.7 277.0 290.6  3.80
  4  850  1414  -3.2  -3.3 100  0.0  -3.3  12  51 282.8 283.4 278.0 292.7  3.53
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Well the NAM is definitely dropping it between 15Z and 18Z.

Date: 3 hour Eta valid 15Z SAT 25 MAY 13
Station: KMPV
Latitude:   44.20
Longitude: -72.57
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
  0 1000   121                                                                 
SFC  964   420   3.2   2.3  94  0.9   2.8 336  18 279.2 280.0 277.7 292.1  4.68
  2  950   538   1.9   1.5  98  0.3   1.7 340  24 279.1 279.9 277.4 291.5  4.50
  3  900   971  -0.9  -0.9 100  0.0  -0.9 355  39 280.6 281.3 277.5 291.7  3.97
  4  850  1426  -2.7  -3.0  98  0.3  -2.8  21  43 283.3 284.0 278.4 293.6  3.61


Date: 6 hour Eta valid 18Z SAT 25 MAY 13
Station: KMPV
Latitude:   44.20
Longitude: -72.57
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
     mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
  0 1000   112                                                                 
SFC  963   420   0.5   0.1  97  0.4   0.4 327  18 276.7 277.3 275.4 287.6  4.00
  2  950   529  -0.0  -0.1 100  0.0  -0.0 335  24 277.1 277.8 275.7 288.1  4.00
  3  900   959  -1.4  -1.5  99  0.1  -1.4 350  49 280.0 280.7 277.0 290.6  3.80
  4  850  1414  -3.2  -3.3 100  0.0  -3.3  12  51 282.8 283.4 278.0 292.7  3.53

Yeah you are right...just seems unrealistic to me to somehow drop nearly 3C in temps by 18z today in the lower levels.

If that is right, then the freezing level is down just under 2000ft by 2pm, with all snow falling down to 1000-1200ft in 3.5 hours from now.

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It will have to get a heck of a lot colder in the next 9 hours for that to happen at MVL.

Mansfield has been 31-32F now for 5 hours straight, yesterday's NAM runs had the summit in the 20s at like 12-15z.

Current profile is this:

3950ft....31F (summit station)

3600ft...32F (top of Stowe's Quad)

2700ft...35F

2100ft...38F (Bolton Valley Base)

730ft....43/40 at MVL

How this goes to that Nam sounding by 21z will be real interesting with no real CAA from anywhere.

 

I felt the NAM was a bit too cold. I'd really doubt if snow gets down to Bolton's base. 

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Here's a pic from the WCAX transmitter on top of Mount Mansfield. You can see the coop rain gauge up there too.

https://twitter.com/stevebottari/status/338266359668543488/photo/1

Yeah I posted that earlier...the Coop will only report the snow that falls in that bucket in the background, regardless of what is on the ground...so hopefully this snow is getting in the bucket and not melting from earlier rainwater. And they will only check it once a day at 4pm. If anything though, it usually does semi-ok getting snow to fall into the gauge in wet snow scenarios so we might get a decent reading. If the snow becomes drier, it'll really under catch with the 40mph winds up there now. Those trees are SE of it so it catches SE flow snow better being in the lee. It is notoriously awful at getting snow in the catch on NW flow.

God forbid they measure what is on the ground. That's why the stake reading will be more accurate and often the snow depth increases more than the "new" snow measurement. Those guys will walk through a foot of snow to get to the can and find only 5.5" in the tennis ball container and that's what they report.

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Yeah I posted that earlier...the Coop will only report the snow that falls in that bucket in the background, regardless of what is on the ground...so hopefully this snow is getting in the bucket and not melting from earlier rainwater. And they will only check it once a day at 4pm. If anything though, it usually does semi-ok getting snow to fall into the gauge in wet snow scenarios so we might get a decent reading. If the snow becomes drier, it'll really under catch with the 40mph winds up there now. Those trees are SE of it so it catches SE flow snow better being in the lee. It is notoriously awful at getting snow in the catch on NW flow.

 

They don't measure the accumulation on the ground? Or do you just mean for liquid equivalent they only measure what falls in the gauge?

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They don't measure the accumulation on the ground? Or do you just mean for liquid equivalent they only measure what falls in the gauge?

The "new" snow measurements are taken from the 8-inch rain gauge inside those wind-chime looking things. What is on the ground is irrelevant except for the snow depth (which is why that is a lot more useful than tallying up the daily snowfalls).

That's why my snowboards collected 287" of snow this past winter at 3000ft (because they are on the ground), while the COOP's can only recorded 156". That's because only 156" found its way into the elevated gauge (like trying to get snow to fall straight down into a coffee can) and then it's only measured once per day. If there is rain before or after the snow that can be a problem too.

I've had this discussion with the guy who runs the program with WCAX...he can drive a snowmobile through a foot of snow but his job isn't to record snowfall if its not in the can. That's why the depth will go up 10" and they report only 6" of snowfall.

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