GaWx

Followup: This was the 11/30/24 CANSIPS fcast for last winter, similar in much of the N Hem including even colder/coldest 1981-2010 anomalies in N Hem again centered over W Lakes: What verified? It did well in most of the Conus but winter verified to be NN vs 81-00 in W Lakes/upper MW. The coldest was to the W in W Dakotas/SE MT, where Cansips was much too warm. So, is it possible that the CANSIPS has a cold bias in the W Great Lakes? @donsutherland1@mitchnick@SnowGoose69 *Edit: corrected for 2 typos

The new CANSIPS for DJF is the 9th in a row with the coldest winter anomalies (vs colder 1981-2010 than 1991-2020) in the N Hem centered over the W. Great Lakes: Any thoughts?

Here are before and after SSTs to see how much Melissa cooled the ocean on and near its track: 10/24/25: 10/30/25: So, it cooled only ~1C/2F around Jamaica/E Cuba (from slightly over 30C to near or slightly over 29C). Unfortunately, that wasn’t nearly enough to keep Melissa from exploding. Much of the area around the Bahamas also cooled some (perhaps ~0.5C/1F) but the full cooling may have to wait til the 10/31 SST map. Also, Melissa wasn’t as strong and was moving much more quickly through the Bahamas thus likely meaning less cooling influence. In contrast, note that most of the Gulf and far W Caribbean cooled hardly at all, if any, as they were too far west to be cooled by Melissa.

Thank you, snowman. Y’all may find this interesting. Eric Webb just posted this at another BB after I asked him the same Q: There's lots of co-variability between ENSO and the IOD, and there's a positive correlation between ENSO & IOD intensity. Oth, when you try to isolate the influence of the IOD alone here in the context of weak to moderate La Ninas, this is what happens: The Nov-Dec 500mb & SLP difference composite of +IOD & -IOD years with weak to moderate La Niña captures some of the things we're currently seeing like the very extended Pacific Jet/+EPO, +PNA, and even perhaps the -SAM/-AAO. The NAO is completely different this year though. Then he posted this: This is what happens if you take that difference composite through the winter. The big takeaway I glean from this is the transition from an early winter +PNA type pattern to a canonical Nina look w/ a +NAM/AO is much sharper in these winters with a bigger -IOD in the preceding fall. Also, the classic Seasonal Footprinting Mechanism (SFM) pattern is more prominent in Feb-Mar in the -IOD years, which would hasten the development of +PMM in the spring and be more favorable for El Niño development later next year. ———— So, Webb and you may be in agreement at least to an extent.

Very strange! When you go to https://www.americanwx.com/bb/ do you see what the first screenshot I posted shows with “General Forecasting and Discussion” showing and not “Weather Forecasting and Discussion”?

What are you saying this very strong Oct -IOD is going to cause in December in the E US? What’s your prediction?

Bump: I don’t think it’s my imagination. I’ll start from the main page: https://www.americanwx.com/bb/ This is what I see, which is a change from how it had been for years: ——————— What is different is seeing “General Forecasting and Discussion” instead of seeing the following below “Tropical HQ”. —————— So, now one has to click on “General Forecasting and Discussion” as an extra step before only after that being able to click on “Weather Forecasting and Discussion”, which then leads to seeing this thread. Are any others seeing this change?

It has risen from 3 to 19 in Jamaica.

Is it my imagination or does it really take an extra click to get to this thread now?

Today’s Euro Weeklies update: 1) 4th run in a row with a very weak SPV late Nov/early Dec with today’s having ~25% of members with a very early major SSW, the highest yet of any run! 2) After having warmed up significantly in the E US the last 3 runs for most of November/early Dec from the cold Nov 2-9 and then mainly NN Nov 10-Dec 7 of the Oct 26 run, today’s has cooled back down notably for much of Nov 10-Dec 7 and is downright cold for the new week (Dec 8-14) with a solid -AO for Nov 24-Dec 14. Keep in mind that the Euro often has trouble seeing cold too far out. So, seeing BN all the way out at weeks 5-6 in today’s run is noteworthy and will be followed closely for future trends. 500 mb week 6: 2m temps week 6:

Today’s Euro Weeklies update: 1) 4th run in a row with a very weak SPV late Nov/early Dec with today’s having ~25% of members with a very early major SSW, the highest yet of any run! 2) After having warmed up significantly in the E US the last 3 runs for most of November/early Dec from the cold Nov 2-9 and then mainly NN Nov 10-Dec 7 of the Oct 26 run, today’s has cooled back down notably for much of Nov 10-Dec 7 and is downright cold for the new week (Dec 8-14) with a solid -AO for Nov 24-Dec 14. Keep in mind that the Euro often has trouble seeing cold too far out. So, seeing BN all the way out at weeks 5-6 in today’s run is noteworthy and will be followed closely for future trends: ————— Week six H5: Week five 2m temps: Week six 2m temps:

Yeah, that is slightly lower than this site shows, which is at 32.72 as of 18Z today: https://cyclonicwx.com/climatology/ This site had it at 31.9 as of 12Z today. So, it appears that cyclonicwx is higher due to being updated sooner. Melissa looks to total out at ~33.5-34 as it transitions to ET. This will end up as the 3rd highest Atlantic storm ACE on record for so late in the season behind only the massive (~60) ACE of the Nov. 1932 Cuba H and Mitch of 1998’s 35.9.

