I'm currently studying meteorology at Penn State University (University Park) and am a member of the AMS, CWOP, and Skywarn for the NWS (CTP).
By: wunderstorm87 , 00:25 GMT le 17 août 2010
Today was a very busy day for thunderstorm activity across the lower Susquehanna valley. Below is a summary and archive of some radar images. Unfortunately I did not save mesoscale analysis images from the SPC so I won't be elaborating on environmental conditions very much.
The set-up: A cold front moved across the area today. Ahead of it a stratus deck was in place for much of the morning. However, this thinned and cleared which gave way for significant instability...including MLCAPE in excess of 2,000 j/kg by 2pm. This led to storms developing around that time.
The first storm to develop was in northern Dauphin county. Weak rotation was evident in it as it passed Lykens and I noticed clouds closer to the ground moving a significantly different direction than the storm was moving. 15-30 minutes after this observation...and as the storm slid into Northern Lebanon county...A tornado warning was issued. Below is an analysis of the thunderstorms image by image.
Velocity at 3:41 P.M. indicated strong rotation. The tornado warning was issued 2 minutes later at 3:43 P.M.
...and at 3:45 P.M.
By 4:15 P.M. the rotation had weakened...but was still present. The tornado warning was allowed to expire at 4:30 P.M.
After the tornado warning expired the cell continued its trek to the southeast while another cell moved northeast behind it and produced quarter size hail near Linglestown before weakening from the rain cooled air left behind from the southeast moving cell.
4:58 to 5:21 P.M. animation. The main storm continued to move southeast. As you can see the NE moving cell mentioned in the image before this has almost decayed completely by the end of this loop.
2 minutes after this image a trained spotter reported a funnel cloud which initiated yet another tornado warning from this cell for northern Lancaster county. You can see the rotation is nearly on top of the turnpike, possibly where this spotter was at.
The tornado warning expired at 5:30 P.M. (the beginning of this loop) but the storm continued SE just south of the turnpike and developed a very intense radar reflectivity of 69 dbz. A 67 mph wind gust was reported at Ephrata.
The VIL with this storm was very intense at 5:49 P.M. at around 60 kg/m^2. I'm surprised no hail reports have come in from this area.
More reports will likely come in from the valley as the night progresses.
I'm not sure if I want to continue blogging on here or not...it will depend on whether or not people read it or like it. I'm certainly willing to blog about other non severe weather related subjects if that is the case.
Thank you for reading.
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42 ° F
|Température:||41.2 ° F|
|Point de rosée:||30.3 ° F|
|Vent:||3.0 mph from the ONO|
|Rafale de vent:||7.0 mph|
Updated: 16:27 EST le 17 décembre 2014