GaWx

The MJO ensemble mean forecasts, especially GEFS, look favorable for cold at mid-month with weak left side:

The EPS continues to be much drier and thus have much less wintry precip (mean is very unimpressive) than the GEFS/GEPS.

18Z GEFS (outside of mountains): active again -Mean wintry amount is impressive, especially in NE GA, upstate SC, and NW 3/5 of NC with 1-2.5” of snow, snowiest run yet for those areas I think -Three (10%) really big dog snows NC, with two of those extending back into N GA -70% of members have wintry precip -50% have wintry not limited to NC -10% (3) in N FL with one as far S as north-central! -30% have IP or ZR included -some early snow 2/12-14, mainly in NC; most activity 2/17-21

12Z GEFS SE US outside of mountains: -20% have wintry precip 2/13-14 mainly GA/SC with all including N GA and most including SC -70% have it 2/16-21 (mainly 2/17-21) -50% have it 2/13-21 that include states outside of NC -~40% have IP or ZR -So, the strong signal for that far out continues with a little bit more of a signal than before for 2/13-14, too. The 12Z EPS like for earlier runs has much less snow than the 12Z GEFS and GEPS.

All models are predicting the AO to drop to -3 or lower at mid month with the likelihood of some days dipping to near -4 being implied. The chance of a sub -2 AO averaged out during 2/15-29 is increasing and is close to becoming likely. (There’s a good chance for a +0.3+ PNA averaged out during the same period.) Here are the strongest -AOs averaged out during 2/15-28(9) for El Niño: 2010: -4.1 (PNA +0.2) 1969: -3.4 (PNA -0.1) 1958: -2.5 (PNA +0.9) 2005: -2.4 (PNA +0.4) 1952: -2.0 (PNA +0.4) 1977: -1.8 (PNA +1.0) 1987: -1.7 (PNA +0.3) 1970: -1.6 (PNA +0.7) AO lowest daily 2/15-28(9) -3 or lower during El Nino: 1952, 58, 64, 66, 69, 78, 2005, 10 AO lowest daily 2/15-28(9) -4 or lower during El Nino: 1958, 69, 2005, 10

The potential for significant SE wintry precip 2/15-20, especially 2/17-20, is not at all going away and is if anything increasing as we get closer while the big picture doesn’t change. At least 75% of the last 3 GEFS runs ending with the 6Z have SE US wintry precip outside of the mountains somewhere within Feb 15-20. About 50% of the 6Z members have it including outside of NC with 4 of the 30 even as far south as N FL. It is hard to look better than this 10-15 days out. The big picture is still very much intact with a hard to beat combo of a very strong -AO, moderate +PNA, -EPO, neutral to -NAO, strong subtropical jet/split flow, and the tendency for 50/50 lows (which tend to hold cold in longer). Moderate+ El Niño climo is quite supportive, too. It never hurts to have analogs on your side. I hope to post more about the very strong -AO later as far as El Niño analogs are concerned.

Also, GEFS has been better than GEPS. Interestingly though, 0Z GEFS today (2/4) has backed off slightly on an actual reversal with a lowest mean just above zero vs -2 on the 0Z 2/3 run. Also, it’s mean though still low edges back up to +9 later vs staying under +7 yesterday.

Today’s extended EPS mean drops to a mere +4 (vs +11 two days ago and +31 nine days ago) with numerous members having a major SSW. Also, like is the case on the extended GEFS, the SPV is now much weaker than normal from mid Feb into March. The chance for a cold E US March continues to increase!

Rainy, windy, and cool here late this afternoon. A good day to stay inside! Update: After ~7 hours of rain that included periods of heavy rain along with rumbles of thunder that I’m still hearing (there even was one cloud to ground strike a few hours ago), it is finally ending for now. I’ll get totals tomorrow. We got another period of rain on Monday but not heavy. I very roughly estimate my Sun-Mon (2/4-5) total to have been 1.75”.

