This Mesoscale Convective System (MCS) lasted more than 24 hours from 2000 UTC on June 21 to 1200 UTC on June 23 in 1998. A sequence of intensification, decay, and regeneration led to this relatively long-lived mesoscale convective event.

• Composite surface and IR satellite images (0621.12Z, 0622.00Z, and 0622.12Z) from the Unisys Weather archive. These composites are intended to give only a brief sketch of the weather for this case. They include a color-filled radar summary, surface conditions, frontal locations (bold lines), and pressure contours (thin blue lines).

Early afternoon convection on June 21 along the front range of the Rocky Mountains in northern Colorado organized into an MCS as it moved eastward across Kansas. The MCS reached its most intense rainout phase in central Kansas as it encountered moist, southeasterly flow from the Gulf. New organized convection which developed in eastern Kansas ahead of the older MCS continued eastward as a new MCS, eventually diving southeastward as it encountered northward-streaming, gulf-coast moist air west of the Appalachian Mountains.

Detailed images:

• Infrared satellite images for the period 0621.2000 to 0622.2300 UTC.
  Image times are EDT==> UTC = EDT(AM) + 4 and UTC = EDT(PM) + 16.

• Hourly surface charts for the period 0621.1900 to 0622.2200 UTC. (The 0622.1200-1400 charts are missing)

• Upper air charts at 300, 500, 700, and 850 mb at 00 and 12 UTC: June 21 and 22.

• Severe Weather Reports from the NWS/NCEP/Storm Prediction Center archive. Each panel includes all reports of tornadoes, hail, and damaging winds for a convective day (Day.12Z-NextDay.12Z).

• Reflectivity swaths consist of the maximum reflectivity value that passed over each grid point, accumulated over time at one-hour intervals. The closed black contours indicate the current positions of the 2-km NIDS radar echoes (convective systems). Colored circles indicate the position of the centroid of enclosed reflectivities with the size of the circle proportional to the enclosed area of echo greater than 25 dBZ.

  Above each two-dimensional swath image is a histogram that represents the NS-averaged value of RainRate (mm/hr) within a series of narrow (0.25 deg wide) longitude strips.

• Hovmoller diagrams consist of NS-averaged (EW-averaged) values of PerCent Echo, RainRate, and Reflectivity plotted as a function of time (UTC).

• Topographic heights and WSR-88D radar locations within the case study area.

  ---

  Created by: L. Jay Miller at ljmill@ucar.edu
  Subject: USWRP/ROC Warm Season Case Study (1998 0621-0622)
  Address: http://locust.mmm.ucar.edu
  Last Modified: 18 March 2002