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WXMAP

This section is simply describing what the various lines, coloured areas are, what interval/units the contours, isobars, colour-filled areas use etc. The use, or meteorological significance of the fields are dealt with in a separate section ... HERE.

The WXMAP site is here.

IMPORTANT: I am not going to attempt a description of the full range of products, just the ones that might be most useful to those who want to 'dip-in' without much knowledge. Also, the fields presented below are not necessarily from the same situation, run-time etc. They are there simply to aid a quick identification for each product.

 


 NOGAPS products (US Navy model)

 Example: Brief description of parameters (etc.) on charts shown.
 MSLP, thickness & 12hr precipitation
MSLPtthkPPN
Gold lines: MSLP isobars. (units = hPa / interval = 4 hPa)
Alternate blue & purple lines: thickness (500-1000 hPa) blue 528 & 552, purple 540 & 564 dekametres [dam])
Colour-fill regions: 12 hour precipitation rate (units=mm/12hr / interval=variable, see colour quadrant top/right of diagram) [ It's not entirely clear if this is the accumulated rainfall in the previous 12hr, or the instantaneous rate at some point in the last 12hr - my thoughts would be the former. ]
 300 hPa height & isotachs
300 ht and isotachs
Green lines: 300 hPa contours. (units = metres / interval = 120 m)
Black (thin) lines: isotachs of the 300 hPa wind. (units = knots [kn]/ interval = 10 kn)
Wind arrows: conventional plots of wind-barbs at 300 hPa (units = kn)
Colour-fill: strongest winds at this level (>= 50kn), according to scale at top/right of diagram. (Use to pick out approximate alignment of jet core).
 500 hPa height & relative vorticity
500 height and rvort
White lines: 500 hPa contours. (units = metres / interval = 60 m).
Colour-fill: Relative Vorticity (at 500 hPa .. roughly the level of non-divergence)
(units=10-5s -1/ interval=2 : see colour quadrant at top-right of diagram - blue implies negative (non-developmental) values & red, orange positive (or developmental) values.
 850 hPa temperature, relative humidity & wind
850Trhwind
Purple/solid lines: 850 hPa temperatures above 0degC. (units=degC / interval=3 degC)
Blue line: the Zero degree C isotherm at 850 hPa (labelled 'FR')
Indigo/dash lines: 850 hPa temperatures below 0degC. (units=degC / interval=3 degC)
Wind arrows: conventional plot for wind barbs at 850 hPa.
Grey-fill: 850 hPa relative humidity. (units = % / interval = 20%: see grey-scale quadrant at top/right of diagram).
 Wave height & surface wind
wave forecasts
Wind arrows: conventional plots of the 'over-sea' wind-barbs (units = knots [kn]).
Colour-fill: Wave height. (units=feet / interval = 3 ft: see colour chart at top/right of diagram - blue - low values, orange-to-red high values.)
[ This would appear to be the 'total' wave height, i.e. wind + swell wave. ]

 

AVN/MRF products (NCEP models)

(These output are in fact in identical format to that above for the NOGAPS model, which makes comparison easy. Only the wave / sea-surface wind field is not included in this set.)

 Example: Brief description of parameters (etc.) on charts shown.
 MSLP, thickness & 12hr precipitation
MSLPtthkPPN
Gold lines: MSLP isobars. (units = hPa / interval = 4 hPa)
Alternate blue & purple lines: thickness (500-1000 hPa) blue 528 & 552, purple 540 & 564 dekametres [dam])
Colour-fill regions: 12 hour precipitation rate (units=mm/12hr / interval=variable, see colour quadrant top/right of diagram) [ It's not entirely clear if this is the accumulated rainfall in the previous 12hr, or the instantaneous rate at some point in the last 12hr - my thoughts would be the former. ]
 300 hPa height & isotachs
300 ht and isotachs
Green lines: 300 hPa contours. (units = metres / interval = 120 m)
Black (thin) lines: isotachs of the 300 hPa wind. (units = knots [kn]/ interval=10 kn)
Wind arrows: conventional plots of wind-barbs at 300 hPa (units = kn)
Colour-fill: strongest winds at this level (>= 50kn), according to scale at top/right of diagram. (Use to pick out approximate alignment of jet core).
 500 hPa height & relative vorticity
500 height and rvort
White lines: 500 hPa contours. (units = metres / interval = 60 m).
Colour-fill: Relative Vorticity (at 500 hPa .. roughly the level of non-divergence)
(units=10-5s -1 / interval=2 : see colour quadrant at top-right of diagram - blue implies negative (non-developmental) values & red, orange positive (or developmental) values.
 850 hPa temperature, relative humidity & wind
850Trhwind
Purple/solid lines: 850 hPa temperatures above 0degC. (units = degC / interval = 3 degC)
Blue line: the Zero degree C isotherm at 850 hPa (labelled 'FR')
Indigo/dash lines: 850 hPa temperatures below 0degC. (units = degC / interval = 3 degC)
Wind arrows: conventional plot of wind-barbs at 850 hPa.
Grey-fill: 850 hPa relative humidity. (units=% / interval=20%: see grey-scale quadrant at top/right of diagram).