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Re: Rain this weekend? Thursday update

Posted by Bret B on February 12, 2015, 9:52 am, in reply to "Re: Rain this weekend? and technical discussion"
187.148.141.155

Not much change in my forecast from Tuesday: I think there is still a good chance of some sprinkles & light showers from today through Monday or so, with a slight possibility of some heavier rains if the computer models are a little off.

Most of the links in my previous post are still saying about the same thing as before, except the latest TRMM data (0900Z) now shows a large area of rains far (500 miles) to our SW, and an isolated heavy thunderstorm complex quite a bit closer (200 miles.) The TRMM data is up to several hours old, so these rain features have certainly changed by now, but you can see these rains are getting closer.

http://trmm.gsfc.nasa.gov/trmm_rain/americas/americas_3hrly_zoom.gif


Her is an animated view of the last few days of TRMM data, every 3 hours: http://trmm.gsfc.nasa.gov/trmm_rain/americas/americas_3hrly.mpg

It's pretty small, but it covers more of our area of interest than their large animation: http://trmm.gsfc.nasa.gov/trmm_rain/Events/latest_central_america_3hrly_rain.mov

And the NHC Tropical Weather Discussion ( http://www.nhc.noaa.gov/text/refresh/MIATWDEP+shtml/ ) mentions the low pressure well to our SW spinning and triggering the large area of rains mentioned above: "...AN UPPER LEVEL CYCLONE IS SPINNING AT 17N121W WITH UPPER DIFFLUENCE OVER ITS E SEMICIRCLE ENHANCING SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN AN AREA BOUNDED BY A LINE FROM 21N120W TO 16N97W TO 08N122W TO 21N120W...." "Upper diffluence over its E semicircle" means the low is causing the high-altitude air to its east to spread out. This creates a suction which lifts lower-altitude air up which makes that low moist air unstable, leading to precipitation.

Next update tomorrow AM.
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