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Wintry Winter Storm Dec 7-10

gfs_asnow_us_30.png
 
Still great pattern guys, and theres still good potential on the table.
 
If i were in the Carolinas I'd be getting pretty intrigued. As ARCC mentioned just sharpen up the trough and its game on for the Carolinas
How likely is it for the trough to sharpen up? Not that familiar with common model biases at this range.
 
Really hoping you Carolina folks get your early season snow! Ready to start seeing some happy folks around here! :D
 
The time of day this storm passes over the Carolinas on the 18z GFS is as least conducive as possible for scoring, need this to come during the overnight to optimize the chances for wintry weather. GFS has surface temps in the low-mid 40s @144 hours, a sharper trough axis and stronger low could certainly generate more dynamic cooling and melting in the low-mid levels to drive temps back several degrees, but we need to hit the diurnal cycle much better than what's depicted in this run... The heaviest precipitation comes during the middle of the afternoon, that probably won't get it done here
gfs_mslp_pcpn_frzn_seus_24.png
 
Euro on the other hand has the heaviest precipitation over NC coming in during Friday morning (but still heavy into the afternoon) and of course a stronger low and heavier precipitation that generates more lift and low-mid level melting that changes some of the precipitation over to heavy wet snow in east-central NC. Little details such as when the heaviest precipitation occurs wrt the diurnal cycle matter because it could end up being the difference between moderate-heavy cold rain w/ temps in the mid-upper 30s, or low-mid 30s w/ heavy, wet snow...

ecmwf_slp_precip_nc_25.png
 
Euro on the other hand has the heaviest precipitation over NC coming in during Friday morning (but still heavy into the afternoon) and of course a stronger low and heavier precipitation that generates more lift and low-mid level melting that changes some of the precipitation over to heavy wet snow in east-central NC. Little details such as when the heaviest precipitation occurs wrt the diurnal cycle matter because it could end up being the difference between moderate-heavy cold rain w/ temps in the mid-upper 30s, or low-mid 30s w/ heavy, wet snow...

View attachment 1707
I apologize for the weenie question but does this have any chance of going a bit NW?
 
Only 1 GEFS member show a solution similar to the Euro.
 
Only 1 GEFS member show a solution similar to the Euro.

About half of the Euro ensemble suite backs up the op so it's legit to a degree. The GEFS is notoriously underdispersive and clearly an inferior ensemble esp w/ coastal cyclogenesis thus the solutions are not only more erroneous, but more times than not they're way too similar to the operational model
 
Only 1 GEFS member show a solution similar to the Euro.

Several GEFS members (Ec and members 2, 5, 6, 7, 17, & 20) actually have a similar solution, they just show the frontal wave moving further NW w/ snow closer to the W piedmont and mountains of NC, none literally take the Euro track but it's in between the various extremes in the GEFS
gefs_ptype_ens_se_24.png
 
Yeap euro is definitely still king. It nailed the last major event a couple of years ago almost a week out. The gfs was throwing out clown maps and the euro held fast with us wake county folks getting screwed by the warm nose.


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I would really be all in if it wasn't for that secondary wave digging into the tn valley potentially screwing the pooch and inducing a southerly flow. Overall though the preceding airmass over parts of the Carolinas and VA would certainly support a wet snow event in places.

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From WxSouth on Facebook.

The Plot thickens. The European Model (and now GFS too) continue to show a strong piece of energy dropping in behind the initial rainfall in the Southeast Thursday night. At the same time this is going on, a new piece of the Polar Vortex is plunging due south through Wisconsin Friday . Its a strange setup, and a testament to the new strong Ultra-Ridge in the Western Part of North America. If that ridge builds so tall, the tables turn quickly for the Eastern States, with a Snowstorm coming up the East Coast. Right now though, this is so complicated and has timing issues of the various pieces, the models can hardly resolve it this far out.
But I'd keep informed of the weather along the East Coast, from Georgia up the East Coast for Thursday night and Friday. I have much more breakdown on the temperature profiles, moisture transport, and question how far west to pull the moisture in the Cold air at wxsouth.com.
The chances are growing though for the first snow flakes of the season for part of NC, Virginia and further north....followed by a slug of intense cold air (which has it's own snow seperately in TN, KY, WV) on Friday night and Saturday. Trends on models will mean everything from this point on, as anything is possible, from full phasing, to a nudge eastward, but the map below shows the area I'm watching.

FB_IMG_1512263946063.jpg
 
From WxSouth on Facebook.

