February 5-7 Wintry Mess Potential

[Sugarloaf1989]

0.32" of rain here overnight, I guess about 0.20" of ice. It was 34F here when the rain started, dropping down to 31F.

Currently 33F with ice coated trees.

[ORH_wxman]

Pretty sure the ASOS METAR reports flat ice....it's not radial ice. So it would be the equivalent of like 0.10-0.15 of radial ice on tree limbs.

[ORH_wxman]

edit: Chris beat me to it...lol

[dryslot]

Some round 1 totals...

000
NOUS41 KGYX 061900
PNSGYX
MEZ007>009-012>014-018>028-NHZ001>015-070700-

Public Information Statement
National Weather Service Gray ME
200 PM EST Thu Feb 6 2020

...SNOWFALL REPORTS...

Location                     Amount    Time/Date       Provider

...Maine...

...Androscoggin County...
4 S Turner                   3.5 in    1153 AM 02/06   Trained Spotter
2 WNW Auburn                 3.0 in    1220 PM 02/06   Trained Spotter
2 W Lisbon Falls             3.0 in    1256 PM 02/06   NWS Employee
2 E Lewiston                 2.8 in    1148 AM 02/06   Trained Spotter

...Cumberland County...
2 SSW Cumberland             5.0 in    1253 PM 02/06
1 N Cumberland               5.0 in    0135 PM 02/06   Trained Spotter
3 ENE Westbrook              4.4 in    1004 AM 02/06   Trained Spotter
Sebago 2.4 ESE               4.3 in    0900 AM 02/06   COCORAHS
1 SSW South Portland         4.1 in    0128 PM 02/06
Portland Jetport             4.0 in    1002 AM 02/06   ASOS
Gray NWS Office              3.4 in    0100 PM 02/06   Official NWS Obs
1 SSW Brunswick              3.3 in    0125 PM 02/06   Trained Spotter
Yarmouth 1.8 E               3.1 in    0800 AM 02/06   COCORAHS
New Gloucester               3.0 in    0848 AM 02/06   Public
2 SE New Gloucester          2.9 in    1130 AM 02/06
2 WSW Falmouth               2.7 in    0805 AM 02/06   NWS Employee
Falmouth                     2.5 in    0802 AM 02/06   Public

...Franklin County...
Weld                         2.3 in    0906 AM 02/06   Public
1.0 W Kingfield              2.0 in    0830 AM 02/06   COOP
Farmington 4.8 NNW           2.0 in    0900 AM 02/06   COCORAHS

...Kennebec County...
Mount Vernon                 2.5 in    0947 AM 02/06   Public
1 SE Augusta                 2.1 in    0137 PM 02/06   Trained Spotter
Clinton                      1.8 in    1131 AM 02/06
Winthrop                     1.5 in    0830 AM 02/06   UCOOP
Winthrop 5.8 NE              1.3 in    0800 AM 02/06   COCORAHS

...Knox County...
Hope                         2.0 in    1147 AM 02/06   Trained Spotter

...Lincoln County...
Westport Island 2.2 SSW      3.0 in    0800 AM 02/06   COCORAHS
Waldoboro 1.5 NNE            2.0 in    0805 AM 02/06   COCORAHS

...Oxford County...
Rumford                      2.5 in    0822 AM 02/06   COOP
Dixfield 9.0 S               2.2 in    0900 AM 02/06   COCORAHS
Hartford 1.4 N               1.9 in    0832 AM 02/06   COCORAHS

...Waldo County...
Belfast 14.2 W               1.5 in    0800 AM 02/06   COCORAHS

...York County...
2 SSW East Baldwin           4.2 in    1200 PM 02/06   Trained Spotter
2 ESE Goodwins Mills         4.1 in    1208 PM 02/06   Trained Spotter
Kennebunk                    3.8 in    1112 AM 02/06   Public
5 NW Hollis                  3.6 in    1141 AM 02/06   NWS Employee
Parsonsfield 3.9 NE          3.0 in    0800 AM 02/06   COCORAHS
2 NNW Saco                   3.0 in    0131 PM 02/06   Trained Spotter
2 NE Kennebunk               2.9 in    0820 AM 02/06   Public

[dendrite]

AMATT

[dendrite]

11 minutes ago, Lava Rock said:

I'm going to clear tonight and throw down a bunch of rock salt. If I don't snowblow and it ZR/IP all day tomorrow, it'll freeze hard like cement and I won't be able to clear it.

