New Year Storm Thread 12/29-01/01

[Ginx snewx]

[ORH_wxman]

  On 12/29/2019 at 3:11 PM, radarman said:

Thanks, it is a nice writeup.  As an eyewitness I disagree with their comments about the east slope and the berks.  It was catastrophic there, for sure the equal to pics from N ORH county, albeit with the worst accretion slightly higher up in elevation. (Esp over ~1200')   Single most impactful weather event I've ever observed for sure in parts of Ashfield/Goshen/etc..  Crushed.

Even at Umass there was a significant electrical disturbance and dirty power.  The MA1 radar held up valiantly for a while and we observed strong echoes out on the east slope, pouring, but the UPS batteries only last an hour or two.

Expand  

Yeah I remember seeing big damage from Berkshires. But as you said, much higher in elevation. I think even MPM at 1000 feet didn't get much ice but at 300 feet in Leominster off to the east side of the ORH hills had catastrophic damage. You had to go much higher off to the west to see the equivalent damage. 

[moneypitmike]

  On 12/29/2019 at 2:15 PM, mahk_webstah said:

Even if a lot of sleet at least we start the true pack building

Expand  

It's not building if it's melted within the week following. 

  On 12/29/2019 at 2:19 PM, ORH_wxman said:

ORH is an interesting forecast. They have a pretty high max temp in the warm layer...which usually tells me to go ZR...but the cold layer below it is deep and gets to around -6. That's clear sleet there. 

So which method do we give more weight to? Typically when the warm layer gets higher than 3C, you're gonna go ZR...but when the cold layer goes to -6C or colder, it's sleet. But in this case a lot of guidance has both occurring around the ORH area. 

Expand  

Split the diffference.  A lot of meh.

[moneypitmike]

  On 12/29/2019 at 3:21 PM, ORH_wxman said:

Yeah I remember seeing big damage from Berkshires. But as you said, much higher in elevation. I think even MPM at 1000 feet didn't get much ice but at 300 feet in Leominster off to the east side of the ORH hills had catastrophic damage. You had to go much higher off to the west to see the equivalent damage. 

Expand  

The difference between my place at 1000' and a mile away at 1200' was staggering.

[ORH_wxman]

  On 12/29/2019 at 3:22 PM, moneypitmike said:

 

Split the diffference.  A lot of meh.

Expand  

I could see ORH getting IP/ZR in enough of a split to minimize the impact. Like they end up with quarter inch or less of accretion with an inch of sleet...and maybe even some cold rain for a while early on. 

[Ginx snewx]

  On 12/29/2019 at 3:28 PM, ORH_wxman said:

I could see ORH getting IP/ZR in enough of a split to minimize the impact. Like they end up with quarter inch or less of accretion with an inch of sleet...and maybe even some cold rain for a while early on. 

Expand  

The wind speed component is a factor.  As Ryan as pointed out wind increases accretion rates. Complex formulas involved but Utilities especially need all parameters to prepare. 

Once the occurrence of freezing rain was determined by one of the above methods, estimates of ice accretion thickness on surface objects were calculated at each model grid point using the simple ice accretion model (Jones 1998). The uniform radial ice thickness on a cylinder, accumulated over the duration of a storm, is calculated by

where R_eq is the uniform radial ice thickness (mm), N is the number of hours of freezing precipitation, ρ_i is the density of ice (=0.9 g cm⁻³), ρ₀ is the density of water (=1.0 g cm⁻³), P is the precipitation rate (mm h⁻¹), V is the wind speed (m s⁻¹), and W is the liquid water content (W_j = 0.067P^0.846_j

[moneypitmike]

  On 12/29/2019 at 3:28 PM, ORH_wxman said:

I could see ORH getting IP/ZR in enough of a split to minimize the impact. Like they end up with quarter inch or less of accretion with an inch of sleet...and maybe even some cold rain for a while early on. 

Expand  

The RGEM surface temps would argue for a fair amount of plain rain unless there's a colder layer above it.  This is going to go down as 40-page event discussion that will be pedestrian outside of 4 posters in SNE. 

[40/70 Benchmark]

  On 12/29/2019 at 3:35 PM, Ginx snewx said:

The wind speed component is a factor.  As Ryan as pointed out wind increases accretion rates. Complex formulas involved but Utilities especially need all parameters to prepare. 

Once the occurrence of freezing rain was determined by one of the above methods, estimates of ice accretion thickness on surface objects were calculated at each model grid point using the simple ice accretion model (Jones 1998). The uniform radial ice thickness on a cylinder, accumulated over the duration of a storm, is calculated by

where R_eq is the uniform radial ice thickness (mm), N is the number of hours of freezing precipitation, ρ_i is the density of ice (=0.9 g cm⁻³), ρ₀ is the density of water (=1.0 g cm⁻³), P is the precipitation rate (mm h⁻¹), V is the wind speed (m s⁻¹), and W is the liquid water content (W_j = 0.067P^0.846_j

Expand  

Yea, just give me an ice-clown map...thanks lol

[40/70 Benchmark]

  On 12/29/2019 at 3:36 PM, moneypitmike said:

The RGEM surface temps would argue for a fair amount of plain rain unless there's a colder layer above it.  This is going to go down as 40-page event discussion that will be pedestrian outside of 4 posters in SNE. 

