SE Mid-Long Range Discussion

[NCSNOW]

I'd keep my eye on Thurs-early Sat time period aka 0zGFS. Outside long shot in NC at some miniscule/novelity freezing drizzle. However the I-95 cities should like this run. Seems the Tues storm leaves behind some energy that cranks up off the Carolina coast. The Tues storm exiting and HP building in to our north as the storm exits could have the chance to tighten the pressure gradient and deposit @ dam some surface cold air in our region.

Also right on cue for our January 10 hopefully pattern change, the GFS seems to be willing to cooperate for the moment;

[Met1985]

I'd keep my eye on Thurs-early Sat time period aka 0zGFS. Outside long shot in NC at some miniscule/novelity freezing drizzle. However the I-95 cities should like this run. Seems the Tues storm leaves behind some energy that cranks up off the Carolina coast. The Tues storm exiting and HP building in to our north as the storm exits could have the chance to tighten the pressure gradient and deposit @ dam some surface cold air in our region. Doesnt appear to me the next 9 days via 0z GFS we do any better than average to a notch below temp wise in NC.

Ya this run of the GFS is a lot better than what has been on there. Not taking much stock in the long range. Seems like through the boards people are getting more and more certain there will be a pattern change but when and to what extent.

[Met1985]

It was the weekend of Apr 7-8, 2007.

Yep that was the date it happened. Thanks for talking about it. I do remember it was an all out killing cold. Killed everything and with the snow that was an Easter to remember.

[Marion_NC_WX]

Wow...I like the look of this.

[Met1985]

Wow...I like the look of this.

Wow that is a sight for sore eyes!

[Marion_NC_WX]

Folks...if we are anywhere close to this in 2 weeks, then I think we'll be all getting in line for winter storms...

[pcbjr]

Folks...if we are anywhere close to this in 2 weeks, then I think we'll be all getting in line for winter storms...

Pop a ridge on the west coast and YEAH

[HKY_WX]

Folks...if we are anywhere close to this in 2 weeks, then I think we'll be all getting in line for winter storms...

GFS has been hinting at this for a couple days now. It seems to correlate very well with the change in polar winds the EURO has been advertising and which is now coming to fruition. A SSW doesn't seem to be too far off.

[Met1985]

Looking at this mornings GFS it still hold a chance of snow along the TN/NC boarder and in a large area of TN looks to get some type of frozen precip. This is the first time the GFS has been consistent from run to run over the last 2-3 days for these areas at least get some type of frozen precip.

[FoothillsNC]

For a few days now the ECMWF has shown a long zonality over the entire Pacific around days 5 through 10 now we're getting close to that period, and it still shows up. If thats the case, a major "snapping of the rubberband" period is about to come, and a big ridge will pop up soon. That's always tricky to forecast as to where the ridge goes, but right now, most indicate it will be a western ridge/eastern trough:

zonal Pac: day 4

So that by day 9 and 10, there is strong ridging in northern Scandinavia and another northwest Canada, leaving 2 polar vortex, one in western Alaska/eastern Siberia, the other in eastern Canada...thats a pretty good, cold look for the eastern half of the US. However its way too early to say yet where the strong amplification big ridge/deep trough will develop, and chances are it won't lock in yet. The good news is the GFS still shows long range pattern change to colder, and has several cold airmasses invading, and with all the s/w in the flow which it still has, our chances of getting hit by a winter storm are still going to be good imo, this Winter.

[NavarreDon]

For a few days now the ECMWF has shown a long zonality over the entire Pacific around days 5 through 10 now we're getting close to that period, and it still shows up. If thats the case, a major "snapping of the rubberband" period is about to come, and a big ridge will pop up soon. That's always tricky to forecast as to where the ridge goes, but right now, most indicate it will be a western ridge/eastern trough:

zonal Pac: day 4

So that by day 9 and 10, there is strong ridging in northern Scandinavia and another northwest Canada, leaving 2 polar vortex, one in western Alaska/eastern Siberia, the other in eastern Canada...thats a pretty good, cold look for the eastern half of the US. However its way too early to say yet where the strong amplification big ridge/deep trough will develop, and chances are it won't lock in yet. The good news is the GFS still shows long range pattern change to colder, and has several cold airmasses invading, and with all the s/w in the flow which it still has, our chances of getting hit by a winter storm are still going to be good imo, this Winter.

