SE Mid-Long Range Discussion

[NavarreDon]

Here is the GSP short term. It matches up pretty well with Roberts post above:

THIS LEADS TO THE NEXT FORECAST CONCERN WHICH IS THE SRN STREAM LOW

THAT EJECTS ACROSS THE TN RIVER VALLEY DURING THE DAY ON TUE. THE 00

UTC RUNS OF THE GFS AND ECMWF SELDOM AGREE MUCH BETTER THAN THEY DO

TONIGHT WITH THE STRENGTH AND TIMING OF THE EJECTING SOUTHERN STREAM

WAVE. THE SFC HIGH WILL QUICKLY SLIDE OFF THE MID-ATLANTIC COAST

MONDAY NIGHT...WHICH WILL PROVIDE LITTLE SUPPORT FOR THE MAINTENANCE

OF COLD AIR DAMMING. WE ARE IN A MILD PATTERN ANYWAY...AND SFC WET

BULBS AND THICKNESSES SUPPORT RAIN OVER THE FOOTHILLS AND PIEDMONT.

THERE WILL BE A PERIOD OF FAIRLY STRONG SSE ORIENTED UPSLOPE FLOW

INTO THE MTNS MON NIGHT AND EARLY TUE. THE RESULTING DYNAMIC COOLING

MAY BE ENOUGH TO SUPPORT A BRIEF WINTRY MIX AND THEN A PERIOD OF

FREEZING RAIN IN A NARROW BAND ACROSS THE NC BLUE RIDGE FROM ABOUT

THE BLACK MOUNTAIN AREA UP TO GRANDFATHER MOUNTAIN. BOTH THE GFS AND

ECMWF DEVELOP 1310 TO 1315 METER 1000-850 MB THICKNESSES IN THIS

AREA. HOWEVER...THE 850-700 MB THICKNESS ARE VERY WARM AND THE SFC

WET BULBS ON BOTH MODELS RISE ABOVE FREEZING WITH THE ONSET OF THE

HEAVIER PCPN. IT/S STILL TOO EARLY TO SAY FOR CERTAIN THAT THERE

WON/T BE ANY ICING PROBLEMS...BUT THE MODELS WILL HAVE TO TREND

COOLER FOR THAT TO HAPPEN.

P-TYPE ISSUES ASIDE...THERE WILL BE A PERIOD OF HEAVY RAIN WITH 1 TO

1.5 INCHES OF QPF POSSIBLE. HOWEVER...BOTH THE ECMWF AND GFS DEVELOP

THE HEAVIEST PCPN A LITTLE WAYS EAST OF THE MTNS AS THE NARROWING

AXIS OF CLOD AIR DAMMING WILL DISPLACE THE BEST LIFT A LITTLE EAST

OF WHERE WE TYPICALLY GET IT WITH UPSLOPE. HOPEFULLY THIS WILL PAN

OUT AS THE SE APPALACHIANS DON/T NEED ANY MORE RAIN AT THIS POINT.

[DaculaWeather]

And contrary to what FFC says:

THIS WILL SPREAD MOISTURE

INTO THE CWA ON CHRISTMAS DAY. PROBLEM IS EACH MODEL HAS A DIFFERENT

LOCATION AND STRENGTH. THE GFS SPREADS THE MOISTURE ACROSS CENTRAL

GA...THE NAM ACROSS NORTH GA...AND ECMWF SOMEWHERE IN BETWEEN.

WHATEVER DOES HAPPEN...IT WILL BE LIGHT IN NATURE WITH AMOUNTS

GENERALLY LESS THAN A HALF INCH.

[NavarreDon]

Here is the GSP short term. It matches up pretty well with Roberts post above:

THIS LEADS TO THE NEXT FORECAST CONCERN WHICH IS THE SRN STREAM LOW

THAT EJECTS ACROSS THE TN RIVER VALLEY DURING THE DAY ON TUE. THE 00

UTC RUNS OF THE GFS AND ECMWF SELDOM AGREE MUCH BETTER THAN THEY DO

TONIGHT WITH THE STRENGTH AND TIMING OF THE EJECTING SOUTHERN STREAM

WAVE. THE SFC HIGH WILL QUICKLY SLIDE OFF THE MID-ATLANTIC COAST

MONDAY NIGHT...WHICH WILL PROVIDE LITTLE SUPPORT FOR THE MAINTENANCE

OF COLD AIR DAMMING. WE ARE IN A MILD PATTERN ANYWAY...AND SFC WET

BULBS AND THICKNESSES SUPPORT RAIN OVER THE FOOTHILLS AND PIEDMONT.

