Thursday, June 18, 2015

strong high pressure ridge... (am.18.jun.15)>

Some scattered clouds are visible to the south, otherwise it's mostly clear and hazy at sunrise this Thursday morning.  My overnight low here in the upper part of town is one of the warmest of the year -- 68.2F (20.1C) -- and there has been no precipitation since last report.  The humidity reading is 48%.

A huge ridge of high pressure has been nosing into northwest India the last 36 hours or so, and will strengthen and push in even more aggressively during the coming 24 hours.  High pressure is a mark of stability, with warmer air in the mid- and upper-levels of the atmosphere preventing packets of air from rising too high, and thus preventing the development of much shower/thunderstorm activity.  Of course our dynamics along the front slopes of the mountains can counteract that effect when there is strong daytime heating of the surface layers occurring... but we should see only weak and isolated afternoon thunder development, if any, through Friday.  Hazy sun and occasional clouds will be the dominant features of our weather, along with temperatures warming close to the highest levels of the season and the year.  The warmest temp I've recorded this year was 89.4F (31.9C) back on the 23rd of May -- and that could be surpassed by the time Saturday afternoon rolls around.

The other major thing happening will be an increase in our humidity.  Models continue to advertise the first surge of real tropical moisture of this pre-monsoon season over the weekend, as a deep southeasterly flow begins to develop.  The risk of some heavier showers and thunderstorms will be on the increase as early as Saturday, but more likely on Sunday into Monday, as the moisture content of our air mass rises dramatically.  Yes, it is an interesting time of year!

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