February 5th beefed up swfe thread-let's get some December 2007 juju,

[J Paul Gordon]

Because it's not support by other models (domestic or foreign) in the 12z suite today.

I guess the question to ask you is why would you expect forecasters to jump/react to it?

I'm not expert enough to be sure why they react to one model and not to another. The responses I'm getting to my question are very helpful. I had something of an intuition (even somewhat informed scientifically, but not solid enough to  consider sound) as to why the NAM might be discounted. Hearing from others helps. 

[dryslot]

12z Euro a tic NW a tic warmer for SE areas

[CoastalWx]

Euro would probably ping to the Pike briefly.

[CoastalWx]

That's a dendrite to PWM hit right there.

[CoastalWx]

Solid 10-12" from near Rt 2 up through the lakes region. Probably max in the middle or so.

[ORH_wxman]

Rt 2 to monads jack on the Euro.

 

I'm surprised how wet this run is. Really large area over 1" liquid equiv.

[dendrite]

That's a dendrite to PWM hit right there.

Just saw it. Tasty.

[dryslot]

Snow map adjustments forth coming in the afternoon pkg i presume

[dryslot]

Just saw it. Tasty.

 

sweet spot

[CoastalWx]

Just saw it. Tasty.

 

I think you are literally the sweet spot on that run.

[Sey-Mour Snow]

I'm at work on phone, hows it looking for southern half of CT

[radarman]

Euro would probably ping to the Pike briefly.

 

Generally warm mid-levels push up the valley to near Rt 2.  Even find their way down the Mohawk trail near Berkshire East quite often.  Standard local modification on these forecasts out here, but not overly concerning really. 

[SouthCoastMA]

Hoping for a quickly approaching dry slot down this way after 2-4"

[ORH_wxman]

I think you are literally the sweet spot on that run.

 

 

Looks a bit south of him to me...he's def in the sweet spot of the ML fronto later on in the afternoon..but the monads region gets shellacked harder by the front end WAA.

 

Probably nitpicking though...there's a large area over 1" of qpf from the MA/CT border up to about dendrite.

[OceanStWx]

Was this from the HPC? RGEM was similar.

 

It seems there was a (I like the terminology) "NAM sponsored" shortwave that none of the other models have, suggesting convective feedback. However, HPC doesn't seem completely 100% all in that it was convective feedback, despite a non-NAM based forecast.

 

It's something we did discuss a couple days ago, that these southern stream system can have convection that affects surface low track. It's probably why these models have been ticking north in the short term, the NAM just may have overshoot that correction.

THE 12Z NAM STARTS OUT WEAKER AT THE 700 HPA LEVEL WITH THISSYSTEM.  IT APPEARS TO USE CONVECTIVE/GRIDSCALE FEEDBACK TOSTRENGTHEN THIS SYSTEM MORE THAN THE OTHER DETERMINISTIC GUIDANCELATE TODAY AND TOMORROW, WHICH FORCES ITS SURFACE LOW ON A MOREWESTERLY TRAJECTORY.  EVEN IF FEEDBACK WAS NOT INVOLVED HERE, THENAM OCCASIONALLY SHOWS A STRONG BIAS WITH SYSTEMS, WHICH SEEMS TOBE DUE TO ITS WRF PHYSICS PACKAGE.  COORDINATION WITH THE WINTERWEATHER DESK YIELDED ANOTHER ODD NAM-SPONSORED SHORTWAVE BEINGSTRENGTHENED AS IT MOVES INTO DRY AIR UP THE APPALACHIANS, WHICHALSO LOOKS SUSPICIOUS.  A NON-NAM COMPROMISE IS ADVISED WITHAVERAGE CONFIDENCE CONSIDERING THE SYSTEM'S PROGRESSIVE NATURE.

[CoastalWx]

Looks a bit south of him to me...he's def in the sweet spot of the ML fronto later on in the afternoon..but the monads region gets shellacked harder by the front end WAA.

 

Probably nitpicking though...there's a large area over 1" of qpf from the MA/CT border up to about dendrite.

 

He picked up ground in the aftn verbatim, but yeah that's a big area of 1" qpf from near the pike on north. It makes sense to me anyways as far as the distribution goes. Whether it's 1.1" or 0.9"....Dendrite or AFN jackpot...probably a difference of an inch or two, but the general idea is there. I do think the WAA thump is probably best near the pike to srn NH and then points north pick up ground later on while we dryslot or just have some showery precip until it cools a bit aloft. Areas like Ray will probably not see any pellets or perhaps a few after the lift is gone. Pretty much mostly snow from nrn CT to the Pike I would guess.

[radarman]

Rt 2 to monads jack on the Euro.

 

I'm surprised how wet this run is. Really large area over 1" liquid equiv.

 

JJBASHB might be the board winner today.  Hoarfrost Dave should do really well too... seems like we have a dearth of posters east of EEN unfortunately. 

[dryslot]

 

It seems there was a (I like the terminology) "NAM sponsored" shortwave that none of the other models have, suggesting convective feedback. However, HPC doesn't seem completely 100% all in that it was convective feedback, despite a non-NAM based forecast.

 

It's something we did discuss a couple days ago, that these southern stream system can have convection that affects surface low track. It's probably why these models have been ticking north in the short term, the NAM just may have overshoot that correction.

