NNE Winter 2013-14 Part I

[dryslot]

We do not toss.

image.jpg

 

No we do not

[MaineJayhawk]

No we do not

 

Agree.  In fact, we not only do not toss, we bang like a door in a hurricane.

[Lava Rock]

13km Euro definitely keys on the coast. Like 1.1" QPF from the Monadnocks through PWM, then tapering to 0.6" up against the Whites.

Portland has no use for that much snow. please shift towards my house please.

[OceanStWx]

Portland has no use for that much snow. please shift towards my house please.

 

Gut tells me PWM won't jackpot in this, but I have little to back that up right now.

[OceanStWx]

Let me know what you think. I just got in and haven't looked at much yet other than a weenie NAM sim radar to see where the highest reflectivities end up. lol

This is what I mean. I look at the GFS and lift looks fine for the coast, but it also looks excellent back from your area through the foothills. I think that added upslope component will jackpot inland from the coast. This kind of lift in a saturated snow growth zone should rip 1"/hr rates for at least a few hours up here.

[powderfreak]

The storm hasn't come but we had a nice surprise snowstorm last night and today on Mansfield... this is what I'm always talking about with these types of small, under-the-radar events out-performing the big ticket synoptic storms. 

 

 

[dendrite]

This is what I mean. I look at the GFS and lift looks fine for the coast, but it also looks excellent back from your area through the foothills. I think that added upslope component will jackpot inland from the coast. This kind of lift in a saturated snow growth zone should rip 1"/hr rates for at least a few hours up here.

GFS_DGZ.jpg

Nice. Looks like I'll have to set the alarm on Sunday, but it should be worth it.

[OceanStWx]

Nice. Looks like I'll have to set the alarm on Sunday, but it should be worth it.

image.jpg

image.jpg

 

I'll be diving into my fgen procedures next. Should be a small but impressive window of lift.

[eyewall]

Hopefully BTV doesn't scale back anymore on those maps.

[powderfreak]

Hopefully BTV doesn't scale back anymore on those maps.

 

I think they are getting gun shy... the meso-models have some pretty good frontogenic forcing lifting through our area, but it all depends on that forcing the lifts north through the area.  Seemed like they either cut ratios or QPF. 

 

Its right in line with my thoughts though... 4-7" valleys, 5-9" mountains.  I really think the quick movement is going to be hard to really exceed 6" in a lot of the valleys up here unless it really rips for a 3-4 hour period. 

 

18z GFS isn't impressive up here, lol. 

[powderfreak]

I find it interesting that BTV went with warnings for 5-10" while BUF and ALB both went with 5-10 inch advisories. 

[mahk_webstah]

No we do not

We do not toss.  We prepare to chuck.

 

I wonder what their ratio assumptions are...didn't say so in the last afd.  I figure .8 should translate to 12 inches.

[mahk_webstah]

This is what I mean. I look at the GFS and lift looks fine for the coast, but it also looks excellent back from your area through the foothills. I think that added upslope component will jackpot inland from the coast. This kind of lift in a saturated snow growth zone should rip 1"/hr rates for at least a few hours up here.

GFS_DGZ.jpg

That's it?  1 inch an hour is good, but how bout 2? Especially if we get the 18:1 ratios talked about a couple days ago.

[OceanStWx]

We do not toss.  We prepare to chuck.

 

I wonder what their ratio assumptions are...didn't say so in the last afd.  I figure .8 should translate to 12 inches.

 

This is what the GFS thinks. Probably on the more conservative side.

 

Forget it, formatting sucked. Basically anywhere from 16:1 to 11:1 during the accumulation.

[OceanStWx]

That's it?  1 inch an hour is good, but how bout 2? Especially if we get the 18:1 ratios talked about a couple days ago.

 

 

We start with a larger area of 1"/hr then narrow our focus with time. I think the potential is definitely there for bigger rates, I have a few projections from the 18z GFS that look pretty good for it.

[OceanStWx]

What I like about the GFS depiction here is that the areas of strong frontogenesis are nearly collocated, or at least sloped towards the cold side. That is a strong signal for great lift along that developing front.

 

Around the horn clockwise from the top left, 700 mb, 500 mb, 850 mb, 925 mb.

 

[OceanStWx]

And here is a cross section from near BTV to roughly PVC.

 

My color curves of the bottom right are all screwed up because it doesn't dynamically change for the colder than typical air mass. However, if you can read the numbers that's 15+ ubar/s through the -12 to -18 C layer.

