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Southeast Mid/Long Range Discussion I


WilkesboroDude

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Keep in mind that at long range the GFS has poor resolution, so this could mean heavy snow for WV and nowhere else.

That, and TD snow maps are too high usually... IWXM has the best snow map resolution usually (except when they fail to generate... which has been happening a bit more recently)

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Looks like after the 25th we could see a big surge of cold air making its way down into the South and East. It is in the long range but the GFS has been showing this dip in the jet stream on and off for about a week and the Euro has picked it up now. Until then enjoy the nice weather.

0z GFS living up to that idea of colder air after the 25th...

40+ inches of snow build up for Ontario...and probably cold chasing moisture for the South and up and down the spine of the mountains eventually...closer to the 28th.

Hour 192 next weeked...

GFS_3_2012102000_F192_SNOWIN_SURFACE.png

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0z GFS living up to that idea of colder air after the 25th...

40+ inches of snow build up for Ontario...and probably cold chasing moisture for the South and up and down the spine of the mountains eventually...closer to the 28th.

Hour 192 next weeked...

Ya well it being over 150 hours out the solution will change every run from now till about 5 days to go around the 28th. The Euro has already changed course and went of more of a zonal pattern but that is expected until we get closer to the end of next week.
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GFS and the Euro are back to a very cold solution. The GFS is very cold looking with again a chance of upslope snow for the mountains. Seeing the freezing line dip way down south. The Euro tries to bring in cold air and then a cutoff low forms which again I think would bring some upslope snow to the mountains and also brings in cold air pretty far south. Again these are only one solution but the GFS has been hinting and continues on hitting the cold solution. The NAO and the AO would agree with this big surge of cold air as they both take a dip farther into the negative range. With each run a little more excitement about what could be coming down the road.

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The Arctic front that's on tap for the end of the month has trended a little colder today with the last two model runs of the GFS bringing widespread 20's to the eastern US. That said...the GFS is usually a little too cold...but the first widespread freeze is now looking likely for the eastern US.

Synoptically there is alot going on around this timeframe and guidance models will continue to struggle trying to work this situation out. There is the little matter of a tropical system that could possibly mingle with the Arctic front near the east coast. This would be an extreme and unlikely outcome but it remains a possibility. Then there is the possibility of a secondary low pressure system forming on the tail end of the Arctic front. If that were to happen farther east then snow becomes possible in the eastern US.

Alot of things to work out over the next week but one thing looks to be for sure and that is some very cold air for this time of year!

11j5j6f.jpg

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I decided that this thread is more appropriate for my record cold GFS post:

Well, what do I know? Not only was the 18Z GFS not warmer than the 12Z GFS at 850, it was actually colder! It gets as low as an incredible -7 C at KATL (on 10/29)! Going all the way back to 1948, the coldest I've been able to find in Oct. at KATL at 850 is the -7 C of 10/31/1993, a day that included flurries (almost unheard of in Oct.) and the coldest Oct. high on record (41 F). MeteoStar has lows of 28, 28, and 29 on 10/28-30. This would be a record tieing low followed by a new record low followed by another record tieing low! Actually, 28 would tied for the coldest in all of Oct. on record. So, this is the second GFS run in a row giving KATL a tie for the coldest alltime Oct. low on record! I fully expect a warmer run at 0Z..does that sound familiar? ;) Actually, the coldest 850's could warm ~4 C to ~-3 C and still possibly be cold enough for a tie of the alltime Oct low of 28 F based on looking at old 850 maps.

Keep in mind that a record low in Oct. at KATL is, if anything, a positive indicator as far as cold and snowy winter prospects are concerned. If one were to average out the DJF's for those winters that had a record low in the preceding Oct., one would see that they average pretty chilly and include some of the coldest and snowiest winters in KATL history. If we do get a record low this Oct, Tony's moles will certainly get credit.

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The Arctic front that's on tap for the end of the month has trended a little colder today with the last two model runs of the GFS bringing widespread 20's to the eastern US. That said...the GFS is usually a little too cold...but the first widespread freeze is now looking likely for the eastern US.

Synoptically there is alot going on around this timeframe and guidance models will continue to struggle trying to work this situation out. There is the little matter of a tropical system that could possibly mingle with the Arctic front near the east coast. This would be an extreme and unlikely outcome but it remains a possibility. Then there is the possibility of a secondary low pressure system forming on the tail end of the Arctic front. If that were to happen farther east then snow becomes possible in the over the eastern US.

Alot of things to work out over the next week but one thing looks to be for sure and that is some very cold air for this time of year!

11j5j6f.jpg

Lol just beat you to it over here. It loosk very interesting and with the snow pack building up north and down into Canada these cold fronts coming down from up north are really going to hold the cold air. This is a very good sign if we keep the snow pack into late fall and into winter.
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Thanks to a tropical or hybrid storm off of the east coast on the 0Z Sun GFS run, the cold air doesn't come in strongly on this run. It barely makes it to ~0C for the coldest at 850 at KATL. For those who want it really cold, hopefully this storm won't be so wound up and close to the east coast on subsequent runs and on the 0Z euro. Hopefully, that solution is totally bogus.

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Wow at the 6z GFS. Model madness right now and quite entertaining.

Yeah... Big 3 seem onboard for a sig pattern change end of month, timing between the arctic front and tropical system needs to be watched, no way to know at this range whether they will hook up in time for an east coast storm. Most of the 6z gfs mems show it being too late, but there are a couple with "somewhat" interesting solutions for our friends just to the north. One member, see below, kind of went off the deep end and is attempting to recover from one too many drinks last night! :weenie:

06zensp006p06228.gif

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Yeah... Big 3 seem onboard for a sig pattern change end of month, timing between the arctic front and tropical system needs to be watched, no way to know at this range whether they will hook up in time for an east coast storm. Most of the 6z gfs mems show it being too late, but there are a couple with "somewhat" interesting solutions for our friends just to the north. One member, see below, kind of went off the deep end and is attempting to recover from one too many drinks last night! :weenie:

p006 had WAY too much cider last night,

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Yeah... Big 3 seem onboard for a sig pattern change end of month, timing between the arctic front and tropical system needs to be watched, no way to know at this range whether they will hook up in time for an east coast storm. Most of the 6z gfs mems show it being too late, but there are a couple with "somewhat" interesting solutions for our friends just to the north. One member, see below, kind of went off the deep end and is attempting to recover from one too many drinks last night! :weenie:

Ya seems like the solutions currently are to the extreme. That would entail significant snow in the Apps but still 10 days away anything can happen especially the interaction with the tropical system and the front. Nice to have something to track though.

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Yeah... Big 3 seem onboard for a sig pattern change end of month, timing between the arctic front and tropical system needs to be watched, no way to know at this range whether they will hook up in time for an east coast storm. Most of the 6z gfs mems show it being too late, but there are a couple with "somewhat" interesting solutions for our friends just to the north. One member, see below, kind of went off the deep end and is attempting to recover from one too many drinks last night! :weenie:

06zensp006p06228.gif

Knoxvilles heaviest snow was a storm similar to that in November of 1951 I believe.

Something's on the horizon but I think it'll be snow for the apps and the interior northeast. Clingmans Dome is the furthest south snow will likely fall if it happens. How do I know? It's climatological ly favored for November and it has happened in late October before.

EDIT:

The 12z GFS operational isn't giving much of a storm or cold air at all. I haven't seen what the Euro is doing. My guess is the Euro has been phasing the storm and the op GFS has not.

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Rumor has it the GGEM was at the party also, same result this morning, one hell of a hangover and a 970-960 occluding into the central mid-atlantic... How come we weren't invited?

Yes, it is mostly bypassing the SE to the north. Although it is a very interesting scenario, all this is doing is screwing up our potential record cold shot of 10/29-31. I assume it is related partially to the heat it is bringing up from the tropics. It would give us some cold on the backside, but it isn't nearly as intense on the GFS and it delays the chill regardless. The coldest 850 at KATL on the entire 16 day run is only down to +1C vs. the -7 C of yesterday's 18Z GFS. I hope this changes back to a weaker TC that drifts NE out to sea instead of screwing with our potential record cold. However, I don't like the trends since the 0Z models. Although I don't want the screwup, it is fascinating from a meteorological standpoint to see how this one storm is having that much of a warming influence on the eastern US in the nearterm.

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Has there ever been a measurable snow outside the mtns,in the Southeast,in Oct?

Just FYI, the 12Z GFS is not giving any measurable snow outside of the mountains in the SE (it is far too warm). Even the far northern mountains of NC and TN are just under 1". Also, the NE US outside of the mountains doesn't show any accumulation. Moreover, the liquid precip. is mostly light in much of NC and E TN.

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The GFS looks suspect.

Yes, it is suspect and needs to be arrested for lack of support for cold. ;)

Regarding the potential record cold for late Oct. that was shown on yesterday's 12Z and 18Z GFS (28's for KATL, which would have tied the alltime Oct. record low), it is all history as of the last several GFS runs with the coldest being 34, 31, and 36, respectively, on the 0Z/6Z/12Z runs of today. Still nice and cold on those days, but nothing near record cold. Maybe it will change back. It is still a good ways out and the GFS solution is so extreme.