THE 12Z NAM STARTS OUT WEAKER AT THE 700 HPA LEVEL WITH THISSYSTEM.  IT APPEARS TO USE CONVECTIVE/GRIDSCALE FEEDBACK TOSTRENGTHEN THIS SYSTEM MORE THAN THE OTHER DETERMINISTIC GUIDANCELATE TODAY AND TOMORROW, WHICH FORCES ITS SURFACE LOW ON A MOREWESTERLY TRAJECTORY.  EVEN IF FEEDBACK WAS NOT INVOLVED HERE, THENAM OCCASIONALLY SHOWS A STRONG BIAS WITH SYSTEMS, WHICH SEEMS TOBE DUE TO ITS WRF PHYSICS PACKAGE.  COORDINATION WITH THE WINTERWEATHER DESK YIELDED ANOTHER ODD NAM-SPONSORED SHORTWAVE BEINGSTRENGTHENED AS IT MOVES INTO DRY AIR UP THE APPALACHIANS, WHICHALSO LOOKS SUSPICIOUS.  A NON-NAM COMPROMISE IS ADVISED WITHAVERAGE CONFIDENCE CONSIDERING THE SYSTEM'S PROGRESSIVE NATURE.

 

Are you at the WFO today? Short term? Long term?

[ORH_wxman]

He picked up ground in the aftn verbatim, but yeah that's a big area of 1" qpf from near the pike on north. It makes sense to me anyways as far as the distribution goes. Whether it's 1.1" or 0.9"....Dendrite or AFN jackpot...probably a difference of an inch or two, but the general idea is there. I do think the WAA thump is probably best near the pike to srn NH and then points north pick up ground later on while we dryslot or just have some showery precip until it cools a bit aloft. Areas like Ray will probably not see any pellets or perhaps a few after the lift is gone. Pretty much mostly snow from nrn CT to the Pike I would guess.

 

This is def the wettest Euro run I think yet. Probably being a tad more amped with the shortwave helps up the qpf.

[dryslot]

Basically the GFS is the least

[Damage In Tolland]

He picked up ground in the aftn verbatim, but yeah that's a big area of 1" qpf from near the pike on north. It makes sense to me anyways as far as the distribution goes. Whether it's 1.1" or 0.9"....Dendrite or AFN jackpot...probably a difference of an inch or two, but the general idea is there. I do think the WAA thump is probably best near the pike to srn NH and then points north pick up ground later on while we dryslot or just have some showery precip until it cools a bit aloft. Areas like Ray will probably not see any pellets or perhaps a few after the lift is gone. Pretty much mostly snow from nrn CT to the Pike I would guess.

Couple hours of pock marks on my dome here, then back to light snow ?

[CoastalWx]

This is def the wettest Euro run I think yet. Probably being a tad more amped with the shortwave helps up the qpf.

 

Yeah I agree. I was surprised too. Hopefully it's one of those WAA absolutely killing it with snow rates. Seems like from mid morning until like 1pm or so is the main show. Should rip. That's the period of heaviest stuff anyways.

[OceanStWx]

Are you at the WFO today? Short term? Long term?

 

I'm on the sidelines for this one. I'll be on midnights to inject a little   to the late weekend/early week storm.

 

Wish I did have better access to data though.

[HIPPYVALLEY]

Rt 2 to monads jack on the Euro.

 

I'm surprised how wet this run is. Really large area over 1" liquid equiv.

 

We like.

SWFE's generally treat N Franklin Co and the Monads well.

 

Generally warm mid-levels push up the valley to near Rt 2.  Even find their way down the Mohawk trail near Berkshire East quite often.  Standard local modification on these forecasts out here, but not overly concerning really. 

 

My experience over the 6 winters I've been here is that, in this area,  if there is a threat of a mid-level warm layer intruding most if not all of the meaningful precipitation has fallen as snow and we get an hour or two of light freezing mist/drizzle to finish.

[OceanStWx]

Basically the GFS is the least

 

Several runs now it's been the low end of the QPF spectrum. Even still it's a healthy snowfall for much of the region, just more of a low end warning/high end advisory.

[Baroclinic Zone]

Is there a crude way we can use the 850 images to determine the sleet line.  I could have sworn we used the -3c isotherm.

[moneypitmike]

Nothing to fret here.  I'm good for 8-12, probably right in the middle.

 

For the record, it's more exciting when there's a question/doubt of qpf. 

 

30.5/17

[ctsnowstorm628]

Is there a crude way we can use the 850 images to determine the sleet line.  I could have sworn we used the -3c isotherm.

I think that sounds about right. Usually there is a sneaky warm layer above 0C with these types of events.

[dryslot]

I'm on the sidelines for this one. I'll be on midnights to inject a little   to the late weekend/early week storm.

 

Wish I did have better access to data though.

 

lol, Toss out a couple

[powderfreak]

Is there a crude way we can use the 850 images to determine the sleet line. I could have sworn we used the -3c isotherm.

Look at a sounding and see at what H85 temp the warm layer first goes above 0C. A few days ago I had it around -2C or -3C at H85 when the first above 0C layer hit the 700-800mb area. I'm not sure if that's changed in recent guidance though.