Mesoscale Precipitation Discussion 0253
NWS Weather Prediction Center College Park MD
1131 AM EDT Sun May 11 2025

Areas affected...Eastern Georgia into Southwestern South Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 111531Z - 112131Z

SUMMARY...
A slow-moving line of training thunderstorms has developed across
eastern Georgia. Flash flooding will be possible as rainfall rates
with the strongest cores up to 3 inches per hour.

DISCUSSION... A nearly stationary line of storms has developed
across eastern Georgia in a north-south line. A moisture gradient
has set up in a pseudo dry line but in the mid levels based on 850
mb SPC mesoanalysis. On the dry side the dewpoints are as low as
6C over central Georgia, whereas on the moist side they're as high
as 13C. Thus, this is a robust gradient of moisture over the area.
The storms have formed on the moist side of that gradient, which
appear unlikely to move much over the next several hours. This
will support the potential for multiple hours of heavy rain over
the area.

HRRR and RRFS model simulations of reflectivity suggest the storms
will persist into the afternoon hours across this area, although
the behavior of individual heavy rain cores will vary through this
period. One of the biggest points of uncertainty is how the line
of convection will behave once the storms entering far southern
Georgia from the Florida Panhandle reach the latitude of the line
of storms in eastern Georgia. Assuming the mid-level dry line
weakens or dissipates as the storms tracking from Florida
approach, this should diminish the local forcing allowing the
storms to stay in place, resulting in an overall weakening of the
storms and a lessening flash flood threat. However, the RRFS
suggests that with daytime heating in full swing, that more storms
may form along the coast and result in a new training line
potentially linked to the sea breeze or the frictional gradient
along the coast resulting from the predominant onshore
southeasterly flow.

While 12Z FFGs in the area of these training storms are around 3
inches in an hour and 4 inches in 3 hours, the latter criterion
could very well be exceeded with the persistence of thses storms
over the next few hours. Flash flooding is possible.

Wegman

ATTN...WFO...CAE...CHS...FFC...JAX...TAE...

ATTN...RFC...SERFC...NWC...

LAT...LON   33888267 33868195 33528151 33078117 32518097
            32028124 31188169 30938256 31538343 32088362
            32448358 32968346 33448303