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Yes, it is mostly bypassing the SE to the north. Although it is a very interesting scenario, all this is doing is screwing up our potential record cold shot of 10/29-31. I assume it is related partially to the heat it is bringing up from the tropics. It would give us some cold on the backside, but it isn't nearly as intense on the GFS and it delays the chill regardless. The coldest 850 at KATL on the entire 16 day run is only down to +1C vs. the -7 C of yesterday's 18Z GFS. I hope this changes back to a weaker TC that drifts NE out to sea instead of screwing with our potential record cold. However, I don't like the trends since the 0Z models. Although I don't want the screwup, it is fascinating from a meteorological standpoint to see how this one storm is having that much of a warming influence on the eastern US in the nearterm.

I understand where you are coming from Larry in that a record min in Oct. for ATL correlates to enhanced p-type potential for the DJF period there from a statistical perspective. At the same time, cold this time of year just adds to our electric bill, therefore I prefer a uncommon meteorological event. Conversion to sub-tropical looks to occur off the EC of FL on this run of the GFS, supported to a large extent by the big 3 operationals (in general over the past 24hrs). As delta just mentioned, this run does look suspect, one can even see extra-tropical characteristics off the coast of NC around 162hrs (& conv feedback beyond 180). Then going from ~5640m to 5340m @ H5 in about 72hrs as it occludes off the tidewater, pretty unreal for Halloween, and unbelievable at this range. Any chance for record mins is fading fast, our best case scenario from a cold perspective would be for it wrap into NE and the OH Valley so that we would be on the cold side (yes to the south), and then we would only be dealing with highs in the 40's outside of the mountains, lows not too far from there, but cold nonetheless. Let the waffling continue... Just keep it close throughout the week and hopefully we can park a 970'ish over PA in time for Halloween!

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I understand where you are coming from Larry in that a record min in Oct. for ATL correlates to enhanced p-type potential for the DJF period there from a statistical perspective. At the same time, cold this time of year just adds to our electric bill, therefore I prefer a uncommon meteorological event. Conversion to sub-tropical looks to occur off the EC of FL on this run of the GFS, supported to a large extent by the big 3 operationals (in general over the past 24hrs). As delta just mentioned, this run does look suspect, one can even see extra-tropical characteristics off the coast of NC around 162hrs (& conv feedback beyond 180). Then going from ~5640m to 5340m @ H5 in about 72hrs as it occludes off the tidewater, pretty unreal for Halloween, and unbelievable at this range. Any chance for record mins is fading fast, our best case scenario from a cold perspective would be for it wrap into NE and the OH Valley so that we would be on the cold side (yes to the south), and then we would only be dealing with highs in the 40's outside of the mountains, lows not too far from there, but cold nonetheless. Let the waffling continue... Just keep it close throughout the week and hopefully we can park a 970'ish over PA in time for Halloween!

Yes, it is a pretty decent correlation to wintry precip. as well as cold. I know you wouldn't want it very cold now, but record cold for the entire month of Oct. would also be an uncommon met. event. Also, it is mostly bypassing the SE on the 12Z GFS although you're admittedly in about the best area of the SE to get some decent rain and some wind. Per the 12Z GFS, you get ~1" of rain. So, I can't blame you for wanting it similar to the 12Z GFS.

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Yes, it is a pretty decent correlation to wintry precip. as well as cold. I know you wouldn't want it very cold now, but record cold for the entitre month of Oct. would also be an uncommon met. event. Also, it is mostly bypassing the SE on the 12Z GFS although you're admittedly in about the best area of the SE to get some decent rain and some wind. Per the 12Z GFS, you get ~1" of rain. So, I can't blame you for wanting it similar to the 12Z GFS.

I do find it interesting that this run hinted at a pre-frontal RN event (PRE) for the Coastal Plain. They are notoriously hard to predict and model correctly so that is something to watch going forward. This could possibly turn into a larger scale flooding event for the 95 corridor from the Carolinas into the SNE, if one does indeed setup. Folks sometimes wonder what would happen if we had a hurricane during the cool season, term sometimes used "blizzacane," well that is not technically possible do to the cooling of the tropical regions in the NH hemisphere as the Earth tilts this time of year, but this setup may be as close as one has seen in a while; interaction between a transitioning TC and our first real shot of cold air. Timing would have to be about perfect for a phase that takes a storm into the east coast, as currently depicted by the operational. Any chance for winter-type is off the table, however the Apps from NE NC up into WV still have a chance. Way too far out though, and as we have learned never buy these extreme solutions in the extended. Wait, watch them loose it, then come back to something similar, but more subdued which we originally saw in the long range. Wash, rinse, & repeat.

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