THERE WILL BE A PERIOD OF FAIRLY STRONG SSE ORIENTED UPSLOPE FLOW

INTO THE MTNS MON NIGHT AND EARLY TUE. THE RESULTING DYNAMIC COOLING

MAY BE ENOUGH TO SUPPORT A BRIEF WINTRY MIX AND THEN A PERIOD OF

FREEZING RAIN IN A NARROW BAND ACROSS THE NC BLUE RIDGE FROM ABOUT

THE BLACK MOUNTAIN AREA UP TO GRANDFATHER MOUNTAIN. BOTH THE GFS AND

ECMWF DEVELOP 1310 TO 1315 METER 1000-850 MB THICKNESSES IN THIS

AREA. HOWEVER...THE 850-700 MB THICKNESS ARE VERY WARM AND THE SFC

WET BULBS ON BOTH MODELS RISE ABOVE FREEZING WITH THE ONSET OF THE

HEAVIER PCPN. IT/S STILL TOO EARLY TO SAY FOR CERTAIN THAT THERE

WON/T BE ANY ICING PROBLEMS...BUT THE MODELS WILL HAVE TO TREND

COOLER FOR THAT TO HAPPEN.

P-TYPE ISSUES ASIDE...THERE WILL BE A PERIOD OF HEAVY RAIN WITH 1 TO

1.5 INCHES OF QPF POSSIBLE. HOWEVER...BOTH THE ECMWF AND GFS DEVELOP

THE HEAVIEST PCPN A LITTLE WAYS EAST OF THE MTNS AS THE NARROWING

AXIS OF CLOD AIR DAMMING WILL DISPLACE THE BEST LIFT A LITTLE EAST

OF WHERE WE TYPICALLY GET IT WITH UPSLOPE. HOPEFULLY THIS WILL PAN

OUT AS THE SE APPALACHIANS DON/T NEED ANY MORE RAIN AT THIS POINT.

And contrary to what FFC says:

THIS WILL SPREAD MOISTURE

INTO THE CWA ON CHRISTMAS DAY. PROBLEM IS EACH MODEL HAS A DIFFERENT

LOCATION AND STRENGTH. THE GFS SPREADS THE MOISTURE ACROSS CENTRAL

GA...THE NAM ACROSS NORTH GA...AND ECMWF SOMEWHERE IN BETWEEN.

WHATEVER DOES HAPPEN...IT WILL BE LIGHT IN NATURE WITH AMOUNTS

GENERALLY LESS THAN A HALF INCH.

Yikes not a lot of collaboration between offices!

[Carvers Gap]

The long range GFS is beginning to look interesting, somewhat blocky and a repeating eastern trough. I think it will take some time to get that pattern in place - if indeed it actually happens. But, it is a start. Teleconnections still look terrible. Thankful for the +PNA. Torch we would w/out it. If, if, if, this pattern is going to switch, certainly looks like mid-January might be the time if one takes the models and adds a week or two to the dates.

[metwannabe]

There's more in the extended range, of course, and maybe a slight hint of eastern troughing, but thats still a guess. Have no idea where the next major cutoff will occur, this run did it for New England and if i recall one in Texas again at some point. Right now we need to build a major western ridge to get some serious cold to shoot down our way, but unfortunately that doesn't really show up, and I don't trust any of the models that show the setup beyond 7 days because the models have all built false western ridges a few times in Nov and Dec, only to get beaten down quickly... we need to get it within 7 days to have a real shot of that.

Euro has shown this now last two runs but it is day 9/10 time frame (Ak votex splitting, building western ridge and digs out a deep EC trough)....hopefully first of week it will still be there within the 6-7 day time frame. I don't post much but read plenty and thoroughly enjoy your detailed explanations!! Thank you!

[FoothillsNC]

And contrary to what FFC says:

THIS WILL SPREAD MOISTURE

INTO THE CWA ON CHRISTMAS DAY. PROBLEM IS EACH MODEL HAS A DIFFERENT

LOCATION AND STRENGTH. THE GFS SPREADS THE MOISTURE ACROSS CENTRAL

GA...THE NAM ACROSS NORTH GA...AND ECMWF SOMEWHERE IN BETWEEN.

