Weekend Threat 12/14-12/15

[Allsnow]

hr 75 mod snow continues 850's and surface the same…this looks very similar to the 12z euro…at least with the overrunning 

[Allsnow]

hr 78 850's to phl and surface is along 95

[earthlight]

Just glancing at 66 hours on Ewall (from my phone)..not a terrible look. Wave spacing could be a little better but it is improved over what I was looking at on the non-euro models last night.

[Allsnow]

hr 81 rain/snow line around ttn….preciep looks to be ending 

[earthlight]

Without any major amplification that disturbance at 66 hours basically turns into a glorified light WAA snow event.

[Allsnow]

hr 84 just light drizzle is left over…looks like frz drizzle nw

[earthlight]

Earlier phase?

There's no phase with that initial weak disturbance until it's east of us, and the main shortwave that's in the Deep South is too far disconnected from the northern stream entity to induce any major cyclogenesis.

[JetsPens87]

GFS looks pretty strung out, and that may not be a terrible thing. By the time the warmer air plunges in, most of the precip is over.

[Heisy]

earthlight, 100% agree, but honestly, I think thats the best case scenario with this event, and maybe that WAA will over preform. when it comes to spitting precip. 

[PB GFI]

Hour 78 is colder ,here  at 84 SNJ and East End Long island get to 40 , From Wetsern Nassau thru the City and down thru CNJ Temps 30 -32 range  and its in the mid to upper 20`s Just N and NW

[earthlight]

GFS looks pretty strung out, and that may not be a terrible thing. By the time the warmer air plunges in, most of the precip is over.

Id rather see the initial shortwave dampen out or slide towards the baroclinic zone, and the polar energy amplify and phase with the stronger shortwave over the Southeast states. But hey we can't all get what we want, can we?

[PB GFI]

Close enough to the Euro , Its mainly snow on the front end ,change to sleet and FRZ at the end , but it looks like most of the precip will

have fallen as snow

[dbc]

Id rather see the initial shortwave dampen out or slide towards the baroclinic zone, and the polar energy amplify and phase with the stronger shortwave over the Southeast states. But hey we can't all get what we want, can we?

Isn't that basically what happened with the Jan 1996 blizzard and then thanks to the blocking it just stalled out?

[Heisy]

Id rather see the initial shortwave dampen out or slide towards the baroclinic zone, and the polar energy amplify and phase with the stronger shortwave over the Southeast states. But hey we can't all get what we want, can we?

 

if we had a decent block, yes. 

[JetsPens87]

Id rather see the initial shortwave dampen out or slide towards the baroclinic zone, and the polar energy amplify and phase with the stronger shortwave over the Southeast states. But hey we can't all get what we want, can we?

 

Now you're talking. Combine with some blocking, and keep that arctic airmass locked in place.

[jm1220]

Hey Jm,

I think I remember you from way back in the day on WWBB and Eastern (my old handle used to be stormchaser16), good to hear from you.

 

As I stated in my post above, the coastal is only going to aide in bringing in the warmer air in this setup it seems (unless it truly bombed way early and dynamics took over, but that hardly appears to be the case in this progressive flow). We really  should just be holding our hopes on the overrunning IMO unless something drastically changes.

 

Either way, how active has this early season been for this forum, I mean come on folks this is awesome!

I didn't think December would have chances like this, that's for sure.

[Superstorm93]

 

 

ALL EYES THEN TURN TO A DEVELOPING STORM SYSTEM MOVING OUT OF THE

SOUTHEASTERN STATES. ALL THE 11/12Z MODELS GUIDANCE ARE IN AGREEMENT

WITH THE LOW MOVING OUT OF THE SOUTHEASTERN STATES...TAKING A TRACK

OFF THE MIDDLE ATLANTIC COAST...AND TRAVELING NORTHEAST...PASSING

SOUTHEAST OF LONG ISLAND. MODEL GUIDANCE DIFFERS HOWEVER ON

TIMING...SPEED...AND STRENGTH OF THE LOW. IN ADDITION...MODELS ARE

ALSO NOT IN COMPLETE AGREEMENT WITH THE STRENGTH AND EXACT POSITION

OF A HIGH PRESSURE SYSTEM...NORTH OF THE CWA...WHICH WILL BE A MAJOR

PLAYER IN THIS EVENT.

KNOWING THIS...DID NOT MAKE TOO MANY CHANGES TO THE FORECAST KNOWING

THAT THE NEXT COUPLE OF MODEL RUNS WILL CONTINUE TO SHOW DIFFERENT

SCENARIOS ON HOW THIS EVENT WILL PLAY OUT.