Great advice! For anyone interested, that last YouTube link is no longer to a livestream. Here’s an updated storm-chaser Jeff P. (with his host) livestream from near Ground Zero. This is from decimated Black River on the coast. Jeff was just saying they need helicopters there ASAP because there are a whole lot of folks who are injured and need to be airlifted to a hospital. Edit: He just quoted a Reuters reporter he just saw who called this a “humanitarian crisis”. Edit 4:25PM: New live-stream Jeff P. link: they’re now driving N out of the devastated Black River:

New from Webb I have pretty high confidence December is gonna try to make things real interesting this year. I can’t quite figure out what’s going to happen in the heart of the winter this year. Do we get a mid winter thaw as we get an Indian Ocean to Maritime Continent orbit with another favorable S2S look later in January or do we keep the good times rolling throughout most of this period? If the tropospheric circulation anomalies can get anchored into the stratosphere (a stratospheric warming event for ex), that’s probably how we can keep the good times rolling well into January. The stratosphere likely won’t matter much for this first round of mjo forcing in December, but it probably will be an important factor in January and February I.e. could help keep the -NAO/-AO going beyond the timescale of the initial mjo forcing (as mentioned previously) or enhancing wave reflection Feb (+TNH) if its strong by then.

Webb posts on multiple forums because this isn’t from the Philly discord you mentioned.

From Eric Webb at another BB just now: A few other things I think that are playing into our favor at least for December: Being in a La Niña with a slower-moving and more amplified MJO (due in part to the easterly QBO) makes a subsequent -NAO and weaker polar vortex/-NAM more likely. The current global tropics SSTa are also almost the exact opposite of the MJO phase speed & SST correlation pattern derived from Suematsu & Miura (2021), favoring slower MJO events that typically have stronger and more consistent extratropical teleconnections as Yadav et al (2024) + Yadav & Straus (2017) and Tseng et al (2020) have argued respectively.

Live feed from chaser Jeff P. is linked at the bottom. He’s been stationed in a house in Santa Cruz (~20 miles inland and ~15 miles W of worst wind damage. Yesterday, he/his host tried to drive to Black River but could go only a couple of miles west to Lacovia due to roads that were washed out, had big potholes, had deep mud from the prior 4-6+ feet of extreme rainfall induced flooding/landslides coming off the nearby ridges, and had debris such as trees and utility poles (some made of concrete!) blocking the road. So, they kept having to turnaround and try different routes to no avail and thus went back to home base. Here’s a link to the recording of that 2 hr, 51 min never a dull moment live feed from yesterday (this isn’t live): ———————— In today’s (LIVE) feed, it looks like they took a different route initially to the E and SE (i.e. further away from the worst hit area) instead of W. Then they turned back W further S (only couple of miles from coast). They went W through Junction (15 miles SSE of Santa Cruz), Bull Savanna, and Flagaman. They were temporarily stopped at Pedro Cross, just a few miles E of Treasure Beach, because the road was being cleared. They resumed a NW course approaching Newell. LIVE feed: Edit: they’re now at Wally Wash Pond (11:33AM EDT) moving NW just a few miles SE of Black River.

For much of the time hurricane force winds extended outward only 30 miles. Now it is up to 60 miles while TS force extend about the same as they’ve been: From NHC 11PM advisory: Hurricane-force winds extend outward up to 60 miles (95 km) from the center and tropical-storm-force winds extend outward up to 185 miles (295 km).

BULLETIN Hurricane Melissa Advisory Number 34 NWS National Hurricane Center Miami FL AL132025 500 PM EDT Wed Oct 29 2025 ...MELISSA STARTING TO ACCELERATE NORTHEASTWARD OVER THE BAHAMAS... ...DAMAGING WINDS, FLOODING RAINS, AND A DANGEROUS STORM SURGE CONTINUING IN THE BAHAMAS THROUGH TONIGHT... SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...22.9N 74.8W ABOUT 80 MI...130 KM SE OF THE CENTRAL BAHAMAS ABOUT 890 MI...1435 KM SW OF BERMUDA MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H PRESENT MOVEMENT...NE OR 35 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...974 MB...28.77 INCHES

Forecasting some strengthening during next 24 hours: FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 22.9N 74.8W 80 KT 90 MPH 12H 30/0600Z 25.1N 73.5W 85 KT 100 MPH 24H 30/1800Z 29.1N 70.3W 90 KT 105 MPH 36H 31/0600Z 34.4N 65.2W 85 KT 100 MPH 48H 31/1800Z 40.7N 58.7W 75 KT 85 MPH 60H 01/0600Z 46.6N 52.3W 60 KT 70 MPH...POST-TROP/EXTRATROP 72H 01/1800Z 52.0N 45.4W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 02/1800Z 56.0N 32.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 03/1800Z 57.0N 27.5W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin

From 4 hours ago, this stream from Jeff P. shows he and his friend driving around surveying the damage starting in Santa Cruz, Jamaica, where’s he’s been and which was just to the east of the worst damage, and then heading west to the worst damage with their main goal to see if they could help others:

Hey Roger, I’ve noticed what seemed like a (slight?) partial correlation between high sunspot months (say 130+) and low ACE with possibly a couple of weeks of lag. One hypothesis is that the increased solar energy heats up the upper atmosphere more than the lower, which if true could lower instability in the tropics.

Here’s what a very knowledgeable non-met recently posted about my observation regarding the historic January in the SE US occurring despite a very strong SPV What lucked out for us is that even with the stronger SPV last winter, it was rooted to the Hudson Bay TPV so cold air was nearby last winter most of the time, when it’s locked up and wound up on the other side is when it’s a issue,