Robert, it sounds like there is a pretty good chance that things may take a turn to the much more interesting. Thanks for taking time to post your thoughts even on Christmas.

[Psalm 148:8]

Robert, it sounds like there is a pretty good chance that things may take a turn to the much more interesting. Thanks for taking time to post your thoughts even on Christmas.

+1 Merry Christmas! And thanks again, Robert for your tireless contributions.

[Met1985]

Thanks Robert it all sounds good to me! Also Merry Christmas everyone. It has already been a great morning with my wife and son! Hope everyone has save travels and fills up on food!

[burgertime]

Man 00z Euro at 240 looked pretty funny. Clearly something was wrong with it at 240.

[FoothillsNC]

Man 00z Euro at 240 looked pretty funny. Clearly something was wrong with it at 240.

looks like the SV map was bad data, the other sites looked different.

[Bevo]

For a few days now the ECMWF has shown a long zonality over the entire Pacific around days 5 through 10 now we're getting close to that period, and it still shows up. If thats the case, a major "snapping of the rubberband" period is about to come, and a big ridge will pop up soon. That's always tricky to forecast as to where the ridge goes, but right now, most indicate it will be a western ridge/eastern trough:

So that by day 9 and 10, there is strong ridging in northern Scandinavia and another northwest Canada, leaving 2 polar vortex, one in western Alaska/eastern Siberia, the other in eastern Canada...thats a pretty good, cold look for the eastern half of the US. However its way too early to say yet where the strong amplification big ridge/deep trough will develop, and chances are it won't lock in yet. The good news is the GFS still shows long range pattern change to colder, and has several cold airmasses invading, and with all the s/w in the flow which it still has, our chances of getting hit by a winter storm are still going to be good imo, this Winter.

"That, Mr. Anderson, is the sound of inevitability"

The pattern always changes. Only a matter of time. Hope the sharks didn't eat all of the jumpers...

[FoothillsNC]

12z globals both have strong amplification in the day 7+ period so its getting closer (still not a given since the Pac. if so charged). So there's no need for details but we probably will be watching a developing east coast major snowstorm soon. Right now the location could be just onshore, just inland or futher down the coast (to even an outside chance of cutoff in SE)...it all depends on the s/w in question around western Canada at the time the ridge goes up.

Before this occurs, the current week storm is progged to bomb out in eastern Maine (big northeast snows), which helps to eradicate the strong Southeast ridge...so we're kind of entering a new pattern, and its doubtful we'll have southwest cutoffs for a while. 12z Ecmwf develops a low in Virginia on the arctic front and turns it into a major east coast snowstorm by day 8 and 9, with additional strong s/w dropping due south through Tennessee Valley on day 10...take that with a grain of salt, but the gist is that very strong longitudinal flow is coming, which has been advertised a few days now , for this given time frame. With the tendency for cutoffs, it makes you wonder what could happen, but since its a new type of pattern, we may end up with just a deep east coast storm, and then it moves out. The one good news is blocking ridge shown on ECMWF over the North Pole, and strong ridging lately over eastern Greenland on GFS , so that might help force cold air back down right after the day 9/10 storm...too far out to speculate. Atleast there's no record warmth shown in the Southeast for a while now, and we can soon start to track a storm and colder air for the midAtlantic and Northeast, even if we aren't the recipients of any snow. However if everything backs up a little , which is possible since models are frequently too far east, that would change things a good bit. Just something to watch.

[pcbjr]

12z globals both have strong amplification in the day 7+ period so its getting closer (still not a given since the Pac. if so charged). So there's no need for details but we probably will be watching a developing east coast major snowstorm soon. Right now the location could be just onshore, just inland or futher down the coast (to even an outside chance of cutoff in SE)...it all depends on the s/w in question around western Canada at the time the ridge goes up.

