knocker

I do not agree with that assessment. The ecm is not completely different and still does not support the gfs surge into Greenland next Friday due to a wave developing on the front south of Newfoundland tracking NE to Iceland and inhibiting amplification of the ridge. The later ec amplification into Greenland is due to a Nor'easter tracking up the eastern seaboard. Having said that there are alot of options on the table so best take a watching brief

I am constantly reminded that on occasion it is very silly of me to ignore the advice of some time ago that my posting on this site is not welcome.

Possible strat driven as the vortex at 50mb moves a tad towards Europe

Bottom line - the control run is at a lower resolution

https://mailchi.mp/caa/how-we-know-that-global-warming-is-accelerating-and-that-the-goal-of-the-paris-agreement-is-dead

Griteater's Winter Outlook (23-24).pdf

A new study published in Nature suggests there may be more wiggle room left for the ice sheet before it sets on an irreversible decline. Even if human-driven climate change pushes global temperatures above that 2C threshold, an increasingly likely possibility, the Greenland ice sheet could avoid full collapse if temperatures come back down relatively quickly, the study says. https://www.npr.org/2023/10/18/1205601646/a-new-study-points-to-a-key-window-of-opportunity-to-save-greenlands-ice-sheet

Abstract Climate models predict a weak poleward shift of the jets in response to continuing climate change. Here we revisit observed jet trends using 40 years of satellite-era reanalysis products and find evidence that general poleward shifts are emerging. The significance of these trends is often low and varies between datasets, but the similarity across different seasons and hemispheres is notable. While much recent work has focused on the jet response to amplified Arctic warming, the observed trends are more consistent with the known sensitivity of the circulation to tropical warming. The circulation trends are within the range of historical model simulations but are relatively large compared to the models when the accompanying trends in upper tropospheric temperature gradients are considered. The balance between tropical warming and jet shifts should therefore be closely monitored in the near future. We hypothesise that the sensitivity of the circulation to tropical heating may be one factor affecting this balance. https://www.nature.com/articles/s43247-023-00792-8

I wouldn't say it was ineffectual. The trough development and the strong jet does result in the low SW of the UK tracking NE across the country as the blocking high changes orientation

The ecm ens do vertical profiles out to t120 and this Saturday 1200 for Reading

The gfs forecast sounding for Saturday is a quite a good illustration of why surface temps, based on the 850mb temp, can be a tad tricky if the lapse rate in the boundary layer is modified by such as cloud, etc Original post: https://community.netweather.tv/topic/99056-model-output-discussion-mid-summer-onwards/?do=findComment&comment=4930843

The gfs forecast sounding for Saturday is a quite a good illustration of why surface temps, based on the 850mb temp, can be a tad tricky if the lapse rate in the boundary layer is modified by such as cloud, etc

Because the temp profile is modified lower down, particularly in the boundary layer by the advection of cooler air Original post: https://community.netweather.tv/topic/99056-model-output-discussion-mid-summer-onwards/?do=findComment&comment=4914391

Because the temp profile is modified lower down, particularly in the boundary layer by the advection of cooler air

Interesting to note that it has moved on from coffee

Yes it is very interesting as you have our weekend low being absorbed within the developments and the huge temp differential and block courtesy of the east European ridge

And a recent paper on the QBO ABSTRACT In the tropical stratosphere, deep layers of eastward and westward winds encircle the globe and descend regularly from the upper stratosphere to the tropical tropopause. With a complete cycle typically lasting almost 2.5 years, this quasi-biennial oscillation (QBO) is arguably the most predictable mode of atmospheric variability not linked to the changing seasons. The QBO affects climate phenomena outside the tropical stratosphere, including ozone transport, the North Atlantic Oscillation and Madden-Julian Oscillation, and its high predictability could enable better forecasts of these phenomena if models can accurately represent the coupling processes. Climate and forecasting models are increasingly able to simulate stratospheric oscillations resembling the QBO, but exhibit common systematic errors such as weak amplitude in the lowermost tropical stratosphere. Uncertainties about the waves that force the oscillation, particularly the momentum fluxes from small-scale gravity waves excited by deep convection, make its simulation challenging. Improved representation of processes governing the QBO is expected to lead to better forecasts of the oscillation and its impacts, increased understanding of unusual events such as the two QBO disruptions observed since 2016, and more reliable future projections of QBO behaviour under climate change. The Quasi-Biennial Oscillation: Impacts, Processes, 1 and Projections 2 James A. Anstey1,10†, Scott M. Osprey2,3,10†, Joan Alexander4, Mark P. Baldwin5 3 , Neal Butchart6, Lesley Gray2,3, Yoshio Kawatani7, Paul A. Newman8, and Jadwiga H. Richter9 QBO_review_2022_NREE_pre-proof.pdf

Mention of the QBO is cropping up a fair bit of late which raises the question once again of the mechanism of the QBO and effects on Tropospheric weather. A couple of papers that may be of interest if one, like me, is trying to get to grips with the subject' including the original one by Baldwin, et al. It is a very complex subject and research is ongoing QBO.pdf QBO.pdf

Does he give any justification for this comment, such as a statement from ECMWF? Or is this merely his opinion in which case we can safely ignore.

It's the new kid on the block that has replaced Monty Python and the Holy Grail

Introduction May 2023 was a very different month, in terms of weather, for Spain and Italy. While Spain struggled in unusually warm and dry conditions, Italy experienced waves of heavy precipitation which resulted in floods and tragic losses of life. Here we will discuss the causes, and put May precipitation in that region in the context of continental-scale precipitation and the past two decades of satellite observations. https://disc.gsfc.nasa.gov/information/data-in-action?title=Floodings in Italy, May 2023&utm_source=newsletter&utm_medium=email&utm_campaign=earthdata-discovery-072023

Some of the largest and most persistent circulation errors in global numerical weather prediction and climate models are attributable to the inadequate representation of the impacts of orography on the atmospheric flow. Existing parametrization approaches attempting to account for unresolved orographic processes, such as turbulent form drag, low-level flow blocking or mountain waves, have been successful to some extent. They capture the basic impacts of the unresolved orography on atmospheric circulation in a qualitatively correct way and have led to significant progress in both numerical weather prediction and climate modelling. These approaches, however, have apparent limitations and inadequacies due to poor observational evidence, insufficient fundamental knowledge and an ambiguous separation between resolved and unresolved orographic scales and between different orographic processes. Numerical weather prediction and climate modelling has advanced to a stage where these inadequacies have become critical and hamper progress by limiting predictive skill on a wide range of spatial and temporal scales. More physically based approaches are needed to quantify the relative importance of apparently disparate orographic processes and to account for their combined effects in a rational and accurate way in numerical models. We argue that, thanks to recent advances, significant progress can be made by combining theoretical approaches with observations, inverse modelling techniques and high-resolution and idealized numerical simulations. npj Climate and Atmospheric Science (2019) 2:10 ; https://doi.org/10.1038/s41612-019-0065-9

Which is precisely how the models have evolved since the second world war. The study of teleconnections, including troposphere/stratosphere interactions, is still pretty much in it's infancy but with a fair bit of it being incorporated in the models as they continue to develop. But at the end of the day, as far as I'm aware, this is mainly a thread for interpreting the model output, which I suspect is not helped by the information overload now available

I often thank my lucky stars that I was kicked out of this forum