raindancewx

ACE is sustained winds in every named tropical storm measured every six hours, in knots. That number is squared and divided by 10,000. Each 6-hour ACE value for each storm is summed for the season. So sustained winds of 115 mph (category three) give 100 knots. That value would 100*100 / 10,000, i.e. 1 point. If the storm was 130 kts six hours later, it would 130 * 130 / 10,000. The ACE figures I referred to are for the Atlantic. The six hour time frame for measurement is used because it corresponds to old ship reports and things like that pre-satelite era.

Yep. Especially in the Fall. If you rank Nino 3.4 by month for "coldness", the event last year was most impressive in the Fall. October and November 2020 were both top ten cold ENSO events since 1950. The later/earlier periods were no where near that. These are your coldest ever Novembers in Nino 3.4, using a constant baseline (CPC uses a sliding baseline) of 26.49C. Top ten sounds real strong out of 71 years right? Problem is only like 23 or 24 of the years are La Ninas. So the peak is really only slightly above the middle of the pack for a La Nina, and then it was weaker in winter Spring. 1955 -2.24 1973 -2.16 1988 -1.84 1975 -1.44 2010 -1.43 1999 -1.37 2007 -1.32 1998 -1.25 1964 -1.23 2020 -1.21

That look on the Euro is somewhat similar to at least one of the cold ENSO (non-La Nina) years in the 1960s. Can't remember if it's 1960-61, 1961-62, 1962-63, or 1967-68 but I think at least one of those is similar. The warmth by Indonesia with another big IOD phase is not something I was looking at a few weeks ago.

That bath water by Indonesia seems way more important to the global pattern at the moment than the weak little cold-Neutral look we have. Still a lot of light blue / white (-0.4C to +0.2C waters v. 1981-2010 averages) in the 120-170W, 5N-5S Nino 3.4 zone.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 28JUL2021 22.1 0.8 25.1-0.4 26.7-0.4 28.7-0.1 04AUG2021 21.7 0.7 25.1-0.2 26.7-0.3 28.6-0.2 11AUG2021 20.9 0.1 24.8-0.4 26.5-0.4 28.6-0.2 18AUG2021 20.5-0.1 24.4-0.6 26.0-0.9 28.6-0.2 25AUG2021 20.6 0.0 25.0-0.0 26.5-0.3 28.5-0.3 01SEP2021 20.3-0.2 24.7-0.3 26.5-0.3 28.4-0.3 29JUL2020 20.1-1.2 24.7-0.8 26.3-0.8 28.4-0.5 05AUG2020 19.8-1.3 24.6-0.7 26.3-0.7 28.4-0.4 12AUG2020 19.9-0.9 24.8-0.4 26.4-0.6 28.3-0.5 19AUG2020 19.5-1.1 24.3-0.7 26.0-0.9 28.4-0.4 26AUG2020 20.0-0.6 24.2-0.8 26.1-0.7 28.6-0.2 02SEP2020 18.9-1.7 23.6-1.4 25.8-0.9 28.4-0.4 For this week, +1.4C in Nino 1.2, +1.1C in Nino 3, +0.7C in Nino 3.4, and even in Nino 4 compared to 2020. Last year, conditions were solidly La Nina by now. This is not that. Nino 3.4 is 120W-170W. You have some warm water below the surface at 160W and west. The waters below the rest of Nino 3.4 are somewhat cold but not incredibly. You also have some warmth way at depth which diminishes the totality of the cold signal quite a bit.

It doesn't work reliably in Baltimore/DC and south, but in La Nina years, ACE over 150 is almost a pre-requisite Summer trait for the big NE snowy winters. Pretty sure there are no La Ninas more than +20% or +30% for NYC/Philly snow totals since 1930 when ACE is not at least 150. I know you guys don't live up there, but if you hit 150 ACE in the Summer, you at least have a shot at a lot of Nor'easters with blocking. The big ACE La Nina years since 1931-32 are these, in order of highest ACE: 1933, 2005, 1995, 2017, 1950, 1998, 2020, 1999, 2010, 1955, 1964. If you use Baltimore, the 11-year average snowfall is (44.6+19.6+62.5+15.4+6.2+15.2+10.9+26.1+14.4+18.1+18.6)/11 --> 22.9, and essentially a coin flip for near-normal to snowy conditions using the 1991-2020 snow average. 1933-34, 2005-06, 1995-96, 1999-00, 1955-56, 1964-65 are all near average to snowy using the most recent 30 years. 2020-21 and 2010-11 would probably be snowy patterns too with less bad luck.

