During the late afternoon and early evening, GOES-14 Visible (0.63 µm) images (below; also available as a large 59 Mbyte animated GIF) revealed additional thunderstorms which produced hail and damaging winds across eastern Missouri and southern Illinois (SPC storm reports). These storms fired along an outflow boundary left in the wake of another mesoscale convective system (MCS) that moved through the region earlier in the day.Side note: there was a planned outage of GOES-14 SRSO-R imagery from 1059-2119 UTC. During this time, the GOES-13 (GOES-East) satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes. Visible (0.63 µm) images (below) showed the mesoscale convective system that produced hail as large as 4.0 inches in diameter in the St. Louis, Missouri area. Finally, late in the day another MCS developed in North Texas, just west of the Dallas/Fort Worth area. GOES-14 Visible (0.63 µm) images with parallax-corrected SPC storm reports (below; also available as a large 54 Mbyte animated GIF) showed the large hail and damaging winds produced by this storm. One feature of interest was the “storm-top plume” that emanated from the largest cluster of overshooting tops, and was blown northeastward.
A larger-scale view using GOES-13 (GOES-East) Visible (0.63 µm) images (below) showed the motion of this sea ice, which extended farther south off the coast of Newfoundland. The general southeastward ice motion was driven by the flow of the Labrador Current.According to data from the Canadian Ice Service, the concentration of this medium to thick “first year ice” (Labrador | Labrador/Newfoundland) was as high as 9/10 to 10/10 (below). The departure of normal of portions of this ice was as high as 9/10 to 10/10 above normal.
Time series plots of surface data for Walnut Ridge (KARG) located just to the northeast and Newport (KM19) located farther to the south-southwest are shown below. Surface reports indicated that the visibility was reduced to less than 1 mile at 1756 UTC at Newport, and less than 3 miles at 1735 UTC at Walnut Ridge.On the previous day, a comparison of the 1849 UTC Aqua MODIS Visible (0.65 µm) image and the corresponding Normalized Difference Vegetation Index (NDVI) product (below) showed that there were many areas upwind (to the southwest of) Portia and Walnut Ridge — in both southern Lawrence and northern Jackson counties — that exhibited low NDVI values (tan color enhancement), indicative of recently-plowed and/or unplanted agricultural fields within that part of the Mississippi Alluvial Plain. It is possible that field plowing activities on that windy day may have been the catalyst for the some of the blowing dust plumes. Similarly, a comparison of the 1849 UTC Aqua MODIS NDVI and Land Surface Temperature (LST) products (below) showed that the land surface in areas with less vegetation were warming up more quickly, with some LST values in excess of 90º F (darker red enhancement).
During the subsequent daytime hours on 04 April, more interesting (tropospheric) waves were seen in the vicinity of this subtropical jet stream — small packets of waves that were propagating westward, against the ambient flow –one over Florida/Georgia/South Carolina, and another over South Texas. Unfortunately, these features fall into the “What the heck is this?” blog category, so no coherent explanation of them can be offered at this time.An interesting question from Shea Gibson:
— Shea Gibson (@WeatherFlowCHAS) April 5, 2016