GaWx

1) UKMET runs since yesterday have been showing a very weak TC forming Wed or Thu off the SE US coast followed by NE movement OTS: Here’s today’s 12Z run for that one: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 90 HOURS FORECAST POSITION AT T+ 90 : 29.4N 77.6W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 13.06.2024 96 29.8N 76.6W 1012 28 0000UTC 14.06.2024 108 30.8N 75.7W 1012 21 1200UTC 14.06.2024 120 32.2N 75.0W 1014 23 0000UTC 15.06.2024 132 CEASED TRACKING 2) This is the first UKMET run showing a TCG in the W GOM as it has just gotten to within the 168 hr range. This one has significantly lower SLP than the TC it has for off the SE US. It is then moving NW toward the middle to upper TX coast: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 162 HOURS FORECAST POSITION AT T+162 : 26.1N 92.9W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 16.06.2024 168 27.2N 93.8W 1003 26

I was at 96.2 at 3:10PM. Some 3PM temps: KSAV 95, KCHS 95, KSSI 97, KJAX 97, KGNV 95, KTLH 97, KVLD 96, KAYS 95. Skies are clear with no haze and winds are from the W, the typical direction for the hottest highs in summer. These are all at or near the hottest of the YTD. One good thing is that DPs aren’t too bad with upper 50s to low 60s most areas. Edit: 97.5 for me at 3:43PM! Edit #2: I hit my high at 97.5 again at 4:20PM Highs: SAV, CHS, GNV: 96; SVN: 97; JAX, VLD: 98; TLH: 99; Mods, please pin this thread. Thanks. @buckeyefan1

Chesco, Have you analyzed # of lows by decade at or above a certain high level, such as # aoa 75?

If you’re referring to ONI, I’d largely agree as of now at least. I count -1.5- low point as strong. But in terms of RONI, the data I’ve analyzed suggests a -1.5- low point is still a good possibility, especially when considering the bc June Euro implied prog of -1.4 or lower for RONI per my analysis above.

# of highs of 100+/95+ in Savannah, GA: 1900s: 7/83 1910s: 7/108 1920s: 10/136 1930s: 18/178 1940s: 27/190 1950s: 24/221 1960s: 3/118 1970s: 10/112 1980s: 47/289 1990s: 26/228 2000s: 9/159 2010s: 26/293 AVG: 18/181 Largest#: 1980s/2010s Smallest #: 1960s/1900s (2020-3: 1/79)

Note that the far EPAC MDR has a decent sized area near 31C with no area anywhere near that big in the nearby WCAR/GOM. That is actually at record warmth there just like the WCar/BoC have record warmth. Do you think that this being the warmest area could keep energy from concentrating enough in the WCar/GOM to form a TC?

June OND Euro prog for ONI/actual ONI/RONI ’23 +2.04/+1.92/+1.49 ’22 -0.25/-0.92/-1.03 ’21 -0.30/-0.98/-1.21 ’20 -0.49/-1.27/-1.52 ’19 +0.67/+0.51/+0.24 ‘18 +1.1/+0.9/+0.8 ’17 +0.4/-0.8/-1.1 ‘16 -0.4/-0.7/-1.1 ’15 +2.4/+2.6/+2.3 ’14 +1.3/+0.6/+0.5 ’13 +0.6/-0.2/-0.2 ‘12 +1.2/+0.1/-0.1 *’11 +0.1/-1.0/-0.9 *’10 -1.0/-1.6/-1.7 *’09 +1.3/+1.0/+0.9 *’08 +0.3/-0.4/-0.4 *’07 -1.1/-1.3/-1.3 AVG +0.5/-0.1/-0.3 Analysis: - The June Euro avg miss for ONI was 0.6 too warm. - It missed too warm 16 of 17! - When there was no El Niño, it missed on avg too warm by 0.7. - When there was El Niño, it missed on avg only by +0.2. - Out of 17, biggest misses were +1.2 (‘17) and +1.1 (‘12 and ‘11) - June Euro is progging SON/OND at -0.3 (vs -0.5 in May). - Based on avg miss of +0.7 for non-Nino, bias corrected June Euro prog for OND ONI is -1.0. Based on largest miss of +1.2, OND ONI could end up as low as -1.5. Based on smallest miss for non-Nino of +0.2, OND ONI could end up as high as -0.5. - Based on the assumption that RONI, which in MAM was 0.64 cooler than ONI and has been at least 0.4 cooler than ONI for a year, will be at least 0.4 cooler than ONI in OND, this implies that bc June Euro OND RONI prog is for -1.4 or cooler. *SON instead of OND (OND N/A) Sources: Euro progs https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table Actual ONI: https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt Actual RONI: https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt

Wow, what a two day rise of the WCS PDO! It rose ~0.6, the fastest two day increase on this chart. But this is likely just a dead-cat bounce reaction to the prior two week very steep drop. Even after this bounce, it is still very low (at -2.26) and the corresponding NOAA PDA is probably still down at ~-3 to -3.5.

