bluewave

The summer forcing pattern seemed like it got compressed into the Southern Hemisphere for some reason. Maybe that is why the -SOI intervals struggled to weaken the trades along the equator. Notice how far south the VP anomalies wound up relative to the early June forecasts. At least the models got the forcing correct west of the Dateline where the warmest 30C SSTs wound up.

Didn’t say no coupling. But possible weak coupling with competing influences will make for some very low skill winter forecasts. May be too much variability for any of the current seasonal models to correctly decipher. Notice how poorly they all did with the summer forcing forecasts east of the Dateline. We need a strong -AO -NAO +PNA signal as an insurance policy.

Upper 80s to some 90s has been the post 9-16 norm since 2010. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Ending Date Highest Max Temperature Sep 16 to Oct 10 Missing Count 2022-10-10 88 0 2021-10-10 88 0 2020-10-10 83 0 2019-10-10 96 0 2018-10-10 84 0 2017-10-10 92 0 2016-10-10 90 0 2015-10-10 89 0 2014-10-10 87 0 2013-10-10 89 0 2012-10-10 81 0 2011-10-10 88 0 2010-10-10 90 0

It then gets really tricky as to what even the MEI threshold needs to be to resemble some type El Niño forcing this winter. Pretty impressive disconnect between the tropics and extratropics. We may end up with a mix of competing forcing influences which will make any seasonal forecasts even lower skill than usual. We may need some type of -NAO -AO carryover assist from the summer for a shot at better winter than last year.

Score another win for RONI stealing the thunder from this El Niño attempt.

Most of the week two pattern matches are La Niña years with the exception of 2009,2004 and 1968.

The SST warming further south closer to subtropics and tropics along with the recent study in low spring snow cover resulting in more summer blocking. The area east of Maritime Canada experienced record low winds high amounts sunshine this summer under the record south based Greenland block. Most of the studies have been posted in other sections of the forums.

You make the mistake of assuming that I am implicating the changes in increasing 500 mb heights to higher latitude SST warming. The higher latitude SST warming is mostly a result of rising 500 mb heights above the surface increasing resulting in near record light winds and sunshine heating the SSTs below. My arguments have been supported by studies which show the SST warming in the lower middle to tropical latitudes have been driving stationary or repeating Rossby wave trains resulting in record 500 mb heights.

I am sure you can always pick out some locations which don’t match up since there is no such thing as a perfect match. This is largely due to the warming and rising 500 mb heights which I mentioned. But you would be hard pressed to find any other summers since 1950 with an Aleutians Trough, -EPO +PNA, NE Trough, and near record -NAO. The differences you mention near Baffin Island are probably result of the warmest Atlantic SSTs on record interacting with the -NAO -AO projection. So the -NAO block was displaced south of Greenland instead of being anchored closer to the pole like in 2009. Plus the antecedent record Canadian blocking in May and massive +PNA didn’t leave much room for cool air this summer in North America.

The only summer since 1950 to match the 500 mb pattern this summer was 2009. We tied for the deepest summer Northeast trough on record with 2009. But there was much less cold around the Northern Hemisphere this summer. Nearly identical positions of the Aleutian trough/ -EPO/ NE Trough/ -NAO. 500 mb ridging locations were also stronger due to the steadily increasing 500 mb heights and warming temperatures. This was especially true with Canadian Ridging which set new monthly records since the spring along with the block south of Greenland. A colder era would have allowed for lower 500mb heights and more expansive troughs. So the Northeast trough would have had an actual cool air source to work with instead of the 500mb ridging crowding out the troughs.

The forcing pattern this month just west of the Dateline would be great to have during the winter. Hopefully, the amazing summer blocking pattern repeats to some extent with winter wavelengths. Would be nice to see the post +IOD winter pattern not experience an excessive rebound in SSTs near Indonesia. But that MJO 4-6 has had a habit of firing up at the most inopportune times during many winters back to 15-16.

Easy to get record high dew points and training convection when the When the SSTs are 80° off the Jersey Shore and upper 70s in the Long Island Sound. These bouy temperatures would be more common in July than in September. Coastal Waters Roundup...For Informational Purposes Only National Weather Service New York NY 300 PM EDT MON SEP 11 2023 ...Ocean Waters... STATION/POSITION TIME TEMP WIND PRES WAVE WND WV SWELL AIR SEA DIR/SP/G HT/PER HT/PER HT/PER/DIR (UTC) (F) (DEG/KT/KT) (MB) (FT/S) (FT/S) (FT/S/D) NY Harb Entrance 1850 76 1013.7 20 S Fire Is NY 1850 1013.7 3/12 23 SSW Montauk P NOT AVBL 25 SE Block IS 1856 74 N/A 3/12 2/ 6 2/140/12 15 E Barnegat NJ 1856 80 N/A 3/13 2/ 6 2/130/13 Texas Tower #4 1840 N/A 4/13 ...Long Island South Shore (WeatherFlow - Wind is MPH)... STATION/POSITION TIME TEMP WIND PRES WAVE WND WV SWELL AIR SEA DIR/SP/G HT/PER HT/PER HT/PER/DIR (UTC) (F) (DEG/KT/KT) (MB) (FT/S) (FT/S) (FT/S/D) Great South Bay 1845 77 81 CALM N/A CITY SKY/WX TMP DP RH WIND PRES REMARKS Breezy Point N/A 79 N/A N/A S7 N/A Jones Beach CG N/A 77 N/A N/A SE8 N/A Amityville N/A 77 N/A N/A S10 N/A Boat Channel N/A 75 N/A N/A S8 N/A Fire Island CG N/A 77 N/A N/A SE5 N/A Pt O Woods N/A 77 N/A N/A S6 N/A Blue Pt N/A N/A N/A N/A S7 N/A East Moriches N/A 75 N/A N/A SE9 N/A Shinnecock Inl N/A 75 N/A N/A SE8 N/A Mecox Bay N/A 75 N/A N/A SE8 N/A Napeaque N/A 77 N/A N/A SE10 N/A ...Long Island Sound... STATION/POSITION TIME TEMP WIND PRES WAVE WND WV SWELL AIR SEA DIR/SP/G HT/PER HT/PER HT/PER/DIR (UTC) (F) (DEG/KT/KT) (MB) (FT/S) (FT/S) (FT/S/D) Kings Point 1836 77 76 360/ 6/ 8 1014.9 Execution Rocks 1915 78 73 30/ 6 N/A Western LI Sound NOT AVBL Bridgeport NOS 1836 79 77 170/ 5/ 6 1012.9 New Haven NOS 1836 78 78 200/ 8/ 9 1014.9 Central LI Sound NOT AVBL Ledge Light 1915 150/ 9/ 10 N/A

