Long duration overrunning to coastal disco 02/07-02/09

[codfishsnowman]

Jerry I swear Asteroid Armageddon could hit and some body would post they were pissed because they were outside the crater, insanity

youre in a great place this winter, in fact in the recent snowy seasons youve done quite well overall, outside of a few real successes much of western mass has been on the outside looking in, even much of ct has crushed us until this year (although eastern and northeastern ct continues to crush). it def has something to do with the area, the shadowing/downsloping, too far from most bm storms, too close from tucked in events etc but at the end of the day there is still room in our climo for at least a little better. this pattern is much better than a month ago no doubt but even with our geographic disadvantages weve got a long way to go to say we are having an epic stretch....

[N. OF PIKE]

BOX got more aggressive.

box sharpened up the haves and the have not's there.

 

they will prob sharpen up a bit more this p.m , perhaps shaving the area in between ORH hills and CF Band (around 495)

[Damage In Tolland]

Everyone pounded

*** MAJOR WINTER STORM IMPACTS THE REGION WITH HEAVY SNOW

ACCUMULATIONS ALONG WITH BLOWING AND DRIFTING SNOW ***

1) SNOW TOTALS...

GOOD MODEL AGREEMENT AMONG THE GLOBAL AND HIGH RES MODELS THIS

PERIOD WITH CLASSIC SYNOPTIC SETUP FOR HEAVY SNOW HERE WITH ARCTIC

HIGH PRES OVER EASTERN QUEBEC AND MODEST FRONTAL WAVES TRACKING

ALONG OR JUST SOUTH OF 40N. WITHIN THIS SETUP IS A ROBUST AND LONG

DURATION ONSHORE LOW LEVEL JET/MOIST COLD CONVEYOR BELT /CCB/ WHICH

WILL TRANSPORT COPIOUS MOISTURE INTO THE COLD AIRMASS OVER SOUTHERN

NEW ENGLAND. THIS STRONG AND MOIST LOW LEVEL JET/CCB WILL ENHANCE

SNOWFALL RATES VIA FGEN ON THE NOSE OF THE JET ALONG WITH AN UPSLOPE

COMPONENT ACROSS THE WORCESTER HILLS AND EAST SLOPES OF THE

BERKSHIRES. CONVERSELY THIS WILL RESULT IN A BIT OF A SHADOWING

EFFECT ON THE WEST SIDE OF THE WORCESTER HILLS INTO THE CT RVR VLY

IN RESPONSE TO DOWNSLOPING WIND COMPONENT. FURTHERMORE...STRONG

COASTAL FRONT AND ITS ASSOCIATED FRONTAL CIRCULATION WILL ENHANCE

SNOWFALL RATES ACROSS NORTHEAST MA AND POSSIBLY INTO NORTHERN RI.

NOW THAT THE GFS IS DOWN TO 13KM RESOLUTION WE ARE ABLE TO SEE SOME

OF THESE DETAILS WITH THE GFS PRECIP MAX IN NORTHEAST MA WITH QPF UP

TO 1.65 INCHES STORM TOTAL. GFS HAS A SECONDARY MAX OF 1.5 ON THE

EAST SLOPES OF THE BERKS. NAM A BIT HIGHER WITH JUST OVER 2" IN

NORTHEAST MA. LIKEWISE FOR THE HI RES ARW AND NMM WITH JUST OVER 2"

QPF ACROSS NORTHEAST MA AND SECONDARY MAXES IN WORCESTER HILLS...

EAST SLOPES OF BERKS AND A MINIMUM OF 0.50 TO 0.75 IN BETWEEN.

NOW THAT THE HI RES AND GLOBAL MODELS /GFS/ ARE PICKING UP ON THESE

MESOSCALE EFFECTS WE HAVE INCREASING CONFIDENCE FOR HIGHER SNOWFALL

WITH A FEW AREAS /AS MENTIONED ABOVE/ RECEIVING 18-24" OF SNOWFALL

BY 12Z TUE! OTHER STORM ATTRIBUTES INCLUDE GUSTY NORTHEAST WINDS

FROM THIS LOW LEVEL JET WITH WINDS OF 30-40 MPH ACROSS EASTERN MA

AND INTO RI. THIS WILL RESULT IN CONSIDERABLE BLOWING AND DRIFTING

SNOW YIELDING NEAR WHITE-OUT CONDITIONS AT TIMES.

2) PTYPE...

