GaWx

We’re getting hit hard with what looks like a severe thunderstorm even though it’s not warned yet! It started at 7:15PM.

On 9/8/2026 at 12:48 PM, GaWx said:

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

 After having a Medi-TC on both Sep 8th UKMET runs (TCG late 9/13 to early 9/14), the subsequent 5 runs’ textual output showed nothing. But the newest UKMET (12Z 9/11 run) brought it back albeit slightly delayed vs the two 9/8 runs with TCG ~18 hours later. This run gets it all of the way down to 986 mb. Wouldn’t it be amazing for the Mediterranean to have a TC stronger than the strongest so far in the Atlantic?

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 78 HOURS
FORECAST POSITION AT T+ 78 : 34.5N 13.5E

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 15.09.2026 84 34.1N 14.1E 1010 30
1200UTC 15.09.2026 96 35.3N 16.5E 1003 43
0000UTC 16.09.2026 108 35.8N 16.7E 998 51
1200UTC 16.09.2026 120 35.4N 15.6E 993 46
0000UTC 17.09.2026 132 35.0N 17.3E 992 41
1200UTC 17.09.2026 144 35.1N 19.7E 989 51
0000UTC 18.09.2026 156 35.0N 22.5E 986 60
1200UTC 18.09.2026 168 35.2N 26.1E 991 48

@LongBeachSurfFreak

7 minutes ago, 40/70 Benchmark said:

How about region 4?

Nino 4 on latest UKMET strengthened slightly from a peak of ~+1.3 in Sep on the Aug run to a peak of ~+1.4 in Nov on the new run:

Aug run: peak of ~+1.3 in Sep (non-relative)

Sep run: peak of ~+1.4 in Nov (non-relative)

The UKMET, which pretty much nailed the 2023 ONI peak of ~+2.0, just updated for Sept: it peaks at ~+3.3 in Nov:

 The prior run (Aug) had peaked at only +3.1:

Regarding Nino 1+2, it also strengthened:

New run: a little >+4 (this like for 3.4 above is not relative and thus doesn’t taken into account GW well):

Prior run (Aug): ~+3.8

Mean of last 3 days worth of CFSv2 runs has this for Sep 25-Oct 1st:

The latest Euro Weeklies suggest to watch the Gulf during Sep 28-Oct 4th:

Latest 10 day CFSv2 ens mean for RONI shows the downward trend continuing: note for SON through NDJ how much lower are the blue lines (the most recent 8 members) vs the red lines (the earliest 8 members):

The just released WCS daily PDO for yesterday was up to -0.58! They haven’t been this high since way back in late June. It has risen ~1.07 over just the last 10 days. It had dipped to as low as -2.19 on Aug 1st. In case anyone is wondering, it hasn’t been red since it went barely positive on ~6 dates between 3/31/25 and 4/19/25 (highest was ~+0.08 on 4/5/25). One can also see it barely missed going red on 3/1/26. But unlike then and Mar-Apr of ‘25, there’s obviously now a supportive for a higher PDO full fledged very strong Nino:

I got ~0.6” 9-10AM from a nice batch of convection moving NNE over almost the entire SAV area.

9 minutes ago, 40/70 Benchmark said:

1958, 1987 and 1973 look like best matches to me.

I’d love this combination for the SE US!

8 hours ago, mitchnick said:

Except the 2 elephants in the room, 2/83 and 1/16, did make it up the coast, especially 2/83.

Edit: Forgot 2/58 & 3/58. Up the coast as well.

Also,

-3/24/1983 Miller A Gulf coast major snowstorm that crossed over N FL and then offshore the SE

-2/8-10/1973: historic Miller A deep Gulf snow storm that crossed C FL to well off SE coast

3 hours ago, gallopinggertie said:

While obviously not in the same ballpark as Iniki, Lowell seems to be the worst hurricane impact to Kauai since that one:

https://www.civilbeat.org/2026/09/hurricane-lowell-parts-of-kauai-like-a-war-scene/

A lot of gusts over hurricane strength in Kauai were reported, including at spots near sea level. Lihue’s highest sustained wind was 61 mph so the island did end up getting 50-knot winds. 

https://www.weather.gov/hfo/lowellpns

Thanks for that info.

 It seems that this has been a really bad year for Hawaii! When was the last season as bad as this? And the season is far from over!

-H Lala: extreme rainfall and very strong winds to H force in some cases

-TS Moke: additional heavy rains along with gusty winds only a week after Lala thus hampering recovery efforts

-H Lowell: lots of damage from sustained TS force/gusts to H force W islands, significant storm surge, and very high waves 

47 minutes ago, Weather Will said:

JB in a recent post shows data that the El Niño is leveling off below projections.  Any comments from the experts?

I’ve been following this closely. CFSv2 has dropped RONI peak from +3.5 to +3.0 over last month or so due to August pause. That’s just a pause though and notable 3.4 warming has finally resumed. But I don’t see it catching back up. Thus,  I’m currently at +3.0 for my educated guess.

