Adjustments to Pan-Africa plot

[tdjames1]

• [x] Bolder lines and bigger labels for the MSLP.
  See commit 8dd4f19
• [x] More contour levels needed for the MSLP as currently missing showing any low-pressure areas and contours are too high to pick out sub-topical highs sometimes as well as too high to give an indication of the pressure over East Africa itself. See commit 8dd4f19
• [ ] #33
• [ ] #34
• [x] 24hour pressure change could be more useful (and easier to automate) than marking the centre of the subtropical highs.
  Pressure change is useful for broad indication of where pressure is intensifying wrt the sub-tropical highs - try using fewer contour levels to reduce visual noise
• [x] Suggestion of trying 930-1040 mb contour levels instead of just the four contour levels. This will create a very “messy” looking plot particularly over Africa, Arabia and in association with the Jetstream in both hemispheres so this will want to be tested and modified over time to make it less messy but have enough levels to work to show the lows and highs. Sam’s suggestion is that using levels 960, 980, 990, 1000, 1004, 1008, 1012, 1016, 1020, 1024, 1028, 1032, 1036, 1040 mb could work. See commit 8dd4f19
• [x] Whatever pressure levels we choose the suggestion was to have the 1020 mb line in bold as this is usually a good indicator of the sub-tropical highs. See commit 8dd4f19
• [x] Suggestion to add the dry intrusion limits to pan Africa plot as an indicator of the ITCZ as the plot seems like it has space to potentially add an additional field, particularly over Africa itself. Need to add mask to confine it to over Africa (e.g. based on lat/lon)
• [ ] #35

[tdjames1]

Action point from meeting on 16/06/2021:

• [x] Create two separate plots, one which has the mslp, wind and streamlines and another that includes the pressure change and the humidity field over Africa and streamlines.

[tdjames1]

Converted remaining items to separate issues.