Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 05 2025 16:18:57 AWUS01 KWNH 051618 FFGMPD NCZ000-SCZ000-052217- Mesoscale Precipitation Discussion 0367 NWS Weather Prediction Center College Park MD 1218 PM EDT Thu Jun 05 2025 Areas affected...Central/Eastern NC and Northern SC Concerning...Heavy rainfall...Flash flooding possible Valid 051617Z - 052217Z Summary...Isolated to scattered flash flooding is possible this afternoon across portions of central to eastern North Carolina and northern South Carolina. Discussion...A surface low pressure is helping drive a heavy rainfall risk this afternoon across portions of central and eastern NC into northern SC. Close to and just north of the low center we are seeing very efficient warm rain processes in play, with PWs around 2", high freezing levels and a deeply saturated profile. This is allowing for hourly rainfall around 2" despite the less than impressive radar/satellite depiction. The low is expected to take more of an easterly turn this afternoon, and would expect this area of efficient rainfall to push east along with it through portions of central NC. The rainfall intensity will likely vary, with both upticks and downticks through the afternoon near the low center...but the environment will remain similar, and thus upwards of 2" an hour rainfall will remain possible at times. To the east and southeast of the low we are seeing increasing instability with daytime heating. This should support the expansion of some deeper convection over this corridor. These cells may tend to move quicker than the shallower convection near the low...but will still be capable of short duration heavy rates given the high PW airmass in place. Plus, certainly possible the warm front extending east from the low acts as a focus for at least some brief training. Overall, expecting an isolated to scattered flash flood risk to exist over the next several hours across portions of central to eastern NC. The HRRR has been struggling with the convective evolution this morning. Based on recent observational trends, it appears like the experimental RRFS and REFS may be handling this a bit better with regards to rainfall placement and magnitudes. Through 21z REFS neighborhood probabilities of exceeding 3" are 40-70%, with 5" exceedance probabilities peaking at 10-20%. The probabilities of 2" in an hour increase to 40-70% early this afternoon as well. Given the placement of the warm front and instability axis, not expecting the rainfall axis to get much farther north than it currently is, and some backbuilding to the south (near the warm front) is possible as well. Chenard ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4poGHp11DDA8Kh7HwH5czAuh5H0xJAMJcLQzZjETqU8tPpQk2ZAw641K4FPRnBIecs56= yyjXBARe-FaQe0YwcFbSh-M$ for graphic product... ATTN...WFO...CAE...GSP...ILM...MHX...RAH... ATTN...RFC...ALR...NWC... LAT...LON 36057932 35977850 35617813 35047760 34497778=20 34157841 34167887 34387977 34668041 35008059=20 35468061 35808045 35978003=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .