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Southern App. Surprise Heavy Snow Possible Tonight


FoothillsNC

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After looking at the new models and especially RUC, it appears that strong damming will still be ongoing late tonight with much more moisture than initially thought coming in from the due south across western NC around dark tonight. The confluence in New England maintains surface high pressure longer, which was always a possibility, and this event is coming down to the last few hours as a nowcast type of event, similar to the early Dec. snows in western NC,ne Ga. The models show possible strong dynamic cooling with very little 850 warm advection (temps around 0 to +1 for much of event, low thkns.) but excellent lift from a strong lobe of moisture, under low heights and marginal thermal profiles, with damming and some teens dewpoints in VA working south, so for areas above 2500 feet, dynamic cooling usually plays a big role in P-types here. Also, there may be pockets of ZR right up against the mountain chain esp. in the northern foothills, where a mix with snow, and especially sleet, is possible at times even in lower elevations of central and northern foothills. For the northern mountains of Ashe, Avery Mitchell Watauga and Yancey, this could be a mostly heavy snow event with up to 6". For the central mountains around Asheville and Waynesville, the snow will probably be just a little higher than the valley floor, but its a close call and will depend on dynamic cooling....could swing either way and some areas may be mostly rain , some mostly snow, others a mix. Pockets of heavy accum. are possible really anywhere in western NC mountains, but I feel more strongly a little further north into the northern mtns.

If the center of the high remains inland longer, or if the precip arrives even earlier , it becomes even more of a mostly snow threat...if a little later, or less moisture and lift, then more of a rain or mix threat. Big bust potential either way on this one, since its so close.

post-38-0-39455500-1295263503.jpg

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Wow Robert, Suprised to wake up to this! Of course I am at 2190 so it sounds like it will be really close. You have been nailing everything this winter so when you make a post like this it gets the blood boiling. Hopefully there will be enough qpf & things will fall into place for a snow event. I lost quite a bit of snow yest. but still have almost solid ground cover. Would like to add to it tonight. Thanks for the post.

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Wow Robert, Suprised to wake up to this! Of course I am at 2190 so it sounds like it will be really close. You have been nailing everything this winter so when you make a post like this it gets the blood boiling. Hopefully there will be enough qpf & things will fall into place for a snow event. I lost quite a bit of snow yest. but still have almost solid ground cover. Would like to add to it tonight. Thanks for the post.

Thanks Don, lets see where the best moisture goes. Could just sideswipe the mountains, but its going to be close tonight. If the good moisture and lift doesn't really hit the mountains , then this would probably be mostly just light rain and hardly any snow accum. anywhere.

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Thanks Don, lets see where the best moisture goes. Could just sideswipe the mountains, but its going to be close tonight. If the good moisture and lift doesn't really hit the mountains , then this would probably be mostly just light rain and hardly any snow accum. anywhere.

I'm like Don. Sitting at about 2250 ft. Hopefully, things will come into place.

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Thank you for the heads up Robert. Im in northern Mitchell county. I teach high school and drive a school bus route near the Tennessee line. If you can, please keep us updated here concerning this event. Thanks again!

Thanks Don, lets see where the best moisture goes. Could just sideswipe the mountains, but its going to be close tonight. If the good moisture and lift doesn't really hit the mountains , then this would probably be mostly just light rain and hardly any snow accum. anywhere.

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It looks like the best lift is just going to miss far sw NC on this one, with good omega right over the eastern escarpment, so if the dynamic cooling works and surface temps aren't too warm then even Forest City Morganton Lenoir and Lake Lure Wilkesboro area could get a quick switch to wet snow. The South Mountain chain is actually in a really good spot on this with maybe just cold enough to make snow there as well. The RUC even has a circle of snow there, I know we don't have posters there though, just neat to see it showing up just south of Morganton.

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As always, Foothills is 1st to the party. Looks like NWS thinks east of AVL though:

Snippet from NWS:

WE STILL VIEW THIS AS A SUB-ADVISORY EVENT...BUT JUST

BARELY...AND WILL NEED TO REVISIT THE POSSIBILITY OF HEADLINES FOR

THE AFTERNOON PACKAGE. IN THE INTERIM...THE SNOWFALL FORECAST WILL

BE INCREASED TO 1 TO 2 INCHES FROM THE LAKE LURE/BLACK MTN AREA

NORTH ALONG THE EASTERN ESCARPMENT

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As always, Foothills is 1st to the party. Looks like NWS thinks east of AVL though:

