GaWx

Not yet: BULLETIN Tropical Storm Melissa Advisory Number 17 NWS National Hurricane Center Miami FL AL132025 1100 AM EDT Sat Oct 25 2025 ...MELISSA NEAR HURRICANE STRENGTH AND FORECAST TO RAPIDLY INTENSIFY THIS WEEKEND... ...LIFE-THREATENING AND CATASTROPHIC FLASH FLOODING AND LANDSLIDES EXPECTED IN PORTIONS OF SOUTHERN HISPANIOLA AND JAMAICA THROUGH THE WEEKEND... SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...16.5N 75.1W ABOUT 155 MI...245 KM SE OF KINGSTON JAMAICA ABOUT 235 MI...375 KM SW OF PORT AU PRINCE HAITI MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...WNW OR 285 DEGREES AT 1 MPH...2 KM/H MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES

Best for Jamaica but worst for SW Haiti with insane amounts of rainfall

Hopefully the hurricane models are somewhat too strong as is not uncommon. 0Z and 6Z Euro say it won’t quite make it to cat 3 status before landfall although it was too weak as of 8AM (991 mb) and only down to 988 mb at 2PM. So, the implication is likely at least cat 3 offshore. But then it weakens her 20 mb by the time it gets to Kingston with ENE movement over E Jamaica. Is that a realistic possibility? Regardless, Kingston eastward still gets extremely heavy rain (15-20”+), which likely remains the biggest danger. ——————- Recon through 9:10AM:

8:27 AM EDT: 986 mb very near H status 943 URNT12 KWBC 251227VORTEX DATA MESSAGE AL132025A. 25/12:03:08ZB. 16.41 deg N 074.88 deg WC. NAD. 986 mbE. 195 deg 16 ktF. OPEN SWG. C18H. NAI. NAJ. 167 deg 65 ktK. 067 deg 10 nm 12:00:31ZL. NAM. NAN. 325 deg 46 ktO. 242 deg 13 nm 12:06:34ZP. 14 C / 2460 mQ. 21 C / 2443 mR. 15 C / NAS. 12345 / NAT. 0.01 / 1 nmU. NOAA2 1113A MELISSA OB 14MAX FL WIND 68 KT 299 / 16 NM 10:47:30Z

BULLETIN Tropical Storm Melissa Intermediate Advisory Number 16A NWS National Hurricane Center Miami FL AL132025 800 AM EDT Sat Oct 25 2025 ...MELISSA NEAR HURRICANE STRENGTH AND FORECAST TO RAPIDLY INTENSIFY THIS WEEKEND... ...LIFE-THREATENING AND CATASTROPHIC FLASH FLOODING AND LANDSLIDES EXPECTED IN PORTIONS OF SOUTHERN HISPANIOLA AND JAMAICA THROUGH THE WEEKEND... SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...16.4N 75.0W ABOUT 160 MI...260 KM SE OF KINGSTON JAMAICA ABOUT 235 MI...375 KM SW OF PORT AU PRINCE HAITI MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 1 MPH...2 KM/H MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES

6Z Euro is very similar to the 0Z with strongest again at 968 S of C Jamaica, 988 near Kingston, and sharp right turn to E tip of Jamaica exiting at 992.

If this is realistic, it could mean that the W 1/2 of Jamaica is saved from as devastating a blow as earlier feared although there’d still be extremely heavy rainfall especially in SE Jamaica along with the devastating consequences of that in that portion of the island.

BULLETIN Tropical Storm Melissa Intermediate Advisory Number 15A NWS National Hurricane Center Miami FL AL132025 200 AM EDT Sat Oct 25 2025 ...AIR FORCE HURRICANE HUNTER DATA SUGGEST MELISSA IS ALMOST A HURRICANE... ...LIFE-THREATENING AND CATASTROPHIC FLASH FLOODING AND LANDSLIDES EXPECTED IN PORTIONS OF SOUTHERN HISPANIOLA AND JAMAICA THROUGH THE WEEKEND... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...16.3N 74.9W ABOUT 170 MI...275 KM SE OF KINGSTON JAMAICA ABOUT 235 MI...375 KM SW OF PORT AU PRINCE HAITI MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NW OR 315 DEGREES AT 3 MPH...6 KM/H MINIMUM CENTRAL PRESSURE...986 MB...29.12 INCHES

Also, the 0Z Euro is not nearly as strong as prior runs with 968 mb the strongest when 35 miles S of C Jamaica at hour 54. Then it landfalls at hour 72 at 982 before a sharp turn ENE to E tip at 992. That is a change in the heading from NE across the island on prior runs. Rainfall is still torrential in E Jamaica with 18” at Kingston.

