March 31, 2010

Stunning Day of Convection and BIG storm coming

There was magnificent cumulus and cumulonimbus today over our region. The reason? A very large change in temperature with height associated with very cold air aloft, coupled with warming at low levels from the increasingly powerful sun. Here is a plot (sounding chart) of temperature and dew point at 5 PM this afternoon at Forks, on the NW Washington coast. This is based on observations taking from a balloon-launched radiosonde. Very rapid temperature decline with altitude.

As the surface heated up during the day, the convection grew and blossomed with some the cumulus forming well-defined anvils. Here is a stunning video from Dale Ireland's cloud cam in Silverdale (click on link or picture to see it):

The developing convection was very evident on the high resolution visible satellite imagery today. Below are two images. The first in the morning when the instability was just developing and the latter in the mid afternoon when some of the convection has grown into full blown cumulonimbus with well defined anvils (which look like oval cottonballs from space).

Beautiful to look at and impressive anyway you care to view it.

Major weather changes are in store Friday and Saturday. Moderate to heavy precipitation over the region...with a very strong low moving just north of us. Winds will be very strong over the coast (40-60 kts), northwest Washington (30-50 kt) and breezy (20-40 kt) over the PS lowlands on Friday. Take a look at a forecast chart of sea level pressure and surface winds at 5 AM on Friday. A 988 mb low right off the WA coast and very strong coastal winds (45 kt sustained). We are talking about a very significant springtime event.

Maybe even the Weather Channel will cover it!

1 comment:

  1. Great clouds over in the Methow Valley yesterday, too- my husband and I ran outside to sketch and photograph them:


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