GaWx

On 10/20/2026 at 7:57 PM, Chinook said:

Anybody reading this from Arizona? There's a rare enhanced risk for severe storms in Arizona, with 5% risk of tornadoes.

 I just read that part of AZ on Wednesday had a tornado watch for the first time in 15 years!

It appears per models that due to a combo of a large Tahiti SLP rise/smaller Darwin fall and despite it being way down at -43 today, it should break the very long current -SOI streak and go positive by ~Oct 25th. That means that the current -SOI streak would end near 74 days.

23 minutes ago, LongBeachSurfFreak said:

Absolutely. You can see the fronts are gone in Josephine. But the convention is not particularly deep near the center. It also has a relatively large area of tropical storm force winds in the northern quadrant (gradient driven)


.

1. For you: How’s the surf in your area?

2. For all: Can a subtropical cyclone attain hurricane force winds but still not be classified as tropical? We know there are ST depressions and storms, but I’ve never heard of a subtropical H. Why not?

1 hour ago, NorthHillsWx said:

93L looks subtropical. Looks much more tropical in nature than the last nor Easter everyone was freaking out over on social media. This one is actually maintaining convection over the center, has highest winds in central convection, and is over the Gulf Stream 

Special Tropical Weather Outlook
NWS National Hurricane Center Miami FL
340 PM EDT Wed Oct 21 2026

For the North Atlantic...Caribbean Sea and the Gulf of America:

Special Outlook issued to raise formation probabilities for AL93

Offshore of the East Coast of the United States (AL93):
Updated: Shower and thunderstorm activity has become better
organized in association with a storm-force low pressure area
located a few hundred miles off the mid-Atlantic United States
coast. The system has continued to acquire subtropical
characteristics today and has become separated from fronts. If
these trends continue, a subtropical storm could form later this
afternoon or tonight while it accelerates northeastward.

Regardless of the status of the system, high winds, coastal
flooding, and dangerous surf are expected along portions of the U.S.
East Coast during the next few days. For more information, including
hurricane-force extratropical wind warnings, please consult
statements and warnings from local National Weather Service offices
and the Weather Prediction Center, along with the High Seas
Forecasts and the Storm Warnings issued by the National Weather
Service.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...70 percent.

Evidently, this was already declared STS Josephine just a few minutes ago.

————————

12Z UKMET was still another having run it even though the text technically called it a TS (I don’t think it is capable of distinguishing T from ST):

TROPICAL STORM 93L ANALYSED POSITION : 36.7N 69.0W

ATCF IDENTIFIER : AL932026

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 21.10.2026 0 36.7N 69.0W 995 44
0000UTC 22.10.2026 12 37.5N 69.4W 991 47
1200UTC 22.10.2026 24 38.8N 68.4W 985 49
0000UTC 23.10.2026 36 39.9N 65.1W 984 66
1200UTC 23.10.2026 48 41.4N 59.5W 982 61
0000UTC 24.10.2026 60 43.0N 56.6W 986 51
1200UTC 24.10.2026 72 43.0N 54.8W 990 46
0000UTC 25.10.2026 84 42.8N 51.4W 994 41
1200UTC 25.10.2026 96 41.7N 45.7W 1004 38
0000UTC 26.10.2026 108 CEASED TRACKING

 The GEFS NAO prog continues to correct to more positive. Check out how much it has risen over the last 8 forecast days:

Oct. 13th fcast mean had it never getting >+1 and that on Oct. 15th with it later down to sub -0.8 for 6 days with it continuing through end of forecast period; It had Oct. 27th down at -0.9:

 Today’s forecast is so much more positive: it actually peaked way up at +1.73 on Oct 19th and with forecast now dipping only to -0.7 on Oct 22nd followed by a sharp rise to +0.8 on Oct 27th (vs the  Oct 13th run having it down at -0.9):

 Per @Stormchaserchuck1this solidly +NAO in Oct. is actually a good sign if one wants the chance for a -NAO domination in winter to increase. I’m just passing that along as it isn’t my own idea. Forecast models are suggesting a good chance of a -NAO in Feb, regardless. Before that will be tough imho due to at least solar but we’ll see.

6 minutes ago, BlizzardWx said:

What could be interesting is if el nino forcing indeed is summarily shoved eastward could the typical warm anomaly that sits over the Great Lakes be pushed far enough east that we get more cold air into the US like the CFS is showing? We could also get the moisture from having an active storm track into the south like you would expect in strong el nino. So I am not saying I am buying it, but just wondering out loud on what it will actually mean. Does shifting the forcing east linearly shift the pattern? That isn't always the case either. 

Absolutely that can happen with how E based it is progged to be! This is especially the case for Feb as the CFS has been showing. I’m expecting a very mild Dec and a mild to NN first half of Jan. Then the fun times could really get going starting late in Jan and especially in Feb and possibly continuing through early March.