All months since March this year have at least resembled the 1961 look nationally, although the placement/extent of the cold matching 2021 has not been perfect. You can see the Summer finished too cold in 1961 compared to this year. My view is you can't treat weak La Ninas in the old days like weak La Ninas today. They tend to be surrounded by warmer waters in the Pacific now. But the old cold-Neutrals years often had that. So that's why a lot of those years are working well as analogs right now. Locally, there is something of a signal in the temperature matches for a very cold December followed by a much warmer late winter. The monsoon in my exact spot has not been strong, but it has been quite consistent for southern NM and Arizona this year. Those areas won't need any cold/extra moisture in winter to remain above average...so my guess is they won't be cold or wet. Here we've been dry with near average temps which is a more mixed signal. The hottest driest cold-ENSO Summers tend to be colder/wetter winters here (1954, 2007, 2011, 2012, 2016, 2020) while the wettest/coldest cold-ENSO Summers tend to be warmer/drier winters here (1933, 1999, 2005, 2008, 2013, 2017). Not quite sure what to do with a Summer with below average hot days and rain yet. Last year had ~88 days hit 90, with ~40% below average rain in Summer. This year is more like 25% below average rain. As of yesterday, only 55 days have hit 90 - fewest since 2008 (64 is average for a year).

If you included the necessary prior conditions to the immediate trigger for the recent flooding, you'd have Henri and all the other flash flood events from the near record wet Summer in Boston and NYC in there, and I'd expect you'd end up a lot closer to 400.

The surface observations are much warmer than last year in Nino 1.2, but also warmer in Nino 3, 3.4 and 4. Have to catch up to last year before we have any chance to surpass it. Aug 2021 v. Aug 2020 at the surface Nino 1.2: +0.76 Nino 3: +0.17 Nino 3.4: +0.14 Nino 4: +0.15

I'm absolutely convinced that those of you in the Northeast are only capable of posting in this thread when unusual things happen in the wide wide world of not-New Jersey. At the end of the day 3 inches of rain in an hour is way more impressive than the west beating old highs by a small amount for five minutes a day whether you want to admit it or not.

Nora remnants provided a nice widespread area of rains out here. I think we have a shot at 1-3 more dying hurricanes helping out through 10/31. Some of my analog matches on US temps/precip show a very wet October for the SW.

The relatively strong intensity of the flooding and tornado activity in the Northeast is reminiscent of Allison - another storm that wouldn't see it's upper dynamics completely destroyed by landfall. I've mentioned previously that I'm looking at 2001 as an analog for seeing similar Nino 3.4 conditions to both winter 2020-21 and July/Aug. After Ida hit, I noticed that the intensity in millbars was near identical to Carla in 1961, an extraordinary powerful hurricane, famous for damaging or destroying something like 60,000 buildings in Texas. The flood threat with Carla was extensive too. You can see the spread was similar in breadth to Ida, just further west due to land falling to the west. If you look nationally, the US weather pattern for temperatures has been very close to 1961 since March. You had incredible heat in the NW for instance in June. Locally, the Jan-Aug high temperatures in 2021 are an incredible match to 1961. Third closest match to 2021 in the past 90 years in 1961. Can't be easy to get this level of heat in the NW in a cold ENSO year given the Earth has warmed in 60 years. So the 1961 June heat is impressive.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt 100-180W subsurface was -0.83 in Aug 2021, compared to -0.80 in Aug 2020. More rain for me today. A rare, long-lasting light rain courtesy of the death of Nora. Monsoon has now matched last year locally, still a month to go.

I like to compare the old footage to the new footage for hurricanes in similar areas. Ida: Carla: Lots of electrical grid damage here - Hurricane Hilda: Hurricane Betsy: - the modern levee system was designed to prevent another Betsy. Kinds of a legendary storm. Hurricane Beulah: Another amazing system Hurricane Camille:

The clustering below of big bad storms reminds of me some periods in the 1930s and 1960s. Carla (1961), Hilda (1964), Betsy (1965), Beulah (1967) Camille (1969) for some comparable Gulf monsters to the recent four. That period from 1964-1969 was pretty rough down there. Freeport (1932), 1933 - several Gulf Coast hits and a nasty stronger Isabel too for the NE, Hurricane "1" in 1934 is kind of legendary in some ways, 1935 had the five in the Keys, and then 1938 had the New England hurricane and a hurricane hit the central Gulf. 1933 is a nuts season, but 1932 doesn't really get it's due. Carla: 1961 (931 mb right before Landfall, similar spot to Laura, likely similar to Laura for winds too) Hilda: 1964 (950 mb at landfall) - stronger Oct 1964 version of Delta in October 2020 (970 mb) Betsy: 1965 (942 mb, hit right near Houma like Ida) Beulah: 1967 (950 mb landfall S. Texas, lots of floods and tornadoes) Camille 1969 (900 mb just around landfall - 175 mph winds based on observations)

Let's keep nuking this god damned drought.