I’m hopeful for the winter after this next one. I’m hoping El Niño will return in 2025-6. The Hunga Tonga volcano may favor a multi-year El Niño within 2025-9 per a paper I’ve linked the forum to. If so, maybe the PDO would finally go back to positive with the WPAC perhaps finally cooling down. If we get that combo, I could see 2025-6 being much colder than recent winters for much of the E US. 2025-6 would probably also have a falling -QBO, which during El Niño would favor a major SSW. Also fwiw, it would be the 2nd winter after the most recent major land based volcano eruption of earlier this year. Those winters tend to be somewhat cooler than the prior winter. Then as we approach the next solar min, I could see a -NAO driven winter either in 2028-9 or more likely in 2029-30. Coincidence or not, all six -NAO winters since 1979-80 have been with sunspots under 35 and within two years of a minimum. So, perhaps??

- There looks like an acceleration in the rise since 2011. - The largest annual rises (based on peak to peak) have been associated with the four strongest El Niño years but also in 2012 (following a two year La Niña) and 1999. 1999 is hard to explain. 1999’s rise over 1998 was so large that it nearly rose back to the 1997 peak, which is weird since it was in the midst of a similar strong La Niña to the 1998 Niña! - The biggest annual drops (based on peak to peak) were after the three strongest El Niño years. Thus, there’d be a nice drop for the 2024 peak vs 2023 peak assuming the pattern holds. Edit: - Looking at the animation, the annual peaks have been mostly in Oct (22) although I see 4 in Sep. and 4 in Nov. Why are the peaks almost always in autumn? - The one exception to the autumn peaks is 1998, which technically peaked on Jan 1st as it was slowly dropping from the big late Sep 1997 El Niño related peak. The 1998 autumn peak, which was in mid Sep, wasn’t able to quite reach the Jan 1st level. This can be clearly seen by slowing the animation way down. This slowdown can be done by pausing the animation and then manually controlling the animation via the bottom scroll bar. - So, summary of the annual peaks: -22 in Oct -4 in Sep -4 in Nov. -1 in Jan - There’s also a very minor secondary peak in most years within a month of March. Why? My hypothesis is that it is related to the typical 60N to 60S annual global ocean SST peak, which is in/near March as per the image at this link: https://climate.copernicus.eu/july-2023-global-air-and-ocean-temperatures-reach-new-record-highs - Based on peak to peak rises, 2015 looks like it was pretty close to 2023. Both peaks rose over 1 cm from their respective prior year peaks. - This article attributes El Niño related rises to more rainfall over the oceans. But I would have thought it would be due to spikes of warmth during El Niño leading to ocean expansion. Any opinions about this?

Interesting and great observation! You got me curious. So, I looked back to 1850-1950 via Eric Webb’s table. I found that it was a bit different. For that period, I counted after neutral periods ended 12 of 21 (57%) went to El Niño and 9 of 21 (43%) went to La Niña. So, whereas El Niño was somewhat more frequent, it wasn’t nearly like the one-sidedness of 1950+. For 1950+, I count 12 of 13 neutral periods (92%) that went to El Niño after ending and 1 of 13 (8%) that went to La Niña after ending. So, for 1850-present, I count 24 of 34 neutral periods (71%) that went to El Niño and 10 of 34 (29%) that went to La Niña. Thus, when looking at the full 174 year period, there still does appear to be a pretty good favoring of El Niño after neutral periods end. Next I looked at only multi-year long neutral periods. For 1950+, 6 of 6 (100%) went to El Niño. For 1850-1950, 9 of 14 (64%) went to El Niño vs 5 of 14 (36%) going to La Niña. Thus, after 1850-present multi-year neutral periods, 15 of 20 (75%) went to El Niño and 5 of 20 (25%) went to La Niña. That’s pretty significant and thus tells me there really MAY be an inherent favoring of going to El Niño rather than La Niña at the end of multi-year neutral periods as opposed to that being a mere coincidence. So, for strictly single year long neutral periods for 1950+, 6 of 7 (86%) went to El Niño vs 1 of 7 (14%) going to La Niña. But for 1850-1950 I count only 3 of 7 (43%) that went to El Niño vs 4 of 7 (57%) going to La Niña. Thus for 1850-present for strictly single year long neutral, I count 9 of 14 (64%) going to El Niño and 5 of 14 (36%) going to La Niña. This all tells me there’s more of a chance that the single year neutrals going to El Niño more often have been coincidental even though that’s not 100% conclusive. If we assume that going to El Nino after a multi-year neutral period is truly favored over going to La Niña, does anyone have a theory as to why that would be the case?