Before this occurs, the current week storm is progged to bomb out in eastern Maine (big northeast snows), which helps to eradicate the strong Southeast ridge...so we're kind of entering a new pattern, and its doubtful we'll have southwest cutoffs for a while. 12z Ecmwf develops a low in Virginia on the arctic front and turns it into a major east coast snowstorm by day 8 and 9, with additional strong s/w dropping due south through Tennessee Valley on day 10...take that with a grain of salt, but the gist is that very strong longitudinal flow is coming, which has been advertised a few days now , for this given time frame. With the tendency for cutoffs, it makes you wonder what could happen, but since its a new type of pattern, we may end up with just a deep east coast storm, and then it moves out. The one good news is blocking ridge shown on ECMWF over the North Pole, and strong ridging lately over eastern Greenland on GFS , so that might help force cold air back down right after the day 9/10 storm...too far out to speculate. Atleast there's no record warmth shown in the Southeast for a while now, and we can soon start to track a storm and colder air for the midAtlantic and Northeast, even if we aren't the recipients of any snow. However if everything backs up a little , which is possible since models are frequently too far east, that would change things a good bit. Just something to watch.

Man, if we could only get blocking with that 850mb 216hr ....

[Carvers Gap]

Full latitude trough showing up very late in the period on both the 12z and 18z GFS - maybe even some earlier runs...I can't remember. Anyway, it's nice to see something different. Beginning to look like a pattern change is indeed in the works. My question is will there be a substantial storm to preceed it. Foothills alluded to the potential for an East coast storm. Wouldn't be surprised either to see a big one roar up the coast. I'm still somewhat shy of buying into a turn colder after getting burned time after time this winter, but this appears to be an artic outbreak that will begin in the norther plains. I will be interested to see if there is a mechanism to drive it southeast. I'm guessing it will make into this region, tempered but abrupt due to the warmth we have had. And as for the warm, it really hasn't felt warm here due to the dampness in the air. Many have wondered if that stratospheric warming event will make it to the troposphere. If it gets cold and storm for an extended period, I don't think we can deny that it had some impact on reasonable weather.

Also, these point size defaults are driving me crazy.

[downeastnc]

DAY 3 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0229 AM CST SUN DEC 25 2011

SRN/ERN CAROLINAS...

AS WITH ERN GULF COAST REGIME...EXPECT STG SHEAR BY MANY

MEASURES...MAIN CAVEATS BEING CONVECTIVE MODE AND INSTABILITY.

SUBSTANTIAL SLY SFC FLOW COMPONENT SHOULD BE SUSTAINED FOR SEVERAL

HOURS AHEAD OF COLD FRONT AND/OR ANY PRE-FRONTAL TROUGH/CONVERGENCE

LINE THAT MAY DEVELOP. THIS WILL ADVECT AT LEAST PARTIALLY MODIFIED

MARINE AIR INLAND FROM ATLC...MAIN UNCERTAINTIES BEING

1. HOW FAR INLAND FOR NEAR-SFC BASED PARCELS AND

2. HOW MUCH MODIFICATION...I.E. WHETHER BOUNDARY-LAYER THETAE WILL

BE HIGH ENOUGH TO OFFSET POOR MIDLEVEL LAPSE RATES AND YIELD

SUPPORTIVE MLCAPE.

You just never know what these kinda setups will do, I have seen some seriously thin squall lines putting down widespread 50-70mph gust with little actual thunder and lightning this time of the year from similar setups.

[Solak]

Is that ULL out there in TX/NM actually retrograding to the West, or is just stalled out and making it look that way?

[FoothillsNC]

Is that ULL out there in TX/NM actually retrograding to the West, or is just stalled out and making it look that way?

its about to get the boot eastward, due east. The models are in pretty good agreement now. Seems like its been out there forever. This should be a good wintertime cold rain event in the CAD areas, with a strong TMB boundary in the piedmont, so any severe would work on that line, mostly for the midlands up to central and eastern NC.

[POWERSTROKE]

looks like all models showing a change coming

[griteater]

While there is no indication that we will be torching anytime soon given that the SE ridge will undergo a beat down, I am very unimpressed with the prospects of us moving into a cold pattern in the near term. We have a very strong vortex in place over Alaska (again), with strong Pacific flow coming into the west coast / westem Canada. Sure, we may see a +PNA ridge go up in western Canada leading to a storm and a post-frontal shot of cold air in the east, but there is no evidence of any type of sustained period of high lattitude blocking leading to sustained cold air moving south out of the arctic.

