I'm a CMU Honors student and love meteorology and extreme weather. I've been fascinated by weather since I was 5, and plan on becoming a meteorologist
By: wxchaser97 , 2:26 AM GMT on March 12, 2013
Tropical Cyclone Sandra is a tropical cyclone over the South Pacific. Sandra has a one-minute wind speed of 90kts and is moving SE at 5kts per the latest update from the JTWC. Sandra should continue to move in a southerly direction and weaken steadily over the next few days. Sandra shouldn't be too much threat to any land areas, except for some islands to her east. Current Satellite image of Sandra is shown below in figure 1.
Figure 1: Satellite image of Sandra.
Sandra has past her peak intensity. She once had a good-strength eye/eyewall with strong convection elsewhere. At that time, she was a category 3 SSHWS equivalent cyclone. Dry air has overcome Sandra and has induced weakening. The northern eyewall has been completely eaten away by this dry air. This is evident in microwave imagery seen in figure 2. The dry air is due to a trough to the north pumping in this dryness. While Sandra is listed to have 105mph winds, this is unlikely due to the lessening of organization. Cloud tops have also been warming showing that Sandra is weakening. ADT had been fooled by colder cloud tops that didn't represent the actual organization of Sandra earlier. ADT values have been dropping to more reasonable values and the weakening flag is still on. Dry air is entrained throughout the whole circulation, especially on the northern side. Also, moderate to high wind shear is impacting Sandra. This isn't helping with any efforts to stay alive. Sandra maintains a strong circulation shown in the most recent ASCAT image, figure 3. SST's are favorable for strengthening right now, but they will become unfavorable as she heads south. Even thought they are, the warm waters are cancelled out by waning convection, shear, and dry air. All and all, I expect Sandra to continue SSE and weaken steadily over the next couple days. Unfavorable conditions will continue to batter her until she degenerates in a few days from now. I wish I could do more of an analysis but I am not that familiar with southern hemisphere tropical cyclones and the geography down there. My general forecast for Sandra can be seen below in figure 4.
Figure 2: Most recent microwave image showing the not so great structure of Sandra.
Figure 3: ASCAT image of Sandra wind field and circulation.
Figure 4: My forecast for Sandra.
Have a great night everyone. Sorry it wasn't a lot but I felt like I needed to get something written out. Oh and if the last image doesn't show up please let me know because I have been having a little trouble with seeing some of my imgur images. The larger amount than usual of images is to hopefully cover anything I missed. I'll be back on Friday with my special severe weather/ 1 year anniversary blog, Friday or Sunday with my local forecast blog, and sometime this weekend with my 2013 hurricane season forecast, busy week for me.
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