Stormchaserchuck1

We are going to have a -NAO event in 4-5 days.. it's trended less cold in the US, but for like 5 days the NAO will be effected in the typical time lag period. Edit: It is a 4 week major Stratosphere warming, and we aren't going to get 3-4 weeks of -NAO, you are right about that.. They couple with major -NAO +time historically about 2/3 times. This was also the 1st Stratosphere warming event since Nov.. it's been all cold Stratosphere Nov-Feb

Stratosphere Polar Vortex was strong, then it got ripped apart in March. https://x.com/NOAAClimate/status/1907805453859295460 Since 2000, these are the analogs where we had a strong 10mb PV Nov-Feb, getting torn up in March. Look at how in the following May, it shows this battle over the Arctic at 500mb.. it takes time for Stratosphere to make it to the surface.. in this case 2 months. There is even a +100dm anomaly over the Hudson Bay which is anomaly for 8 years in a short wavelength month like May. Following June-Sept: Again, see how the ridging gets split in middle by Arctic trough. Dominant 10mb vortex recenters with High pressure actually getting moved to the edges, down to the surface. ^It has even + and - years (4-4), so there's no global warming general thing in play. The warm March seems to be a warm signal for the Summer.

Here's the SSTA change year-to-year, shows where it is compared to last year at this time: That cool water near Africa actually has a correlation of spreading west for the season. Here was my post on opposite conditions last year:

Well there's no thunderstorms, like at all.. I hope this cap holding is not a trend that continues into the Summer like it did last year.

Definitely a big bust on severe wx in the area today. It looks like the only place that is hitting is way down near Arkansas and Tenn.

That means if you subtract 0.2 to account for global warming trend (which is about what it is: 0.2 to 0.3), this event did officially hit Weak Nina.

What's your prediction, Barry?

We did have +NOI, which is a little High pressure off the West coast. That's what I look for, for ENSO effects. And the year before in Strong El Nino, although we had mostly -PNA, it was -NOI. The North Pacific High region has greatest ENSO correlation effects, not the PNA (very misunderstood).. although I guess you can say in west-based events it's more PNA-correlated.

CSU's numbers were way high last year.. I think they were going with a near record season. I think Gawx has researched it, and come to the conclusion that they have an over-active bias on seasonal forecasts, based on several years of putting out forecasts. I don't think 17NS, 9 Hurricanes is that far off the progression average though.. 8 of the last 9 years have had 7+ Hurricanes. 4 of the last 5 years have had 18+ Named Storms. We had a quiet period mid-season last year that may signal a turn to less active conditions though.

This STJ aspect of this past Winter really looks like a La Nina

This is what the Winter looks like vs the 30-year average I'll probably give my Winter forecast a "D+". It's a D because of precip. March ended up pretty much wiping out the negative temp anomalies. When the US climate division data updates, which is usually about mid-month, ill do a final map comparison and analysis on my discussion forecast.

Pretty much a >90% chance it will be negative for the Winter. -QBO with El Nino favors Stratosphere warmings. The weight is 3-1. I'm not saying this next Winter will be El Nino, that's just the strongest correlation with -QBO. Last Winter the +QBO really correlated at 10mb. Paired up with -ENSO, they usually work out that way. March actually has a pretty neutral historical signal.. and it was warm Stratosphere March

Pattern is moistening up now.. I've noticed that everytime we have an oncoming drought in the eastern 1/2 of the country, it gets wet real fast, since 2002 really.

+35 SOI today. +26 yesterday. It's been positive every day since February 24th.. today marks the 40th consecutive day in a row. It's been making runs like this, and makes me thing that we continue to work with a long term -ENSO state. From 2020-2023, the SOI was positive 31 months in a row! ^Even during the Strong El Nino, the SOI was not that negative relatively, and matched the lack of big +PNA pattern that year.

Here's a good image showing how the subsurface has been leading the surface for some time.. even before 2 years ago, it was working with a good lead time like this.. I would have to go through those long ENSO threads to find the older data, but I'm pretty sure it's been like this for 3-4 years.

13-17 isn't low.. the long term average for 100 years was 9 Named Storms/year.. and with the activity over the last 30 years, it has increased to 10 Named Storms/year. I'd say a wild card is if the NAO goes positive this Summer.. we are at a Solar max and it has +0.2 correlation with +NAO. +NAO keeps high pressure across the basin, leading to less activity. Last year there was a clear difference when the NAO was positive vs negative.. It was the least active in parts of Aug-Sept period since 1993 when the NAO was positive, then when it switched to negative late season we had all those strong storms.