Expand  

Wouldn't be the first time and won't be the last.

[Typhoon Tip]

12z NAM looks more like a big sleet dump for everyone N of he Pike.. I mean, just eye-ballin' the FOUS grid

[moneypitmike]

  On 12/29/2019 at 3:35 PM, Ginx snewx said:

The wind speed component is a factor.  As Ryan as pointed out wind increases accretion rates. Complex formulas involved but Utilities especially need all parameters to prepare. 

Once the occurrence of freezing rain was determined by one of the above methods, estimates of ice accretion thickness on surface objects were calculated at each model grid point using the simple ice accretion model (Jones 1998). The uniform radial ice thickness on a cylinder, accumulated over the duration of a storm, is calculated by

where R_eq is the uniform radial ice thickness (mm), N is the number of hours of freezing precipitation, ρ_i is the density of ice (=0.9 g cm⁻³), ρ₀ is the density of water (=1.0 g cm⁻³), P is the precipitation rate (mm h⁻¹), V is the wind speed (m s⁻¹), and W is the liquid water content (W_j = 0.067P^0.846_j

Expand  

  * 0 = MeH

[40/70 Benchmark]

  On 12/29/2019 at 3:39 PM, Typhoon Tip said:

12z NAM looks more like a big sleet dump for everyone N of he Pike.. I mean, just eye-ballin' the FOUS grid

Expand  

That is what I am rooting for...give me 3-4" of sleet that will pad the stats, melt slowly and keep my power.

[radarman]

The high res nammy sends a cold front through the Berks around 5pm tomorrow.  By then it's probably pinging more than accreting, but the wind shift could bring down a few.

[PaulyFromPlattsburgh]

I am highly concerned that many local weather stations are undermining icing threat. mesoscales really starting to point to a confined but solid area of significant icing

[moneypitmike]

  On 12/29/2019 at 3:38 PM, 40/70 Benchmark said:

Wouldn't be the first time and won't be the last.

Expand  

As we said earlier, big ice is a really difficult thing to achieve for any large area.

[moneypitmike]

  On 12/29/2019 at 3:44 PM, PaulyFromPlattsburgh said:

I am highly concerned that many local weather stations are undermining icing threat. mesoscales really starting to point to a confined but solid area of significant icing

Expand  

Given how confined it is, a simple mention of that fact that could a case in a small area should be enough.  This will not be a wide-spread area of significant (damaging/disrupting) icing.

[weathafella]

The press is really minimized vs earlier guidance so far today 

[moneypitmike]

  On 12/29/2019 at 3:47 PM, weathafella said:

The press is really minimized vs earlier guidance so far today 

Expand  

I've heard this song before......

[dryslot]

Pull?

[HIPPYVALLEY]

  On 12/29/2019 at 3:53 PM, dryslot said:

Pull?

Expand  

Sleet to Bangor? 

[dryslot]

  On 12/29/2019 at 3:56 PM, HIPPYVALLEY said:

Sleet to Bangor? 

Expand  

They probably see some RN, The slp tracks close or over them on some models.

[weathafella]

  On 12/29/2019 at 3:56 PM, HIPPYVALLEY said:

Sleet to Bangor? 

Expand  

If you could get thunder sleet up there it would be banging sleet while we bang in Bangor.  In fact, you can even remove the thunder to make that work in some circumstances...

[bobbutts]

  On 12/29/2019 at 3:39 PM, Typhoon Tip said:

12z NAM looks more like a big sleet dump for everyone N of he Pike.. I mean, just eye-ballin' the FOUS grid

Expand  

Yeah

[HoarfrostHubb]

  On 12/29/2019 at 3:41 PM, 40/70 Benchmark said:

That is what I am rooting for...give me 3-4" of sleet that will pad the stats, melt slowly and keep my power.

Expand  

I think 2-4” of sleet will be in the cards for many N of the Pike and S of NH

[HoarfrostHubb]

  On 12/29/2019 at 4:03 PM, bobbutts said:

Yeah

Expand  

Wow.  Zero freezing rain.  I’ll take that please

[wx2fish]

I find it odd that the gfs is basically as cold as the nam and mesos at the surface in a CAD setup

[40/70 Benchmark]

  On 12/29/2019 at 4:03 PM, HoarfrostHubb said:

I think 2-4” of sleet will be in the cards for many N of the Pike and S of NH

Expand  

Agree.

[moneypitmike]

  On 12/29/2019 at 4:03 PM, HoarfrostHubb said:

I think 2-4” of sleet will be in the cards for many N of the Pike and S of NH

Expand  

Imagine if this were snow.....

[Damage In Tolland]

Leave it to MPM to downplay a significant icestorm over a relatively large area of NW RI/ NE and NW CT all the way up to VT and east to ORH and says it will impact 3-4 posters. Better check the HREF

[40/70 Benchmark]

Ha...no snow or frz rain here on the NAM...mainly IP with a bit of rain, presumably late Monday night into Tuesday.

I buy it.