WHATEVER DOES HAPPEN...IT WILL BE LIGHT IN NATURE WITH AMOUNTS

GENERALLY LESS THAN A HALF INCH.

GFS and the other models setup looks good for a widespread rain event. I guess if the models are wrong and it heads much futher west than shown, n. Ga and the western Carolinas could miss out on the axis, but being so close to the event, it would be a pretty big bust. The strong southeast flow overtop a damming boundary is usually a good stratiform rain-maker from ATL to CLT and the whole central-western Carolinas, and the model has a good 1 to 1.50" event .

After this storm, the GFS and ECMWF have a subtle pattern change look to me, but I don't want to get anybody too excited, since we're in such a bad pattern, and one that might continue basically for a while. But I've been studying the Pacific and how the models handle the S/w coming through the train or parade of systems underneath the Alaskan vortex. That feature could possibly retrograde some 500 to 1000 miles toward Bering Straight or eastern Siberia, which would pump a major western Ridge after a week to 10 days. I think ECMWF did it sooner, but anyway the downstream result is allowing shortwaves to carve out an eastern or maybe central US trough. The 6z GFS showed several deep diving shortwaves (and there is a LOT of them that could do it-- so no model will key on the proper one I don't think)....but the best hope we have now is just that, on the 6z (and a few other runs) where systems might down far enough south, and we're certainly not torching after the storm this Tuesday. A step down type of colder airmasses will be coming, still nowhere cold enough in most of the south for a while, but a lot of marginal close calls in Tenn/NC and esp. the mountains are coming up, and if one dives far enough west (but not the southwest) then we'll eventually have just enough cold air to offer up something. A few recent runs of the GFS had a decent look but its so far out its hard to say if its the usual GFS fantasy range or a result of actual subtle pattern changing and by then we're into January, so its not much of a stretch.

[DaculaWeather]

I have pics of that event...if I recall it was Easter weekend of 2008, maybe 2007. After a mild Winter, in April saw the coldest air of the season come down for my area...killed everything dead, leaves on trees, all flowers, some shrubs, etc. It took over 6 weeks to produce leaves again. I'd never seen a time where all the vegetation around a whole region looked like that. Never want to see it again.

I would have no clue if it were me!

Go here: http://www.daculaweather.com/surface_maps_2005.php and click on March 28th... that was Easter, not sure if it might be the event you were talking about. There was nothing for Easter in 07 and 08 though.

[NC_hailstorm]

The strat forecasts on the ECMWF look weaker today.It's probably going to take more than one wave to break the vortex so we'll see.

[FoothillsNC]

I would have no clue if it were me!

Go here: http://www.daculawea...e_maps_2005.php and click on March 28th... that was Easter, not sure if it might be the event you were talking about. There was nothing for Easter in 07 and 08 though.

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

[CandymanColumbusGA]

And contrary to what FFC says:

THIS WILL SPREAD MOISTURE

INTO THE CWA ON CHRISTMAS DAY. PROBLEM IS EACH MODEL HAS A DIFFERENT

LOCATION AND STRENGTH. THE GFS SPREADS THE MOISTURE ACROSS CENTRAL

GA...THE NAM ACROSS NORTH GA...AND ECMWF SOMEWHERE IN BETWEEN.

WHATEVER DOES HAPPEN...IT WILL BE LIGHT IN NATURE WITH AMOUNTS

GENERALLY LESS THAN A HALF INCH.

Just an FYI, this is for Christmas Day. Robert was talking about Monday night/Tuesday...

The Christmas rain has been a tricky forecast from the get go for Alabama and Georgia. The GFS was bone dry for a few days while the Euro kept bringing rain. The GFS eventually came around to the Euro but the Euro then backed off the timing as the cut-off low hangs back in Texas. The models bring us rain due to isentropic lift and it looks like it'll be fairly light. Either way, it's looking really cloudy and dreary for most of MS, AL and GA.

Beyond that, we get in a mostly zonal flow. There is hope with the NAO forecast to get near neutral and PNA to slightly dip negative for something in the first week of January or thereabouts. I'm not fully buying the trough the GFS is showing at the end of it's 00Z run but a return to the active shortwaves in the Southwest, as the 6Z shows, looks more plausible just going by what we've seen this season.