The Plot thickens. The European Model (and now GFS too) continue to show a strong piece of energy dropping in behind the initial rainfall in the Southeast Thursday night. At the same time this is going on, a new piece of the Polar Vortex is plunging due south through Wisconsin Friday . Its a strange setup, and a testament to the new strong Ultra-Ridge in the Western Part of North America. If that ridge builds so tall, the tables turn quickly for the Eastern States, with a Snowstorm coming up the East Coast. Right now though, this is so complicated and has timing issues of the various pieces, the models can hardly resolve it this far out.
But I'd keep informed of the weather along the East Coast, from Georgia up the East Coast for Thursday night and Friday. I have much more breakdown on the temperature profiles, moisture transport, and question how far west to pull the moisture in the Cold air at wxsouth.com.
The chances are growing though for the first snow flakes of the season for part of NC, Virginia and further north....followed by a slug of intense cold air (which has it's own snow seperately in TN, KY, WV) on Friday night and Saturday. Trends on models will mean everything from this point on, as anything is possible, from full phasing, to a nudge eastward, but the map below shows the area I'm watching.

FB_IMG_1512263946063.jpg
Great post, but its hard to get that moisture that far north with strong cold front suppressing it south. Or will the cold relax and trend north/ NW but still be cold enough to support " Frozen".
 
The system is quite suppressed and it's kind of late in the game for those shenanigans, but suppression is your friend in the medium range!
 
Great post, but its hard to get that moisture that far north with strong cold front suppressing it south. Or will the cold relax and trend north/ NW but still be cold enough to support " Frozen".
Seems the past few years the frozen stuff almost always trends NW.
 
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We should be watching the speed and depth (but mainly speed) of the central US trof as it retrogrades south around 12/07 12z. If it moves faster and a little more amplified (not more zonal but "sharper"), then we could get initiation of that low and maturing pretty rapidly. Enough so to give us a solid low in the 'benchmark' around 12/8
 
Looking forward to a possible prolonged and heavy rain event for my area, something we could use after recent dryness following Irma's heavy rains of nearly 3 months ago. Per the 12Z Euro, it may be a rainy period with only rather short breaks for a whopping 54 hours lasting from 7 AM Wed til 1 PM Fri! I'd better make sure my treadmill is in working order. As a result of this being so long, the Euro qpf is 2". Whereas I think this is most likely overdone when considering the consensus/ensembles, it is a sign of solid rains likely to come, regardless. As an added bonus, the rain would likely be a rain cold for the second half of this period. Even the warm biased Euro has 50s to start and then down to as cold as the nasty high 30s for the last 12 hours of the rain. That's what can happen even near the coast with 850s only near +4 C, N to NE winds, no sunshine, and steady light to moderate rains. But this cold could easily be overdone as the 18Z GFS has temps no colder than the mid 40s with the rain. That run still gives us a nice 1.25" of qpf.
 
Great post, but its hard to get that moisture that far north with strong cold front suppressing it south. Or will the cold relax and trend north/ NW but still be cold enough to support " Frozen".
And there is the rub, always in the south. So rarely do we get a reasonable system, it's always if, if, if down here. Timing is what it takes. I like to be sure there is moisture in place, others want the cold. I figure I'm 70 and I've never seen a winter when it didn't get cold enough to snow, but most winters it didn't because it didn't rain, lol. It takes both, but over the top, it is timing in the south. If the cold air push is not overpowering the moisture push, if the moisture push isn't overpowering the cold, if the winds are right, if the moon isn't a bowl crescent that catches the rain....if either is even on the map at the same time, lol. It's all about timing the pieces into a harmonious winter confection, and not the usual heartbreak :) In the south, timing is designed to break your will, make you weep, and tear out your hair on the way to the cliff. But it keeps you coming back for more torture by giving you the occasional moment of ecstasy....like 100 years ago when Atl got over 2 inches of ip/snow :) It's Lucy 99, and Charlie Brown 0. Climo says no, so I usually start from there....at least until CR blew my mind by defying climo and making it his 'itch, with his Xmas storm....and Larry did the same for Sav. I even got an inch out of that XMas one, lol. T
 
Seems the past few years the frozen stuff almost always trends NW.
Looking forward to a possible prolonged and heavy rain event for my area, something we could use after recent dryness following Irma's heavy rains of nearly 3 months ago. Per the 12Z Euro, it may be a rainy period with only rather short breaks for a whopping 54 hours lasting from 7 AM Wed til 1 PM Fri! I'd better make sure my treadmill is in working order. As a result of this being so long, the Euro qpf is 2". Whereas I think this is most likely overdone when considering the consensus/ensembles, it is a sign of solid rains likely to come, regardless. As an added bonus, the rain would likely be a rain cold for the second half of this period. Even the warm biased Euro has 50s to start and then down to as cold as the nasty high 30s for the last 12 hours of the rain. That's what can happen even near the coast with 850s only near +4 C, N to NE winds, no sunshine, and steady light to moderate rains. But this cold could easily be overdone as the 18Z GFS has temps no colder than the mid 40s with the rain. That run still gives us a nice 1.25" of qpf.
That'll feel like an Atlanta winter night, lol. 38 and pouring rain. Buckhead was famous for that, lol. Damn dp! T
 
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