jconsor

Our next US hurricane threat comes from an unlikely place so early in the season - the eastern/central Pacific! Fausto is expected to track west in general direction of Hawaii by mid next week, but big questions remain on whether it turns more NW and weakens (a la EPS) or continues westward and threatens Hawaii. Even a tropical storm strength system passing near Hawaii so early in the season would be in rare company. Check out my latest blog with more details: https://hurricanehacker.substack.com/p/eastern-pacific-stealing-tropical (Note - while my blog is mainly Atlantic focused, when there is a land threat in the eastern or central Pacific I will cover it. The subsequent posts on Fausto will be more in-depth than this one... please follow the blog on Substack for updates.)

Bertha has been a rather confounding/challenging TC to forecast. I'd be wary of being fooled by its current appearance (LLC decoupled from convection). Posted in-depth thoughts on Bertha's future here at my blog: https://hurricanehacker.substack.com/p/bertha-gaining-strength-heading-for

While there is typically relatively high uncertainty for nascent, not well defined systems, I agree with NHC and posters here that the uncertainty here is unusually high due to the forecast coast-parallel track and the strong dependence of the track later this week on how quickly future Bertha gets organized in the next day or two. I go into the potential scenarios and all of the details here: https://hurricanehacker.substack.com/p/tropical-storm-bertha-likely-to-form?r=etzas

Will the tropical system off the west coast of Florida manage to organize despite moderate northerly wind shear over the next few days? It's expected to spend three to five days over the very warm waters of the Gulf of Mexico, which suggests we shouldn't count this system out. While a weaker system is the most likely scenario, there is the potential for a stronger system if it continues moving west under strong central/southeast US ridging and doesn't turn quickly northward toward Florida. https://hurricanehacker.substack.com/p/tricky-forecast-for-gulf-of-mexico

Everyone is focused on the TX/LA impacts (rightfully so), but just wanted to note that by Fri this could easily have a "second coming" and bring tropical storm conditions to the coastal Carolinas. I wrote about this in my blog: https://hurricanehacker.substack.com/p/low-pressure-high-water-gulf-system?r=etzas

Seeing some potential interesting tropical mischief in the GOM next week. A stalled frontal boundary providing vorticity, remnant energy from the system entering the BOC this weekend dragging up lots of tropical moisture, and indications of a pocket of lower shear and diffluence between central US trough and a persistent GOM ridge: https://x.com/yconsor/status/2065067111521652967

13/6/2 with 90 ACE (I think a reasonable range for ACE accounting for uncertainty at this stage is 60-115 ACE). My ACE forecast is slightly lower than the mean of the seasonal forecasts on https://seasonalhurricanepredictions.bsc.es/forecast/seasonal-predictions See https://seasonalhurricanepredictions.bsc.es/about/forecasters for more background on how each group/agency produces its seasonal forecasts. 268Wx and Univ. of Arizona have shown particular skill vs. other forecasts in past +ENSO years like 2019 and 2023 (when ACE was generally notably higher than most seasonal forecasts) and in -ENSO years like 2022 and 2024 (when ACE was generally notably lower than most seasonal forecasts). Interestingly, 268Wx and Univ. of Arizona this year represent the far high end of the forecast spectrum in terms of ACE/level of activity. -Yaakov

Went into more depth on the potential implications of the persistent -PDO for how the El Nino evolves and the degree of atmospheric coupling in the thread below. Would honestly surprise me to see this El Nino and the pattern in the Atlantic tropics evolve like 1982, 1987, 1997 and 2015. I'm thinking we most likely see something about halfway in between those years and "Active El Ninos" like 1951, 1969, and 2018 - perhaps something a little more active than 1957, 1965, 1976 and 2002 in terms of Atlantic activity. https://x.com/yconsor/status/2052132299139858764

The equatorial east Atlantic and west Africa have seen persistent westerly wind anomalies and above normal precip since mid-March, which is uncharacteristic of developing El Ninos. https://x.com/yconsor/status/2045877323635810439