[FoothillsNC]

GFS brings down some cold air into the east later on and still has that very active look, so any amplification can occur about anywhere, but lately its' more central and eastern sections, not southwest, so thats a little good news. The 120 to 144 hour system has my attention last couple of runs, for possible high mtn snow in Tn/NC. Right now it doesn't tap the gulf well enough to get moisture, but the temps might support it if it digs a little more. Something to watch next week. And it uses that cutoff over the Northeast and pulls down pretty cold air in the east, and then that pattern repeats, with a couple of very good shots of cold air in the Eastern half of the country. Still has the retrograding look in Alaska too, so be on the lookout for systems dropping to the southern Plains if that happens, and damming events in the east with cold on both sides of any southern stream system...its only a slight possibility right now, but better than nothing. And it still has a huge deep cutoff in the Southeast very late in the run, something its been showing a few days now. There could be a really warm day between systems but overall it looks to be turning colder that what we've been through. Hopefully we get some more agreement with Euro , it has been looking cooler for us as well. The key is to keep systems out of the southwest. Overall, still not very boring , and quite the opposite...active as could possibly be. Hard to believe a Nina could keep on generating this much rain.

[EmersonGA]

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

I lost all of my tomatoes that year. We got down to 22 if I remember correctly and I think we had some snow flurries. It was wierd to see nothing but brown trees everywhere.

[dsaur]

Once again, another major cutoff will open up around Arkansas/West Tennesse and cut toward the Central Appalachians. The system tilts nicely to a very negative/diffluent advection right over the Deep South, and this one will have a good boundary just laid down, so that translates to excellent rain potential in Ga and SC, where it's been missing somewhat. Looks like in-situ cold air damming for north GA and esp. the western Carolinas on late Monday night and through early Tuesday, but no snow or ice here...just cold rains (and hard classic heavy rains it appears for 6 to 8 hours). The setup isn't right for ice in the dam regions, but GFS shows surface and 950 temps in the mid 30's duration of the event fairly common extreme ne GA and western Carolinas into western VA.

I've been out working in the woods, and around the property, and the ground is as wet as if it had rained overnight. This is a most welcomed change. Once the central and southern parts start getting the heaviest rains again it is just a matter of time 'til a big hit. And with Jan. coming it is great timing for these rains. It still worries me that the big rain here didn't translate up to S.C. Maybe this next one will. Meanwhile I'm still looking at some light rain tomorrow hopefully, or at least just south of me. Lol, dang, that's different...just south of me T

[andyhb]

Not quite 5 days out, but I'm beginning to think svr wx could be an issue on Tuesday across portions of the Carolinas. With that vigorous shortwave moving across the area, wind profiles look very strong, with a powerful southerly/south-southwesterly LLJ and significant backing of the sfc winds off of the Atlantic into the sfc cyclogenesis. GFS/NAM suggest an influx of 60's dews into the central/eastern portions of the Carolinas by Tuesday afternoon. Whether enough instability and theta-e inflow off of the Atlantic can manifest itself will be the main question (due to weak lapse rates), as per usual with these cold season svr potentials, but the kinematic environment at least looks favourable. NAM is also about 12 hours faster than the GFS with the passing of the shortwave.

[Isopycnic]

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

This event...

All the leaves died off then the drought killed the second set. a lot of trees died that year...

Drought in September...

[Isopycnic]

[FoothillsNC]

This event...

All the leaves died off then the drought killed the second set. a lot of trees died that year...

Drought in September...

yep, 2007 was awful in so many ways...in my notes I have written ugliest Spring ever then lots of trees literally died that Summer around here. The drought ranked number 1 I think...something like 22" of rain here that year. Unreal. I've got a few pics I may post if I can find (even though we might need a separate thread lol).

[WeatherNC]

12z Euro 216 & 240

0z EC @ 240 for comparison, GFS also hinting at, ens members too

[FoothillsNC]

Perpetual SE ridge would argue it is going north Some signs though, of it finally eroding, after day 7, maybe getting displaced into the Baja, desert SW... They deserve it as far as I am concerned, we had to deal with it for Dec, let them bask in the likes for Jan., while we wreak the troughiness Equatorial warming is more pronounced this winter compared to recent years, no real data to support it but I am sure it exists, just a general observation. Unsure what it means, maybe a narrow window during the heart of winter, Jan, early Feb, before it reasserts itself into Spring.