Yeah I’m clearing mine. I’d be more torn where Gene is. 

[The 4 Seasons]

1 minute ago, OceanStWx said:

The math checks out. It's good to remind everyone that ASOS measures an elevated flat surface, so not your typical power line or tree branch radial measurement. That conversion would be more like 0.15" ice.

I never really understood why you take both sides of a small branch measure both and them up and divide by 2. I get the fact that this represents the true ice accretion on a radial object like a branch but it wont match up to all the surrounding reports that the NWS/Media puts out from ASOS measurements or humans just measuring on a flat surface.

They should denote the method of measuring or just standardize it to one way only. Both of those methods are going to give you two completely different results. 

For example, the ice storm we had this year. One spotter in North Haven measured 0.50 on a flat surface and i measured many tree branches that had 0.38 or so on one side and almost nothing on the other. So that means id have to take [0.38+0]/2. The result is .19 and that doesn't jive with any of the reports in my area and probably be thrown out.

[HoarfrostHubb]

Ice wars

[The 4 Seasons]

14 minutes ago, OceanStWx said:

The math checks out. It's good to remind everyone that ASOS measures an elevated flat surface, so not your typical power line or tree branch radial measurement. That conversion would be more like 0.15" ice.

So when the NWS forecasts ice accumulations are they assuming radial measurements on branches or flat surfaces?

[dryslot]

Its getting cleared and let the chips fall where they may.

[HoarfrostHubb]

Wachusett Mountain closing early partly due to icing on the lifts

[OceanStWx]

12 minutes ago, ORH_wxman said:

edit: Chris beat me to it...lol

[CoastalWx]

2 minutes ago, dryslot said:

Its getting cleared and let the chips fall where they may.

It's a slippery slope when you talk ice accretion.

[forkyfork]

the southern half of CT gets rocked on the latest hrrr. wow

[forkyfork]

[dryslot]

1 minute ago, CoastalWx said:

It's a slippery slope when you talk ice accretion.

Its a roll of the dice generally, Some times its snake eyes.

[forkyfork]

[The 4 Seasons]

3 minutes ago, HoarfrostHubb said:

Wachusett Mountain closing early partly due to icing on the lifts

Stratton looks pretty dismal. Not a good day for skiing, unless you don't like crowds and don't mind ice and fog and freezing drizzle.

 

[ORH_wxman]

I know old school for everyone used to be radial ice. Current NWS forecasts for elevated horizontal ice....which is flat ice. I'm not sure how long they have done this though...I couldn't tell you if they have done it for the past 7 years or the past 27 years.

 

But when we discuss all the impacts to trees and powerlines, those numbers have historically been derived from utility companies and they almost exclusively talk ice in radial ice measurements. When I discuss ice accretion, I'm almost always talking about radial ice, because those numbers are what we used to forecast for impacts to trees and powerlines.

[Lava Rock]

5 minutes ago, dryslot said:

Its getting cleared and let the chips fall where they may.

it'll all be forgotten as you sit at trails end enjoying your beverage

[OceanStWx]

5 minutes ago, The 4 Seasons said:

I never really understood why you take both sides of a small branch measure both and them up and divide by 2. I get the fact that this represents the true ice accretion on a radial object like a branch but it wont match up to all the surrounding reports that the NWS/Media puts out from ASOS measurements or humans just measuring on a flat surface.

They should denote the method of measuring or just standardize it to one way only. Both of those methods are going to give you two completely different results. 

For example, the ice storm we had this year. One spotter in North Haven measured 0.50 on a flat surface and i measured many tree branches that had 0.38 or so on one side and almost nothing on the other. So that means id have to take [0.38+0]/2. The result is .19 and that doesn't jive with any of the reports in my area and probably be thrown out.

Well the ASOS measurements are relatively new, so we're kind of standardizing them now. We have typically forecast radial and measured that way in New England. I think part of spotter training going forward needs to focus on stating your measurement method and the NWS will have to decide how to report it on an LSR (e.g. reporting flat but remarking that it was taken radial). 

