Precipitable Water represents the water content in the (column above) atmosphere.
Imagine if all the available moisture above you actually precipitated to the ground, then the (precipitable water) value would represent the amount of rainfal.
Higher precipitable water = Lower transparency.
This new map in conjunction with the Water Vapour satellite image should give you a good indication of your transparency conditions.
Precipitable Water is available for both GFS and ACCESS-R/ACCESS-G on all regions.
CFN has a few options to plot your location on the various forecast maps and satellite images.
1. You can start typing the first few characters of the nearest city/town or a postcode nearby. A drop down menu will appear and give you the list of locations available in the CFN database.
2. If your device's GPS is activated then CFN can read your coordinates directly.
A red pulsating cross will overlay any map you navigate to and will remain until you close the website or choose a different location.
CFN now supports overlays for the various forecast map types.
1. Select the base layer by selecting any map type.
2. Click on the padlock icon of any other type to overlay it on top as a 50% transparency blend.
There are many possible combinations so experiment.
You can still change location, map time, map type of the underlying map or even the forecast model on the fly (GFS/ACCESS). All touch functionality is preserved.
To change the overlay type to another map click on the padlock of any other button. To go back to the normal viewing click again on the golden padlock to disable it.
Blending the two maps is easier than flicking back and forth between them and you can change the time while still in blend mode.
As an example, the illustration shows a blend of the Surface Wind with the Jet stream Map overlay that could be an indication of the seeing forecast. The areas of good seeing are blue and darker with shorter wind vectors.
How should one interpret the predictions when the two lines (GFS & ACCESS) on the Meteogram diverge and completely disagree...?
I was thinking the same thing last night when Access noted near 100% cover and GFS showed zero ( GFS was correct )???
Then i looked at the detailed plots
Ref attached plots for today
It seems that in some cases, low middle and high cloud are all low but total cloud is very high????
( last night, i had a set of zero, zero, zero, 100% )
How should one interpret the predictions when the two lines (GFS & ACCESS) on the Meteogram diverge and completely disagree...?
Mike
If the predictions from GFS and ACCESS disagree you can choose to either disregard one model (i.e. GFS because it is a US global model compared to to the more accurate Australian regional model) or look at the yr.no meteogram (European global model) for further comparison. Cloud Free Night presents the forecast (and observed) information to assist you in making the best decision for your planned activities.
I was thinking the same thing last night when Access noted near 100% cover and GFS showed zero ( GFS was correct )???
Then i looked at the detailed plots
Ref attached plots for today
It seems that in some cases, low middle and high cloud are all low but total cloud is very high????
( last night, i had a set of zero, zero, zero, 100% )
Andrew
This situation has been observed once before and is most likely associated with the recent upgrade to the ACCESS-R model. If you were looking at Mount Burnett's meteogram last night you would not have seen this anomaly which was probably due to fog being predicted by the model for locations near the coast (e.g. Melbourne and Geelong) and somehow counting towards the total cloud cover value. This situation will require further investigation and possible modification to the meteogram, and be clarified once the updated model documentation is released by the Bureau of Meteorology.
Ahh OK. Makes sense for this mornings data, esp when you look at the RH% as well.
I can't seem to see any way to get history for yesterday to see if it was also that high for the Melbourne Access model at the time the big discrepancy was there.
If the predictions from GFS and ACCESS disagree you can choose to either disregard one model (i.e. GFS because it is a US global model compared to to the more accurate Australian regional model) or look at the yr.no meteogram (European global model) for further comparison. Cloud Free Night presents the forecast (and observed) information to assist you in making the best decision for your planned activities.
Cheers, so ACCESS is likely to be more accurate..?
Cheers, so ACCESS is likely to be more accurate..?
Mike
I don't know about the fog scenario, but for SE QLD weather, the ACCESS has been spot on in numerous occasions in recent months when GFS had incorrectly predicted a totally clear night.
Ahh OK. Makes sense for this mornings data, esp when you look at the RH% as well.
I can't seem to see any way to get history for yesterday to see if it was also that high for the Melbourne Access model at the time the big discrepancy was there.
Andrew
The last four days of ACCESS-R model data used to create the meteograms are available for download from the Bureau of Meteorology server, but only the latest model data and meteograms are available from the Cloud Free Night website. The ACCESS-R model data from the last 24 hours has been saved offline for further investigation.
Just as a follow up, we have massive fog here now ( 8PM melb time )
and about 10km inland from coast.
The Access model shows low cloud at 94% and total cloud at 100%, whereas last night there was no fog, low cloud was nil and total cloud was very high.
Certainly looking like "possible" fog due to high RH% is part of the calcs.
All good fun. Hope the feedback helps refine the models.
Just as a follow up, we have massive fog here now ( 8PM melb time )
and about 10km inland from coast.
The Access model shows low cloud at 94% and total cloud at 100%, whereas last night there was no fog, low cloud was nil and total cloud was very high.
Certainly looking like "possible" fog due to high RH% is part of the calcs.
All good fun. Hope the feedback helps refine the models.
CFN has a few useful shortcuts that you may use when viewing the site on a tablet or a mobile phone. These touch events will also work seamlessly on a desktop computer equipped with a mouse or a touchscreen monitor.
1. If you swipe horizontally the top banner of the website you will navigate between the Meteogram, Map and Satellite pages, which are the main sections on CFN. So keep swiping left or right. The section will wrap around when reaching the limit.
2. Sometime it is also very handy to quickly toggle between the global GFS model and the more accurate local ACCESS model. To quickly swap between the two models, just run your finger over the model name on the top left hand side of any map.
3. Finally, in the satellite section you can trigger the animation on or off by swiping the map horizontally. It will start playing or stop if already playing.
Cloud Free Night
