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NNE Winter 2013-14 Part I


klw

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I was living down in York, ME back in '98--only a few miles in from the shore.  The 32 line waffled back and forth over us a few times:  we would ice up for a bit then drip, ice back up, only to drip again.  A few more miles inland was a very different story though.

 

In December 2008 I was living where I am now.  We had more snow from that one than IP or ZR but we did ice up some toward the tail end making for some interesting scenes around the 'hood:

 

3110050067_643805c087_z.jpg

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How far North do you think the low level warm air makes it up the Champlain Valley? Is the ice threat as great as in the sheltered valleys east of the Green Mountain spine?

I'd always give the nod to the Valleys east of the Spine, but I've also seen these events where the CPV funnels cold air down the valley on north winds. I forget the year but it was March, and everyone else was near freezing, yet BTV had a gusty north wind and it started raining at 19F, while MVL/MPV were over 10F warmer. That was the only time I ever lost power in BTV, we picked up 1/2-3/4" of ice and transformers started going boom.

In the right set up, BTV can get a great cold drain down the CPV, constantly driving a fresh airmass into the rain zone.

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We've been picking up fluffy tenths several times today... I've probably accumulated 1-1.5" in like 1/4" bursts today.

 

Radar lighting up briefly again and its snowing nicely....huge fluff flakes.

 

 

This is pure dust...comes down in clumps.  This is the top of the car after like 1 minute in this burst.  It accumulates like 1/4" at a time.  As soon as it covers up you have an instant 0.3".  

 

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Did you run the WFO's zone thru the grids for the 18z GFS?

 

Ran everything over with 12z data. Basically was between 1.25 and 1.75" QPF (probably conservative), results in a 2-5" snowfall for foothills and closer to 12" up in Somerset. And a swath of a half inch ice across southern NH and all along the coast of ME into the foothills. Seems fairly reasonable at this time.

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Ran everything over with 12z data. Basically was between 1.25 and 1.75" QPF (probably conservative), results in a 2-5" snowfall for foothills and closer to 12" up in Somerset. And a swath of a half inch ice across southern NH and all along the coast of ME into the foothills. Seems fairly reasonable at this time.

 

Is there a formula that gives you an equation of how many inches of ice to qpf raitio base on amounts?

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Is there a formula that gives you an equation of how many inches of ice to qpf raitio base on amounts?

 

There are four tools that we have to convert our QPF to ice.

 

One is straight change all QPF to ice where there is ZR/ZL in the grids (rarely is that the case except when QPF is very light).

 

Two is to use an algorithm that figures out the maximum amount of ice that could form before the temperatures warmed to 32 degrees. This is good for marginal situations.

 

Three uses research done in IL to figure out how much ice would build up based on QPF, wind, and hourly precip rate (from your forecast). This tool also factors in RA, SN, and IP mixes to cut down on ZR totals.

 

A fourth and final tool ignores mixed precip from above.

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Do i want to know what the non conservative number would be for ice based on that tool with the qpf as modeled right now?

 

Well the max we could have is if all QPF went into ice production, so about 1.50" ice. The low end is about a third of an inch. So everything else is somewhere in between.

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Well the max we could have is if all QPF went into ice production, so about 1.50" ice. The low end is about a third of an inch. So everything else is somewhere in between.

 

1.50" is devastation, We saw those totals plus in 1998, But qpf was a lot more as well, Even .50" ice is a major problem

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This is absolutely horrendous timing as who wants 1"+ of ice right before Christmas and prolonged power outages? Additionally for those of us who get rain we will lose our snowcover (we may go back to bare ground here just in time for the holiday). Honestly I can't get excited about this one.

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Event totals: 0.9” Snow/0.01” L.E.

 

The BTV NWS discussion indicates that today’s snow was from a weak mid level trough that moved through out of the central Pennsylvania/New York area.  There was 0.9” of fluff on the snowboard at 6:00 P.M., and since I could only pull 0.01” of liquid out of it, that makes it the driest snow I’ve analyzed this season.  The rounding error can get pretty big when you’re down at just a hundredth of an inch of liquid, but in this case even before rounding the liquid came in at 0.010”.  Those snow globe flakes in the air today were just a little 90:1 fluff floating around.  That recent larger storm was really helpful in making some season snowfall gains and we're currently running roughly five inches ahead of average.

 

Details from the 6:00 P.M. Waterbury observations:

 

New Snow: 0.9 inches

New Liquid: 0.01 inches

Snow/Water Ratio: 90.0

Snow Density: 1.1% H2O

Temperature: 21.6 F

Sky: Flurries

Snow at the stake: 10.5 inches

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1.50" is devastation, We saw those totals plus in 1998, But qpf was a lot more as well, Even .50" ice is a major problem

 

Well the part that concerns me is that the QPF in my grids was a quick and dirty blend of HPC and SREF (only available through Saturday), GFS, and Euro. What I've seen as far as the ensembles go point towards a scenario where 2-3"+ of QPF is not out of the question. So our forecast may actually be on the conservative side when it comes to liquid.

 

This is going to be a juicy air mass south of the mid level front. GYX and CHH will probably be pushing 99th percentile PWATs.

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Well the part that concerns me is that the QPF in my grids was a quick and dirty blend of HPC and SREF (only available through Saturday), GFS, and Euro. What I've seen as far as the ensembles go point towards a scenario where 2-3"+ of QPF is not out of the question. So our forecast may actually be on the conservative side when it comes to liquid.

 

This is going to be a juicy air mass south of the mid level front. GYX and CHH will probably be pushing 99th percentile PWATs.

 

That would be similar numbers to 1998 qpf wise, Devastation would occur, This is very concerning at this juncture

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From GYX morning afd (boldface mine):

TOTAL RAINFALL AMOUNTS COULD BE AROUND 1 INCH... THOUGH
ACCUMULATED ICE WILL BE LESS THAN THAT DUE TO DRAINING EFFECTS.
BUT IT SEEMS LIKELY AT THIS POINT THAT A HIGH END ADVISORY OR LOW
END WARNING LEVEL EVENT CAN BE EXPECTED. THE HIGHEST LIKELIHOOD TO
SEE SIGNIFICANT ICING IS ACROSS THE FOOTHILLS OF WESTERN MAINE
WHERE COLD AIR DAMMING WILL BE STRONGEST.
WILL NOT ISSUE A WATCH
AT THIS POINT AS THE EVENT WILL NOT BEGIN UNTIL SATURDAY NIGHT AND
THE LOCATION OF WARNING LEVEL ICING IS TOO UNCERTAIN.

 

Not what we want to hear...

 

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Not looking good up this way fellas.

 

We have 15" on the ground in Freeport but I think that's going to be gone come Christmas Eve. 

What a shame.

Huh? I think we're safe atm up here of complete meltdown. It's the lesser of two evils. Would you rather have rain and 50F and destroy the pack or frz rain and 30F with power outages.

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