There is a massive difference between:

warm>storm>cold>warm>storm>cold

and

warm>storm>cold>cold>storm>cold

[andyhb]

For Tuesday's aforementioned svr threat.

...SERN CONUS...

BAND OF CONVECTION SHOULD BE ONGOING ALONG OR JUST AHEAD OF SFC COLD

FRONT AT START OF PERIOD...CARRYING OVER MRGL TORNADO AND

WIND-DAMAGE POTENTIAL FROM LAST FEW HOURS OF DAY-1 PERIOD.

IT NOW APPEARS THAT FOREGOING AIR MASS WILL DESTABILIZE SUFFICIENTLY

TO SUPPORT EXTENSION OF AT LEAST MRGL SVR PROBABILITIES SEWD ACROSS

PORTIONS WRN/NRN FL AND SRN GA. PROBABILITIES SUPPORTING

CATEGORICAL SLGT RISK ARE INTRODUCED FARTHER N WHERE STRONGEST

COMBINATION OF SHEAR AND AT LEAST MRGL SFC-BASED INSTABILITY ARE

EXPECTED FROM MIDDAY INTO LATE AFTERNOON LOCAL TIME. AIR MASS

MODIFICATION OVER ERN GULF AND ATLC SHOULD SUPPLY WARM SECTOR WITH

LOW-60S SFC DEW POINTS ACROSS MUCH OF AREA CONTAINING SVR

PROBABILITIES...AS WELL AS POTENTIAL FOR MID-60S OVER WRN FL AND

COASTAL SC/SRN NC. MAIN LIMITING FACTOR WILL BE WEAKNESS OF

LOW-MIDDLE LEVEL LAPSE RATES...KEEPING MLCAPE BELOW 500 J/KG OVER

MOST AREAS.

MEANWHILE...STRONGEST DEEP-LAYER WIND FIELDS AND LOW-LEVEL VERTICAL

SHEAR WILL SHIFT NEWD ACROSS SRN PIEDMONT/COASTAL PLAIN REGION OF

GA/CAROLINAS. PREFRONTAL HODOGRAPHS ARE EXPECTED TO ENLARGE BENEATH

50-60 KT LLJ...COMBINING WITH STG SLY SFC FLOW COMPONENT OFF ATLC

WITH POTENTIAL FOR 0-1 KM SRH 300-500 J/KG. THIS SHOULD SUPPORT

SOME TORNADO POTENTIAL...ALTHOUGH MAIN STORM MODE IS LIKELY TO BE

QUASI-LINEAR.

PRIND WEAKENING OF DEEP-LAYER SHEAR AND LIFT WITH SWD EXTENT...AND

OF BOUNDARY-LAYER INSTABILITY WITH TIME...WILL REDUCE SVR THREAT

OVER ERN/SRN FL RELATIVE TO AREAS FARTHER N AND NW.

..EDWARDS.. 12/26/2011

[NavarreDon]

Here is portions of the GSP afd a little long but some good stuff

A STRONG UPPER LOW OVER WEST TEXAS THIS MORNING WILL EJECT QUICKLY

ACROSS THE LOWER MISSISSIPPI VALLEY TONIGHT AND LIFT ACROSS THE SRN

APPALACHIANS ON TUE AS AN OPEN WAVE. SFC CYCLOGENESIS WILL OCCUR

THIS AFTERNOON OVER THE NRN GULF...WITH THE LOW MOVING ACROSS THE

SRN APPS ON TUE. THE LATEST NAM AND GFS MODEL DATA IS A LITTLE

COLDER ACROSS THE NC MTNS TONIGHT. THE NAM HAS A LARGE AREA OF

1305-1310 METER 1000-850 MB THICKNESSES ACROSS THE SW AND CENTRAL

MTNS AT 0900 UTC...WHICH RETREAT UP ACROSS THE NRN MTNS BY 12 UTC.