As someone else who also hates the spread of misinfo, especially when it is done purposefully to overhype/get more attention and sell more of a product, I fully endorse his post about this error about the AMO. Spreading misinfo on the internet is a pet peeve of mine. We’re in the Age of Misinfo, sadly. It’s the least we can do to try to reduce the spread of it. Even unintentional errors should be corrected. Keep in mind that there are numerous less informed guests that read these threads. So, we’re not just targeting members in our attempt to make corrections.

Yeah, I realize that. I’m just looking ahead.

BULLETIN Tropical Storm Melissa Advisory Number 13 NWS National Hurricane Center Miami FL AL132025 1100 AM EDT Fri Oct 24 2025 ...AIRCRAFT DATA SUGGEST THAT MELISSA COULD BE REFORMING TO THE EAST... ...LIFE-THREATENING AND CATASTROPHIC FLASH FLOODING AND LANDSLIDES EXPECTED IN PORTIONS OF SOUTHERN HISPANIOLA AND JAMAICA THROUGH THE WEEKEND... SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...15.7N 74.6W ABOUT 215 MI...345 KM SE OF KINGSTON JAMAICA ABOUT 250 MI...405 KM SW OF PORT AU PRINCE HAITI MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H PRESENT MOVEMENT...ESE OR 105 DEGREES AT 2 MPH...4 KM/H MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Watch is in effect for... * Southwestern peninsula of Haiti from the border with the Dominican Republic to Port-Au-Prince * Jamaica A Tropical Storm Warning in effect for... * Southwestern peninsula of Haiti from the border with the Dominican Republic to Port-Au-Prince * Jamaica Tropical Storm Melissa Discussion Number 13 NWS National Hurricane Center Miami FL AL132025 1100 AM EDT Fri Oct 24 2025 The Air Force Reserve reconnaissance that has been flying through Melissa this morning found the center significantly further to the east-southeast than what was observed last night. How much of this position is related to a real motion, or a center reformation is unclear at this time. The storm remains about the same on satellite imagery this morning, with a large burst of deep convection, primarily along its southeastern flank, with evidence of northwesterly shear still undercutting the outflow. A WSFM microwave pass shows very deep hot towers, but not with that much structure beyond that. In addition, there hasn't been a significant change to Melissa's intensity, with peak 850 mb flight level winds of 49 kt, and these winds support maintaining 40 kt intensity this advisory. As has been stated for the last few days, the lack of persistent steering currents, due to competing mid-level ridges to the southeast and northwest of Melissa, is responsible for the storm's very slow motion. This is likely to continue for the next day or so, and much of the system's motion could be just as influenced by center reformations during this time period. After 24 hours, the mid-level ridge located to the northwest is expected to strengthen to the north of Melissa, and the guidance is coming into better agreement on a very slow westward motion through 72 hours. Beyond that time frame, a strengthening mid-latitude trough expected to move into the Southeastern U.S., should provide an avenue for Melissa to escape the Caribbean Sea to the northeast by the end of the forecast period. The track guidance overall has shifted south over the first few days, but there is still substantial spread in solutions at the end of the forecast period, related to when and how fast Melissa turns to the northeast. The latest NHC track forecast is a little south of the prior one early on, but is shifted a little eastward in 4-5 days, roughly a blend of the latest HCCA and GDMI model aid solutions. On the forecast track, Melissa could potentially be near western Jamaica by day 4 and near or over southeastern Cuba by day 5, though timing still remains more uncertain than usual. The GFS and ECMWF-based SHIPS shear guidance indicates the deep-layer shear is lower than yesterday, between 14-17 kt, but there still appears to be mid-level shear undercutting the outflow layer. Until Melissa also become better aligned vertically, any intensification is likely to be slow to occur over the next 12 h or so. After that, once Melissa's structure improves, environmental conditions still appear favorable for a period of rapid intensification (RI). Every single Google DeepMind member shows the system become a Category 4 hurricane or higher, and the uncertainty is more related on the timing of when RI occurs. After 96 hours, Melissa could weaken some due to the combined effects of land interaction, and an increase in southwesterly vertical wind shear by the end of the forecast period. The latest NHC intensity forecast is on the higher end of the model solutions, but more or less in line with the latest GDMI guidance. Key Messages: 1. Jamaica: Due to Melissa’s slow motion, the risk of a prolonged multi-day period of potentially damaging winds, heavy rainfall resulting in life-threatening flash flooding and numerous landslides, and storm surge continues to increase for Jamaica. Preparations to protect life and property should be rushed to completion, since strong winds and flooding rains could begin in Jamaica on Saturday or Sunday. 2. Haiti: Heavy rainfall will result in catastrophic flash flooding and landslides across southwestern Haiti into early next week. Extensive damage to roads and buildings is expected, potentially isolating communities for an extended period of time. This is a life-threatening situation and immediate preparations to protect life and property should be taken. Strong winds could also potentially last for a day or more over the Tiburon peninsula of Haiti. 3. Remainder of Hispaniola and Eastern Cuba: Heavy rainfall could also produce significant, life-threatening flash flooding and numerous landslides in southern Dominican Republic. Interests in Cuba should monitor the progress of Melissa since the risk of heavy rainfall, damaging winds, and storm surge appears to be increasing. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 15.7N 74.6W 40 KT 45 MPH 12H 25/0000Z 15.9N 74.5W 45 KT 50 MPH 24H 25/1200Z 16.3N 74.6W 60 KT 70 MPH 36H 26/0000Z 16.5N 75.3W 70 KT 80 MPH 48H 26/1200Z 16.6N 76.0W 85 KT 100 MPH 60H 27/0000Z 16.6N 76.8W 105 KT 120 MPH 72H 27/1200Z 16.6N 77.5W 125 KT 145 MPH 96H 28/1200Z 17.5N 78.3W 130 KT 150 MPH 120H 29/1200Z 20.4N 76.7W 105 KT 120 MPH...INLAND $$ Forecaster Papin

Hey Anthony, I had just added this at the end right before you posted: The caveat is that this recent decades pattern of -NAOs during only weak sunspot periods has been due to randomness. I’m only looking at the period since 1980, when -NAO winters started becoming rare. There have only been 6 (13%) of them with a -NAO. All were within 2 years of a sunspot minimum with sunspots averaging <35 during DJF. I can’t prove it hasn’t been coincidental though. That’s why I said, Therefore, based on the last 45 winters and assuming that pattern continues, ~2028-9 should be the next winter with a good shot at a sub -0.25 NAO averaged out.

There have been only 6 (13%) sub -0.25 NAOs averaged over DJF since 1980 and they were all within ~2 years of a sunspot cycle minimum: 1984-5, 1986-7, 1995-6, 2009-10, 2010-1, and 2020-1. Being that this autumn has been in a persistent very active sunspot period after the peak only about a year ago, 2025-6 will still be during a mainly active sunspot period. As we get out to 2028-9 and going into the early 2030s, we should then be within ~2 years of the next cycle min. Therefore, based on the last 45 winters and assuming that pattern continues, ~2028-9 should be the next winter with a good shot at a sub -0.25 NAO averaged out. Hopefully like was the case in the mid-1980s and 2009-1, we’ll get two -NAO winters between 2028-9 and ~2031-2. The caveat is that this recent decades pattern of -NAOs during only weak sunspot periods has been due to randomness.

IF the NHC forecast were to play out, Melissa could end up having the 3rd highest ACE on record for so late in the season of the last 100 years behind only Mitch of 1998 and the Nov Cuba H of 1932! Wilma wouldn’t qualify because it dissipated too early (10/25). Going back further to 1851 on the record, only storm #6 of 1896 would appear to quite possibly have higher ACE later than Melissa again assuming NHC forecasts verify. So, Melissa could very well end up in rare company regarding the lateness of a very large ACE for a single storm on record. ———— Edit: This from yesterday’s Euro Weeklies illustrates well how high the ACE potential is: this shows 4.1 the normal ACE or ~15, which is near the normal for the peak week climo centered around Sept. 11th! That is almost entirely from Melissa. But that is only for Mon (10/27) through Sun (11/2). So, that doesn’t even include today through Sun.

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.