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About dtk

  • Birthday August 30

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  1. To this and the other question regarding next steps for HiRes guidance... 1) NAM (including nests) are frozen. They will be replaced in the coming years. 2) SREF is also frozen (and now coarse resolution). Effort is being re-oriented toward true high resolution ensembles. 3) HRRR will include ensembles in the DA in 2020, but we cannot afford a true HRRR-ensemble. The HREF fills some of this void in the interim. 4) All of the above are going to be part of some sort of FV3-based, (truly) high resolution convection allowing ensemble. We are still several years away as there is still science to explore for defining the configuration. There's also serious lack of HPC for a large-domain, convection allowing ensemble.
  2. Yes, it is a measurable improvement over the current operational GFS. We have the quantitative and qualitative assessments to prove it.
  3. As a reminder, this is what you actually said "Yeah, unfortunately for the rest of the season I'll be putting the FV3 in the same camp as the CMC. Sad, this is supposed to be America's "innovation" in weather forecasting. In reality it looks like they just made the GFS worse."
  4. I guess we need to have more weenies involved in the evaluation process. Clearly, the professional meteorologists that helped get the package approved for implementation don't know what they are looking at. Sad.
  5. I'm gone from the threads for a really long time....only to come back and see references to "sampling" and "suffering from convective feedback". The more things change, the more they stay the same...
  6. Yes, the cool/low height bias with increasing forecast time is already well known and documented. In fact, I am pretty sure there is already a fix for this particular issue, though it is too late to include in the Jan. 2019 implementation.
  7. It's all part of our plan to get people to pay attention. In reality, it is going to be dead wrong. This is a pretty solid implementation, considering that we haven't had a chance to put a ton of new science into the package (outside of the model dynamics and MP scheme, a few DA enhancements, etc.). For things like extratropical 500 hpa AC, it has gained us about a point (about what we'd expect/want from a biannual upgrade). Improvements are statistically significant. I should caution, our model evaluation group has noted that there are times where the FV3-based GFS appears to be too progressive at longer ranges. It's not clear how general this is and for what types of cases this has been noted.
  8. FV3-based GEFS will not be implemented until early FY 2020 (probably Q2...e.g. about Jan 2020). Some of this is driven by human and compute resources as there is a requirement for a 30 year reforecast for calibration before implementation. Definitely 2017. All official retrospectives and real-time experiment use the Lin-type GFDL MP scheme.
  9. By most objective measures, the operational GFS did quite well with this storm (<120h lead time). I really like looking at the phase space bias for storms. This clearly shows the right of track (poleward) bias of the GFS. It looks like ECMWF had significant westward bias (forward speed) relative to most models: I don't have the plot handy, but FV3-GFS performed somewhere between the operational GFS and ECWMF for mean track error.
  10. ECMWF & Canadian globals are coupled to dynamic ocean models. HWRF, HMON, and COAMPS-TC are also coupled (to POM and/or HYCOM depending on model/configuration). These are the models that are capable of simulating the effect...I cannot comment on how well they actually do it.
  11. Neither the op GFS nor the FV3-GFS are coupled to an actual ocean model. Both of them use a parametric model to simulate the diurnal warming/cooling of SST...neither of them can simulate the effects of upwelling. The reason the FV3-GFS doesn't deepen storms nearly as much as the operational GFS is a bit complicated, but at least partly driven by some of the physics changes that have been made (e.g. new cloud microphysics).
  12. Sref as we know it is in the process of being phased out with something radically different. It's going to take a couple of years, but folks are working in the direction of a convection allowing ensemble (think hrrr, nam3k, ncar ensemble).
  13. Great post. I'm pretty sure the global models have set monthly records for day 5/6 skill in the NH yet again over the past couple of months.