University of Arizona has a bold forecast, much more active than other forecasts to date: 9 hurricanes and 4 majors with an ACE of 155. Their model is based on machine learning initialized with ECMWF seasonal forecast SSTs. They cite forecast significantly above normal tropical Atlantic SSTs as the main factor. News release: https://has.arizona.edu/news/forecast-2026-hurricane-activities-over-north-atlantic More technical summary: https://has.arizona.edu/sites/default/files/2026-04/April-2026-Tropical-Cyclone-Forecast.pdf Seasonal hurricane predictions that have been issued so far: https://seasonalhurricanepredictions.bsc.es/forecast/seasonal-prediction Univ. of Arizona has a very good track record. They started issuing Apr outlooks in 2022. Their Jun forecasts were notably higher than almost all others in 2017, 2019 and 2023 and ended up verifying well (In Jun 2017 they forecast 181 ACE and actual was 225, while most other outlooks were in the 100-130 range). In Jun 2019 they forecast 151 ACE and actual was 132, while most other outlooks were in the 80-105 range. In Apr 2023, they forecast 163 ACE and actual was 148, while most other outlooks were in the 90-130 range). Notice that all 3 years had El Nino conditions at the time of forecast initialization and the Nino was forecast to strengthen - but in 2017 and 2019 that strengthening failed to occur and in 2023 the Nino ended up weaker than many models had forecast and while it limited Atlantic activity to a degree, it was less impactful than expected. In 2022, 2024 and 2025 their Apr outlooks were notably lower than almost all others (In 2022 UA forecast 129 ACE and actual was 96, while almost all other outlooks were in the 150-190 range. In 2024, they forecast 156 ACE and actual was 162, with almost all other outlooks in the 185-230 range. In 2025, they forecast 110 ACE and actual was 133, with most other outlooks in the 145-190 range.) You can download all of the historical hurricane season prediction data for past years from the Univ of Barcelona site linked above. Personally I would go with an ACE range of 80-130 right now. Main reason is I believe the standing wave of low-level westerlies over the eastern Atlantic and west Africa will help lead to an Atlantic Nino, energize the W. African monsoon (WAM) and lead to an active wave train, while as we know El Nino influence on shear is mainly west of 60W. Also, the persistent very warm SST anomalies in the NW Pacific from E of Japan to S of AK and the SW Pacific east of AU/NZ (e.g. negative IPO) along with the above-mentioned Atlantic Nino and African standing wave would likely lead to resistance toward WWBs reaching the eastern Pacific (with the focus remaining near the dateline). This would tend to shift the Walker circulation west of a typical moderate to strong Nino. I think there's a 55% chance RONI stays below strong Nino levels through Aug-Oct. Not ruling out a strong Nino, but I think a super Nino RONI-wise is unlikely (<15%) through Aug-Oct. My main analog years are 1951, 1963, 1969, 2006, 2015, and 2018, with more emphasis on the first three given the strong WAM that prevailed.

Nice points. I agree - the lean toward La Ninas has acted as at least a slight brake on the global temp rise over the past three decades. Global temp anomalies past 10 years or so have increased more rapidly in the extratropics than the tropics. See this post from Dr. Joseph Fournier: https://www.linkedin.com/posts/joseph-fournier-7077087_following-the-15-year-great-hiatus-2000-activity-7449541780481654784-8jWQ? The attached graph is from the same post and is generated using satellite temperature estimates.

I agree it's ironic. I think that mainly has to do with how slow the downward propagation ("drip down") of above normal heights from the stratosphere to the troposphere was this year. See the attached graphic of polar (65-90N) height anomalies past several months, courtesy of meteorologist Todd Crawford on LinkedIn. Here's his full post: https://www.linkedin.com/posts/todd-crawford-5a02092_the-stratospheric-polar-vortex-spv-had-activity-7447251962808569889--JnW?utm_source=share&utm_medium=member_desktop&rcm=ACoAAAB0F_QB1PGc4wDzKl0eXPl_N7X02RAnqV4 Looks to me like there is a direct link between the recent increase in polar blocking (starting in early Apr near Scandinavia with a separate area near the Arctic Circle) + the forecast near-record strength Greenland blocking last week of Apr, with the notable stratospheric warming event in late Feb and early Mar.

https://www.weather.gov/source/crh/snowmap.html?zoom=7&lat=40&lon=-74&hr=24 Just to see the breadth of this storm is impressive! Totals as high as 20" extended all the way down into Delaware and the eastern suburbs of Philly in sw NJ, and then as far ne as near Boston (still snowing heavily in parts of eastern New England). The true jackpot appears to be RI with multiple reports of 30-33"! Part of SE MA southwest of Boston has seen 24-28". (Circled in purple) Wouldn't be surprised to see some scattered 36"+ reports in RI, like was seen in eastern MA or RI in big ones like Feb 1978, Apr 1997 (April Fools Storm) and Jan 2015 (Juno). Other jackpots we have discussed already - the N-S band from coastal central NJ to ne NJ to Westchester County and sw corner of Staten Island (circled in light blue). Most of NYC aside from NE Queens was pummeled by this band at times, but it was nearly stationary over NE NJ for many hours before it started focusing near NYC. And of course the eastern/central LI jackpot (circled in black).

Yep, you got the subsidence between the two bands. Where are you located and approximately how much snow did you receive? I grew up in NW Nassau (Roslyn). Looks like my area was close to the minimum for the entire NYC/LI area - happens somewhat frequently in the past 25 years, yet when I was growing up (late 1980s to mid-1990s) we had near the highest seasonal snowfall totals for all of NYC/LI.

Thank you! However, I don't see Montauk wind gusts in the NWS local storm reports. Do see lots of 60-70 mph gusts across NYC and LI. So 80-85 mph gusts on Montauk are believable. https://mesonet.agron.iastate.edu/lsr/?by=wfo&sts=202602221435&ets=202602231435&settings=0110110