Carvers Gap

I like the trends so far at 12z on US models. Rain changing to snow showers on Friday. Potential winter storm Sunday. Another system Wednesday. Let's see if we can get US modeling some support. You all can post the maps.

Looks like the Para will join its older sibling in modeling more wintery weather with yet a second system, the west TN system mentioned above for Wednesday(para may be a hair slower).

The regular 12z GFS has a light wintry mix over western portions of the forum area Tuesday-Wednesday. Para hammers middle TN w the Sunday system - E TN does pretty decently as well.

Somebody post the para-gfs map. It is a good one - not great but good.

Beginning to look like the Para-GFS has scored the short range coup with this Sunday system. Now admittedly, most models had this a few days ago, and then lost it. However, the para has held steadfast - when it has run.

12z GFS is now on board.

The 0z CMC has light snow along a frontal passage around Tuesday, but whiffs on Sunday and is suppressed with the Friday system. We will find out if the GFS has "rediscovered" the old pattern or is on a wild tangent. Normally, I would discount that business, but as Fountain notes...it has held its own this winter against the Euro. Really would like the CMC to start trending towards something Sunday.

There are three minor/moderate events for various areas of the forum area on the 6z GFS...Sunday, Wednesday, and Friday.

Good trends on the 6z GFS regarding the Feb13 time frame as well...really good trends if you live along the Southern border of TN or northern edges of the GOM states.

So, the 0z Euro is now getting to UKMET levels over Iowa now in terms of cold....not once but twice. -20s on M/T and again on F/S. One of the lows with the second round of cold is -25.9F.

I think it is going to depend on two things, the strength of the amplification and the amount of cold air which feeds into that trough. I thought we would have seen that this weekend, but the phase was a few hours off and the cold not nearly as strong. That said, the aforementioned window late next week/has a chance to form a strong storm along a potentially powerful frontal boundary. That type of cold running around the continent of NA is just asking for trouble. Time will tell. Fun times to track.

Ensembles are still quite aggressive with surface HP. To echo Webber from yesterday, when you start seeing those powerful highs on washed out ensembles...pretty good signal for cold. Will be interesting to see if operational modeling gets more severe with cold as we get closer to the end of next week. I am really torn as to whether it comes out in waves or just comes out as one big air mass. Webber did note today on Twitter that the Pacific construct(go read his Tweet for details) is raising the possibility that it comes out of the West in its entirety as one air mass.

What percentage of days have you all had snow on the ground since Christmas? The mountain about 1 mi behind my house is 2400', and it has had something on the north slope about 75%+ of the days since then.

I mean, that is a great look. -NAO, ridging along the West Coast, AN heights up top and in Alaska.....

Great share, man.

Looks like a window to follow. If we can manage to put snow on the ground then, it might now leave for several days. Mountains might keep snow for the rest of the month. Interestingly, Holston, have the Smokies kept continuous snowfall on the ground since Christmas?

I have refereed to this winter as an odd mix of the 89-90 winter and 95-96. Think we may be about to see both. Anyway, I was thinking back to this event as I have seen the Euro op float this idea twice in a row now. Charleston, SC, during December of 1989 got hammered by snowfall. Probably doesn't make any of you feel better about our chances, but I thought that was interesting. https://www.postandcourier.com/news/the-legendary-snowstorm-of-89-gave-charleston-a-white-christmas-after-a-difficult-year/article_f48d8e78-f00b-11e7-aa4a-d325d9b04ec5.html If we get December 1989 cold in February 2021, I won't complain...Feb is a much more active month in terms of precip and has increasingly changing wavelengths.

Yep. And I think the block will force that cold out of the Rockies maybe even without phase 8.

I think right now it looks like we are getting a surge of cold about every 5 days beginning with Sunday. The real question is whether the entire air mass comes east in one swoop. Modeling tried that yesterday, and overnight(and so far today) modeling has pushed that back about 72-96 hours. If the entire air mass comes out, I would "think" there is a chance for a very big storm along that front. If the cold comes out in pieces, we will have to hope that we don't get in the "warm-up and rain" pattern after each cold snap. Right now, we just want to see the OLR maps push precip to the dateline in the equatorial Pacific. If they do that, I think we are in business. If force, I would think late next week or weekend would be our next window. However, things are changing so rapidly on modeling....I doubt M-F next week is even ironed out. Looks like cold Sunday which will be followed by a brief but intense warm-up, followed by another strong cold front after that. It is along that second front that I will be watching for mischief.

IMO, if the extreme cold(both the CMC and GFS have 1060+ highs) gets into MT, we are about two cutters away from that surging into the East. One thing to remember is that cold air is quite shallow and that wrecks havoc on modeling. Right now, modeling has not lost the cold signal. What it did gain was a healthy SER next week which is going to fight it. I will take my chances on the edge with this. Cold air is still within d7

By 180, the cold overwhelms the pattern(not in the d8-10 frame) on the 12z GEFS. I should point out that the cold is not lurking in day 8-10. It is much closer than that. The coldest air is at d8-10.

Now take a look at next Weds on the 12z GEFS. I cherry picked this frame(there aren't many warm ones after Sunday). It is Tuesday, and that is phase 7 nearly perfectly. Go to Tropical Tidbits and see where it goes after that.

Everyone, take a look at phase 7....Now, take a look at what next week is trending towards. The MJO is driving the bus in short term modeling. Since the US modeling is winning some battles right now(no surprise...Euro is again mortal during shoulder season). The EMON looks nearly identical, but actually goes into 8. This is why I think medium and LR modeling may well be right on the potential for severe cold. As for skepticism, people who are scientists should take it in healthy doses every day. I am a natural skeptic. The best problem solving teams always need people who say, "Wait a minute, have you thought about this?" Group think is bad mojo in my book.

I don't think extreme cold is off the table. Of course nothing to do with weather and climate forecasting is a certainty. Now that modeling is working out the details with the weekend nada storm, seems to be getting a better handle on when the cold will arrive. I will say this (and it is no certainty), but if we go MJO phase 8, have a -NAO, and have incredibly cold air in NA...that cold is likely coming into the SE. If we like the idea that the Euro caved to US modeling this weekend, it is worth noting that the US MJO was very aggressive in racing across phase 7. I am not sure if it is right, but it is worth noting. Honestly, kind of exciting seeing that type of cold on a map.

What is the knock on the UK...feel like I have missed something? UK is always really amped. Bout the only thing I have used it for (other than cold yesterday) is to see if it gives me a clue to the Euro run.