[powderfreak]

Everyone pounded

GOOD MODEL AGREEMENT AMONG THE GLOBAL AND HIGH RES MODELS THIS

PERIOD WITH CLASSIC SYNOPTIC SETUP FOR HEAVY SNOW HERE WITH ARCTIC

HIGH PRES OVER EASTERN QUEBEC AND MODEST FRONTAL WAVES TRACKING

ALONG OR JUST SOUTH OF 40N. WITHIN THIS SETUP IS A ROBUST AND LONG

DURATION ONSHORE LOW LEVEL JET/MOIST COLD CONVEYOR BELT /CCB/ WHICH

WILL TRANSPORT COPIOUS MOISTURE INTO THE COLD AIRMASS OVER SOUTHERN

NEW ENGLAND. THIS STRONG AND MOIST LOW LEVEL JET/CCB WILL ENHANCE

SNOWFALL RATES VIA FGEN ON THE NOSE OF THE JET ALONG WITH AN UPSLOPE

COMPONENT ACROSS THE WORCESTER HILLS AND EAST SLOPES OF THE

BERKSHIRES. CONVERSELY THIS WILL RESULT IN A BIT OF A SHADOWING

EFFECT ON THE WEST SIDE OF THE WORCESTER HILLS INTO THE CT RVR VLY

IN RESPONSE TO DOWNSLOPING WIND COMPONENT. FURTHERMORE...STRONG

COASTAL FRONT AND ITS ASSOCIATED FRONTAL CIRCULATION WILL ENHANCE

SNOWFALL RATES ACROSS NORTHEAST MA AND POSSIBLY INTO NORTHERN RI.

Congrats east slope.

[moneypitmike]

How much for Lunenberg?

[powderfreak]

BTV WRF has been very consistent the past several runs...just crushing eastern Mass from the east slopes through the coastal plain, and then back on the Berks east slopes and Catskill east slopes.

 

[moneypitmike]

BTV WRF has been very consistent the past several runs...just crushing eastern Mass from the east slopes through the coastal plain, and then back on the Berks east slopes and Catskill east slopes.

 

WRF.JPG

 

What a trouncing for the Essex county (I think that's Essex).  That shadowing is a killer--looks a little further east than typically takes place.  It has me in a 1.25"--I like.

[CT Valley Snowman]

Heaviest shadow is actually just east of the valley on a couple models with the western ct river valley doing pretty well out by route 10 and 202. Not sure I'm buying that but could be possible.

[powderfreak]

Heaviest shadow is actually just east of the valley on a couple models with the western ct river valley doing pretty well out by route 10 and 202. Not sure I'm buying that but could be possible.

Blocked flow and not a ripping easterly jet at high speeds. It's why sometimes BTV can do really nicely in the middle of the Champlain Valley if the slower flow allows air to pile up, upwind of the barrier. It's inversion and flow speed related.

If this was a strong low with good mixing and deep easterly flow the valley would be toast.

[moneypitmike]

Heaviest shadow is actually just east of the valley on a couple models with the western ct river valley doing pretty well out by route 10 and 202. Not sure I'm buying that but could be possible.

 

I think the GFS and RGEM suggested this.

 

Thanks for the explanation, PF.

[Johnno]

Heaviest shadow is actually just east of the valley on a couple models with the western ct river valley doing pretty well out by route 10 and 202. Not sure I'm buying that but could be possible.

Yea more than one model has the look of a Granby Hartland into Granville Ma jackpot....qpf wise atleast

[ORH_wxman]

Blocked flow and not a ripping easterly jet at high speeds. It's why sometimes BTV can do really nicely in the middle of the Champlain Valley if the slower flow allows air to pile up, upwind of the barrier. It's inversion and flow speed related.

If this was a strong low with good mixing and deep easterly flow the valley would be toast.

 

 

Yeah the light NE flow down here would favor the E ORH hills but it would have trouble carrying over the spine. It wouldn't carry over into much of the county like a strong deep layer E flow.

[moneypitmike]

Yeah the light NE flow down here would favor the E ORH hills but it would have trouble carrying over the spine. It wouldn't carry over into much of the county like a strong layer E flow.

 

Thanks for the comments Will, Scott, and John.

 

The BOX map reflects it as well.

 

I'm going to do some clearing before things ramp up--want my accurate measurements. 

[HIPPYVALLEY]

Blocked flow and not a ripping easterly jet at high speeds. It's why sometimes BTV can do really nicely in the middle of the Champlain Valley if the slower flow allows air to pile up, upwind of the barrier. It's inversion and flow speed related.

If this was a strong low with good mixing and deep easterly flow the valley would be toast.

Yeah, it's been bizarre to see several models depicting a relative screw zone well E of the valley. Usually doesn't work out that way but this set-up is unusual.

BOX has actually upped snow totals here.

[powderfreak]

Yeah the light NE flow down here would favor the E ORH hills but it would have trouble carrying over the spine. It wouldn't carry over into much of the county like a strong deep layer E flow.

Yup, same up here with those weak NW flows that can just back it up to BTV, rather than push it downwind into my backyard. I always look for at least 25kts or higher, the 10-15kts doesn't do it. Especially with a low level inversion with less mixing.

I love those mesoscale nuances.

[CT Valley Snowman]

Blocked flow and not a ripping easterly jet at high speeds. It's why sometimes BTV can do really nicely in the middle of the Champlain Valley if the slower flow allows air to pile up, upwind of the barrier. It's inversion and flow speed related.

If this was a strong low with good mixing and deep easterly flow the valley would be toast.

