GaWx

With the 30+ area growing in 170W-160W (far W Nino 3.4) and the strong WWB just to its west, let’s see what western and possibly central 3.4 does in the near future.

It has been warming in Nino 3, 3.4 and 4, but this is no longer an EP Nino. It has been warming in 3.4 faster than others and cooling in 1+2. Look at the TAO maps I just posted. This transition has occurred earlier than models and I expected. I thought it would take at least another month.

After cooling back the last couple of days to the E, today’s 5 day TAO has for the first time this Nino the +2.5 isotherm (warmest anomaly on this) well to the west…..in the 157-170W region, which is W Nino 3.4 or E Nino 4: look at the strong WWB near 175-165E! It is also cooling some W of the dateline: Compare to 8 days ago, which was warmer E of 140W (warmest of season) and cooler 150-175W; it was then slightly warmer W of the dateline:

At 400 PM EST (2100 UTC), the disturbance was centered near latitude 18.7 North, longitude 77.7 West. The system is moving faster toward the northeast near 17 mph (28 km/h), and an additional acceleration toward the northeast is expected through the weekend. On the forecast track, the system is expected to move across southeastern Cuba tonight and the southeastern Bahamas and Turks and Caicos Islands Saturday morning. Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Some slight strengthening is possible during the next couple of days, but the system's chance of becoming a tropical cyclone appears to be decreasing. * Formation chance through 48 hours...low...30 percent. * Formation chance through 7 days...low...30 percent. The estimated minimum central pressure is 1004 mb (29.65 inches).

Last but not least, the PNA. Although it has been weakly negative so far this month, it is now rising and much of the rest of the month looks like a weak to moderate PNA on the GEFS. That could very well bring the full month PNA to above +0.25, which would mean a legit +PNA. That would make it +PNA in all 6 months of June-Nov. The link below has the monthlies. The only other year since 1950 with that (+0.25+ in all 6 months) was 2021. Barely missing that was 2009, which had one month dip to just below the +0.25 with a +0.21 in November. So, fwiw, 2023 is mirroring 2009 very closely PNAwise. 2023 has also been fairly similar to 2009’s NAO and AO. https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.pna.monthly.b5001.current.ascii.table

Whereas the Euro Weeklies have a strong SPV in late Nov as just posted, the GEFS has a strong -AO for then (similar to late Nov of 2022 and 2021). Interesting:

More can kicking regarding the timing on when the SPV gets weaker than normal on the Euro Weeklies. Back on Nov 1st, they had this occur at the start of Dec or ~30 days out: Today’s run delays it the most yet as it waits til Dec 20th, which is still 30+ days out: When will the can kicking stop? Is this just a mirage or is it real? Do the Euro Weeklies have a bias toward weakening the SPV too much in Dec?

I think “EP-CP mix” and “basin wide” refer to essentially the same thing. I like to call it EP-CP mix because EP and CP are the two main types of El Niño and this is looking like a cross between them. Some prefer to call it basin-wide. I’m just trying to communicate my thoughts as clearly as possible.

Check this out: cyclonicwx’s OISST based Nino 1+2 anomaly cooled substantially and is now down to only +1.852. As just posted, Nino 3.4 just rose to +1.890. Thus, for the first time this El Niño, the Nino 3.4 anomaly is warmer than that for Nino 1+2 (though Nino 3 is still warmer at +2.019). This no longer looks like a pure EP Nino to me as it is more like an EP-CP mix/basin wide Nino:

We didn’t have to wait long at all for the next cyclonicwx.com OISST update as it came out on time this time. So, like the other datasets and the other OISST, the 3.4 anomaly warmed significantly since yesterday (from +1.812 to +1.890) though it is again 0.08 cooler than the +1.97 WCS OISST 3.4 anomaly:

Looking back at the relationship between the peak of weeklies (OISST based) and the peak of trimonthlies/ONI (ERSST based) since 2006-7: 2006: 1.2 v 0.9 2009: 1.9 v 1.6 2014: 0.9 v 0.7 2015: 3.0 v 2.6 2018: 1.1 v 0.9 So, for these last 5 El Niños, the weekly peak has exceeded the trimonthly peak every time (not surprising due to the math, alone, of course even with them based on different datasets). The weekly peak exceeded trimonthly peak between 0.2 and 0.4 with the average being 0.3. This suggests that the weekly peak can end up as warm as +2.3 and still end up at only +1.9 for ONI. Keep in mind that they use different base periods (in addition to them being different datasets) to come up with anomalies.

Do you think it’s possible that heavier than normal cloudcover cooled things off too much/skewed things in the CRW and OSTIA datasets the prior few days and less cloudcover today allowed for the big jump? Doesn’t cloudcover mess with the accuracy of satellite based SST datasets? PS How long before the cyclonicwx OISST updates? I hope we don’t have to wait 8 days again.

TAO 5 day averaged SSTa maps covering 3.4 have recently been cooling back some. But along comes this nonsense from CRW lmao: a warming of 0.17C in 3.4 in one day?? This amount of warming in just one day is laughable/not credible. It was probably too cool the prior day(s):

It is a good tweet showing the extreme contrast. But Noll’s maps are off with the drawing of the Nino 3.4 region. He has 3.4 from 120W to 170E instead of 120-170W. So, his 3.4 is too long. Thus, that 2023 western green area is hardly in 3.4 as it is almost all west of there. I’d like to see more rising air move into 3.4 the next few months. That would seemingly favor MJO phases 8 and 1 more than what this 2023 map suggests. His map has rising air mainly in the W portion of Nino 4, the E portion of Nino 3, and Nino 1+2 of the Nino regions and thus leaves 3.4 out. Other opinions?