 The CFSv2 for the last 2 months worth of daily 10 day mean runs has been persistent in showing Feb ‘27 to have an extreme couplet of a much warmer than normal E Canada and a cold dominant CONUS. No other mid-Oct. 10 day CFSv2 mean (back to 2012, its first one) has shown anything anywhere close to this, which has not only 80% of Conus BN but also a very mild E Canada acting as a very strong block:

 In this post in the main forum, I compared this mid-Oct CFSv2 forecast to all other CFSv2 mid-Oct forecasts for Feb (back to first one for Feb ‘12) and its implications regarding what may actually happen in Feb ‘27:

Aside: @buckeyefan1would you mind pinning this winter outlook thread? It is getting relatively little viewing and thus few posts (only 50 in 6 months) due to being so far down on the topics list even after a recent post since 5 other threads have already been pinned.

12 hours ago, MJO812 said:

Great video. This El Nino might screw up the warm forecasts.

https://youtu.be/4gP_R1OGeQ8?is=EA6MCfhV6sw9i-6k

Anthony,

 Maybe this person saw this latest 10 day CFSv2 mean for Feb ‘27 (Nino): 80% of CONUS BN; much AN E Canada:

 No other mid Oct 10 day mean for Feb back to 2012 has had anything even closely resembling this extreme couplet, and a cold dominant Feb US/much warmer than normal E Can have been on EVERY 10 day mean since they started going out that far in mid August! 
 
 Check out how much Feb of ‘27 differs from all other 10 day mean forecasts made in mid-Oct for other Febs back to the start of the CFSv2:

2026: 1% of CONUS BN; BN E Can:

2025: 0% of CONUS BN; BN E Can

2024 (Nino): 0% of CONUS BN; AN E Can

2023: 33% of CONUS BN; BN E Can

2022: 6% of CONUS BN; BN E Can

2021: 20% of CONUS BN; BN E Can

2020: 1% of CONUS BN; BN E Can

2019 (Nino): 5% of CONUS BN; BN E Can

2018: 20% of CONUS BN; BN E Can

2017: 3% of CONUS BN; BN E Can

2016 (Nino): 4% of CONUS BN; AN E Can

2015 (Nino): 0% of CONUS BN; BN E Can

2014: 4% of CONUS BN; BN E Can

2013: 1% of CONUS BN; BN E Can

2012: 15% of CONUS BN; BN E Can

 Feb: % BN Conus; E Can anom

‘27 (Nino): 80% BN US; much AN E Can

’26: 1% BN US; BN E Can

’25: 0% BN US; BN E Can

’24 (Nino): 0% BN US; AN E Can

’23: 33% BN US; BN E Can

’22: 6% BN US; BN E Can

’21: 20% BN US; BN E Can

’20: 1% BN US; BN E Can

’19 (Nino) 5% BN US; BN E Can

’18: 20% BN US; BN E Can

’17: 3% BN US; BN E Can

’16 (Nino): 4% BN US; AN E Can

’15 (Nino): 0% BN US; BN E Can

’14: 4% BN US; BN E Can

’13: 1% BN US; BN E Can

’12: 15% BN US; BN E Can

—————————————

Analysis of above: 

-Feb of ‘27 80% BN US vs only 33% (‘23) for next closest! Avg of only 7.5% BN US for 2012-26 and a mere 2% BN for the four El Niño cases!

-The other 4 Nino Febs had no more than 5% BN US! The two strongest Nino Febs had US BN of 0% (‘24) and 4% (‘16)! So, there’s virtually no resemblance to ‘27.

-BN in the SE US virtually nonexistent on any of 2012-2026 with most of them mild. But in stark contrast, 2027 has a very cold SE!

-Feb of ‘27 has by far the warmest E Can. Only 2 others had any degree of AN (much less intense than ‘27) and they were the 2 strongest El Niños (‘24 and ‘16).

——————

 In closing, Feb of ‘27 has been very persistently (for 2 months!) showing on the CFSv2 a highly unique (among all Febs on record) extreme couplet of a cold dominant CONUS and extreme blocking/very warm E Canada. The CFSv2 has been trying to tell us something it never has and though I’m not at all saying to trust it, I am suggesting that it not be dismissed.

The latest CFSv2 10 day mean prog for RONI for Oct is +2.5 and for Nov is +2.75. The current record high for any month since 1950 is the +2.5 of Jan of 1983. Judging by the blue lines all being at or below +2.75, this graph’s +2.75 mean for Nov is likely heading down in future 10 day runs. @40/70 Benchmark’s prediction for RONI is looking pretty good:

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

23 hours ago, GaWx said:

Indeed as it on today’s Euro Weeklies gets down to +14 in early Nov, weakest run yet. Nothing earth shatteringly weak but interesting, regardless:

Today’s Euro Weeklies 10 mb zonal mean wind prog is even weaker than yesterdays, which had its lowest at 14 m/s, with it down to 12 m/s:

Today’s GEFS NAO forecast is even more positive than yesterdays, which itself was much more + than last week’s GEFS: 

Today: gets down to only -0.6 and then quickly rises to +0.5 followed by drop back to 0:

Yesterday:

Last week: 

23 minutes ago, roardog said:

Beating that record is not a slam dunk yet then. 