2 minutes ago, The 4 Seasons said:

So when the NWS forecasts ice accumulations are they assuming radial measurements on branches or flat surfaces?

NWS is supposed to forecast flat ice now. This was never how it was done regionally. So ice storm criteria of 0.5" is more akin to damage expected from radial accretion. If we issued ice storm warnings for flat ice that's like 0.2" radial. That's not going to be much damage. 

[OceanStWx]

4 minutes ago, CoastalWx said:

It's a slippery slope when you talk ice accretion.

Delete your account.

[dryslot]

Just now, Lava Rock said:

it'll all be forgotten as you sit at trails end enjoying your beverage

And that's the reason why its getting done, We have to load and pack tomorrow afternoon.

[OceanStWx]

Just now, ORH_wxman said:

I know old school for everyone used to be radial ice. Current NWS forecasts for elevated horizontal ice....which is flat ice. I'm not sure how long they have done this though...I couldn't tell you if they have done it for the past 7 years or the past 27 years.

But when we discuss all the impacts to trees and powerlines, those numbers have historically been derived from utility companies and they almost exclusively talk ice in radial ice measurements. When I discuss ice accretion, I'm almost always talking about radial ice, because those numbers are what we used to forecast for impacts to trees and powerlines.

Honestly I think the directive was updated recently to explicitly state elevated flat surface. So New England is kind of trying to increase our criteria closer to 0.75" for a warning.

If we were doing a high level briefing for ice I think we would still produce radial ice maps for utilities to use though.

[HoarfrostHubb]

For the average person, flat ice could make sense since it is what is on a walkway, stairs or a driveway.  But raidal is important too since that is when trees and power lines come into play.

Maybe report both if possible?

[ORH_wxman]

1 minute ago, OceanStWx said:

Well the ASOS measurements are relatively new, so we're kind of standardizing them now. We have typically forecast radial and measured that way in New England. I think part of spotter training going forward needs to focus on stating your measurement method and the NWS will have to decide how to report it on an LSR (e.g. reporting flat but remarking that it was taken radial). 

NWS is supposed to forecast flat ice now. This was never how it was done regionally. So ice storm criteria of 0.5" is more akin to damage expected from radial accretion. If we issued ice storm warnings for flat ice that's like 0.2" radial. That's not going to be much damage. 

This matches what my memory is from 2008....I was almost certain they were forecasting and reporting in radial ice back then, but I wasn't 100% sure since I didn't look at the NWS forecast in great detail....I was mostly on here going back and forth with Ekster on how many people would be without power the next day.

[The 4 Seasons]

Just now, OceanStWx said:

Honestly I think the directive was updated recently to explicitly state elevated flat surface. So New England is kind of trying to increase our criteria closer to 0.75" for a warning.

If we were doing a high level briefing for ice I think we would still produce radial ice maps for utilities to use though.

They definitely should increase it to .75 or even 1.00 because it seems radial ice is about 50% maybe up to 60 or 70% of that of flat ice measurements.

.5 is the threshold for the majority of the Northeast. Which would translate to around .3 for branches.

[CoastalWx]

I'll take the HRRR winds.

[ORH_wxman]

4 minutes ago, OceanStWx said:

Honestly I think the directive was updated recently to explicitly state elevated flat surface. So New England is kind of trying to increase our criteria closer to 0.75" for a warning.

If we were doing a high level briefing for ice I think we would still produce radial ice maps for utilities to use though.

0.75 would be a good number too since that would be like a third of an inch of radial ice. You start getting the power issues around that mark...I've always noticed around 1/3 to 3/8 when the damae starts accelerating....which made me think that 1/2 radial was too steep a criteria for ice storm warning. .

[The 4 Seasons]

4 minutes ago, ORH_wxman said:

This matches what my memory is from 2008....I was almost certain they were forecasting and reporting in radial ice back then, but I wasn't 100% sure since I didn't look at the NWS forecast in great detail....I was mostly on here going back and forth with Ekster on how many people would be without power the next day.

If you ever want to go back and look at any NWS products from any FO for the past 25 or so years you can find them here.

https://mesonet.agron.iastate.edu/wx/afos/list.phtml