NAM MODEL SOUNDINGS AT FRANKLIN AND CASHIERS IMPLY A PERIOD OF SLEET

AND FREEZING RAIN STARTING AFTER MIDNIGHT...WITH PCPN CHANGING TO

ALL RAIN TOWARD MORNING. THE GFS IS A LITTLE WARMER AND LOOKS TO BE

MAINLY LIQUID...WITH JUST A LITTLE SLEET AND A FEW PATCHES OF

FREEZING RAIN AT ONSET. IT STILL APPEARS THAT THE BULK OF THE

COOLING WITH THIS EVENT WILL BE DRIVEN BY OROGRAPHIC ASCENT AS A 60+

KT LLVL WARM SECTOR JET CROSSES THE MTNS. THIS SHOULD CONFINE

WINTRY PCPN TO SOUTH AND EAST REACHES OF THE MTNS...WITH DOWNSLOPE

HELPING TO WARM THE BNDRY LAYER CLOSER TO THE TN LINE. ALSO...NONE

OF THE MODELS IMPLY THAT WINTRY WX WILL HOLD ON ONCE THE HEAVIER

RAIN STARTS OWING TO A STRONG WARM NOSE UP AROUND H8. STILL...A

PERIOD OF LIGHT FREEZING RAIN AND SOME SLEET LOOKS LIKELY ACROSS

THE SW MTNS...AND ALSO ACROSS THE EASTERN ESCARPMENT OF THE BLUE

RIDGE UP IN THE NRN MTNS. AT THE MOST...THIS SHOULD BE A LOW END

ADVISORY LEVEL EVENT WITH ANY GLAZE CONFINED MAINLY TO ELEVATED

SFCS...AND IT WON/T AFFECT THE MTNS UNTIL WELL AFTER DARK TONIGHT.

THEREFORE...I/M GOING TO HOLD OFF ON ANY ADVISORIES WITH THIS

PACKAGE.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

AS OF 315 AM MONDAY...THE MODELS ARE IN VERY GOOD AGREEMENT ON THE

POSITION OF THE UPPER SHORTWAVE AND SFC LOW PRESSURE AT 12Z TUESDAY.

AN IN SITU WEDGE WILL STILL BE IN PLACE ACRS THE CWFA...WITH SELY

850 MB WINDS OF 50-65 KTS ALOFT. VERY STRONG LLVL WAA AND MECHANICAL

LIFT WITH DEEP MOISTURE WILL BE AIDED BY DECENT QG FORCING AND UPPER

DIVERGENCE. SO A NEAR 100% POP TUESDAY MORNING SEEMS APPROPRIATE.

THERE ARE SOME DIFFERENCES AMONGST THE THERMAL PROFILES/SFC TEMPS

INVOF THE NC MTNS...HOWEVER...AS DYNAMICAL COOLING MAY LOCK IN

SUB-FREEZING TEMPS INVOF THE EAST-FACING SLOPES OF THE NRN MTNS/BLUE

RIDGE ESCARPMENT PAST DAYBREAK TUESDAY MORNING...WITH SOME

ADDITIONAL ICING POSSIBLE. ALL GUIDANCE HAS TEMPS WARMING ABOVE

FREEZING BY 15Z TUE...SO IT STILL LOOKS LIKE ANY TRAVEL PROBLEMS DUE

TO ICE SHUD BE OVER BY MIDDAY.

