Atmospheric Scientist/AI Professional/Certified Consulting Meteorologist
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As surmised earlier this summer, the GWO has remained firmly in the El Niño attractor and is poised to transit phases 7-8 as the tendency becomes negative. While this favors a western ridge aloft, one is situated over central NOAM. My read is that the Pacific wave train is interacting with persistent, east-shifted El Niño large-scale tropical heating, perhaps reinforcing downstream wave activity and amplifying the ridge further east.
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El Nino’s prodigious subseasonal fingerprint is once again trolling the y-axis in the latest forecast.
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A new capability coming soon to gsdmsolutions.com: a way to explore subseasonal model skill and its relationship to the evolving global atmospheric state.
gsdmsolutions.com/blog/subse…
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New at gsdmsolutions.com: (1) Pentad-mean (1-5, 6-10 and 11-15 day) forecast maps from the AIFS-ENS. I have started by generating these for the compound maps showing WAF, waveguides, psi200’ and chi200’ and (2) forecast verification for AAM, VPM, Tauf and TauM.
On today’s forecast sequence you can see the modeled westward shift in the intense large scale wave number 1 chi200’ field with attendant renewed strong forcing of Rossby wave trains in both hemispheres.
The maps use stippling/hatching to show areas of reduced ensemble signal-to-noise in the psi200’ & chi200’ fields.
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Holy El Niño - I’m gonna have to extend the y-axis on these plots before the year is through!
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Even as the MJO briefly moves away from the El Niño attractor, robust subtropical westerlies will sustain in the SH and build in the NH.
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New on gsdmsolutions.com: you can now composite on precipitation, which has also been added to the Response-Lag Atlas.
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The Response-Lag Atlas in gsdmsolutions.com has an ENSO filter now, using the @webberweather ONI dataset. And I’m working on adding additional response variables.
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New daily maps on gsdmsolutions.com help highlight the “return address” for extreme weather!
Tropical heating/Rossby wave source —> wave train —> momentum fluxes, repositioning the storm tracks/waveguides and significant circulation anomalies.
These pentad-mean maps include WAF, Ks (waveguides), chi200 and psi200 anomalies. Admittedly busy but lots of info in a single graphic.
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Simply remarkable RWE dispersion continues from the quasi stationary ENSO forcing regime across the C-E tropical Pacific. Note the pronounced wave energy flows both emanating from this source poleward into both hemispheres - and into it - suggesting a role for the synoptic scale eddies in its maintenance. In the JMA version, which shows OLR anomalies, you can clearly see the connections between these wave energy flows and the intense convective anomalies in Texas responsible for the huge floods there and the intense convection over parts of S America.
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There is a CORe outage impacting updates on gsdmsolutions.com. I have developed a plan to backfill using GFS/GDAS, supported by a multi-season evaluation vs CORe. I’m also emailing NCEP to inquire about the CORe status.
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The strong El Niño background state looks to be relentless - probably indefinitely!
A very El Nino-like AAM/GWO & MJO background state is driving a large component of the record-breaking ridge over the Upper Midwest next week.
Left image from @dgoldweather’s site
gsdmsolutions.com
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While the atmosphere has likely reached peak AAM loading, the circulation is going to remain in a configuration consistent with a very eastward shifted Walker cell and seasonally enhanced/intense belts of subtropical westerly wind flows for the remainder of boreal summer. The expected regional responses are likely still well captured by variations of MJO 8-1 and high amplitude GWO 7-8, respectively.
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Some plausible composites for NH z500’. We may see regional circulation responses with some of these characteristics at many times during the next few weeks, including:
* an extended or strengthened Pacific subtropical jet
* increased Rossby wave activity entering the North Pacific waveguide
*cyclonic height anomalies over the extratropical central/eastern Pacific
*anticyclonic wave breaking or ridge amplification downstream toward Alaska and western Canada
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While the atmosphere has likely reached peak AAM loading, the circulation is going to remain in a configuration consistent with a very eastward shifted Walker cell and seasonally enhanced/intense belts of subtropical westerly wind flows for the remainder of boreal summer. The expected regional responses are likely still well captured by variations of MJO 8-1 and high amplitude GWO 7-8, respectively.
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Top 10 tornadoes I have chased:
1. Dimmitt, TX 6-2-1995
2. Red Rock, OK 4-26-1991
3. Allison, TX 6-8-1995
4. Webb, Iowa 6-11-2004
5. Colton, SD 6-7-1993
6. Big Spring, NE 6-10-2004
7. Hill City, KS 6-9-2005
8. Big Spring, NE 6-12-1993
9. Ollie, MT 6-20-1999
10. Waterloo, IA 5-11-2000
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The atmospheric circulation is certainly on board with Mumbo-Nino with AIFS ENS predicting a greater than 2 sigma projection in GWO phase 7 soon.
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Two new additions to gsdmsolutions.com!
1. Global index forecasts with ensemble spread out to 45 days driven by the ECMWF S2S forecast. This updates on odd days. The 1-15 day forecast and spread still comes from the AIFS-ENS and the ECMWF subseasonal forecast extends that with the spread provided by 100 ensemble members.
2. A response-lag atlas that complements the Composite Engine by identifying the lead times for the most significant responses to GWO/MJO “events”. For now, this is flagging 2-m air temperature anomalies but more response variables will be added over time. I have provided details so you can understand the essential aspects of the methodology.
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Another blog post on the causes for extreme weather events with a focus on the ongoing extreme heatwave over parts of Europe. Enjoy!
gsdmsolutions.com/blog/retur…
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ENSO-related CPAC convective forcing doing real work, engaging the torques over the next few days to rebuild a huge subtropical jet stream in the Southern Hemisphere with corresponding peak AIFS-ENS mean AAM values of 23 Had.days (or simply 2 AAM units per the chart if you don’t want to get fancy) in the lower latitudes. These westerlies will impinge upon the Andes and quickly reverse the sizable developing TauM spike there, leading to a big orbit in the “El Nino attractor”. Thus, high-amplitude GWO 6-7 JJA composites may work quite well from late Week 1 into Week 2. You can create these at gsdmsolutions.com.
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