What I've noticed is that the troughs are futher west. The last one a couple days ago jogged west a little, this new one is already inching west a little (was supposed to ride just east of apps-- now west), so in a few days I won't be surprised to see ECMWF come west with its east coast deep trough. Also fits with what both models show as far as the Alaskan vortex backing up in a few days. Obviously both models miss the placement of deep troughs and the tendency for cutoffs is definitely there. It could swing any way though, but I'm leaning toward that being a major south central or southeast storm in about 8 to 10 days. I won't even guess at any details though, other than say it could be a deep , colder system, compared to recent ones.

[FallsLake]

Looking at the 12z GFS (Dec 24) it does provide a nice shot of cold air at day 9; but it warms back up afterwards. So I don't think this is the pattern change we're all waiting for. Many have been stating mid January and that may be the correct time span to look at.

12z GFS (Dec24) for day 9.

[WeatherNC]

12z GFS ens @ 78hrs

[downeastnc]

From RAH IRT severe threat Tues

REGARDLESS...DEEP LAYER AND LOW LEVEL SHEAR IS

FORECAST TO BE VERY STRONG AS A 50KT+ LOW LEVEL JET DEVELOPS ON

THE EASTERN PERIPHERY OF THE MID LEVEL LOW AND SURGES NORTH ACROSS

NC. THE TYPICAL CONCERN OF HOW MUCH DIURNAL DESTABILIZATION AND

INLAND PENETRATION OF THETA_E RICH ATLANTIC AIRMASS CAN SUPPORT A

SEVERE WEATHER THREAT. WHILE THE CLIMATOLOGY OF LATE DECEMBER

ARGUE STRONGLY AGAINST SEVERE WEATHER...THE RECENT WARM LA NINA

PATTERN IS ATYPICAL IN ITS OWN RESPECT.

Well if it aint gonna snow at least a decent severe threat could be in the making.......

[Snowless in Carrollton]

From RAH IRT severe threat Tues

REGARDLESS...DEEP LAYER AND LOW LEVEL SHEAR IS

FORECAST TO BE VERY STRONG AS A 50KT+ LOW LEVEL JET DEVELOPS ON

THE EASTERN PERIPHERY OF THE MID LEVEL LOW AND SURGES NORTH ACROSS

NC. THE TYPICAL CONCERN OF HOW MUCH DIURNAL DESTABILIZATION AND

INLAND PENETRATION OF THETA_E RICH ATLANTIC AIRMASS CAN SUPPORT A

SEVERE WEATHER THREAT. WHILE THE CLIMATOLOGY OF LATE DECEMBER

ARGUE STRONGLY AGAINST SEVERE WEATHER...THE RECENT WARM LA NINA

PATTERN IS ATYPICAL IN ITS OWN RESPECT.

Well if it aint gonna snow at least a decent severe threat could be in the making.......

How is the recent warm La Nina pattern atypical ? I thought La Nina's were known for bringing warmth ?

[ATL_Militarypolice]

How is the recent warm La Nina pattern atypical ? I thought La Nina's were known for bringing warmth ?

Foothills and others have mentioned why in their past posts...Yes typical La Nina's bring warmer than normal temps to our area. Typical La Nina's also bring dryer than normal conditions to the South; however, that isn't happening right now.

[WilkesboroDude]

[jaxjagman]

Don't think you are suppose to post Euro on this board from Accuweather,kinda like a copyright thing.

[WilkesboroDude]

Don't think you are suppose to post Euro on this board from Accuweather,kinda like a copyright thing.

Your probably right. I only post Euro images from Accuweather if they are released to the general public on Facebook. Not sure if it is allowed here...mods plz remove if needed.

[jaxjagman]

Your probably right. I only post Euro images from Accuweather if they are released to the general public on Facebook. Not sure if it is allowed here...mods plz remove if needed.

If it's on facebook it's probably not legit as well.It's a rarity they even post the Euro on blogs.

[jaxjagman]

[Met1985]

looking at the latest GFS models it still has some snow for TN/NC boarder and out to 90 hours looks like TN could get in on something.