Stormchaserchuck1

I agree but we have like a +0.25 correlation tendency right now.

The monthly composites page is down, or I would show you I'm referring to the -PNA, it's anomaly from Feb-March 2018-2024 has been record breaking by like 150%. Even if we neutralize that this year.. we need cold 500mb to get snow going into March. Actually in the last 8 years... last January we had snow in +PNA/-NAO, this early Jan we got snow in +PNA/-NAO.. when the indexes have been super favorable is the only time we're getting >4". Otherwise it's been a near shutout. I'll post the Feb 2018-2024 map when the CDC page comes back online. It seems like after our coldest day of the year, Jan 27th, something flips a switch and we amplify -PNA... this year it might be closer to neutral, but I don't think we're going to reverse the pattern anytime soon.

I've been noticing our Springs have been warming up fast in the decadal trend period.. that's why I kind of cringe when I hear of excitement Feb 20 - March 15.. I think something about the sun angle has been associated with -PNA conditions in the late Winter (my theory). I think our best chance is actually days 4-7, when we have -EPO.. then the block lifts out and stays at 90N. the 18z GEFS still has south-based +NAO, which could flare up somewhat of a SE ridge at 500mb.

That Atlantic trough is far enough south where it's no longer a +NAO. Is that the frame where it goes furthest south, or does it sustain? (I know GEFS has been consistently showing +NAO in the long range.. but EPS has been leading the way in the Pacific). ^Nice 4 wave trough pattern around a -AO..

23z Hrr has quite a bit of fz. rain here... about 0.4". Models no longer showing a lot of sleet like they did yesterday.

Was excited until I saw hr456

Back in the day, I made a daily index of all the strongest N. Hemisphere 500mb areas: 1. south NAO (north-central Atlantic) 2. North NAO- Greenland. 3. AO (arctic circle, although this one was rare), 4. EPO. 5. Gulf of Alaska. 6. PNA (Aleutian Islands). 7. WPO Bering Strait. I found that [1] the south-NAO had +temperature correlation in the Mid Atlantic and Southeast, and neutral to positive 500mb heights. AO was negative temps and heights, but moreso north, so a combination of those two is close to neutral for the Mid Atlantic.. average high temperature now is 40, so that's saying low 30s is probably the best case scenario. We know how those borderline events, with +NAO (south-based) or more recently -pna, we know how they trend from the medium to short range when a N. Hemisphere major index area is in a constant. They don't trend toward more snow... I'm a believer of the AO, but it's a short wavelength pattern, where we have some unfavorable things stacked directly underneath. Pacific isn't bad though, and it's mid Winter, when we average upper 10s to 20s snowfall/year.. so maybe we can squeeze in some snow.

No problem.. you're probably the only one who does a real discussion. Active precip jet is a bit atypical for a Weak Nina, huh?

AO is too far away. A neg 500mb NE of New Foundland is the reason why our H5 never goes negative for the threat(s).. I said earlier +NAO/-EPO is a big ice storm pattern, especially mid-Winter. I just think it's more of a setup for ice, although we may do a few inches on the front end.

See that pressure pattern of -500mb heights south of Greenland/Iceland vs +Heights off of Africa.. that's +nao. What you are looking at is -AO. When the negative 500mb moves south of New Foundland latitude.. that's -NAO, but north of that is +NAO. That latitude difference correlates with +temps in the Mid Atlantic and Southeast.

Any flakes in Baltimore?

NAO remains positive through Day 15.. You guys may say it's not, but what you are looking at is the AO. The NAO is actually SLP calculated between Iceland and the Azores. What's happening for the next 15 days is a "south-based +NAO", and I've run the maps, it goes with warmer than average conditions in the Mid Atlantic and Southeast. This is why 500mb never gets cold. I'm still of the opinion that the coming storms are mostly rain or ice.. we will do well if we exit this +NAO pattern with more than a few inches of snow total. +NAO/-EPO, which is modeled for some of the time, is correlated to icestorms.

Anything more than 2-3" with the pattern would be a blessing imo Usually in the medium-long range you want to see a negative-500mb trough. That it is mid-Winter makes a little less so, but I still don't trust borderline conditions at this timerange without +PNA or something stable like that, just based on experience from the last 10+ years. A big score of 6-12"+ would be an anomaly with the coming 500mb pattern.

I'll take 1" of sleet. Will probably look good Thursday morning with ice coated on everything.

I'm thinking models are too bullish.. We never have below average 500mb. https://www.meteo.psu.edu/ewall/ENSHGTAVGNH_0z/ensloopmref.html Hope I'm wrong.

The actual anomalies is what matters. Everything I've seen looks pretty neutral..

5800dm heights coming up for NW Russia in mid Winter! Looks to be about a +600dm anomaly, which I think is record breaking Loading area for -AO/-NAO later on.. let's see how that evolves/works out

5800dm Heights coming up for NW Russia in mid Winter! That's the H5 loading pattern area historically for -NAO several days later

Yeah, completely different 500mb from several days ago https://www.meteo.psu.edu/ewall/ENSHGTAVGNH_18z/ensloopmref.html EPS crushed it leading the way.. kind of a historic bust for the GEFS having >+300dm anomalies on the mean.. now the High pressure never centers over the N. Pacific ocean.. it's all Alaska or the Arctic circle.

End of the 12z GEFS run at Days 15-16 had Arctic blocking. That matches -EPO patterns And is a cold pattern at the surface in the eastern 2/3 of the CONUS Whether it verifies or not is another issue. Models have trended from predominantly -PNA pattern, to now -EPO in the last few days.

I used to climb up there in the Summer when it would go bear.. beautiful view of the green valleys around, but otherwise desolate. You can drive right up to 7,000', half way up the mountain. They are getting a train of moisture for the next 7 days.

Mount Shasta, CA, on top of the mountain, is expected to get 100" over 7 days.

That is a 1045mb High pressure in NNE when it starts snowing on the GFS run. If it trends weaker, will the storm come north?

Looks like 1" of QPF, 85-90% frozen here on the GFS.

Wow big ice storm for MD on the GFS!