In addition to Euro warm bias (though not nearly as bad as BoM was last year), folks shouldn't forget that model forecasted ONI needs to be reduced a good bit to best estimate where RONI will be.

From pro met 57 from your area, he not surprisingly doesn't buy the GFS as it is on its own of the ops just like has been the case quite often: "Here's a comparison of the 12Z GFS, Canadian, and Euro valid in 10 days, which is 12Z June 16. Which one is not like the others? This is happening in EVERY basin since the last GFS change (I'm not calling it an "upgrade")." http://wxman57.com/images/12ZModels.JPG

1. My perception that Raindance’s forecast last winter was “sort of deemphasized” can best be illustrated by the lack of replies in his winter forecast thread: There was only a pretty small % of active members posting (including my post) during the subsequent 2 weeks (through Oct 25) followed by not even a single post in Nov-Feb! Rightly or wrongly, that gave me the impression that there was a deemphasis of sorts. If he had had a cold E US forecast, I bet there would have been many more posts there than the 17 replies. I mentioned: “bias resulting from desires for a cold winter. I’m also vulnerable due to the same desire.” When I said this, I wasn’t talking about member forecasts. I was talking about member desires and was thinking that that lead to limited activity in Raindance’s thread. 2. I know you and others (including myself) have a lot of respect for Raindance’s forecast related contributions, especially because of the enormous amount of detail he backs his forecasts up with and how well he has done in recent years. I also realize you and others have his forecasts as “must reads”. I’m not debating that. You’ve been quite vocal about it. 3. Also, I agree with you about the lack of cold/snowy member forecasts. Yes, the most bullish forecasts/hopes were mainly for NN temps/snow with mild/lack of snow in Dec being balanced out via a transition to cold/snowy by Feb. But even these were significantly colder and snowier than Raindance’s. There was a lot of excitement about Feb potential (me included) vs Raindance not showing that. The Euro and other models were fostering this as many runs had beautiful H5 maps in Jan/Feb! They busted horribly! 4. @snowman19@George001, and I think @Stormchaserchuck1were also mild pretty much from the start. Kudos to them. Snowman19 got numerous weenies, especially when he posted Paul Roundy tweets. George also got some. But alas, they were pretty much right after all! 5. I have an enormous amount of respect for your forecast related contributions! I put Raindance, Griteater (though I don’t know if he did a formal forecast last winter), and yourself at the top as far as member preparation/time put into them and details shown to back them up.

Raindance and others, Per the above WPO data for 2018-24: - All but one winter (2021-2) had +WPO - All Marches had +WPO - May had a lower WPO than preceding winter’s avg WPO in all cases except May after 2021-2 - All but one summer (2023) had a -WPO, the exact opposite of winter. This reminds me of the prevailing more negative NAO of recent summers vs winters. - Every Dec rose vs prior August and all but one rose over 1.00 - So, considering all of the above, seasonal trends have been a major factor during this period. Keeping this in mind, is the flip to a -WPO in May (-0.27, the first -WPO month since Oct), itself, signifying anything different from the prevailing 2018-2023 pattern? Is this flip likely signifying much regarding the WPO for the next winter? - Raindance, I read that your gut favors a -WPO Aug-Oct. But what does your gut say about next winter’s WPO?

Not picking on you or anyone in particular. When Raindance says warm E US winter, he’s sort of deemphasized. But when he says something that appears to possibly promote something other than a warm E US winter (even if it is just a snippet and even if he doesn’t outrightly say he’s expecting cold there), he becomes the must listen to guru by the E US cold winter lovers. Last winter, he was pretty much warm in the E until Mar. Thus he wasn’t getting too much attention before Mar. As Mar came, the attention increased because of Raindance’s chilly Mar since he did well with his warmth through Feb. I’m just having fun but y’all have to know this is pretty much true and that it’s due to bias resulting from desires for a cold winter. I’m also vulnerable due to the same desire.

1. The winter of 2017-8 had a +WPO. https://psl.noaa.gov/tmp/gcos_wgsp/data.73.21.103.151.156.12.50.31.txt 2. Is a -WPO being forecasted by the consensus of models (excluding Weatherbell CFS output, which is totally untrustworthy for reasons I’ve stated)?

