Thursday, 14 January 2016

Dampness seems possible

It will of course be welcome.

The weather forecasts for the next 24 hours have been interesting with various forecasters varying quite a bit in what they are expecting.  Currently the BoM are saying, in their traditional format for Canberra
"Cloud increasing, with a very high (90%) chance of rain in the afternoon and evening. A possible afternoon thunderstorm. Winds west to northwesterly 20 to 30 km/h"
Interestingly they have stopped giving an expected amount of rain: it was 10-30mm early in the day.

Getting to their newer forecasting model Meteye we find for Carwoola (which is of course of interest to me) rain due to start around 11am with expectations from 11.6mm to 45mm up until midnight on 14 January and nothing thereafter.  (I'll note that I have been up on the roof blowing the leaves out of gutters and a small sun shower passed by at about 10:30 so the start time was pretty promising.)

The Captains Flat radar has nothing of significance on the 128km image.
Going to the private sector I refer to an hour-by-hour forecast on Time and Date which has been pretty sound in the past.  They are proposing 9.8mm on the 14th with wetness continuing into the 15th offering another 5mm.  Here is their approach:
Adding a little excitement to the situation the BoM site also includes a flood warning giving a 70% chance of minor to moderate flooding in the Molonglo and Queanbeyan River valleys.  That suggests to me that the expectation is more towards the 45mm end of the scale: I doubt if there would be run off from 11mm over several hours.  This warning has got a fair mention in the media so there shouldn't be too many surprises if something happens.

By 1352 the radar is showing quite a few showers ...
.. but my weather station has not yet been troubled by any liquid.

Lets see what happens.

Here is the radar at 1633
 ... and 1939.
My weather station reported 5.8mm by 1942 and had got to 9.0mm by 2130.  That, surprisingly was all there was..



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