610 AWUS01 KWNH 221801 FFGMPD NYZ000-PAZ000-WVZ000-OHZ000-222300- Mesoscale Precipitation Discussion 1112 NWS Weather Prediction Center College Park MD 200 PM EDT Sat Aug 22 2026 Areas affected...North & Eastern OH...Western PA...Far Western NY...Far Northern WV... Concerning...Heavy rainfall...Flash flooding possible Valid 221800Z - 222300Z SUMMARY...Multiple rounds of scattered thunderstorms capable of 1-1.5", suggest random intersections resulting in widely scattered spots of 1.5-2.5". Low FFG (<2"/3hrs) and larger urban areas suggest incidents of flash flooding are possible this afternoon into evening. DISCUSSION...GOES-E WV shows broad long-wave trough across the Great Lakes with an upstream strengthening/digging shortwave crossing Lake Michigan which is starting to result a developing triple-point in central LP of MI as the main surface low in NW Lake Huron continues to strengthen. A southern stream wave/vorticity center is well defined across south-central OH helping to direct the effective warm front from near CLE to ZZV and UNI eastward with enhanced low level moisture and higher Theta-E air pooled along it, with MLCAPEs reaching 2000 J/kg, where warm conveyor belt moisture is also peaked around 1.3-1.5" for TPW. Surface to boundary layer convergence from SW to SE across the boundary has resulted in broad convective development though cells updrafts are broadening, they remain widely spaced with some hints of multiple north-south oriented bands. Increased convergence near lake-breeze off Erie, further enhances shower activity. Given the moisture and solid instability rates of 1-1.5" are more likely, but totals will probably be in the 1" range given forward propagation/cell motions eastward are expected. Upstream, initial cluster of thunderstorms over SE MI is sliding into the slightly increased unstable air over north-central OH, while further convergence along the cold front across south-central MI into NE IND is starting to build overall as well. Compared to the warm front, mid-level moisture is a bit less and overall TPWs are closer to 1-1.25" but directional and speed convergence may allow for cells to be comparable to the eastern warm front band, but still similarly progressive and likely to result in peak of 1" totals; so no one cell is likely to exceed even the lower FFG values of 1.5-2"/hr. However, given the increasing coverage and broadening updrafts intersecting footprints from each round may allow for widely scattered spots of 1.5-2.5" by 00z and with 3hr FFG in the 1.5-2" range especially along I-70 in central OH to W PA (~2/3hrs across N Ohio) incidents of exceedance are considered possible this afternoon into evening. Gallina ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BUF...CLE...CTP...ILN...PBZ...RLX... ATTN...RFC...RHA...TAR...TIR...NWC... LAT...LON 42607899 42237837 41297833 40787882 39067998 38988142 39398255 39898334 40788374 41398370 41718319 41558246 41838140 42168054 42278010  618 FOUS62 KALR 221830 FFGSJU COUNTY FLASH FLOOD GUIDANCE...PUERTO RICO NATIONAL WEATHER SERVICE SOUTHEAST RIVER FORECAST CENTER...ATLANTA GA 230 PM EDT SAT AUG 22 2026 INCHES OF RAINFALL FOR SPECIFIED DURATIONS REQUIRED TO PRODUCE FLASH FLOODING IN FORECAST ZONES. LOWER AMOUNTS MAY CAUSE FLASH FLOODING IN URBAN OR MOUNTAINOUS AREAS. .B ALR 20260822 Z DH18/DC202608221830 /DUE/PPHCF/PPTCF/PPQCF :IDENTIFIERS ARE 2-LETTER STATE, Z FOR ZONE, 3-DIGIT ZONE NUMBER : :IDENT 1HR 3HR 6HR ZONE NAME :======= ==== ==== ==== ==================== PRZ001 1.9/ 3.6/ 4.9 PRZ002 1.9/ 3.6/ 4.9 PRZ003 1.9/ 3.4/ 4.8 PRZ004 1.9/ 3.4/ 4.8 PRZ005 1.6/ 2.2/ 2.9 PRZ006 1.6/ 2.2/ 2.9 PRZ007 1.6/ 2.2/ 2.9 PRZ008 1.6/ 2.2/ 2.9 PRZ009 1.6/ 2.2/ 2.9 PRZ010 1.6/ 2.2/ 2.9 PRZ011 1.6/ 2.2/ 2.9 PRZ012 2.0/ 3.2/ 4.5 PRZ013 2.0/ 3.2/ 4.5 VIZ001 2.1/ 3.3/ 4.6 VIZ002 2.1/ 3.3/ 4.6 .END $$ S.E.R.F.C. 770-486-0028 or 770-282-2112 Regular Hours 6am-10pm Eastern Time After Hours Please Follow Callback Instructions