Trouble Brewing...

A strong cold front is set to move through later tonight and into tomorrow. More on that in a minute.

Out ahead of the front, and the line of rain and thunderstorms associated with it, the air is fairly moist. Dew points are in the upper 60's and lower 70's. Sunshine is destabilizing the atmosphere as well.

Scattered thunderstorms have developed to our west, and are moving toward the area. Radar shows that these are fairly strong...and a few are reaching severe levels. Expect these to continue to continue to move east at 20-25 MPH.

The squall line associated with the front looks like it will move in late this evening and into the overnight hours. Many cells along the squall line are strong to severe...and will increase in coverage and severity through the afternoon. Now, the question everyone's asking is "How strong will they be when they reach my location?" First, refer to the map below.



The thunderstorms will be moving in late evening and overnight. Decreasing heating of the day will lessen severe chances. Also, after having to traverse the Cumberland Mountains and the Blue Ridge mountains, the line will have weakened quite a bit. It looks like Western NC will be spared...perhaps not receiving much rain at all. The greatest risk area is where much of the severe activity should be concentrated...and the scattered area will consist mainly of strong thunderstorms with a few severe possible making it through. With any severe thunderstorms, the main threat is damaging winds. Since these storms are linear, there's a greater chance for a bow effect to develop. This is where fast, straight-line winds are concentrated, sometimes sustained over 70 MPH. Small hail is also possible, as well as plenty of vivid lightning.

Heavy rain is another major concern with these thunderstorms. Models are not in agreement, however. The NAM is suggesting quite a rain event, especially over SW VA. The GFS is going with a more mundane solution. Looking at radar, I can't help but side with the NAM. These storms and the atmosphere are just too juiced for there not to be a few areas of heavy rain.

It looks to be an interesting evening and night. Watch out for damaging winds, hail, plenty of vivid lightning, and heavy rainfall.

7/19/07-5:39 PM