Agreed

 The most similar that I found to what the Euro Weeklies are forecasting late Oct-late Nov were 2016-7, 2009-10, and 1979-80 with the last two being El Niños:

2016 La Niña: similar late Oct/early Nov though late Nov weaker

2009 El Niño: not as weak late Oct/early Nov and weaker mid Nov vs 2026 (dip ~2 weeks later than 2026)

1979 El Niño: not as weak late Oct but early to mid Nov similar to 2026 although late Nov much weaker vs 2026

16 minutes ago, roardog said:

What’s the record RONI? I forgot now.

Are you asking for the record relative trimonthly 3.4? Or the record relative weekly 3.4?

Weekly record of relative 3.4 is +2.9 (12/29/1982)

Trimonthly RONI record is +2.40 in DJF 1982-3.

Yesterday’s NOAA official relative weekly SSTa update for last week had this: note the 0.3 cooling in Nino 4 to -0.1 and that 3.4 stayed at +2.4:

07OCT2026         4.4        3.4        2.4        0.2
 14OCT2026         4.4        3.5        2.4       -0.1

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

This is now Invest 93L.

 0Z UKMET almost gets to H strength:

TROPICAL STORM 93L ANALYSED POSITION : 35.0N 70.7W

ATCF IDENTIFIER : AL932026

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 20.10.2026 0 35.0N 70.7W 1004 37
1200UTC 20.10.2026 12 35.2N 70.5W 998 40
0000UTC 21.10.2026 24 35.5N 69.8W 998 45
1200UTC 21.10.2026 36 36.2N 69.5W 995 40
0000UTC 22.10.2026 48 36.9N 69.7W 989 51
1200UTC 22.10.2026 60 38.1N 68.1W 982 52
0000UTC 23.10.2026 72 39.4N 63.9W 975 63
1200UTC 23.10.2026 84 42.8N 56.7W 975 57
0000UTC 24.10.2026 96 45.9N 51.6W 986 54
1200UTC 24.10.2026 108 46.7N 48.5W 992 45
0000UTC 25.10.2026 120 48.0N 42.4W 991 45
1200UTC 25.10.2026 132 54.1N 32.9W 980 40
0000UTC 26.10.2026 144 CEASED TRACKING

3 hours ago, MJO812 said:

Euro shows a stretched PV in the long range. We never had a very strong El Nino like this so no one knows what wil happen.

Indeed as it on today’s Euro Weeklies gets down to +14 in early Nov, weakest run yet. Nothing earth shatteringly weak but interesting, regardless:

 Look how much the forecasted mean GEFS NAO has risen from its Oct 13th forecast to today’s forecast!

Oct 13th: peaking at only +1.0 on Oct 15th and then plunging to -1/remaining down at -0.9 on Oct 27th:

Today’s prog (Oct 19th): peaked not til today way up at +1.73 and already after a dip to -0.8 back up to ~0 on Oct 27th:

 I’m assuming this drastic change is related to the actual strong storm offshore the E US that wasn’t even forecasted back on Oct 13th thus leading to lower actual SLP in Iceland today than progged 6 days ago.

Daily NAO: https://ftp.cpc.ncep.noaa.gov/cwlinks/norm.daily.nao.gefs.z500.120days.csv

 After a decent rise in last week’s release from +0.59 to +0.88, the latest weekly IOD update had no change. But that could easily just be a short-lived pause in the general upward trend since June 1st. Based on the history of IOD usually maxing out by Nov, I’m giving it another month to see if we get a very strong IOD peak this late autumn/early winter. One can see on this chart how much stronger was the +IOD in autumn 2023! At this time then, the IOD was already peaking way up at +1.91! Even in 2019 on this date it was way up at +1.94!

https://www.bom.gov.au/clim_data/IDCK000072/iod_1.txt?1791781094025

@snowman19

@LibertyBellasked me this:

“Are these similar to the naturally occurring doldrums at the horse latitudes that Columbus experienced?”

 ————
My answer: Good question. Quite possibly.

13 hours ago, LongBeachSurfFreak said:

For sure, it’s been shockingly cold in the Arctic this summer. So cold air is available to source. And anyone that claims to know exactly what is going to happen during an unprecedented event is just wishcasting. A very warm start, possibly record warm and of course wet is starting to lock in. After that the amount of uncertainty is off the charts. That’s why I think something like 83 or 16 is really on the table just as much as 73 or 98.