SO...FOR NOW...THINKING THAT SNOW OVERSPREAD THE REGION DURING THE

DAY ON SATURDAY. THIS SNOW WILL CONTINUE INTO THE EVENING...WITH A

CHANGE OVER TO A MIX AND/OR RAIN ALONG THE COAST SATURDAY NIGHT. ACROSS

THE INTERIOR...WE ARE EXPECTING AN ALL SNOW EVENT...HOWEVER

DEPENDING ON THE EXACT TRACK OF THE LOW...A WINTRY MIX MAY OCCUR.

THE LOW MOVES NORTH AND EAST OF THE REGION SUNDAY AFTERNOON WITH

CLEARING EXPECTED LATE IN THE DAY.

IT IS TOO EARLY AND THERE IS NOT ENOUGH CONFIDENCE TO GIVE SNOWFALL

AMOUNTS. AS EXPECTED WITH THERE ARE DIFFERENCES WITH THE

MODELS...EXPECT THE FORECAST TO CHANGE A FEW MORE TIMES...BETWEEN

NOW AND THE WEEKEND.

[eduggs]

hr 75 mod snow continues 850's and surface the same…this looks very similar to the 12z euro…at least with the overrunning 

I don't see any "moderate" snow on the GFS prog.  Maybe .2" QPF in 6 hours could be considered "moderate" QPF if you stretch the definition a little bit, but it would probably not result in anything except light snow (with a few pockets of moderate possible).  .25-.5 QPF over 24 hours is pretty light.

[ag3]

At hour 90 Surface temps are in the upper 20`s not 19 850`s ar minus 2 not minus 10 and at this time .20 liquid is falling in 6 hours , that's 10 to 1 on the coastal plain

if u wana say its 8 to 1 I wouldn't argue , its not 15 or 12 to 1 , surface temps have very little to do with snow girth , don't puke -

I said when the precip enters. By hour 90, .19" of precip has already fallen.

[PB GFI]

I said when the precip enters. By hour 90, .19" of precip has already fallen.

Its all good dude , We don't disagree that marginal air kills ratios on the coast , his post was ratios should be good with this storm

I disagreed with that .

[ag3]

Its all good dude , We don't disagree that marginal air kills ratios on the coast , his post was ratios should be good with this storm

I disagreed with that .

He is not wrong.

If it's 19 degrees at the surface with 850s of -11 and all levels solidly below freezing (they are looking at skew soundings), 526 thickness, it most certainly is a very good ratio at the start. At least 12-15 to 1.

The snow growth region is ideal at hour 84 of the 12z euro. Check the skew t-s.

[PB GFI]

Most of it is frozen , for most of the area ,  Surface temps continue to cool day by day on the models  . Also ,  Great CAD look to this system  as well .

[PB GFI]

He is not wrong.

If it's 19 degrees at the surface with 850s of -11 and all levels solidly below freezing (they are looking at skew soundings), 526 thickness, it most certainly is a very good ratio at the start. At least 12-15 to 1.

The snow growth region is ideal at hour 84 of the 12z euro. Check the skew t-s.

At 84 hours  a tenth of an inch of liquid falls , , this is absurd . the majority of it falls at 90 and 96 as per suite ,

and by that time the 850`s and surface are no where near that , yes hes wrong

[PB GFI]

AG , so you know what im looking at , at 84 hrs I see minus 5 to minus 7 , I don't see max snow growth there , with .10 falling  ,

[USCG RS]

Id rather see the initial shortwave dampen out or slide towards the baroclinic zone, and the polar energy amplify and phase with the stronger shortwave over the Southeast states. But hey we can't all get what we want, can we?

Oh how awesome that would be and the ratios that could potentially produce... *drifts off to dream land *

[Rjay]

Wait so Upton is expecting an all snow event lasting for more than 12 hours?

The discussion was posted above...

SO...FOR NOW...THINKING THAT SNOW OVERSPREAD THE REGION DURING THE

DAY ON SATURDAY. THIS SNOW WILL CONTINUE INTO THE EVENING...WITH A

CHANGE OVER TO A MIX AND/OR RAIN ALONG THE COAST SATURDAY NIGHT. ACROSS

THE INTERIOR...WE ARE EXPECTING AN ALL SNOW EVENT...HOWEVER

DEPENDING ON THE EXACT TRACK OF THE LOW...A WINTRY MIX MAY OCCUR.

[ScottB]

Mt.Holly seems to be going for a colder scenario for anything N and NW of PHL. Should be an interesting event to watch the next few days. 

[odwalla]

long time lurker; the discourse in this thread has become completely unintelligible. can moderation please implement SEP? this is not a thread for philadelphia, this is not a thread for useless banter, it is a place to discuss the weekend threat with quantitative observations of model guidance. 

[Storm At Sea]

IMO it's do or die tonight.

[White Gorilla]

If models continue to offer divergent solutions through tomorrow? When are the systems going to be onshore for better sampling?