GaWx

The MEI v2 was just released for JA: +2.5 vs +2.4 for JJ. That’s the 2nd bimonthly in a row at a record high for the bimonth (back to 1979). The record high for any bimonth is +2.9.

 Here’s the rundown for JAs of +0.5+:

2026: +2.5

1997: +2.3

2015: +2.0

1982: +1.9

1987: +1.5

2002: +1.0

1986: +1.0

1994: +0.9

2004: +0.8

2009: +0.6

2006: +0.6

1993: +0.6

2023: +0.5

2018: +0.5

1979: +0.5

1 hour ago, 40/70 Benchmark said:

I was never wishing for a lower RONI because given how warm the Pacific basin is, I think that could predispose the hemisphere to residual MC influence in the mid latitudes, as we are still seeing signs of those competing forces despite the magnitude of El Nino. 

 
 The ONI peak in OND fell by the same 0.5 over the same period:

Aug 1-10: ONI peak +4.15

Aug 30-Sep 8: ONI peak +3.65 and likely to fall further just like RONI as per the location of the blue lines

 So, the difference between the peaks of ONI and RONI didn’t widen.

3 hours ago, forkyfork said:

that's because it's east of 3.4 as bluewave just showed us. be careful what you wish for <3

I know ‘26 became the most E based of any Nino on record in early Sep as I posted that here 2 days ago:

 
 Although 1+2 has warmed in Sep, it like RONI has also fallen in OND fwiw though by not as much (0.3 vs 0.5) making it slightly more E based in OND than it had before:

Aug 9-18: 1+2 OND +4.2

 

Aug 19-28: 1+2 OND +4.0

Aug 29-Sep 7: 1+2 OND +3.9

Heavy showers have moved from offshore W to my home at 1:40AM, a total surprise!

Edit 11:45AM: Follow-up: I’ve been getting more showers moving W from offshore on and off since ~10AM to add to what I got late last night. I’ll check later to see if all of this added up to all that much.

Edit #2: Heavy showers moved W from offshore to my home at 2:25PM.

Edit #3; More showers moving in at 5:10PM.

 I’m at ~0.35” for all of 9/9 as of 8PM.

The CFSv2 progged RONI peak continues to drop steadily with more drops likely:

7/22-31: ASO/OND +3.5

8/9-18: OND +3.45

8/19-28: OND +3.2

8/29-9/7: OND +3.0 with most of the blue lines (most recent 8 runs) lower

 Here’s the preliminary winter outlook from pro met. Chris Martz:

here is my preliminary thinking. . . As y'all probably know by now because of the endless hysteria in the news cycle, we are in an El Niño, which is just the warm phase of the larger El Niño–Southern Oscillation (ENSO). This year, the developing El Niño is unusually intense, and it is expected to officially be a “very strong” El Niño by early winter at the latest. This is marked by very warm sea surface temperatures in the equatorial Pacific Ocean.

 The news media and the United Nations have spun this as some sort of crazy event that will “turbocharge” extreme weather all over the globe, but that's not really how it works. Now, normally in the tropical Pacific Ocean, easterly wind stress associated with the Walker Circulation imparted on the sea surface acts to pile warm water near the surface in the western half of the basin; that is, closer to Asia. This pushes the thermocline down towards the west as warm water pools up north of the Maritime Continent and east of the Philippines. But during El Niño, the easterlies weaken or temporarily reverse (westerly wind bursts), which causes that pool of warm water to slosh back east. That's what's happening right now.
 

There are a lot of meteorological factors to consider when it comes to predicting long-range temperatures, precipitation, and storm tracks. But this year, this “very strong” El Niño will play a dominant role I think as it has in years past (e.g., 1982–83, 1997–98, and 2015–16). Those are my top post-1950 analogs, and I added 1972–73 into the mix as it behaved similarly to the others, although it was only a “strong” El Niño at peak intensity. 1827–28 and 1877–78 would have been good analogs too, but we don't have enough climate data from back then to work with.
 

A key feature of “very strong” El Niño events is that wintertime temperatures are particularly mild relative to average. This is pronounced in the Upper Plains / Midwest and Great Lakes / Northeast. Temperatures across the Desert Southwest and Four Corners region, however, typically run below average. The southeast can swing either way, but generally winds up near “average” (and I use scare quotes there because the weather is rarely “average”).
 

