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Fall Weather Pattern Arrives

Rain and much cooler temperatures behind a cold front will bring a feeling of fall to the east coast today. In addition, an active fall storm pattern developing in the Pacific Northwest this week will bring areas of heavy rains, and very high elevations could receive heavy snow. Wetting rains to the valley floors will spread south Thu and Fri into northern California,where active fires continue. Read More >

Monday night and Tuesday morning will feature some of the coolest temperatures since April/May for most of North and Central Texas with lows bottoming out in the 40s. Some upper 30s readings will be possible for areas to the west of the DFW Metroplex. Isolated areas of frost MAY occur IF temperatures dip closer to 37 degrees.
There will be a low potential for showers and a few thunderstorms on Saturday, mainly across eastern zones. The better threat for more organized thunderstorms will be late Saturday into Sunday. A few storms will have the potential to be strong.

 
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Automatically generated image showing areas of convective inhibition.

 

Thumbnail of automatically generated image showing areas of convective inhibition. Thumbnail of automatically generated image showing areas of convective inhibition. Thumbnail of automatically generated image showing areas of convective inhibition.
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4 Panel Display | Animated Loop

CIN 

The image is a surface based measurement of Convective INhibition (CIN) or what is sometimes more commonly referred to as the strength of the cap.  The value is capped off at 500 J/KG.  In cases where there is no surface based CAPE available this parameter is set to 500 J/KG.

The yellow contours are the Lid Strength Index (LSI).  This is another measure of how strong the cap is.  It shows the thermal difference between a lifted surface parcel and the warmest part of the cap.  Higher values indicate a more stable layer.

In general, the Cap is said to be breakable when CIN is 30 J/Kg or less and/or the LSI is 2 degrees or less.  A negative LSI is rare, but is indicative of freely buoyant low level instability.

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