GaWx

This last post I made about him is to make sure I’m not losing my mind. Also, communicating to him and actually getting a response is very difficult. So, I’d rather just talk to my ENSO thread buddies here and see what y’all think.

What in tarnation is Bastardi talking about….why is he saying 2010-1 is a 30 mb QBO analog to 2025-6? They’re opposites! Can someone here make sense of this? Metric 2010/11 (Actual) 2025/26 (Forecast) Similarity / Difference QBO Phase at 30 hPa – Oct +8 m/s (weak westerly) +10 to +12 m/s (moderate westerly) High similarity – both start in waning westerly phase QBO Phase at 30 hPa – Dec –5 m/s (early easterly onset) –8 to –12 m/s (early easterly) Very close – both transition in December QBO Phase at 30 hPa – Jan–Feb –25 to –30 m/s (strong easterly peak) –22 to –28 m/s (strong easterly) Excellent analog – both reach deep easterly regime QBO Descent Rate ~1 km/month (normal) ~1 km/month (normal) Identical Vertical Structure (50–10 hPa) Easterlies descending from 20 hPa → 50 hPa by Feb Easterlies descending from 15 hPa → 50 hPa by Feb Near-identical shear zone timing ENSO State Moderate La Niña (ONI: –1.4°C) Weak La Niña (ONI: –0.6 to –0.9°C) Moderate difference – 2010/11 colder; 2025/26 milder baseline Polar Vortex Response Major SSW on Jan 20 → vortex split Elevated SSW risk (30–40% probability) Similar setup, but 2010/11 had confirmed SSW Northern Hemisphere Winter Outcome • Coldest U.S. East winter in 30 yrs • Record snow: NYC 61", Chicago 57" • Blocked pattern (–NAO/–AO) • Above-average cold/snow risk: East Coast, Midwest, N. Europe • Potential blocking, but less extreme than 2010/11 Strong analog for pattern, but amplitude likely lower due to weaker La Niña

AAM, which as expected has risen to near neutral after a long period of solid -AAM, is progged to return to La Niña supporting solid -AAM in early Nov: @snowman19

-Atlantic 2025 ACE finally just reached 100. -Though Melissa has yet to produce much ACE (2.2), there’s a whole lot of potential based on the NHC forecast of a combo of very slow movement for many days and reaching cat 4 status in a few days. IF this all materializes, we’d realistically be looking at the possibility of 30+ more ACE though forecasting the ultimate intensity is at a well above average difficulty for this storm. This is still struggling with shear and thus has been holding pretty steady. On the low end, this could never get much above cat 1 and end up with <15 total ACE. Of course, Melissa may not be the last storm. My pre-season prediction was 139 by the way.

Chris, Thanks. I still don’t see why the reduction of sulfates would cause such a sudden warming in the Pacific over a short period in early 2023. That still seems odd and thus it’s pretty fascinating!

I wouldn’t at all be surprised if IOD were to go positive as early as January based on past seasonal patterns and the recent positive favored IOD era we’re now in. If El Niño is going to occur next year, I’d think that would probably also help it rise.

Hey Brian, I checked the coordinates as Gilbert passed over Jamaica: It went from 17.6N, 75.3W to 18.3N, 78.5W over a 12 hour period. Per a lat/long mileage calculator, that’s 216 statute miles, which means a brisk 18 mph. That’s a whopping 6 times faster than the very slow average of 3 mph that Melissa is forecasted to move while adjacent to Jamaica! So, Gilbert held onto its strength while moving right over it at 18 mph. How would Melissa do moving a mere 3 mph but just south of the island? I don’t see how it wouldn’t weaken some, possibly significantly, at some point during that 48 hour period if it is initially at MH strength, even if not immediately due to drier inflow from Jamaica.

Hey Chris, If the sudden early 2023 spike was due to sharp mid-latitude Pacific warming, then what caused that sharp early 2023 Pacific warming?

Thanks Charlie, This tells me that they still don’t know why there was a sudden spike in the first half of 2023. Just a lot of speculation.

I also wonder about that as the highest mountain on Jamaica is over 7,000 feet up! So, hopefully it won’t although it is likely that the enormous rainfall potential is the biggest threat, regardless. 12Z Icon: weaker with strongest being 992 mb near Haiti per WxBell.

Based on the last 11 years or so (back to when the SAI was first tracked in Jerry’s autumn Siberian snowcover threads), the SAI connection to a winter -AO hasn’t worked well at all. I remember that first Oct (maybe Oct of 2014) having a large SAI and getting many of us excited only to end up with a strong +AO winter. So, I don’t think that the SAI matters one way or the other these days. It used to correlate well, but not since it became famous. Maybe it was shy and couldn’t take the popularity.