 The BoM is way up at +3.6 and will likely bust too high like it did in ‘23. However, its SST anomalies are based on a dataset that’s ~0.3 to 0.4 warmer than ERSST, which NOAA uses, and which just adds confusion.
 
 Keep in mind that 1+2 has recently been strong thus making it the most E based on record for early Sept. beating 1997.

 In my two Maroon Bells posts above where I mentioned elevations, I meant I was hiking at 9.5-9.7K ft, not 11.5-11.7K feet lmao. Sorry for the typo!

 I came back to warm/humid GA last week. I hope to return next summer! The change hit me like a ton of wet hot bricks!

@mayjawintastawm@Chinook@ValpoVike

55 minutes ago, OSUmetstud said:

Isnt a NOAA monthly RONI peak of 3.0 equivalent to 3.6 for BOM? Like what's even the issue lol. 

There's an approximate difference of 0.6C in the July verification data between ERSSTv6 and the GAMSSA. 

NOAA's ERSSTv6 does not use any satellite SST data and has 2x2 degree resolution. It’s extremely conservative compared to the verification data for ECMWF and BOM. 

July ‘26 ERSSTv6 relative 3.4 was +1.333 per this:

https://www.cpc.ncep.noaa.gov/data/indices/Rnino34.ascii.txt

 Do you have a link to the monthly GAMSSA data?

Using the image below, the July ‘26 relative 3.4 BoM is ~+1.7 meaning a difference of ~0.37 between it and ERSSTv6:

7 hours ago, mitchnick said:

Meanwhile, for those planning on a fishing trip off Japan, PDO up to -.73 as of yesterday. 

Thanks, Mitch. That means the WCS PDO has risen ~0.92 over just the last 9 reporting days, and that’s the highest daily WCS PDO since way back on June 30th:

14 minutes ago, OSUmetstud said:

And im talking about the peak. 3.4 taking a bit longer to get to the forecast heights does not mean that the peak will be wrong. The record trades are there..the record subsurface etc. 

The ecwmf from a few days ago had a RONI of 2.15 for July with a peak around 3.3C. The BOM RONI of 2.25 with a peak of 3.7C is not even that different relative to its own dataset. 

 This is what I predicted on 8/24/26 for monthly/trimonthly RONI peaks (+3.0/+2.8), which would still be record warm peaks. I’m sticking with these for now. Let’s see what happens. I’ll use NOAA for verification, of course:

“I’m now predicting that the actual monthly RONI peak (in or near Nov) will only be ~+3.0 with a trimonthly peak only ~+2.8. That +2.8 trimonthly would still be a record warm RONI going back to 1950 beating 1982’s +2.4. So, it would still be historic for sure. But it wouldn’t be nearly as warm as the ~+3.3-3.5 trimonthly RONI peak of many runs of various models.”

13 minutes ago, OSUmetstud said:

I think assuming the relatively poor verification of a single month of August is bad logic. Every month prior to the past verified near or higher than models effectively. The warm water is still there and will eventually head west. BOM RONI forecast of 3.7 is effectively an ERSSTv6 RONI forecast of 3.0. Given the sst dataset and satellite integration. It’s in line with other models just biased that warm direction. 

I said in my post that EVERY month since April verified significantly too warm. That’s five months in a row, not just August.  I pointed out Aug because your two maps showed how much Aug had to be revised down. But April, May, June, and July also had to be similarly revised significantly down. Like for Aug, I’m talking about when each was the then current month. In other words, these were very poor forecasts considering they were then the first month. I’ve got all of the maps saved and can post them if necessary.

 In Sept of 2023, the UKMET did much better than the way too warm BoM and was about the best of all models.

Sept ‘23 UKMET progged ONI peak ~+2.0, which verified almost perfectly:

I’ll be anxiously awaiting the Sept ‘26 UKMET ONI peak forecast. Here’s August of ‘26: ~+3.0. Keep in mind that this is ONI, not RONI!

https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/el-nino-la-nina

58 minutes ago, OSUmetstud said:

Bom weekly data runs hotter than other agencies so you gotta compare apples to apples. The latest forecast compared to the one from just under a month ago:

 

 

 Yep, the BoM monthly relative peak actually rose ~0.1 over the last month to ~+3.7, very much unlike the drop of 0.5 of the CFSv2 RONI trimonthly peak. Also, it unlike most others keeps it almost that high in Dec.

 I expect BoM will bust significantly too warm for this progged relative monthly peak of +3.7 like it did in 2023, when it was the warmest and verified way too warm. Also, note that every month since April on the BoM has busted significantly too warm. One can even see that for Aug by comparing your two graphs: the Aug 8th run had Aug way up at +2.7. The Sep 5th run lowered it down to +2.35. (I believe that the BoM uses a different dataset anomaly that makes it warmer than NOAA as you probably realize. I think it uses the warmer CRW as a base at least to an extent. That only adds to confusion.)

The BoM (AUS-Access) had a whopping +2.9 for its peak forecast in its Sept ‘23 run! NDJ verified 0.9 too warm and DJF verified 1.1 too warm vs the NOAA ONI table seen at the link at the bottom of this post:

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/oni/v6/

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.