Saturday, May 7, 2011

Anatomy of a Supercell:Tuscaloosa EF4

The supercell thunderstorm in the radar picture above contains a hook echo(white arrow). A hook echo is the radar signature of precipitation wrapping around a mesocyclone, the rotating column of air within the storm. The area with no precipitation is also known as the bounded weak echo region, or BWER (red arrow). The updraft is so strong in the area of rotation that the rain and hail cannot fall, and have been blown to the southwest (blue arrow), where the rear flank downdraft is (green arrow). Typically this precipitation is only present to the north, but not in this case. From the west, the area of the mesocyclone would be shrouded by rain and hail. The clear mesocyclone is where a tornado may, and in this case does, form. The entire storm moves northeast toward the upper right corner of the radar screen, the mesocyclone or tornado trailing with it. Storms with a hook echo are guaranteed to be tornado warned, it is not just a matter of spotting one forming or on the ground. This is the Tuscaloosa, Alabama storm that spawned a massive EF4, shown by the hook echo above.

Thursday, May 5, 2011

Recent Rainbow After Thunderstorm

The first photo of the two is the original, taken after a short afternoon thunderstorm. The second is the photograph after I altered it to show the rays of the rainbow better. The circular bands are just result of the filter, they are not part of the phenomenon. 




Monday, May 2, 2011

SPC 2 Day Convective Outlook

http://www.spc.noaa.gov/products/outlook/

Photos and Radar of Henry County Supercell

This tornado warned supercell was small, but almost entirely hooked. It could almost be classified as a bow echo. Fortunately, it did not produce a tornado over a densely populated area. These photos were taken from the west of the storm, therefore, the area of indicated rotation is not visible.


Photo and Radar of April 27th Supercell

While there was no major damage from this storm, it was tornado warned, and there were sightings of funnel clouds in Browns Summit and in the area above Winston Salem. It traveled from Winston Salem, Northeast through Rockingham County before crossing into both Henry and Pittsylvania Counties. It remained tornado warned until it began to dissipate.


Monday, April 25, 2011

April 25th Severe Weather Outlook

SWO from wunderground.com
Quoting Dr. Jeff Masters from his blog on Weather Underground:
Major tornado outbreak expected today through Wednesday
Another huge tornado outbreak is likely this week over the U.S., as a strong storm system that is developing over the Mississippi Valley today moves slowly eastwards during the week. A 3-day tornado total of over 100 twisters is quite possible today through Wednesday. NOAA's Storm Prediction Center has issued its "moderate risk" forecast for severe weather today, centered over Arkansas. This region has a significant risk of tornadoes, some of them strong EF-2 and EF-3 strength. A more serious threat of severe weather exists 
for Tuesday over Arkansas and surrounding states, with the Storm Prediction Center calling the situation "potentially significant/dangerous." The heightened severe weather risk extends through Wednesday, with a moderate risk of tornadoes and severe weather in Tennessee and surrounding states. Preliminary tornado reports for the year 2011 show that this year is probably already the busiest tornado season on record for this point in the season. This week's action will substantially pad the record.




It seems like each year, the numbers increase, leaving the question; Are there really more tornadoes, or are we simply detecting more of them? I believe it's highly likely that it's both.

April Storm Clouds

Love these pictures from a recent storm. After watching them for awhile, I noticed some lower level rotation. Never amounted to anything, just a nice sight.