 

Top right shows saturation, obviously green is go here. Plus it has ageostrophic circulation (think: due to frontogenesis). Lots of vertical motion forecast here.

 

Left panels go hand in hand. Bottom is frontogenesis again, sloped into the cold up through 500 mb. The warm side (top) of these warm colors will have the lift. And notice that above the lift (at roughly 500 mb) is a layer of -EPV. Exactly what you want to see for banded precip.

 

[powderfreak]

Agree fully with this discussion from MUCCILLI today...the frustrating thing is the track is darn near perfect for climo heavy snows in BTV's area, passing near Cape Cod... but without a closed 700 or 500mb low, its overall unimpressive up this way.  If we had a nice closed low going through SNE, it would be game on.

 

&&

.SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 322 PM EST FRIDAY...CLOUDS WILL BE ON THE INCREASE ON
SATURDAY AHEAD OF A LOW PRESSURE SYSTEM APPROACHING FROM THE OHIO
VALLEY. ASSOCIATED WARM AIR AND MOISTURE ADVECTION WILL BRING
LIGHT SNOW INTO THE REGION BEGINNING IN THE AFTERNOON HOURS ACROSS
SOUTHERN VERMONT AND EVENING ACROSS THE REST OF THE AREA. ENERGY
IS THEN TRANSFERRED TO A DEVELOPING COASTAL LOW SATURDAY NIGHT
THAT MOVES NORTHEASTWARD UP THE COAST TO A POSITION JUST INSIDE
THE 40/70 BENCHMARK BY SUNDAY MORNING AND OFFSHORE OF THE CANADIAN
MARITIMES BY LATE SUNDAY. THIS IS A FAVORABLE TRACK FOR WIDESPREAD
SNOWFALL ACROSS NORTHERN NEW YORK AND VERMONT. ONLY HINDRANCE IS
OVERALL FAST SPEED OF SYSTEM AND LACK OF CLOSED CIRCULATION AT
850MB/700MB TO HELP FEED IN ADDITIONAL MOISTURE. HEAVIEST SNOWFALL
WILL OCCUR LATE SATURDAY NIGHT AND INTO SUNDAY MORNING (08Z-15Z)
ASSOCIATED WITH BEST FORCING AND POSSIBLE DEFORMATION BAND. SNOW
WILL TAPER OFF TO SNOW SHOWERS BY SUNDAY AFTERNOON AND MAY
CONTINUE INTO SUNDAY EVENING AS UPPER LOW APPROACHES.
HOWEVER...LOW LEVEL MOISTURE WILL BE DECREASING WITH TIME.

OVERALL QPF WILL BE RELATIVELY UNIMPRESSIVE...GENERALLY AROUND
A HALF INCH OR SO. THIS WILL BE MADE UP FOR IN FAIRLY HIGH SNOW
RATIOS. THINKING RATIOS START AT ABOUT 18-20:1 IN COLD ARCTIC AIR
LATE SATURDAY...AND THEN TRANSITION TO MORE 15:1 LATE SATURDAY NIGHT
INTO SUNDAY MORNING AS WARMING TAKES PLACE ALOFT AND CUTS DOWN SNOW
GROWTH ZONE. ALSO OF NOTE IS STRONG LOW LEVEL SOUTHEAST JET (50
KNOTS AT 850 MB) SATURDAY NIGHT THAT WILL ENHANCE SOUTHEAST UPSLOPE
FLOW ACROSS THE EASTERN SLOPES OF THE GREENS AND ADIRONDACK
MOUNTAINS...ESPECIALLY CENTRAL/SOUTHERN VERMONT. THIS SAME JET WILL
PRODUCE DOWNSLOPE FLOW ACROSS THE WESTERN SLOPES...ESPECIALLY IN
WESTERN ADDISON AND RUTLAND COUNTIES. AS THE JET LIFTS NORTH...IT
WEAKENS AND LIFTS...SO OROGRAPHIC EFFECTS WILL BE MORE LIMITED. PORTIONS
OF THE NORTHEAST KINGDOM WILL ALSO BE SOMEWHAT SHADOWED BY THE WHITE
MOUNTAINS. THIS SHOULD ALL EQUAL OUT TO ABOUT 5-10 INCHES OF SNOW AREA
WIDE (LEAST IN THE SOUTHERN CHAMPLAIN VALLEY...WESTERN RUTLAND
COUNTY...AND THE FAR NORTHEAST KINGDOM) WITH SOME LOCALIZED
AMOUNTS NEAR 12 INCHES IN THE FAVORED SOUTHEAST UPSLOPE SPOTS.