It’s highly likely that the IOD is now near its lowest of this cycle per climo. Met. autumn is by far the season when they dip the furthest in a cycle. This is the link to NOAA monthly IODs back to 1870 (I think I got this from snowman): https://psl.noaa.gov/gcos_wgsp/Timeseries/Data/dmi.had.long.data Looking back to 1950, these were when the lowest cyclical monthly lows (<-0.7) were hit: 7/2016, 10/1998, 10/1996, 6/1992, 6/1989, 9/1981, 8/1980, 10/1975, 10/1974, 9/1973, 9/1971, 9/1968, 10/1964, 10/1960, 8/1959, 9/1958, 7/1956, 9/1955, 7/1954 Analysis: -# months since 1950 with these minimums: Sept and Oct each had 6 followed by July with 3, and June and August each with 2. So, all were June-Oct. So, IOD tends to dip to lows ~3 months earlier than ENSO dips. -With no sub -0.7 cyclical low since 1950 in Nov, it would be very surprising if the IOD didn’t rise substantially next month. -Sub -0.7 months have been much less common since 1998 as overall average IODs have risen substantially -Positive IOD months used to be pretty rare but since 2006, 60% have been positive. Since 2017, 70% have been positive! -1870-1899 had 6% positive, 1900-1924 had 4%, 1925-49 had 8%. There were positives in 12% of months during the 1950s. 28% during the 1960s, and 33% during the 1970s. There was a temporary drop back to 23% during the 1980s. Then positives rose to 37% during the 1990s, 43% during the 2000s, 59% during the 2010s, and 60% during 2020-4. Does anyone know why the average IOD has risen so much since the early 1900s and continues to rise?

The hurricane models often overdo intensity by a lot, regardless.

Didn’t the 2023 warming come in way too early to be attributed to the 2023-4 El Niño? I distinctly recall the discussions here and elsewhere about that because it started in spring (as early as March) and also the possibility that Hunga Tonga was the main factor due to the enormous amount of water vapor sent up into the stratosphere. All of this remains mysterious to me.

18Z Euro gives much of Jamaica near or just over 20” qpf with heavy rain still likely continuing for a few more hours with the storm still centered over SW Jamaica and SLP way down at 943 mb, which would apparently be the record low per what I read. Lowest on record 958 (Charlie of 1951) followed by 960 (Gilbert of 1988). It’s then moving slowly NNE while SSE of a strong upper trough that’s then over the E US.

I love this look for Halloween with quite a chilly one in much of the E US! Nice +PNA:

Natgas was relatively little changed today, which is indicative of little change in the GEFS/EPS week 2 forecasts for the E US. So, the cooler model runs released Mon and even moreso on Tue for next week, held up well today. The mainly mild levels of modeled E US HDDs have not returned. True autumn seems to be here.

