![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Flash Flood Guidance
Issued by NWS
Issued by NWS
453 AWUS01 KWNH 300121 FFGMPD MDZ000-VAZ000-WVZ000-OHZ000-KYZ000-300720- Mesoscale Precipitation Discussion 0516 NWS Weather Prediction Center College Park MD 920 PM EDT Sat Jun 29 2024 Areas affected...Far Southern OH...Northeast KY...Much of WV Concerning...Heavy rainfall...Flash flooding possible Valid 300120Z - 300720Z SUMMARY...New bands of heavy showers and thunderstorms are expected to develop this evening which may drive isolated to widely scattered instances of flash flooding. DISCUSSION...An anomalously moist and moderately unstable airmass remains in place this evening across the Upper OH Valley and into the central Appalachians. A couple of broken bands of convection are currently noted over northeast KY, far southern OH and parts of northern WV, and surface observations show much of the focus of this along an elongated surface trough which is at least partially a result of convective outflow from earlier convection. MLCAPE values across areas of the region remains as high as 1500 to 2500 J/kg, and there continues to be a fair amount of shear with the latest RAP analysis showing effective bulk shear values of about 30 to 40 kts. This environment will be largely in place through the remainder of the evening hours with a slow decrease in boundary layer instability given the loss of solar insolation. However, the arrival of a modest MCV which is currently situated over southern OH along with some uptick in southwest low-level flow ahead of a cold front approaching the Upper OH Valley is expected to help generate some new bands of heavy shower and thunderstorm activity later this evening and into a portion of the overnight period. The greatest instability pool coupled with placement of the aforementioned surface trough would suggest areas of northeast KY through central WV would tend to the primary corridor for renewed convection going into the overnight hours. PWs across the region remain anomalously high with values of 2.0 to 2.25 inches and with the CIRA-ALPW data confirming a deep entrenchment of this moisture through the vertical column. Rainfall rates with the additional storms may reach 2 inches/hour, and some localized repeating of storms over the same area may result in some rainfall amounts locally going through 06Z of 3 to 4 inches. Given the heavier rainfall rates, and locally rugged terrain of the central Appalachians, there may be some isolated to widely scattered instances of flash flooding. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ILN...JKL...LMK...LWX...PBZ...RLX...RNK... ATTN...RFC...MARFC...OHRFC...NWC... LAT...LON 39628051 39397931 38547942 37588102 37328274 37508403 38148444 38808393 39458233