 However, these exceptionally mild temperatures do not necessarily persist all winter. In fact, most of this composite is due to “blowtorch” Decembers. And I do expect December to end up 5–10°F above average in the areas you see orange and red contours in the first analog composite map I made below. But the roaring Pacific Jet typically relaxes from mid-January through mid-February, so temperatures will tumble a bit closer to “seasonable.” If this El Niño were weaker, there'd be a good chance of a frigid December in the east. But I doubt that's going to happen.
 

As far as precipitation goes, well, there should be an active subtropical jet stream. So, air parcels moving from west-to-east will tap into Gulf moisture and then be advected northward into the southeast. I expect a lot of rain in the Gulf Coast states (Texas to Florida) and then northward up the east coast into the DMV. Similarly, the western U.S. should expect some major drought relief due to atmospheric river events. After a near-record low snowpack last winter, the ski resorts will be back in business. Elsewhere, it will likely be a bit drier than normal due to persistent high-pressure ridging over the northern flank of the country. Storm tracks are going to favor the southern states.
 

With respect to snowfall, overall, I do expect less of it nationwide outside of high elevation areas simply due to higher-than-average temperatures. But I cannot rule out ONE crippling blizzard in the Mid-Atlantic or in the southeast. It happened in the southeast (Florida, Georgia, and Carolina coastline) in February 1973 and in the lower Mid-Atlantic (Virginia, D.C., Maryland, and southeastern Pennsylvania) in both February 1983 and January 2016. However, it did not happen in 1827–28 or 1877–78 (I checked NOAA NCEI FORT data) or in 1997–98.

So, whether or not we get the “big one” remains up in the air for now. But it will be that one storm that will ultimately determine where the seasonal snowfall will stand (above / below climatology) in the southeast and Mid-Atlantic. If it occurs, many folks will get their seasonal spoonful of snow in one dumping. If it does not occur, it's just going to be a wet winter.

A shower coming moving SW from offshore started here ~5 minutes ago. It likely won’t amount to too much due to it likely being brief due to rapid movement and it not being large. It ended up amounting to no more than a couple of hundredths.

48 minutes ago, Newman said:

I haven't been active in this thread so apologize if it's already been shared before, but Dr. Jonathan Wall has a great project developed on his website at https://snow.wall.cloud/

You can dive really deep into and compare statistical significance of various teleconnections for a few different snowfall criteria (i.e. trace of snow at 10% or more of stations, 25% of stations measuring 0.1" or more snow, total event coverage or magnitude of snow totals, etc), and all of this broken down by NWS CWAs. But what's neat is you can also break it down further with these various teleconnections during El Nino, neutral, and La Nina.

Here is an example between BOX and PHL CWAs in an El Nino winter for the PNA. The PHL CWA leans towards/favors +PNA for number of qualifying days with at least 25% of stations measuring snow in El Nino. Meanwhile, BOX weakly leans towards/favors -PNA. Of course, the caveat is that there are some outliers in both situations and it's not consistent amongst measurable snowfall days. In fact (and you can find this on the website) the most statistically significant teleconnection is a -EPO across both CWAs (most significant when selecting "all winters" and not just separating out ENSO):

 

Here is another example but with QBO during El Nino just for shits and giggles. PHL actually leans towards +QBO for number of qualifying days with measurable snow at 25% of eligible stations (I'll have to look into the details of the data here, I wonder if there's some bias from big dogs that formed during +QBO/+ENSO seasons) and eastern BOX leans towards -QBO but western BOX leans towards +QBO. Again, very very important to note this is not gospel and there are outliers that prove snowstorms can happen in either phase of QBO.

Either way, cool website and wanted to share. All of the details should be there on the site. From the site: "This is a descriptive historical phase comparison: each DJF winter is grouped by its mean index phase. Red favors positive phase, blue negative. The shading estimates the station-rate pattern between qualified stations."

 Thanks for posting that. Regarding the PNA based on analyses I’ve done on snowfall for SE cities like RDU and ATL, a +PNA is the #1 most correlated index to snow in the SE. Since El Niño and +PNA are well correlated, having El Niño on average tends to be good relative to other ENSO for SE snow chances in general.

For anyone who happens to care, this is what I just posted elsewhere about my up to date general feelings about AGW/CC:

1) Anthropogenic Global Warming (human-caused CC) is real, has caused mean global temperature to warm ~2-3F, and is causing it to warm further.

2) Regarding CC reducing snowfall, that’s been true overall, which is intuitive. But for a specific location, the relationship between CC and change in avg snowfall is complex as it can actually cause heavier snowstorms in some cases since warmer air holds more moisture. This is especially the case where normals are well below 32F.

3) What’s debatable are four main things as I see it:

a) Projections of rate of future warming because of realistic possibility of negative feedback loops, on which climate models likely don’t have a good handle.

One example is “CO2 Fertilization Effect”: ^CO2 leads to ^photosynthesis, which leads to greener planet. Also, warmer planet means longer growing seasons and growing in higher latitudes than before. Greener means ^CO2 absorption for globe. So, at some point increase in CO2 would likely decelerate and perhaps later completely stop.


b) I’m not at all saying AGW/CC’s good. The main concern I have is rising sea level caused by combo of melting land based ice and expansion of oceans due to warming waters. Also, it likely leads to increased flooding events since warmer air holds more H2O. That includes wetter TCs. But CC isn’t all bad. Why?

- It’s likely leading to larger crops overall due to a combo of CO2 Fert. Effect, longer growing seasons due to warming, and ability to grow crops at higher latitudes due to warming. That means larger food supply and at least in theory less hunger.

-Cold in the past has killed many more than heat globally. Thus so far, CC has actually lead to reduced deaths from extreme temps. But admittedly assuming globe continues to warm, increased heat related deaths will likely overtake reduced cold related deaths.

c) Storminess: CC may actually be reducing the avg storm strength. Why? It has caused much more rapid warming in Arctic than in tropics. That means reduced temp. difference from poles to tropics, which means slower jet stream, which means less energy available for storms to strengthen.

Possibly related to this: typhoon activity has come down in recent decades.

d) There’s a lot of controversy concerning the connection of CC to individual extreme events aka “CC attribution”. I feel it’s overdone at times or at least there’s often a rush to attribute extreme events to CC without enough time or evidence to soundly prove it. I’m not saying no extreme events have been made worse by it. Almost certainly extreme heatwaves have been made worse by it than would otherwise have been the case. Example: the March SW US heatwave.

But here are some examples of a rush to judgement about the CC connection that needs much more time to study it:

-Nepal disaster. Whereas CC probably was at least a minor cause since it has been leading to melting glaciers overall, was it actually a major cause as some have already claimed? If bedrock failure was indeed the major cause, was that in itself due to GW? This needs much more time to study as it is very complex.

-Wildfire disasters: Whereas a warmer globe has likely helped lead to increased fires in some cases, that likely hasn’t been the case for many fires. Also note that global burnt acreage year to date has actually been during the last 2 years the lowest it has been as of this date since 2012!

————————

Edit: I forgot to mention that the UHI effect needs to be taken into account when comparing temperatures in past decades to today. This is especially the case for comparing temps for large cities/metro pop. that had much smaller pop. in those past decades.

1 hour ago, WxWatcher007 said:

No disagreement there. I’m thinking that as we see more penetrating cold fronts, offshore coastal lows, and CAG season opening up late September into October, things pick up. Maybe we get something else in the MDR, but it seems unlikely to me. 

I still have 3 H and 1 MH for my peak season forecast.

Per my post from two days ago ITT that analyzed El Niño seasons with <4.3 ACE as of then, I’d be wary that despite the very slow start there likely will be some dangerous activity in some areas late Sept to mid Oct especially if I were a (near) coastal resident.

5 hours ago, bluewave said:

The 0-300m ocean heat content is really off the charts.

The warming related to AGW is itself a factor helping to cause 2026-7 to be so much warmer than these prior Ninos since the globe continues to warm. Without that, although 2026-7 would possibly still be the warmest, it at a minimum wouldn’t be as far above these others. In other words, this graph isn’t a fair way to determine the strength of each of these El Niños, themselves, since AGW gives an advantage to later ones.

4 hours ago, forkyfork said:

how many struggling independent ski resorts is this nino going to put out of business? 

The Nino is likely going to greatly help some ski resorts this winter.

Not Atlantic basin per se but this is interesting:

The UKMET has for the 2nd run in a row a TC in the Mediterranean Sea:

12Z UKMET:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 132 HOURS
FORECAST POSITION AT T+132 : 35.8N 21.0E

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 14.09.2026 132 35.8N 21.0E 1008 31
1200UTC 14.09.2026 144 38.7N 24.0E 1007 27
0000UTC 15.09.2026 156 40.5N 24.6E 1007 27
1200UTC 15.09.2026 168 39.6N 22.6E 1008 25

For the first run I’ve ever seen, the CFSv2 ensemble AAM forecast has its key at the bottom of the graph because there’s no room on top on either side! It is approaching 3. Three of the four members of the 9/7/26 12Z run have it exceed 4 on Sept 15th (day 9). I’ve still never seen the AAM get to 4 by the way. Will it finally do so this time?

More decent rain falling here last few minutes (since 3:45), to add to my 0.35”, but radar shows and skies suggest it won’t last more than a few more minutes most likely.

Edit: 3rd rain from a shower fell just after 5PM. Looks like another quick one.

Edit: updated total for Sept 7th here: ~0.4”

6 hours ago, Chinook said:

I am wondering how the El Nino may already be shifting 250mb winds, even as we've just started, in summer. Obviously, we'll expect lots of subtropical jet in winter. As for now, I used the HISTDATA from NOAA to plot this... it's essentially the same as NCEP/NCAR reanalysis but it lacks some capabilities. Anyway, the 250mb zonal winds have been more westerly than average for some of the E Pacific, into southern Mexico, then out to the Atlantic. You can see the evidence of a ridge over the central USA. Now, we know El Nino tends to have these situations where the wind shear is quite high for the Atlantic hurricane season and squash that. But here's the question: if the 250mb winds were so westerly, why has the E Pacific generated some strong storms? Of course, on here, there's the Hawaii area ,which has had a hurricane this summer (and now a couple more storms by Hawaii), with the more-easterly-than-average winds as shown.

 Despite the high level of activity in the EPAC, they’ve almost entirely avoided getting close to MX. Only the two TS Boris and Cristina were right next to MX or C America and those were in early June, well before the Aug 14-Sep 4th period you showed the 250mb wind component anomalies for. 
 
 The only 4 during Aug 14th-Sep 4th that even show MX on the map were the four I’m noting below and one can see that MX isn’t even that close. All of these mainly avoided the areas with average 250 mb wind anomalies of +6+ on your map as their tracks were mainly within the +2 to +6 anomalies (yes still + but not large + anomalies and they may have formed when actual anomalies were lower since your map is just the avg for a 3 week period):

-TS Iselle:

TS Julio:

H Karina:

H Maria: closest to MX of these 4 but still 375 miles away from Cabo

Here’s ‘26 season to date:

 Compare the above ‘26 season to date map with the 2015 full season below. Note that in 2015 by today’s date, the following had already occurred that were either right at or nearer MX than the ‘26 tracks excluding Boris:

-Blanca (cat 4 H)

-Carlos (cat 1 H)

-Dolores (cat 4 H)

-Kevin (60 mph TS) not too far from Cabo

-Linda (cat 3H) not too far from Baja

 A batch of showers formed along the cosst in SC 2 hours ago and has just moved SW into my area with heavy rains and initial gusty winds starting ~2PM. This is adding up nicely and is this my first significant rain of the month.

Edit: It rained for only ~20 minutes and this didn’t add up to as much as I had hoped for. But I still got a not too shabby ~0.35”, the most by far this month to date.

After being pretty flat in August/first few days of Sept, the relative 3.4 OISST anomaly has risen sharply the last two days:

Sept 4th relative 3.4: +2.254

Sept 6th relative 3.4 anomaly: +2.429, a rise of 0.175 in just two days…that’s the most rapid two day rise on this entire chart as it is the most rapid two day rise since June 3rd-5th, which is not on this chart:

The daily WCS PDO has risen back substantially the last 7 days ending yesterday with it up to -0.9, the highest since way back on July 2nd, vs ~-1.65 one week earlier:

12 minutes ago, LakePaste25 said:

Almost to +3C on CRW. CRW mostly measures surface temps, so at some point I would expect it to mix down which would increase OISST but decrease CRW. 

 

Here’s the version of CRW anomalies for Nino 3.4 that best takes into account GW in determining anomalies: it’s +2.5C and rising:

3 hours ago, 40/70 Benchmark said:

Yea, it's gone more east-based than I had envisioned, NVM guidance...which was way off. I don't love that, but like I have been saying, I don't think it makes much of a difference when it's this strong. If anything, it probably helps to limit any residual MC influence that would destructively interfere with potemtial big storm windows. So, while that probably puts the nail in the coffin on any hopes of avoiding a pretty mild season, it  may paradoxically help in terms of  landing that big fish.

I may have to shift from a basin-wide to east-based composite, which makes it more likely that the mean ridge ends up se of Hudson Bay.

CANSIPS appears to have a significant Modoki bias based on several years of data. I thought it had this bias even before this year.

On 9/4/2026 at 1:04 PM, GaWx said:

Nino 1+2 (keep in mind that this is non-relative) had a strong rise yesterday. Get ready for a tweet from Adam, Abraham, and/or others addressing this saying record breaking yada yada yada. Keep in mind though that records from 1982-3 and 1997-8 are based on weeklies, not dailies. Also, highest relative WEEKLY in 1983 was +4.6 and in 1997 was +4.1. Let’s see where the current calendar week relative 1+2 on Monday. It won’t be anywhere near +4.6 although it may get close to +4.0.

 

 

 The latest relative weekly for Nino 1+2 comes in about where I expected, +3.9. This for the 2nd week in a row is at a record high (back to 1981) for the week, warmer than 1997’s +3.6 and 0.4 warmer than the previous week’s +3.5.

 The highest relative 1+2 on record for any week is +4.6 (1983) and the highest relative in 1997 for any week was +4.1, which was set twice.

 Regarding the relative for other regions, Nino 3 warmed barely while 3.4 and 4 stayed the same. The changes overall mean an even more E based Nino than the prior week showed:

  9AUG2026         3.2        2.5        1.8        0.0
 26AUG2026         3.5        2.6        1.8        0.1
 02SEP2026         3.9        2.7        1.8        0.1

 For comparison:

03SEP1997         3.6        2.8        2.0        0.4

 So, early Sept. ‘26 is slightly more E based than the previous most E based early Sept. (back to 1981) of 1997.

https://www.cpc.ncep.noaa.gov/data/indices/rel_wksst9120.txt

15 minutes ago, jaxjagman said:

You're definite talking about IMBY,while you had some freak strorm spawn up into the GOM into Feb of 83 the SE in most parts ran 4C AN

I assume you know that the warmest month of the winter of 1982-3 in the E US, including SE, was Dec by a wide margin. It was a bonafide torch, the only month like that in the SE to NE. The remainder in the SE was pretty close to normal to slightly BN in some areas.

 As a near coastal resident who was directly affected heavily by FIVE H/TS 2016-24, I’m very much enjoying the break from the stress of threats!

 However, looking back at the 6 other El Niño seasons with <4.4 ACE through Sep 6th tells me to still be cautious for the rest of the season, especially late Sept through mid-Oct:

1) 1941: -TS TX/LA border mid Sep
-H TX late Sep
-TS Windwards/MH Honduras/Nicaragua/H Belize late Sep
-H NW Bahamas/MH S FL/H FL Pan early Oct
-TS SE Bahamas/FL Big Bend mid Oct

2) 1929:
-MH NW Bahamas and S FL tip/H FL Pan late Sep

3) 1914: 
-TS FL/GA border mid Sep

4) 1905:
-TS Belize/LA late Sep
-TS W Haiti early Oct
-TS LA early Oct

5) 1904: 
-H upper SC mid Sep
-TS Belize early Oct
-H C Cuba/S FL mid Oct
-TS FL Pan early Nov

6) 1876:
-H/Leewards/MH VI and PR/H Hisp/E Cuba/NC mid Sep
-TS Windwards late Sep/H Nicaragua early Oct
-H Caymans/MH W Cuba/H Keys and SW FL/TS Bermuda mid Oct

 These six very quiet first half of season El Niño analogs are suggesting an avg of 3 TCs (range 1-5), including 1.5 H (range 0-3) and 0.8 MH (range 0-2) yet to come that would have significant to major land impacts. Hopefully though it will be most like 1914 or otherwise 1905 at the worst!

https://www.nhc.noaa.gov/data/

18 hours ago, NorthHillsWx said:

Might as well circle my house and add D4 on next drought monitor. We’ll have to wait 10 more months for another AN month of rain I guess 

1. This very strong El Niño has a good chance to start helping out you and other SE dry areas by Nov and hopefully would then continue on/off through March as climo suggests.

2. I ended up getting very little from the late afternoon thunderstorms. It was only ~0.04”.