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For this exercise, you will use the metview icons in the folder 'HRES_forecast' shown above. hres_1x1.mv & hres_2x2.mv : these work in a similar way to the same icons used in the previous task where parameters from a single lead time can be plotted either in a single frame or 4 frame per page.
hres_xs.mv : this plots a vertical cross section and can be used to compare the vertical structure of Hurricane Nadine and the cut-off low. |
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From 20th to 25th September, Nadine had lost hurricane intensity and was slowly moving over the North Atlantic. A short-wave trough separated into a cutoff and approached from the north. Nadine interacted with a cold front associated with the cutoff on 21st September.
Task 3: Precipitation over France
Study the interaction of the systems and their subsequent development.
First plot the geopotential at 500hPa and MSLP (as in figure 1 This task produces a plot similar to Figure 2 in Pantillon et al.
Choose a hres macro to use, plot the total precipitation (parameter: tp), near surface wind field, relative humidity (and any other parameters of interest).
As for the analyses, the macros ) using the hres_1x1.mv, hres_2x2.mv and hres_xs.mv can be used to plot and animate fields or overlays of fields from the HRES forecast. macro script:
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plot1=["z500.s","mslp"] |
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Q. Was it a good or bad forecast? Why? |
Suggested plots for discussion
The following is a list of parameters and plots that might be useful to produce for later group discussion. Choose a few plots and use both the HRES forecast and the analyses.
For help on how to save images, see the beginning of this tutorial.
| lightblue | | bgColor | lightlightblue |
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| titleBGColor | lightblue |
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| title | Isobaric maps |
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| borderColor | lightblue |
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| bgColor | lightlightblue |
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| titleBGColor | lightblue |
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| title | Isobaric maps |
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- Geopotential at 500hPa + MSLP : primary circulation, Figure 1 from Pantillon et al.
- MSLP + 10m winds : interesting for Nadine's tracking and primary circulation
- MSLP + relative humidity at 700hPa + vorticity at 850hPa : low level signature of Nadine and disturbance associated with the cutoff low, with mid-level humidity of the systems.
- Geopotential + temperature at 500hPa : large scale patterns, mid-troposphere position of warm Nadine and the cold Atlantic cutoff
- Geopotential + temperature at 850hPa : lower level conditions, detection of fronts
- 320K potential vorticity (PV) + MSLP, and,
- 500hPa relative vorticity (see Fig. 14 in Pantillon) : upper level conditions, upper level jet and the cutoff signature in PV, interaction between Nadine and the cut-off low.
- Winds at 850hPa + vertical velocity at 700hPa (+MSLP) : focus on moist and warm air in the lower levels and associated vertical motion. Should not be a strong horizontal temperature gradient around Nadine, the winds should be stronger for Nadine than for the cutoff.
- 10m winds + total precipitation (+MSLP) : compare with Pantillon Fig.2., impact on rainfall over France.
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Task 2: Precipitation over France
This task produces a plot similar to Figure 2 in Pantillon et al.
Choose a hres macro to use, plot the total precipitation (parameter: tp), near surface wind field, relative humidity (and any other parameters of interest).
As for the analyses, the macros hres_1x1.mv, hres_2x2.mv and hres_xs.mv can be used to plot and animate fields or overlays of fields from the HRES forecast.
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Q. Was it a good or bad forecast? Why? |
Suggested plots for discussion
The following is a list of parameters and plots that might be useful to produce for later group discussion. Choose a few plots and use both the HRES forecast and the analyses.
For help on how to save images, see the beginning of this tutorial.
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| bgColor | lightlightblue |
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| titleBGColor | lightblue |
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| title | Vertical cross-sections |
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- Potential temperature + potential vorticity: to characterize the cold core and warm core structures of Hurricane Nadine and the cut-off low.
- Humidity + vertical motion : another view of the cold core and warm core structures of Hurricane Nadine and the cut-off low.
- PV + vertical velocity (+ relative humidity) : a classical cross-section to see if a PV anomaly is accompanied with vertical motion or not.
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