With 3.4 now at +1.8, 3 at +2.0, and 2+1 at +2.0, this is nowhere near a pure EP Nino. The gradient is minimal. 1982 and 1997 had one or both of 2+1 and 3 0.5 to 1.0 warmer than 3.4 well into winter. OTOH, 2015 had 3.4 and 3 neck and neck with 1+2 quite a bit cooler. So, that also wasn’t pure EP. Yet, that was a mild winter. Perhaps that’s because 3.4 and 3 were well into super territory.

BULLETIN Potential Tropical Cyclone Twenty-Two Advisory Number 1 NWS National Hurricane Center Miami FL AL222023 400 PM EST Thu Nov 16 2023 ...DISTURBANCE OVER THE WEST-CENTRAL CARIBBEAN SEA FORECAST TO BECOME A TROPICAL STORM... ...TROPICAL STORM WATCHES ISSUED FOR PORTIONS OF THE GREATER ANTILLES, SOUTHEASTERN BAHAMAS, AND TURKS AND CAICOS ISLANDS... SUMMARY OF 400 PM EST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...15.2N 81.5W ABOUT 365 MI...590 KM WSW OF KINGSTON JAMAICA ABOUT 115 MI...185 KM E OF CABO GRACIAS A DIOS ON NIC/HON BORDER MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...NNE OR 15 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES

No, that was an older one. The next Invest, 98L, just became PTC 22.

If Region 4 were to get too warm in relation to 3.4, I’d be thinking that would possibly invite more MJO phase 6, which on average has been warm in winter. The best bet from what I understand for a cool to cold E US were to be if Nino 3.4 were to be the warmest region anomalywise. As of 11/16, Nino 1+2 and Nino 3 both are ~+2.0 while Nino 3.4 is +1.8 and Nino 4 is +1.5 as you said. So, 3.4 is just about as warm as 1+2 and 3. I’d like to see Nino 3.4 keep its +1.8 or even warm some more into the winter.

For the first time in 8 days, OISST updated at cyclonicwx. On the prior update, it was at +1.64 as of Nov 8th, which turned out to be a short term low just like the WCS short term low of Nov 7th. Its latest (Nov 16th) is a little cooler than WCS’ latest with +1.81 vs +1.89. Its high was +1.83, which was set yesterday. So, like on WCS, it warmed ~0.2C during that week. Looking back at the last few months in 3.4, WCS has tended to be very slightly warmer (~0.05 on average) than cyclonicwx although the latest is .08 warmer.

Varying opinions make for interesting and active forecast discussions. This topic would have nowhere near as many posts as it has had without significant differences of opinion. I do not look forward to the day when seasonal forecasts from models become much more accurate/they all predict the same thing. If that is to ever occur, that would make forecast discussion topics pretty boring.

I don’t see how Aug/Sep can end up THE peak for both Nino 3.4 and Nino 4. They’ve both been warmer in Nov than Aug/Sep. Nino 3.4 per OISST just hit a new daily high of +1.89 on Nov 15th: https://www.cpc.ncep.noaa.gov/data/indices/wksst9120.for

WCS 11/15 updates: -Nino 3.4 OISST barely warmed from +1.88 24 hours earlier to +1.89, which is its warmest so far this Nino. Although it has warmed a decent amount over the 8 days, this slowdown may mean it is topping at least for now. -The PDO rose slightly from -1.27 to -1.25. -I’m sticking with a +1.7 to +1.9 ONI peak for now.

After several runs in a row with TCG from this, the 12Z UKMET dropped TCG.

0Z UKMET: not a H as was on the 12Z, but still maxes out as a 51 knot 984 mb TS once past Bermuda. Before that, it is near Bermuda as a solid (993 mb) TS: NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS FORECAST POSITION AT T+ 54 : 21.5N 74.5W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 1200UTC 18.11.2023 60 22.5N 72.7W 1002 35 0000UTC 19.11.2023 72 28.4N 67.5W 997 44 1200UTC 19.11.2023 84 34.3N 62.1W 993 46 0000UTC 20.11.2023 96 42.5N 54.4W 984 51 1200UTC 20.11.2023 108 51.5N 46.1W 988 49 0000UTC 21.11.2023 120 POST-TROPICAL

12Z UKMET says this may become a H near or past Bermuda: 68 knots/978 mb: EW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 54 HOURS FORECAST POSITION AT T+ 54 : 19.2N 77.5W LEAD CENTRAL MAXIMUM WIND VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS) -------------- ---- -------- ------------- ------------- 0000UTC 18.11.2023 60 19.4N 76.3W 1003 33 1200UTC 18.11.2023 72 23.4N 72.2W 999 43 0000UTC 19.11.2023 84 29.0N 67.0W 989 53 1200UTC 19.11.2023 96 37.5N 60.9W 978 68 0000UTC 20.11.2023 108 48.0N 53.0W 979 58 1200UTC 20.11.2023 120 CEASED TRACKING