Snippet from NWS:

WE STILL VIEW THIS AS A SUB-ADVISORY EVENT...BUT JUST

BARELY...AND WILL NEED TO REVISIT THE POSSIBILITY OF HEADLINES FOR

THE AFTERNOON PACKAGE. IN THE INTERIM...THE SNOWFALL FORECAST WILL

BE INCREASED TO 1 TO 2 INCHES FROM THE LAKE LURE/BLACK MTN AREA

NORTH ALONG THE EASTERN ESCARPMENT

Oh well...I'm heading over to Reynolds tonight to cover a game. Maybe I can slip and slide down Old Fort Mtn. on the way home...:snowman:

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NWS out of GSP thinks there is a chance of snow north of I-40 tonight in NC:

P-TYPE CONCERNS LINGER FOR THIS EVENING. EAST OF THE MTNS...SURFACE

WET BULB TEMPS ARE SOLIDLY ABOVE FREEZING AND SHOULD GENERALLY

REMAIN THAT WAY. HOWEVER...ONCE PRECIP BEGINS...FORECAST SOUNDINGS

SUGGEST A DEEP ISOTHERMAL LAYER NEAR FREEZING. THEREFORE...SOME SNOW

MAY MIX IN WITH RAIN IN THE PIEDMONT/FHILLS NORTH OF I-40 AS PRECIP

BEGINS THIS EVENING. NC MNTN TEMPS THIS AFTERNOON/EVENING WILL BE

ONLY SLIGHTLY COOLER THAN THE PIEDMONT. NEVERTHELESS...THIS SHOULD

BE SUFFICIENT TO ALLOW A MIXED BAG OF SLEET/SNOW/PERHAPS RA/FZRA TO

DEVELOP. THIS WILL BE ESPECIALLY TRUE ALONG THE EASTERN

ESCARPMENT OF THE BLUE RIDGE...WHERE SOUTHEAST UPSLOPE FLOW SHOULD

PROVIDE SUFFICIENT MECHANICAL COOLING TO MAINTAIN TEMPS NEAR

FREEZING ONCE PRECIP STARTS. LIGHT ACCUMS OF SLEET/SNOW WITH TRACE

AMOUNTS OF ICE ARE GENERALLY ANTICIPATED WITHIN THE EASTERN

ESCARPMENT ZONES OF NC. OUTSIDE OF AFOREMENTIONED AREAS...ALL RAIN

IS EXPECTED. SINCE ANY AMOUNT OF ICE ACCRETION WARRANTS AN

ADVISORY...WE WILL ISSUE ONE FOR THESE ZONES.

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The precip isn't far away from the colder air now. The 850's have cooled to -1 and 0 in western NC and even down to ne GA, but the 925 temps are +1 to +3 over said areas. Still a good chance at dynamic cooling and snow beginning the next few hours over the mountains and western Foothills esp. areas bound between Hendersonville-Lake Lure-Morganton and points north and west to the northern Mountains.

the RUC has been back and forth on qpf totals, either way doesn't look like too much, but some areas could get 2" maybe more esp. northern mtns and foothills where maybe up to 4" , but probably less than that. Theres actually some heavy echoes in GA developing that if hold together will get into the escarpment or spine of the Apps. Can't wait to get my cold rain and wetbulb to 35 degrees here.:arrowhead:

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Great Posts Robert! In all honesty I haven't been looking at many models coming up to this even knowing is was mainly going to not be a huge deal. However, looking on radar it seems that the Precipitation shield is way further west than both the GFS and the NAM had it last night, which certainly peaked my interested a bit. The 850mb temperatures are really an example of adiabatic lift at its finest... forcing the air to cool and it rises up orthogonally to the NW Smokey mountain chain.

Wow Robert, Suprised to wake up to this! Of course I am at 2190 so it sounds like it will be really close. You have been nailing everything this winter so when you make a post like this it gets the blood boiling. Hopefully there will be enough qpf & things will fall into place for a snow event. I lost quite a bit of snow yest. but still have almost solid ground cover. Would like to add to it tonight. Thanks for the post.

I'm sitting at around 2140ft or so, so still not really expecting much even if we do get the moisture. Thats really the key here... we need around >.25" in a short period of time to really get the dynamical cooling we need to get accumulating snowfall in the valleys.

I'm like Don. Sitting at about 2250 ft. Hopefully, things will come into place.

You guys are both a bit higher than me, so you stand a little better shot! I'm working on a discussion on my webpage and should have it out momentarily.

