Friday, October 11, 2013

interesting evolution... (am.11.oct.13)>

*Update @ 3:45pm... Thundershowers developed just after 1:00pm, and after a bit of a break for an hour or so, have cranked up again.  It looks like this occasionally shower/thundery weather may stay with us into the evening hours.

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For the third time in the past 24 hours, there was thunder and lightning in the area (overnight), but no rainfall at all here at my location on Tushita Road below the Mountaineering Center.  Skies are now partly cloudy with patchy fog at sunrise, with humidity fluctuating wildly between about 62% and 78%.  The temperature is right around 64F (17.8C), which remains a few degrees above normal for an October morning.

We're on a rather fast trajectory of change at the moment, with fundamental shifts happening in the atmosphere, which will continue for the next few days at least.  The first issue is that there is gradual cooling occurring in the upper-levels, and that is what has been responsible for triggering the thunder development recently.  It will remain marginally unstable both today (Fri) and Saturday, thanks to that cooler air aloft and of course the warmer and more moist air mass here at the surface -- that means we'll continue to have to be prepared for some scattered shower and/or thundershower development.

The second issue is the strong indications of a significant push of drier air arriving over the weekend into early next week.  I'm pleased to see that the computer models are remaining consistent from data run to data run, as far as the remarkable reduction in the moisture content of the air mass over northwest India.  If something doesn't pop up to reverse this evolving pattern, we're going to see our humidity levels drop back down below 50% as early as Sunday, and even perhaps to the 30-40% range by Monday and Tuesday.  Stay tuned for updates as fresh data comes in this weekend...

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