1988-9: 0.9” (Feb) 1989-90: 8.0” (Dec) (record) Same consecutive years for SAV

BULLETIN Tropical Storm Melissa Advisory Number 2 NWS National Hurricane Center Miami FL AL132025 500 PM EDT Tue Oct 21 2025 ...HEAVY RAINS EXPECTED TO SPREAD OVER HISPANIOLA DURING THE NEXT COUPLE OF DAYS... SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...14.2N 73.0W ABOUT 305 MI...495 KM S OF PORT AU PRINCE HAITI MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 15 MPH...24 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES Tropical Storm Melissa Discussion Number 2 NWS National Hurricane Center Miami FL AL132025 500 PM EDT Tue Oct 21 2025 Satellite data indicate that Melissa is struggling in strong shear, which has been the theme for many systems over the deep tropics this year. The low-level center of the storm is exposed to the west of the main area of thunderstorms. Air Force Hurricane Hunters have been investigating the system this afternoon and found that the minimum pressure is around 1003 mb. Based on their observations, ASCAT passes, and Dvorak estimates, the initial intensity is held at 45 kt. Melissa's wind field is also quite asymmetric, with most of the tropical-storm-force winds occurring on the system's east side. Some of the outermost northern bands are approaching Hispaniola, and these heavy rains are expected to spread across that island during the next couple of days. Melissa is a little south of the previous track and it continues to move westward at about 13 kt. There has been no change to the track forecast scenario, which remains complicated. Over the next couple of days, there is fair confidence that Melissa should slow down and gradually turn to the northwest or north and approach Haiti and Jamaica late this week. The motion after that appears to be linked to how strong and vertically aligned the system gets, and that is when the models diverge. If Melissa organizes like the GFS predicts, it could turn northeastward into the weakness in the ridge and move over Hispaniola. Conversely, if Melissa remains sheared and lopsided, it will likely stall and eventually drift westward as a ridge builds north of it. Given the expected continued shear, the NHC track forecast leans toward the latter scenario. This prediction is a little left of the previous forecast and remains a blend of the latest Google DeepMind ensemble mean, the corrected consensus aid HCCA, and simple consensus TVCA. Although the ocean is very warm, the models suggest that the vertical wind shear could persist over Melissa during the next few days. In addition, there is also some dry air in the storm's vicinity. Based on these mixed signals, the strengthening trend is expected to be slow. In fact, the new guidance supports nudging the short term intensity down a bit. If Melissa remains over the Caribbean late this week and over the weekend, the upper-level winds could become more conducive for more significant strengthening. The NHC intensity forecast is in best agreement with the HCCA model. FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 14.2N 73.0W 45 KT 50 MPH 12H 22/0600Z 14.5N 73.7W 45 KT 50 MPH 24H 22/1800Z 15.0N 74.4W 50 KT 60 MPH 36H 23/0600Z 15.5N 75.0W 55 KT 65 MPH 48H 23/1800Z 16.1N 75.1W 60 KT 70 MPH 60H 24/0600Z 16.5N 75.0W 60 KT 70 MPH 72H 24/1800Z 16.9N 75.0W 60 KT 70 MPH 96H 25/1800Z 17.3N 75.0W 65 KT 75 MPH 120H 26/1800Z 17.5N 75.2W 75 KT 85 MPH $$ Forecaster Cangialosi

NG was up another 2.4% today on even colder modeled HDDs vs yesterday: 0Z EPS (purple) had 7 more HDDs vs prior EPS: Then later the 12Z GEFS (purple) had several more HDDs than the prior GEFS runs: @mitchnick@LakePaste25 @Stormchaserchuck1

12Z -GFS (Hisp.), CMC (C Cuba), Icon (weaker than recent runs but still E of Jamaica to Jamaica) and UKMET (Nic/Honduras border) are pretty similar to recent runs. UK: TROPICAL STORM MELISSA ANALYSED POSITION : 14.7N 70.8W ATCF IDENTIFIER : AL132025 LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 21.10.2025 0 14.7N 70.8W 1007 36 0000UTC 22.10.2025 12 14.7N 73.1W 1005 33 1200UTC 22.10.2025 24 15.0N 74.3W 1005 36 0000UTC 23.10.2025 36 15.5N 75.0W 1004 35 1200UTC 23.10.2025 48 16.1N 76.4W 1005 35 0000UTC 24.10.2025 60 16.4N 76.4W 1005 27 1200UTC 24.10.2025 72 16.6N 76.7W 1005 30 0000UTC 25.10.2025 84 16.4N 78.0W 1005 27 1200UTC 25.10.2025 96 15.7N 79.7W 1006 25 0000UTC 26.10.2025 108 15.1N 81.5W 1005 23 1200UTC 26.10.2025 120 15.0N 82.8W 1005 24 0000UTC 27.10.2025 132 15.5N 84.0W 1006 22 1200UTC 27.10.2025 144 CEASED TRACKING