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You da Man again Robert !!!

NWS has come around to your thinking.

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM THIS EVENING TO

9 AM EST TUESDAY...

.TONIGHT...SNOW THIS EVENING. RAIN WITH A CHANCE OF FREEZING

RAIN. SNOW ACCUMULATION UP TO 1 INCH. ICE ACCUMULATION AROUND A

TRACE. LOWS IN THE LOWER 30S. LIGHT AND VARIABLE WINDS. CHANCE OF

PRECIPITATION NEAR 100 PERCENT.

.TUESDAY...MOSTLY CLOUDY WITH A CHANCE OF RAIN AND FREEZING RAIN

IN THE MORNING...THEN PARTLY SUNNY WITH A CHANCE OF RAIN SHOWERS

IN THE AFTERNOON. NOT AS COOL WITH HIGHS IN THE UPPER 40S. LIGHT

AND VARIABLE WINDS. CHANCE OF PRECIPITATION 40 PERCENT.

.TUESDAY NIGHT...CLOUDY. RAIN SHOWERS LIKELY...MAINLY IN THE

EVENING. LOWS IN THE MID 30S. LIGHT AND VARIABLE WINDS. CHANCE OF

RAIN 70 PERCENT.

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FWIW... here is what GSP is thinking. I happen to like this forecast pretty well!

22kg8w.png

looks reasonable, maybe a little light. The max snow is only 1.5" which isn't much for such a juicy system coming in from GA and western SC right now. Also, I didn't draw it on my map but the border of Burke/McDowell/Rutherford and Cleveland has a stretch of mountains with over 2k feet, some nearly 3k peaks, so that area will probably have 2" or so, esp. since they're further east into the deeper moisture.

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looks reasonable, maybe a little light. The max snow is only 1.5" which isn't much for such a juicy system coming in from GA and western SC right now. Also, I didn't draw it on my map but the border of Burke/McDowell/Rutherford and Cleveland has a stretch of mountains with over 2k feet, some nearly 3k peaks, so that area will probably have 2" or so, esp. since they're further east into the deeper moisture.

Just looking at the radar right now, there is going to be a very sharp cutoff between folks who get no precipitation and than those who get more than a tenth. Its looking like areas west of Asheville will be left pretty dry, but just eastward (Black Mountain and points east) might really cash in with some decent precipitation.

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Just looking at the radar right now, there is going to be a very sharp cutoff between folks who get no precipitation and than those who get more than a tenth. Its looking like areas west of Asheville will be left pretty dry, but just eastward (Black Mountain and points east) might really cash in with some decent precipitation.

I'm thinking thes ame, a sharp cutoff somewhere around AVL or just west, with maybe quarter inch amounts just east of there. The temps aloft are so borderline now this may end up being almost totally rain everywhere, really depends on some evap cooling and dynamic cooling, which is always risky, There's not much dry air to help, so we'll see who gets what soon.

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Just looking at the radar right now, there is going to be a very sharp cutoff between folks who get no precipitation and than those who get more than a tenth. Its looking like areas west of Asheville will be left pretty dry, but just eastward (Black Mountain and points east) might really cash in with some decent precipitation.

Ya kinda worried it might be one of the rare times that as I drive into Asheville I get into snow. Ususlly if there is a cutoff it's the other way around. Maybe the back end will fill in just a tad & us to the north of town will see some flakes fly.

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I'm thinking thes ame, a sharp cutoff somewhere around AVL or just west, with maybe quarter inch amounts just east of there. The temps aloft are so borderline now this may end up being almost totally rain everywhere, really depends on some evap cooling and dynamic cooling, which is always risky, There's not much dry air to help, so we'll see who gets what soon.

Well I'm much more concerned about the precipitation than the temperatures... we are falling off rather quickly here in Asheville. We are at 38.9 degrees currently and our dewpoints are still in the 20's. This plus the snow-pack we still have (still a couple of inches in spots) will pretty much ensure we can get most of the column isothermal given moderate to heavy precipitation.

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Ya kinda worried it might be one of the rare times that as I drive into Asheville I get into snow. Ususlly if there is a cutoff it's the other way around. Maybe the back end will fill in just a tad & us to the north of town will see some flakes fly.

I'm kinda in agreement, although there might not be a huge difference between north Asheville or south Asheville. Its going to be a much stronger east/west gradient than north/south just due to the way the 700mb flow is setup which is nearly north/south. The precipitation in GA is starting to pivot right now due to this.

2q34yus.gif

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