I'd actually say a strongly +NAO this Summer (last year we had 9 different daily -500mb periods over Greenland) may lead to a similar result as last Winter with the -EPO. Pacific is kind of in a state right now of Hadley Cell expansion, so look for low pressures and cooler SSTAs from Japan to north of Hawaii. I'll also be watching North Atlantic SSTA's May-September, as it has proven to have high predictability for the following Winter's NAO. Since I incepted a method based on that in 2005, it has gotten the + or negative state right 14-5, and within an estimated 0.54 standard deviation, it has gone 10-9 (Dec-Mar) in real-time/forecasted time.

This early Spring warmup continues to look impressive.. PNA is lowest since October. -PNA/+NAO Richmond forecasted highs: 4-3: 83F 4-4: 86F 4-5: 85F 4-6: 87F Washington DC is currently forecasted 86F for 4-6! I was kind of wrong to say that 90 potential was gone so soon. Gawx posted something last night, that if Atlanta hits 90F, it will be the earliest by 18 days! (they are forecasted 87, 90, 90) For this period of warmth, I looked at what was happening over the NW (Portland hit 82F), and how when the west coast warmth was initialized, models were giving more +EPO pattern. That usually leads to temps overperforming +days.

Nino 1+2 finished March >+1. That actually rolls forward to a strong +PDO signal by the following Fall (although the signal could be because of blossoming El Nino events)

Cold will sometimes produce. Snowfall can be too localized for grand general analogs. Did you have any snow in March? Does Boston still have its <4" streak going?

ENSO subsurface continues to be cold in the central region, which at the very least favors ENSO Neutral this season. Last year I did research on the trend regarding different Hurricane season factors. Here's how ENSO subsurface has been leading surface events: Here's my post from last year which is a 1 year old, but you can still see the long term trends.. I think we had 18 Named Storms last year, 11 Hurricanes. In 1995, the AMO (Atlantic Multi-decadal Oscillation) index switched to positive, and since then it's been rising/still hasn't peaked. Atlantic Hurricane season activity is strongly correlated to the AMO, and Atlantic Hurricane season activity has also been in an upward incline since the 1995 AMO switch. Here is a smoothed graph of number of Tropical Storms by year: Since 1995, we have averaged the following number of storms per year in various ENSO states: El Nino (8 years): 12.5 TS, 5.4 Hurr, 2.5 MH Neutral (10 years): 16.4 TS, 8.2 Hurr, 3.8 MH La Nina (10 years): 17.9 TS, 9.2 Hurr, 4.2 MH In September 2022, the AMO peaked at an all time high of +0.662, and is still rising/in an inclining phase. I plotted monthly AMO numbers, up until the CPC last updated the dataset, which was January 2023: If you smooth out the index, it looks like a very clear rising phase is still underway: Since those AMO graphs, we had record +AMO last Summer, now it's cooled down to be cooler than the last 2 seasons, but still above the 30-year average. We are still on the general AMO trends. The Atlantic activity has been especially strong lately: - 4 of the last 5 years have had 18+ Named Storms - The average in the last 5 years is 20.5 Named Storms/year - 8 of the last 9 years have had 7+ Hurricanes - The average is 8.7 Hurricanes/year for the last 9 years With ENSO Neutral and slightly warm Atlantic SSTs, I'd put the over/under on this season at ~16 Named Storms, just based on long term trends. Remember, the rest of the globe has not been nearly as active as the Atlantic.

Well it's from +PNA. PDO-neutral is still not +PNA favorability, but we have seen a new trend of stronger +PNA episodes over the Winter which brought the PDO up. Rolled forward, it doesn't give a +PNA signal for the following Winter (+12 months) Per the CPC, it was the strongest +PNA Winter non-El Nino since 1950 as Gawx has researched. ^That is a +NOI signal though (high pressure off the west coast), which is a slight La Nina indicator Winter +PNA rolled forward is surprisingly a slight La Nina indicator for the following year, based on 63 years of data (It probably has to do with El Nino's typically switching)

-3c in the central-ENSO-subsurface.. it's not budging. The trends of surface warming through Feb and early March matched oncoming El Nino episodes, but that subsurface is still in Weak Nina range.. all last year it was around -3 to -4. Imo, that's more important than surface SSTs.

I found this interesting, a +NAO in March has a slightly cooler temp correlation in April (usually they all go in the same direction).

Thanks for doing it Roger. April DCA _ NYC _ BOS __ ORD _ ATL _ IAH __ DEN _ PHX _ SEA 1.7 1.8 1.6 1.2 2.1 1.6 2.1 2.7 1.0