Tropical Storm Melissa Discussion Number 1NWS National Hurricane Center Miami FL AL1320251100 AM EDT Tue Oct 21 2025Satellite images, regional Caribbean radar data, and surface observations indicate that invest 98L has developed a well-defined center and organized deep convection to be designated a tropical cyclone. A ship report that recently passed near the center of the system reported a minimum pressure of about 1003 mb. Satellite imagery shows the system is asymmetric, with the low-level center near the western edge of the central dense overcast. The initial intensity is set at 45 kt, based on a blend of the latest satellite intensity estimates, marking the formation of Tropical Storm Melissa. An Air Force Hurricane Hunter aircraft is scheduled to investigate the system this afternoon, and their data should provide a better assessment of Melissa's strength and structure. The system was moving very quickly westward over the past several days, but it has slowed down significantly this morning, which has likely helped Melissa form. The initial motion is estimated to be 280/12 kt. Melissa should continue to slow down and gradually turn to the northwest and then north during the next couple of days toward a weakness in the subtropical ridge. This motion will likely take the storm very near the southwestern tip of Haiti and Jamaica by Thursday. After that time, the guidance diverges significantly with some models like the GFS and HWRF showing a motion to the northeast into the weakness, while the other solutions show a stall or a westward drift on the south side of a building ridge. An examination of the GFS, ECMWF, and Google DeepMind ensemble suites suggest that the majority of the members show Melissa not moving into the weakness and remaining in the Caribbean Sea throughout the week and into the weekend. The NHC official track forecast lies between the Google DeepMind ensemble mean track and the correct consensus aid, HCCA.Melissa is expected to be over the very warm waters of the Caribbean, but the models suggest that vertical wind shear will be moderate with some dry air in the vicinity of the storm during the next few days. Based on these mixed signals, the strengthening trend is expected to be slow and steady, not rapid. However, the future intensity of Melissa is linked to the track and since that is quite uncertain beyond a couple of days, the strength of the storm is also quite uncertain. The NHC intensity forecast is in best agreement with the HCCA model.Key Messages:1. Melissa is expected to bring heavy rainfall and the risk of significant flash flooding and the danger of landslides to portions of Haiti and the Dominican Republic through the weekend.2. A Hurricane Watch has been issued for the southern coast and Tiburon peninsula of Haiti. A Tropical Storm Watch has been issued for Jamaica. Preparations to protect life and property should be completed by Thursday.3. There is significant uncertainty in the track and intensity forecast of Melissa. Interests elsewhere in Hispaniola and Cuba should continue to monitor the latest forecasts.FORECAST POSITIONS AND MAX WINDSINIT 21/1500Z 14.3N 71.7W 45 KT 50 MPH12H 22/0000Z 14.4N 72.8W 50 KT 60 MPH24H 22/1200Z 14.8N 73.5W 55 KT 65 MPH36H 23/0000Z 15.3N 74.2W 60 KT 70 MPH48H 23/1200Z 15.7N 74.5W 60 KT 70 MPH60H 24/0000Z 16.1N 74.6W 60 KT 70 MPH72H 24/1200Z 16.5N 74.5W 60 KT 70 MPH96H 25/1200Z 16.9N 74.5W 65 KT 75 MPH120H 26/1200Z 17.2N 74.9W 70 KT 80 MPH$$Forecaster Cangialosi/Bucci

The 12Z position is estimated to be near 14.3N, 71.3W, per this:AL, 98, 2025102112, , BEST, 0, 143N, 713W, 45, 1003, LOThus we now know with more confidence that the 6Z GFS’ 6 hour position near 14.3N, 70.4W is ~60 miles too far east. It’s likely going to be designated as TS Melissa at 11AM per this: ```AL, 13, 2025102112, , BEST, 0, 143N, 713W, 45, 1003, TS, 34, NEQ, 100, 70, 0, 40, 1009, 150, 35, 55, 0, L, 0, , 0, 0, MELISSA, M, 0, , 0, 0, 0, 0, genesis-num, 035, TRANSITIONED, alB82025 to al132025,``` Melissa’s center is on the W edge of the convection meaning nearly half naked as has been expected initially while the shear is strong.

Whereas the 6Z Euro shifted 200-250 miles NE of the 0Z/12Z runs for that forecast time, keep in mind that the 6Z Euro op is near the NE most 6Z EPS members: 6Z Euro op 144: 40 miles E of easternmost point of Jamaica 6Z EPS 144: large majority are 300-500 miles WSW to SW of the Euro op!

1. 6Z Euro 144: significant shift NE vs 0Z 150 and 12Z 162 (which were both 150-200 miles SSW to SW of Jamaica) with the 6Z 40 miles E of Jamaica. That’s a 200-250 mile NE shift from the 0Z/12Z! 2. Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 AM EDT Tue Oct 21 2025 For the North Atlantic...Caribbean Sea and the Gulf of America: 1. Caribbean Sea (AL98): Satellite, radar, and surface observations indicate that the area of low pressure over the central Caribbean Sea appears to be developing a well-defined center, and is already producing winds up to 45 mph. A tropical storm is expected to form later today while it slows down over the central Caribbean Sea. Heavy rainfall and gusty winds are possible over portions of the ABC Islands during the next day or two. Interests in Puerto Rico, Hispaniola, Jamaica, and Cuba should monitor the progress of this system as there is a risk of heavy rain and flooding, strong winds, and rough surf later this week. The Air Force Hurricane Hunters are scheduled to investigate the system later today. For additional information on this system, including Gale Warnings, please see High Seas Forecasts issued by the National Weather Service. * Formation chance through 48 hours...high...near 100 percent. * Formation chance through 7 days...high...near 100 percent. High Seas Forecasts issued by the National Weather Service can be found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php Forecaster Cangialosi