Lots of rain in southern New Mexico in May, June, July and August has it looking quite lovely. Probably not so apparent if you just look at the drought monitor instead of the vegetation. September is negatively correlated pretty well to cold season precipitation patterns in La Ninas down here. This has my attention -

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 04AUG2021 21.7 0.7 25.1-0.2 26.7-0.3 28.6-0.2 11AUG2021 20.9 0.1 24.8-0.4 26.5-0.4 28.6-0.2 18AUG2021 20.5-0.1 24.4-0.6 26.0-0.9 28.6-0.2 25AUG2021 20.6 0.0 25.0-0.0 26.5-0.3 28.5-0.3 05AUG2020 19.8-1.3 24.6-0.7 26.3-0.7 28.4-0.4 12AUG2020 19.9-0.9 24.8-0.4 26.4-0.6 28.3-0.5 19AUG2020 19.5-1.1 24.3-0.7 26.0-0.9 28.4-0.4 26AUG2020 20.0-0.6 24.2-0.8 26.1-0.7 28.6-0.2 The blend of the four weekly readings comes out to 26.4C or so in Nino 3.4. Still tracking very similarly to 1967 in the western zones. The blend I'm testing in September is still close 1967, 2001-02 (x2), 2011-12, 2013-14 (x2), 2020-21 (x2) to what the monthly data should be for 2021. If the weeklies are similar to the monthly August data, Nino 1.2 is much warmer than last year, with Nino 3, 3.4 and 4 0.1-0.3C warmer too. Subsurface is probably a touch colder overall in August, but it hasn't worked up yet, and has to wash away much more warmth. https://www.psl.noaa.gov/data/correlation/nina34.data 1967 25.88 26.11 26.50 26.74 27.35 27.47 26.97 26.44 25.86 25.97 26.08 25.95 2021 25.54 25.75 26.49 27.10 27.48 27.45 26.97 26.45? 99.99 -99.99 -99.99 -99.99 https://www.psl.noaa.gov/data/correlation/nina4.data 1967 27.60 27.41 27.82 28.44 28.76 28.58 28.52 28.32 28.20 28.33 28.34 28.15 2021 27.26 27.23 27.67 28.19 28.70 28.83 28.68 28.55? -99.99 -99.99 -99.99 -99.99

8/1-8/30 SOI: +3.7 The three La Nina SOI matches for June-August look like what the CFS has for September.

The Cajun Navy is starting to make rescues as in prior flood events. You can give them your location if you need assistance.

The 1938 hurricane season, besides the famous New England storm, had a hurricane ("3") hit the central Gulf Coast in August on a path to the west of the Ida. It was a La Nina year too.

There aren't many hurricanes at this time of year, in this position in the Gulf of Mexico that see rapid intensification, on the order of say, Cat 1/2 to 4/5 in a day or less. A lot of the famous recent storms actually weaken somewhat as they approach, will be curious to see which genre this is. Katrina would have been insane if it had been strengthening up until landfall. I've seen mentions of Katrina and Camille, but Gustav (2008) has been fairly similar too, by timing, magnitude and track. Gustav: 26.9N / 87.7W, 953 mb, 110 mph sustained winds (8/29 UTC) Ida: 27.2N / 88W, moving NW 16 mph, 964 mb, 105 mph sustained winds (9/1 by UTC)

The rains over TN are going to be trouble given the recent circumstances if this has any pop left after landfall.

I was looking at arctic sea ice extent mins in September to see if there is any relationship with the various indexes for winter. The sea ice mins correlate relatively well (r-squared is 0.13 or so from 1979-2020) to the winter WPO. But WPO values have been trending more positively in the 1979-2020 period for winter anyway. So it's likely an auto-correlation thing. The thing with the subsurface is it does correlate with the winter values for Nino 3.4 pretty well in August - r-squared is over 0.7 if you use a polynomial trend line. But the "variance" off the trend line is still +/-0.6C at ~95%. So you can have a -0.8 subsurface in August and end up at a 26.1C Nino 3.4 in winter. The best fit line for a -1.0 subsurface in August is a 25.6C La Nina in winter, about -1.0C against the 1991-2020 baseline CPC uses, but only -0.9C against the 1951-2010 baseline that seems to "work" better for ENSO conditions switching on/off. I think we're closer to -0.8 or -0.9 for August than -1.0 though in the subsurface data. At the end of the day, there has not been a La Nina stronger / colder than 25.5C in a full winter in over a decade. CPC seems to think La Ninas should be classified based on warming math baselines to account for the warmer oceans. To me, that seems wrong. The "strong" La Ninas in the old/cold days don't look like the modern "strong" La Ninas. There is no guarantee of strong or moderate La Ninas even at a once a decade level for winter. I personally think we're in a broadly similar period to the 1950s/1960s now, and if you look, we went from 1955-56 to 1970-71 without a La Nina below 25.5C in winter, and then we went from 1975-76 to 1988-89 without a La Nina below 25.5C in winter. So even at 11+ years, the current streak of weak La Ninas or warmer is not that close to the 15 year record. (1988 to 98, 1999 to 2007, 2010 to now are the most recent streaks).

August comparison, scaled to find waters cold enough to be a La Nina. Still not ahead of last year at the surface or close to it. Much warmer in the zones, but especially no huge batch of cold waters by South America (blues and purples).