.

 
 I closely followed the DMI site’s 80+N Arctic temps showing 2026 being THE coldest on record (back to 1958) by a good margin late May-early August and posted many times about that here and in the Arctic Ice thread. There’s little doubt it was notably colder there than recent summers, especially N of Alaska, and it helped the Arctic ice.

 However, as@bluewave@OSUmetstudemphasized in discussions with me, they convinced me to think that comparing to DMI charts prior to 2002 per Chris (see his quote below) and possibly even to all years through 2025 per @OSUmetstud (due possibly to a cooler ECMWF bias introduced in May of 2026) MAY make the appearance of the summer of 2026 being significantly colder than all years 1958-2025 per the DMI graphs deceptive because of the DMI ECMWF data.
 

Per Chris in Arctic Ice thread:

“Even the less reliable ECWMF only starts in 2002, so an apples to apples comparison to any year earlier than 2002 can’t be made.”

——————

 However, I’m still very open-minded about just how cold it really was in 80N+ late May-early Aug relative to 1958-2025, especially 2002+, pending continued research of other knowledgeable people’s opinions. Look how cold June 2026 was N of 80N per actual ERA5 reanalysis:

1. only ~1/7 is in warmest 1/2 of years vs ~6/7 in coldest 1/2

2. a little >50% is in 4 coldest colors meaning coldest 11 of 87 while only ~6% is in warmest 11, which is <1/8 the size of coldest 11

3. ~25% is in coldest 3 of 8 while only ~1% is in warmest 3 of 87, which is a mere 1/25 of the size of coldest 3

This 80N+ close-up came from this image below: only the relatively small area (~1/7 of 80N+) of light green, beige, yellow, orange, and reds is warmer than the median while >50% (4 coldest colors or coldest 11 of 87) is 87%+ percentile cold!

 So, does this cold of an ERA5 reanalysis (in image above) actually support this cold of a DMI 80N+ June ‘26 (in image below)? Food for thought at least. Keep in mind that it says this at the DMI site, itself:

“The 'plus 80 North mean temperature' graphs can be used for comparing one year to an other.”

34 minutes ago, LakePaste25 said:

Classic CAD. In theory it should be more likely in El Niño due to less SE ridging.  

32 minutes ago, Typhoon Tip said:

Likely related ...

... for one, although the sample size is not appreciably large ( on the order of 10 or 12 spanning 200 years ), of those warm ENSO, something like 9 or 10 had these autumn hybrid like circulations.   Not meaning to say that is what's going on down there at this time, but... you know, if you're going to hybridize a gyre in that region, you wanna start with something like the theme we are in fact seeing so far ( the unusual end September coastal event that was over publicized (snark) being a fair example).  Some guidance couldn't resist and bored that thing down to almost 970 mb..  as it were ... it was just a pedestrian. But still very really and albeit asynchronous low - one which happens to fit the total idea. 

We are still in the correlation window so this weakness/tendency for another low there ... it's suggestive enough.

It's important to note however, El Ninos do not directly cause storm or no storm formation. 

 Thanks.
 So, since this pattern of this offshore low and associated cooler air in the E US is likely indirectly related to the very strong Nino, is this possibly a sign of things to come this winter?

1 hour ago, Typhoon Tip said:

I'm noticing that we are being sort of "cheated" from realizing a stunningly warm October along 80W over the continent, due to "pinch low" phenomenon and/or sneaky llv cool inserts, despite the fact that a truer polar branch of the westerlies (jet) has been situating N-W.  Technically a -PNAP baseline. It just one with limited warm benefits, because anticorrelary/anomalies are taking place within the more typical ridge region of the -PNAP...  Thus masking the former warmer signals to some degree.

The present extended out look has positive anomalies in the 500 mb non-hydrostatic heights ~ 70 % of the time over the eastern mid latitude continent.  This has been going on for awhile actually. In fact, we are like that now... yet have pervasive frost/freeze headlines throughout the OV and it's 25 to 30 F this morning throughout NE.  We've seen temperatures 80/60 with these heights in November before!   it's really interesting, this masking aspect.   

 Is the offshore E US strong low bringing down the cool air into the E US this entire week likely related to the very strong Nino?

0Z 10/12 GEFS forecast for 6Z 10/21: no offshore storm and thus no cool air pinned in E US:

0Z 10/18 GEFS forecast for 6Z 10/21: much cooler E US in reality associated with offshore strong storm working in tandem with 3 Canadian highs keeping cool dry Canadian air pinned in E US:

Cool air this week E US thanks to the above pattern consistent with Euro Weeklies’ significantly cooler change: (had been warm on runs from Oct 12-13 when no offshore storm)

^Further to the above: illustrates the E US cooling power of the offshore storm this week!