Good stuff.

[powderfreak]

Yeah, it's been bizarre to see several models depicting a relative screw zone well E of the valley. Usually doesn't work out that way but this set-up is unusual.

BOX has actually upped snow totals here.

Yeah maybe it doesn't work out like that, and for perspective the "screw zone" is still 6"+, but that's what the meso-scale models are picking up on.

As many have said, without strong jet mechanics and light NE suface flow under more westerly deep layer over-running, this system may have sharper meso gradients than normal. You can certainly see it on the meso-models.

[CT Rain]

I feel pretty confident with our 6-10 forecast for most areas here in N CT. Model QPF is backing down as expected and Euro Ensembles have really pinned down the greatest snow threat.

 

The BUFKIT soundings on the GFS are still quite bizarre. Check out HFD and BDL at 6z Monday. Almost looks like a standing wave kind of pattern with very strong upward vertical motion (negative omega) around 900 hpa and BDL and very strong sinking motion at the same level for HFD. Not sure what the deal is but it's unusual to see on the GFS. 

 

What is a constant in all the model runs is pretty lame looking snow growth. 

[CarverWX]

Looks like Box it thinking more sleet down this way. Was surprised to the amount go down.

[Ginx snewx]

I feel pretty confident with our 6-10 forecast for most areas here in N CT. Model QPF is backing down as expected and Euro Ensembles have really pinned down the greatest snow threat.

The BUFKIT soundings on the GFS are still quite bizarre. Check out HFD and BDL at 6z Monday. Almost looks like a standing wave kind of pattern with very strong upward vertical motion (negative omega) around 900 hpa and BDL and very strong sinking motion at the same level for HFD. Not sure what the deal is but it's unusual to see on the GFS.

What is a constant in all the model runs is pretty lame looking snow growth.

yea noticed that yesterday, overnights snow growth was pretty nice here. Wonder if Chris Ocean States salt nuclei theory for eastern areas produces better rates than depicted. 6-10 seems a good starting point as any adjustment can be made if things evolve different. Box's ramp up took me by surprise, they have some 13Km love. Geez Ryan Thursday looks classic dendritic growth though

[TheSnowman]

What I don't understand about them predicting this much is that the non-detailed models like the GFS and EURO don't have that much precip., as the detailed meso models are clearly hinting at some kind of a band. I presume it will be like a firehose so this will be a complete luck situation with crazy accumulation spreads similar to the Fujiwawa 2 years ago. But just seeing this makes me totally and truly believe them in a dream. 48" in 2 weeks and 1 to 2 feet coming?

[Damage In Tolland]

Still like easy 10 + for N 2/3 of CT. Nothing changed model wise overnight

[Ginx snewx]

[CT Rain]

yea noticed that yesterday, overnights snow growth was pretty nice here. Wonder if Chris Ocean States salt nuclei theory for eastern areas produces better rates than depicted. 6-10 seems a good starting point as any adjustment can be made if things evolve different. Box's ramp up took me by surprise, they have some 13Km love. Geez Ryan Thursday looks classic dendritic growth though

 

Probably pretty crappy dendritic growth in our area - but should be just fine along the coastal front.

 

Not too worried about it though. If anything the models really converged last night to a solution that makes a lot of sense. Max QPF axis narrowed quite a bit and not a tremendous amount of spread in model solutions. I actually think some of the NW Hill towns in CT could wind up doing well with a bit of an upslope assist from the CT River Valley. I do think a lot of areas struggle with exhaust from some funky mesoscale stuff happening to the east. 

[moneypitmike]

 

They really should have coordinated maps between their social media and web communications. 

[Ginx snewx]

Probably pretty crappy dendritic growth in our area - but should be just fine along the coastal front.

Not too worried about it though. If anything the models really converged last night to a solution that makes a lot of sense. Max QPF axis narrowed quite a bit and not a tremendous amount of spread in model solutions. I actually think some of the NW Hill towns in CT could wind up doing well with a bit of an upslope assist from the CT River Valley. I do think a lot of areas struggle with exhaust from some funky mesoscale stuff happening to the east.

can you remember a valley down slope with the weak east flow like this, analog? Ones I remember were ripping like Boxing day, Dec 92, March firehouse

[mostman]

Take a drive from Lowell to Andover and witness a crazy accumulation increase. According to that map.

[Ginx snewx]

They really should have coordinated maps between their social media and web communications.

what's that mean

[Baroclinic Zone]

what's that mean

Maps are coordinated to me.

[CT Rain]

can you remember a valley down slope with the weak east flow like this, analog? Ones I remember were ripping like Boxing day, Dec 92, March firehouse

 

Well, I don't really think it will be "downslope" per se I think the issue is with such weak synoptic scale forcing the smaller scale forcing mechanisms will rule the day. Basically minor elevation differences, convergence along coastal fronts, etc will play a much bigger role than what you typically see. While I won't get screwed through downsloping I could totally get screwed being on the wrong side of a heavier mesoscale band.