Storms Sweep Across the Southeast (author: Madeline Laesser)

On Friday, March 22nd, and going slightly into the weekend, the southeast received significant rain and severe weather in some regions. In figure 1, the imagery shows that there was significant cloud coverage over the southeast region on Friday, specifically Florida, Georgia, and South Carolina. Since this is IR imagery, the clouds are identified based on the heat that is radiating off of them which the satellite measures. The colder cloud tops are associated with more severe weather. The most severe weather happened in the gulf earlier in the day on Friday. The National Weather Service(NWS) offices in Tallahassee and Miami released “special marine warnings” in areas off the coast because of strong winds and possible water spouts. Many areas of the states where this cloud coverage is shown received thunderstorms with quite a bit of rain.

Fig. 1: Infrared(IR) satellite imagery GOES-16 valid at 06 UTC 22 March 2024 to 06 UTC 23 March 2024. Images are in increments of 30 minutes. The color bar is on the bottom in degrees Celsius. Black represents the warmer temperatures, and the blues and greens are colder colors. Note that the horizontal color bar goes from warmest on the left to coldest on the right.

Credit: Colorado State University CIRA RAMMB Slider Page

In figure 2, the radar imagery can give us insight on the intensity of the precipitation at the times shown. Notice that the cold cloud tops on the satellite imagery correspond to where the most intense precipitation is shown on the radar. The precipitation in Florida moved eastwards while precipitation also formed on the north coast of the gulf and had significant coverage over Georgia and South Carolina in the afternoon. The precipitation in Florida is a result of the upward vertical motion caused by the surface low pressure system. The precipitation over Georgia and South Carolina is the result of a shortwave trough in the mid-levels of the atmosphere. Georgia and South Carolina are to the east of the trough axis which is an optimal area for upward vertical motion. Upward vertical motion allows for clouds, precipitation, and more severe weather to form.

Fig. 2: This figure shows composite reflectivity radar images at three time frames. The leftmost image is at 1200 UTC 22 March 2024. The middle image is 1800 UTC 22 March 2024. The rightmost image is 0000 UTC 23 March 2024. The color bar is on the right of each image. The yellow and orange represent the most intense precipitation that can be seen in this image. The light blue is less intense.

Credit: NSSL Multi-Radar Multi-Sensor (MRMS) Operational Product Viewer

In figure 3, the surface analysis shows the low pressure systems that were in the gulf. The low pressure systems were in the regions discussed where the coldest cloud tops were and the most severe precipitation. There was a cold front that was in the southeast. This cold front brought in a dry air mass that is what caused the precipitation to stop on Saturday. The most severe weather this past Friday was in Florida where there were more risks of tornadoes and special marine warnings off the coast. That being said, Georgia received significant rain with many places receiving between 1-2 inches of rain. There were not concerns of floods concerning impacts in these regions like there were in Florida from the surface low pressure system.

Fig. 3: This figure is a surface analysis with fronts and analysis only of the United States valid at 1800 UTC 22 March 2024. The dark red contours represent surface pressure in millibars(mb) in intervals of 4 mb. The surface low pressure systems are denoted by a red L, and the surface high pressure systems are denoted by a red H. The dark red, underlined numbers are the surface pressure(in mb) of the low or high surface system it is near. Cold fronts are represented with blue lines with triangles pointing in the direction it is moving towards. Warm fronts are represented by red lines with semi-circles in the direction it is moving towards. Stationary fronts are represented by alternating cold front and red front symbols. Occluded fronts are represented by purple lines with alternating semi-circles and triangles.

Credit: WPC Surface Analysis Archive