MIDDAY TUESDAY...THE LOW PRESSURE SYSTEM WILL QUICKLY LIFT

NORTHEASTWARD...WITH A PRIMARY LOW TRACKING ACRS THE TN/OH

VLYS...AND A TRIPLE POINT LOW TRACKING FROM CENTRAL GA TO CENTRAL NC

BY LATE AFTN. THE NAM/GFS/ECWMF ARE IN GOOD AGREEMENT ON THE GSP/CAE

CWFA BORDER AS AN APPROXIMATE TRACK OF THE TRIPLE POINT. SO INSTBY

LOOKS TO STAY SOUTH OF THE FA. THAT IS GOOD...BECAUSE HELICITY

VALUES WILL BE THRU THE ROOF...AND VERY LITTLE INSTBY WOULD BE

SUFFICIENT FOR A SMALL TORNADO/WIND THREAT. THE COLD/OCCLUDED FRONT

WILL CROSS FROM SW TO NE DURING THE AFTN HOURS...QUICKLY TAPERING

OFF POPS (EXCEPT FOR UPSLOPE ALONG TN/NC BORDER). STORM TOTAL QPF

LOOKS TO BE A SOLID 1-1.5" CWFA-WIDE...WITH 2-3" ALONG THE BLUE

RIDGE ESCARPMENT FROM HENDERSON COUNTY WEST. THERE COULD BE A FEW

HYDRO CONCERNS IN THOSE AREAS...BUT NOT WIDESPREAD ENUF TO WARRANT

ANY FLOOD WATCHES ATTM. WITH CLOUDS AND PRECIP...TEMPS WILL BE HELD

DOWN TO MAINLY MID-UPR 40S...EXCEPT ALONG SOUTHEAST EDGE NEAR THE

TMB/WEDGE BNDRY WHERE THEY WILL BE IN THE MID 50S OR HIGHER.

TUESDAY NIGHT...THERE WILL BE STRONG LLVL CAA ACRS THE FA IN THE

WAKE OF THE DEPARTING LOW...WITH GOOD NW FLOW UPSLOPE FORCING ALONG

THE TN/NC BORDER. BOTH THE NAM AND GFS IMPLY AT LEAST SCATTERED

SHOWER ACTIVITY...AND SNOW LEVELS SHUD FALL QUICKLY DURING THE

EVENING HOURS. SOME LOCATIONS MAY GET A QUICK INCH OR TWO

(ESPECIALLY ABOVE 3500 FT). THE SHOWER ACTIVITY LOOKS TO QUICKLY

TAPER OFF BY LATE WEDNESDAY MORNING. TEMPS ACRS THE ENTIRE AREA WILL

BE NEAR NORMAL.

[FoothillsNC]

00z ECMWF was a step in the colder, stormy direction, and a pattern change. But its still too early to know for sure, even with several runs hinting at it, and the 6z GFS was nothing like it, although earlier runs were. I still lean toward a strong amplifying period coming up but its too early to say where the ridge goes, and consequently deep downstream trough. The ECMWF likes a big eastern trough, but lacks a good surface low (unlike yesterday), but does have plenty of moisture and cold in the Tenn Valley and rotating trough the southeast, with a few flakes around day 9 and 10 in the Tenn valley, Apps, parts of coastal GA and Carolinas, but only disorganized pockets of flakes. The big deal with that is the very cold air (-9 to -12) and the occasional snow esp. the Apps. and the Lake snows possibly.

The key on how this pattern change evolves is the handling of the big western Ridging and if a closed ridge develops over the North Pole. Its possible too far out to expect or hope for just yet, esp. considering the models have blown things at this time range a lot this Fall, esp. the ECMWF. A big if, but *if* the ridging develops like Euro then it would be a nice Wintry pattern with the Canadian vortex sending front after front of cold air into the east, and Siberia the other cold spot. In fact a large arctic outbreak would be likely right after day 10 if the ECMWF is right, but thats a mighty big *if* right now and just out in fantasy land. Something is about to change it appears esp. since the zonal flow in the Pacific can't last too long and the models have both been hinting at this time period for a quick, sudden amplifying, but we'll have to wait it out to see if its a true pattern change, a quick hitting change (in and out) or more of the same old same old.

[franklin NCwx]

Thanks Robert, I was just going over the 0z runs. The cmc has a similar look to the euro at 180. It digs the trough even farther south than the euro. Would be. Nice interior south snowstorm. And the ensembles have a strong signal for a big eastern trough. Still very far out there like you said. But the pattern sure looks more exciting.

[Cheeznado]

The Op Euro was a pretty big cold outlier compared to its ensemble members- The Euro ens mean looks a lot like the GFS ens mean, i.e. a frontal passage this weekend, but probably dry (or some light rain) and not super cold. No snow except in the mountains. I prefer the current pattern to the one coming up- looks cold but not super cold, but a lot drier. If it is going to be cold it better be really frigid with snow chances. Otherwise warm and wet is what I prefer.

[franklin NCwx]

12z gfs is flat. For next week.