bluewave

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.

1.37 here at KHVN in only 30 minutes with plenty of low lying street and parking lot flooding.

Torrential downpour here at KHVN.

The weaker ridge to our east probably prevented Newark from getting a SW flow and 99-100° instead of the more onshore flow and underperforming highs there.

0.6 in 30 min at the Brooklyn mesonet.

The last time the RONI was at similar summer levels for a developing El Niño was back in 2004. This summer also had the westward forcing lean. Also note the very active hurricane season back in 2004. 2004-2005 was memorable for the El Niño not getting much stronger than it was in August and September.

Yeah, contrast the NYC number of 90 days in 2006 to 1977. No trees blocking the sensors in 1977 allowed NYC and EWR to get close. NYC was so far back in 2006 that it was ridiculous. Data for January 1, 2006 through December 31, 2006 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 NJ PLAINFIELD COOP 30 NJ HARRISON COOP 30 NJ TETERBORO AIRPORT COOP 30 NJ TETERBORO AIRPORT WBAN 29 NJ NEWARK LIBERTY INTL AP WBAN 27 NJ CRANFORD COOP 24 NJ MIDLAND PARK COOP 24 NJ CANOE BROOK COOP 22 NY LAGUARDIA AIRPORT WBAN 22 NY BRONX COOP 21 CT DANBURY COOP 20 NY DOBBS FERRY-ARDSLEY COOP 18 NY WEST POINT COOP 18 NJ CALDWELL ESSEX COUNTY AP WBAN 16 NY MINEOLA COOP 16 NY NEW YORK AVE V BROOKLYN COOP 15 NY PORT JERVIS COOP 13 NY WANTAGH CEDAR CREEK COOP 13 CT NORWICH PUBLIC UTILITY PLANT COOP 12 NY JFK INTERNATIONAL AIRPORT WBAN 12 NJ ESSEX FELLS SERVICE BLDG COOP 11 NY SHIRLEY BROOKHAVEN AIRPORT WBAN 11 CT MERIDEN MARKHAM MUNICIPAL AP WBAN 11 NY ISLIP-LI MACARTHUR AP WBAN 10 NY MONTGOMERY ORANGE COUNTY AP WBAN 10 NY RIVERHEAD RESEARCH FARM COOP 9 NY MIDDLETOWN 2 NW COOP 9 NY FARMINGDALE REPUBLIC AP WBAN 9 NY NY CITY CENTRAL PARK WBAN 8 Data for January 1, 1977 through December 31, 1977 Click column heading to sort ascending, click again to sort descending. State Name Station Type Number of Days Max Temperature >= 90 CT NEW HAVEN COOP 34 NY NEW YORK LAUREL HILL COOP 30 NY WEST POINT COOP 28 NJ PLAINFIELD COOP 27 NJ NEWARK LIBERTY INTL AP WBAN 26 NJ CRANFORD COOP 25 NY DOBBS FERRY-ARDSLEY COOP 25 NY NY WESTERLEIGH STAT IS COOP 23 NY NY CITY CENTRAL PARK WBAN 23 NJ TETERBORO AIRPORT WBAN 23 NJ CANOE BROOK COOP 22 NJ LITTLE FALLS COOP 21 CT STAMFORD 5 N COOP 21 NY NEW YORK AVE V BROOKLYN COOP 19 NY MARYKNOLL COOP 19 NY SCARSDALE COOP 19 NY PATCHOGUE 2 N COOP 17 NY SUFFERN COOP 17 NY WALDEN 1 ESE COOP 17 NJ WANAQUE RAYMOND DAM COOP 16 NJ RINGWOOD COOP 16 NY LAGUARDIA AIRPORT WBAN 14