Not necessarily Modoki but the models are showing at least basinwide, which would be in contrast to the E based Nina of 2017-8 and this was my point. I said “more basinwide”. The contrasts of this and the other 4 factors couldn’t be much bigger vs 2017-8. Also, @snowman19of course meant 2017-8 rather than the 2016-7 he has in his last post.

Interesting discussion he did in advance of the winter of 2017-8 for the SE saying a benign winter wasn’t a shoe-in for 2017-8 largely because of a combo of the Niña not being strong (turned out E based moderate based on RONI), a strong (and dropping) -QBO (at 30 mb), and a very weak sun. His suspicions turned out to be prophetic. Jan was very cold and Dec/Jan ended up quite wintry with three major winter storms. One of those was a once in a multidecadal SE coastal storm that gave even my rarely hit area the biggest hit since at least Dec of 1989. How do these and other anticipated factors for 2024-5 compare? It couldn’t be that much more opposite: 1. very likely rising +QBO vs falling strong -QBO in 2017-8 (30 mb) https://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index 2. likely stronger and more basin-wide Niña expected based on RONI vs E based moderate of 2017-18 RONI: lowest -1.25 in NDJ of 2017-18 https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt Monthly SSTa showing it E based in 2017-18: https://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii 3. many more sunspots a near certainty with it progged near max (sunspots (well) over 100) vs only 8.5 in 2017-8 https://www.sidc.be/SILSO/DATA/SN_m_tot_V2.0.txt 4. Strong -PDO progged vs neutral in 2017-8: https://www.ncei.noaa.gov/pub/data/cmb/ersst/v5/index/ersst.v5.pdo.dat 5. Warmer globe vs 2017-8: 2023 was significantly warmer than 2022/earlier years (record breaking) and 2024 hasn’t backed off yet

The NOAA PDO for May of 2024 comes in way down at -2.97, which compares to the May WCS PDO of -1.86. The last time the May PDO was lower than this was way back in 1950. https://www.ncei.noaa.gov/access/monitoring/pdo/ That tells me that the last few days of NOAA PDOs have very likely been near -4. I’m educatedly guessing that the upcoming winter NOAA PDO will average -1.5 or lower based on the model progs and recent trends. The last 3 winters have been sub -1.5. Getting a sub -2 will be very tough based on there having been only four that low since 1853-4. But there have been 16 sub -1.5 and La Niña will help the chance for, say, a -1.5 to -1.75 winter. I’ll be surprised if it isn’t sub -1.

The avg NAO has, indeed, risen during winter since 1979-80. However, we also know that it has fallen during summer since 2007. So, might the NAO change in recent decades be close to a wash? Are they just talking about winter?

It wouldn't at all surprise me if the hottest highs in much of the Midwest would be cooler due to significantly higher avg relative humidity/much higher crop coverage keeping the ground from heating up as much. Actually, I'd expect that. But I'd expect the lows to be higher.

The Key West buoy’s water temp has come down considerably since the high peaked at a record high for May of 92.3 late on 5/29/24. It is now down to 86.7, which compares to 90.0 at the same time on May 29 & 30. So, a 3.3F drop essentially. A wetter pattern in recent days has been a big help. Watching this area carefully especially because of the threat of more coral bleaching as occurred in 2023: https://www.ndbc.noaa.gov/station_page.php?station=kywf1

The all important RONI ONI difference for MAM is out: -0.64. RONI +0.11 ONI +0.75 RONI ONI difference: DJF: -0.58 JFM: -0.63 FMA: -0.66 (record low; records back to 1950) MAM: -0.64 So, the difference is holding as we go toward La Niña. That’s why I’ve been saying that the equivalent RONI weeklies recently likely had already gotten to ~-0.5. Based on the dailies bouncing back slightly in recent days, I’d guess the equivalent RONI dailies have probably bounced back to the -0.4 to -0.3 vicinity. RONI: https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt ONI: https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt

It is never bad to question the climo base as differences can cause different output. But in this case I don’t see that being the reason. WB uses 1981-2010 whereas TT uses 1984-2009. Not the same but they’re close. Also, WB CFS anomalies are much colder in some areas and warmer in others. From just N of Hawaii westward for 4,000 miles, WB CFS is solidly BN vs AN on TT CFS while just off N America WB CFS is solidly AN (warmer than just about the rest of the NPac) vs NN on TT CFS. So, WB is much colder in one area and warmer in another.