TEMPERATURES WILL ONLY REACH THE SINGLE DIGITS AND TEENS ON
SATURDAY...REMAIN STEADY SATURDAY NIGHT...AND RISE TO 15-25
DEGREES ON SUNDAY. LOWS SUNDAY NIGHT FALL BACK INTO THE SINGLE
DIGITS ON EITHER SIDE OF ZERO.

[MaineJayhawk]

Many thanks to O-St for the maps and learnin'

 

[OceanStWx]

Many thanks to O-St for the maps and learnin'

 

 

Always happy to feed the weenies.

[CoastalWx]

Classic signal for a 2-3"/hr fluff band.

[OceanStWx]

Classic signal for a 2-3"/hr fluff band.

 

Tweaking the grids as we speak. Probably not going to change too much, but just seeing what I can come up with/add some detail to the forecast.

[dendrite]

Always happy to feed the weenies.

Thanks from me too. I miss being able to play with fxnet/IDV on campus.

 

Down to 12F now with 10mph winds...a bit chilly.

[OceanStWx]

Thanks from me too. I miss being able to play with fxnet/IDV on campus.

 

Down to 12F now with 10mph winds...a bit chilly.

 

10.4 F at the WFO, steady 10 mph wind.

[MainePhotog]

10.8°F here. Thanks OceanStWx for the intriguing storm info/graphics.

[powderfreak]

4/-5 with a 12G20 wind and wind chill at MVL of -12F. 

[ctsnowstorm628]

I find it interesting that BTV went with warnings for 5-10" while BUF and ALB both went with 5-10 inch advisories. 

Even with qpf issues, our ratios will be 15:1 at WORST...probably toward the end. 

 

Averaging 18:1 I'd say for a storm total. Lowest qpf amounts I can find are ~0.3" or 5-6". 850mb flow isn't intense, so I don't see shadowing to be as bad as initially thought.

 

I think many in northern VT get 7-9" from this....lowest amounts will be along 91 south of St. J near Wells River/Bradford (4-7"?) and highest along the east slope near Stowe (9-12"?).

 

Muccilli is the man btw. Good dude. 

[ctsnowstorm628]

Tweaking the grids as we speak. Probably not going to change too much, but just seeing what I can come up with/add some detail to the forecast.

What're you thinking in terms of downsloping near Littleton, NH and extrapolated out toward LSC?

 

I went 4-8" below 500' and 6-9" above for VT DOT.

[OceanStWx]

What're you thinking in terms of downsloping near Littleton, NH and extrapolated out toward LSC?

 

I went 4-8" below 500' and 6-9" above for VT DOT.

 

Luckily our grid extends over for a ways into VT, so I can make a forecast that the public never sees for that area. I basically have 4-6" for the Littleton area and fellow NW of the Whites downslopers. That would match up to the Barre to Marshfield area and another downslope zone from South Albany to Morgan Center, VT. I've got a shade under 7" for Lyndonville looking at my grids.

[powderfreak]

Even with qpf issues, our ratios will be 15:1 at WORST...probably toward the end. 

 

Averaging 18:1 I'd say for a storm total. Lowest qpf amounts I can find are ~0.3" or 5-6". 850mb flow isn't intense, so I don't see shadowing to be as bad as initially thought.

 

I think many in northern VT get 7-9" from this....lowest amounts will be along 91 south of St. J near Wells River/Bradford (4-7"?) and highest along the east slope near Stowe (9-12"?).

 

Muccilli is the man btw. Good dude. 

 

Yeah its an interesting forecast with the lower QPF but higher ratios... I hate banking on ratios, but if there's a time for it, this one looks pretty good.  I'm setting my personal expectation around 5-6" at home, maybe 7-8" at the mountain.  Less than that, probably be disappointed, more than that, happily surprised. 

 

I feel like we've been watching this for days and have beaten it into the ground, lol.  I just want it to get going already... I have a feeling tomorrow afternoon and evening is going to be like watching paint dry with a good deal of virga early on.  That's another issue... I wonder if we waste a little modeled QPF on surface dry air from the high to the north.  Hopefully it saturates up quickly and we aren't looking at decent echos producing only 2-4sm light snow.