12Z EPS: -Unlike the GEFS/GEPS and although there are some wet members, there are many dry members and thus the mean is dry/BN in the SE. But keep in mind that it ends 24 hours earlier though it is drier through 2/19 for sure. -Although there are a good number of very cold members, they are balanced by a good number of mild members late in the period. Thus, the mean is warmer than both of the GEFS and GEPS late in the period with the cold temps warming to mainly near normal temperatures by the end of the period. -Unlike the GEFS/GEPS means of above average snowfall in NC, the EPS has BN/little snow. So to summarize my posts regarding the 12Z ensembles for SE wintry precip potential Feb 15-19/20, the GEFS and GEPS means have AN snowfall and cold whereas the EPS mean is drier with BN snow and less cold temps late. Going to be lots of fun to see how this plays out.

-The Canadian ens map you’re showing has near normal precip (white area) for that 5 day period. Near normal is neither wet nor dry in NC in mid Feb. -1/2 of the members have snow in NC outside of the mtns -4 of the 20 (20%) have widespread 3”+ snowfall, all including heaviest of 6”+, in NC. -A good number of the wet members in NC have no wintry outside of the mountains. -2 of the 20 (10%) have wintry as far south as N FL. I haven’t yet had a chance to look at the EPS.

Nope, especially 2/17-20. From 12Z GEFS outside of the mountains 2/15-20: -21 of 30 members have wintry precip in NC. -13 have it in GA including 8 central and/or south -11 have it in SC including 7 in south -3 have it in N FL -6 have ZR and/or IP included, including part or all of the 2 of the 3 in N FL

12Z GEFS big picture in more ways than one: classic split flow has been showing for this period for weeks. This is about as good a look as I’ve seen in recent years this far out. Ingredients are there. But will they mix right? That’s always the tough part for the SE, especially.

12Z GEFS for Feb 16 is by a good margin coldest in at least the last 16 runs. Now let's see how well the ST jet/moisture interacts.

GLAAM prediction from CFS ensemble is saying we’re probably headed to solid +/Nino pattern 2/15+.

The potential isn’t going away folks. Rather, it is persisting and as we get closer it is increasing. The potential on the 6Z GEFS for widespread significant wintry precip during a portion of Feb 15-20 in NC and more specifically from a classic Miller A GOM originating low throughout a large portion of the SE during a portion of Feb 17-20 is about as high as I can remember on any GEFS in recent years when looking out 11-16 days. When I consider not only the actual panels of the run but also similar model runs of the last few days along with the progged solid +PNA/-EPO/-AO, neutral to -NAO, a persistent 50/50 low, a strong El Niño related subtropical jet/split flow, and moderate+ Nino mid to late Feb climo, it is hard to hold in my enthusiasm for what MAY occur. And it is always a matter of what MAY and never nowhere near what WILL when looking out 11-16 days. The MAY is why we have these forecast discussion threads as opposed to nonexistent crystal ball threads. Classic split flow: Many members with Miller A GOM/off SE coast lows:

If the extended 2/3 10 mb forecast along with the most recent CFS 12 run ensemble 2m temperature means in addition to recent Euro Weeklies are any indication of what’s to come, we may very well be getting a cold first half of March at a bare minimum! The mean 10 mb wind never recovers over +7 after not getting below +30 in mid to late Feb on the Jan 25 run!! That 1/25 run had a mere 3% chance for a Feb reversal and now it is 75%+! I’ll delete this image very soon as it is way too large to keep here considering the attachment limits:

About 30% of the 18Z GEFS members have wintry precip in the SE outside of the mountains during 2/17-19.

Meanwhile, though the 12Z EPS has virtually no snow, the 0Z control has moderate snow 2/18 and 3/2-3.

This is about as good as it gets per his monthlies and getting the unrounded peak exactly and thus I think should be the winner! However, he messed up his perfection by “not playing by the rules” (as he stated) since his definition of super is 2.0+, not >2.0 (with which I agree). Thus he voted >2.0 even though he predicted +1.97 unrounded/+2.0 rounded. I still say he wins. Congrats!

That he did. So, congrats @snowman19for that! This one is just like 1965-6, which peaked at +1.98. That one is often left out of the “super” peaking group even though it also rounded to 2.0. Not that it matters wx wise. Edit: for wx though, RONI may matter more.

The unrounded ONI max came in at +1.97. RONI never made strong with another +1.49.

EPS: ~25% of members have strong cold within 2/17-18 but snow is very limited (though it ends a day earlier than GEFS).

12Z GEFS: pretty wet SE 2/18-9 with 9 of 31 members having wintry precip. Many members have a GOM low.

12Z GEFS is warmer 2/15 than any recent run.