Those stormvista SST charts are a little too low of a resolution to be of much help. Check out the August actual rankings for the entire Pacific Basin. Top 5 warmest SSTs at +30C west of the Dateline. So that’s where the forcing keeps getting stuck. We are seeing a temporary slight cooling relative to recent times near Indonesia. But as we have seen in recent years, a steady rebound has occurred as soon as the +IOD peaked in the fall. I can remember how surprised everyone was when the IOD rapidly faded in the late fall of 2019 and the SSTs rebounded to all time levels north of Australia.

That’s the power of Miami dew points in September. Just add a weak stalled out front and we are in business. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=155&network=CT_ASOS&zstation=HVN&var=max_dwpf&w=all&threshold=100&hour=12&sdate=0101&edate=1231&month=sep&_r=t&dpi=100&_fmt=png

The PDO is a bit like a chicken or egg situation. When the -PDO is coupled with with the 500mb pattern we get the Western Trough/SE Ridge pattern associated with a -PNA like last winter. But in 20-21 and to some extent 21-22 ,the -PDO was uncoupled with the pattern with the strong +PNA at times and forcing closer to MJO 7 west of the Dateline. So it’s clearly a remote teleconnection pattern from the WPAC running the show. Last winter we got stuck in the MJO 4-6 forcing pattern which drove the -PDO and created a very strong La Niña type of pattern. Trying to decipher the exact location of the forcing in the WPAC can be challenging ahead of time. Unfortunately, we seem on balance to get longer duration and more 4-5 than 6-7-8 forcing since 15-16. Funny how fleeting the 13-14 and 14-15 more favorable WPAC forcing turned out to be.

The actual data disagrees with you on the WPAC warm pool. This is currently the largest reservoir of +30 C WPAC SST warmth that we have seen outside a weak uncoupled El Niño or La Niña. It’s the reason that the -SOI can’t couple with the Pacific trade wind pattern. Forget what x or y model is showing beyond 10 days. The stronger WWBs keep getting pushed back and the forcing remains west based. This is the actual verification so far below which bears little resemblance to an El Niño pattern. These ENSO models have been like a perpetual GFS 384 snowstorm forecast that keeps getting pushed further out the closer in we get.

The atmosphere never got the memo that this is supposed to be an El Niño. The hurricane season in the Atlantic is in full La Niña mode. We still have stronger trades in the Pacific than we should for an El Niño. So I question how much more the ENSO SST regions can rise without a strong WWB pattern and a steep increase in OHC. It did look like we were trying to make some progress closer to an El Niño back in August. But the WWB pattern couldn’t sustain itself.

The model is clearly showing excessive momentum. It had +2.25 to +2.50 for early September from May and we are only around +1.55.

Yeah that was some block over SE Canada. It does look like the block is correcting stronger for next weekend. But still not quite as strong as a few years ago.

We would probably need some westward corrections to track next few days to get the heavy rains back to around NYC like we saw with Henri. So far the block showing up for next weekend isn’t quite as strong as that. But we’ll see what shorter term model trends emerge this week.

Euro coming around to the AI models idea of windy and rainy conditions for the eastern half of the forum next weekend with Lee.

Confidence has been fairly low even in the early fall with El Niño development since 2012. Our only reasonably good ENSO forecast was in 2015 but that was much stronger and better coupled than we are seeing now. So each ENSO attempt outside 2015 had some major model error. We have been seeing rare instances of an early fall forecast barrier which used to only be reserved for the spring before the WPAC warm pool become such a prominent feature.

The funny thing about the modeling with Lee is that all the models have been taking turns having these west of ensemble mean tracks from run to run. So there is still some question on how fast the trough lifts out of the NE later in the week and ridging builds in behind it. If that trough can’t dig enough, then we won’t have it to safely boot LEE OTS for interests near the Cape. So there is a lot riding on the track in terms of storm impacts and the future of AI in weather forecasting. We could only imagine how AI might impact winter storm forecasting if they show more skill than the regular models with Lee and other test cases going forward.

If one of these random runs west of the ensemble means near Cape Cod actually happen, then it will be a big win for the newer AI models. This will be the big test case coming up. Imagine if they end up being right. Maybe we could actually nail a day 7-10 snowstorm forecast for once.