Expert forecasts for 2025 North Atlantic Hurricane Season

[WeatherBoy2000]

Kinda surprised that CSU reduced their named storms forecast considering we already have 3 and the real possibility we might have La Niña condition by the fall.

I'm not seeing much evidence for that currently:
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

Apart from a couple of outliers that are on Neptune, it looks to be neutral through the rest of this year to high probability, assuming the model ensemble represents uncertainty reasonably.

Models like the NMME/C3S have trended in a more la nina direction. The CPC is now giving a slight edge for la nina redevelopment by fall/early winter:

 https://x.com/NWSCPC/status/1943294137941528908

[LarryWx]

Kinda surprised that CSU reduced their named storms forecast considering we already have 3 and the real possibility we might have La Niña condition by the fall.

I'm not seeing much evidence for that currently:
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

Apart from a couple of outliers that are on Neptune, it looks to be neutral through the rest of this year to high probability, assuming the model ensemble represents uncertainty reasonably.

Models like the NMME/C3S have trended in a more la nina direction. The CPC is now giving a slight edge for la nina redevelopment by fall/early winter:

 https://x.com/NWSCPC/status/1943294137941528908

Summary of latest model progs for Nino 3.4: coolest month (these don’t take into account RONI type of adjustments downward)

BoM (Australian): -0.2 (in August)(too warm overall in prior 2 years; last July was slightly too warm with -0.17 for OND vs actual of ~-0.4)

Euro: ~-0.2 (almost always has been too warm…July forecast last year was only down to -0.11 for NDJ vs actual of ~-0.5)

JMA: ~-0.9 (Nov)(did well 2 years ago but too cool last year as July forecast had -0.87 for OND vs actual of ~-0.4)

MetFrance: ~-0.6 (Dec)(July outlook too warm 2 years ago but did fairly well last year with it actually slightly too cool with -0.61 OND vs actual of ~-0.4)

CFS: -0.5 (Nov)(last July much too cold with -1.32 for OND!)

UKMET: -0.76 (Oct) (this is from June as I don’t see July outlook yet)(did great 2 years ago but last July much too cool with -0.95 in OND)

————

So, my latest guess based on last year’s errors and current forecasts (all listed above) is for an ONI low point this fall/winter of ~-0.4. That would likely mean RONI low of a somewhat ominous (from hit risk standpoint for NE Caribbean to SE US on avg) -0.6 to -0.9.

But -0.6 to -0.9 RONI being “somewhat ominous” for those areas on avg doesn’t mean it will necessarily be a bad season for them as that’s just based on averages with a wide variance.. Actually, the Euro’s last few forecasts have had it near to slightly quieter than the 1993-2015 avg for those regions as a whole unlike what it showed for that area last year at this time.

[WeatherBoy2000]

I'm not seeing much evidence for that currently:
https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

Apart from a couple of outliers that are on Neptune, it looks to be neutral through the rest of this year to high probability, assuming the model ensemble represents uncertainty reasonably.

Models like the NMME/C3S have trended in a more la nina direction. The CPC is now giving a slight edge for la nina redevelopment by fall/early winter:

 https://x.com/NWSCPC/status/1943294137941528908

Summary of latest model progs for Nino 3.4: coolest month (these don’t take into account RONI type of adjustments downward)

BoM (Australian): -0.2 (in August)(too warm overall in prior 2 years; last July was slightly too warm with -0.17 for OND vs actual of ~-0.4)

Euro: ~-0.2 (almost always has been too warm…July forecast last year was only down to -0.11 for NDJ vs actual of ~-0.5)

JMA: ~-0.9 (Nov)(did well 2 years ago but too cool last year as July forecast had -0.87 for OND vs actual of ~-0.4)

MetFrance: ~-0.6 (Dec)(July outlook too warm 2 years ago but did fairly well last year with it actually slightly too cool with -0.61 OND vs actual of ~-0.4)

CFS: -0.5 (Nov)(last July much too cold with -1.32 for OND!)

UKMET: -0.76 (Oct) (this is from June as I don’t see July outlook yet)(did great 2 years ago but last July much too cool with -0.95 in OND)

————

So, my latest guess based on last year’s errors and current forecasts (all listed above) is for an ONI low point this fall/winter of ~-0.4. That would likely mean RONI low of a somewhat ominous (from hit risk standpoint for NE Caribbean to SE US on avg) -0.6 to -0.9.

But -0.6 to -0.9 RONI being “somewhat ominous” for those areas on avg doesn’t mean it will necessarily be a bad season for them as that’s just based on averages with a wide variance.. Actually, the Euro’s last few forecasts have had it near to slightly quieter than the 1993-2015 avg for those regions as a whole unlike what it showed for that area last year at this time.

CSU's current analogs are mixed bag when it comes to US impacts. 2008/2021 were very impactful, 2011 had one notable storm (Irene), while 2001 was overall very quiet with only three land falling storms, none of them hurricanes. In fact, the worst storm of that season had already happened by this point in the year.

In the end, everything points to a cooler enso by the fall, so it shouldn't be an obstacle for Atlantic activity.