GOES-R product utility near Atlanta Center

The weather situation today could only be described as messy. We began by monitoring the ongoing convection over Detroit Center and also a second area of ongoing convection along the warm front in the center of the Eastern U.S. for the potential impacts to east/west flight routes. Later in the afternoon, as the convective activity in DTW quieted, we shifted the focus to the SE U.S. along the front, and the convective activity over Atlanta Center.

Earlier in the day the FAA issued a program which routed flights from the West Coast further south that usual, swinging them south through NW, central TX, and then back north to Atlanta (Figure 0 below).

Figure 0. 20130812 1700 UTC ASDI flight routes... note the flights running along the southern border of the U.S. as per the program initiated this morning to route traffic south of ongoing convection in the eastern U.S.

With this came the concern of timing of the expected convection around Atlanta Center as the warm front sagged SE. The simulated satellite imagery from the NSSL-WRF (Figure 1) showed scattered convection developing ahead of the complex in western TN and KY at 1900 UTC with further development through the afternoon.

Figure 1. 20130812 1700 UTC - 20130813 0000 UTC NSSL-WRF Simulated IR

However, the Nearcasting model (Figure 2) showed some instability in the theta-e field over the same location but by 1600 UTC, increasing the likelihood of convective initiation in the area earlier than the simulated satellite was suggesting.

Figure 2. 20130812 1600 UTC Nearcast Theta-E forecast

The GOES-R Convective Initiation product began to show higher probabilities (60+ %) of convective initiation by 1515 UTC (Figure 3), the probabilities increasing in intensity (70+ %) and also spatially through 1602 UTC. Shortly after that, the CTC picked up on several cooling signals (<-10K/15) just west of Atlanta Center (Figure 4).

Figure 3. 20130812 1445 - 1602 UTC GOES-R Convective Initiation

Figure 4. 20130812 1545 - 1602 UTC Cloud Top Cooling

Notice several of the areas of higher GOES-R CI probabilities just east of Atlanta Center correlated with the CTC cooling signals several scans later, which in turn led to a number convective cells initiating. Using the two products together allowed for a broader view of the convective process from probability of initiation to detected cooling signal, to rapid convective growth.

Despite occurring several hours earlier than the WRF simulated IR indicated, the location of all of this activity within the model was correct. Additionally, the Nearcast Theta-e did indicate marginal instability in the Atlanta area where scattered convection did develop.