Extended Streamflow Guidance
Issued by NWS Ohio RFC
Issued by NWS Ohio RFC
750 FGUS61 KTIR 261354 ESGTIR WATER RESOURCES OUTLOOK NATIONAL WEATHER SERVICE OHIO RIVER FORECAST CENTER WILMINGTON OH 955 AM EDT Friday July 26 2024 THE FOLLOWING IS THE 30-DAY WATER RESOURCES OUTLOOK FOR THE MONTH OF AUGUST .WATER RESOURCES STREAMFLOW OUTLOOK... The streamflow outlook for the month of August calls for normal to slightly below normal values across the Ohio River basin. Isolated rises associated with summertime convection cannot be ruled out, but large scale river basin rises seem unlikely. The only caveat at this point would be a tropical system impacting the region and given the uncertainty in these, normal to below normal flows seems plausible. ..................................................................... .HYDROLOGIC FLOOD AND DROUGHT POTENTIAL... Flood potential across the region seems low after we experienced elevated flows in the Wabash River in July thanks in part to repeated rounds of mesoscale convective systems (MCS). While we remain susceptible to MCSs in August, it is less likely than late June and July. The main driver of flood for August will likely be a tropical system or a stalled boundary with training convection. The later of the potentials would likely only impact isolated areas and not bring widespread flooding. Concerning drought,much of the eastern half of the region sits in some level of drought. Given the scattered nature of expected rain, areas of drought are forecast to remain or increase in severity for August. With August routinely being one of our drier months along with hot temperatures, expansion of drought to the west also seems likely. The only likely large scale system that could derail this train of thought would be tropical connections/systems. ..................................................................... .PAST 30 DAY HYDROLOGICAL AND METEOROLOGICAL REVIEW... RAINFALL DEPARTURES... Over the past 30 days, the only focus of hydrologic impacts would have been in the far western basin within the Wabash and Little Wabash basins. As of current, all points have dropped back below Action Stage. Rainfall over the past 30 days follows closely with the impacted basins noted above. Western Kentucky, Indiana, southeastern Illinois and far northwestern Ohio all recorded at or above normal precipitation. Areas just outside of our basin recorded values significantly higher than ours. The remainder of the Ohio Valleyt sat at or below normal precipitation for the last 30 days. https://www.weather.gov/ohrfc/images/dynamic/latest30day.jpeg SOIL MOISTURE CONDITIONS... Moisture values across the region sit at or below normal as of current. The driest areas reside in southwestern Ohio, southeastern Ohio and much of West Virginia. https://www.cpc.ncep.noaa.gov/soilmst/w.shtml STREAMFLOW CONDITIONS... Given mostly dry conditions over the past week, most streamflow values sit around normal to well below normal. The only area with normal to slightly above normal streamflow values would be in western Indiana and southeastern Illinois. https://waterdata.usgs.gov/index.php?id=real ..................................................................... .ATMOSPHERIC TELECONNECTION AND OSCILLATION FORECASTS FOR THE NEXT MONTH... TELECONNECTION/OSCILLATION PATTERN ARCTIC OSCILLATION Positive trending Neutral = Below to near normal precipitation NORTH ATLANTIC OSCILLATION Positive trending Neutral = Below to near normal precipitation PACIFIC/NORTH AMERICAN TELECONNECTION Positive trending Neutral = No Correlation ENSO - EL NINO/LA NINA OSCILLATION Neutral trending to La Nina = No Correlation https://www.cpc.ncep.noaa.gov ..................................................................... .TECHNICAL DISCUSSION... The Ohio Valley looks to remain in a rather active weather pattern with continued chances for showers and storms regionwide. Our summertime weather pattern remains in place with us either sitting under a large scale ridge allowing Gulf moisture to stream in or on the front side of the ridge as it propagates west putting us in the sights of storm complexes as they roll down the front side of the noted ridge. Whichever pattern we are in, neither strongly promotes regionwide rain and increases the likelihood of drought persisting or increasing in severity for portions of the Ohio Valley. A tropical system seems like the most likely opportunity to bring widespread abundant rain which could both help and hurt our overall conditions depending on the amount of rain it brings. Even with a tropical system, more likely than not the rain would be beneficial. Overall for the second half of summer into early fall, it is a wait and see pattern as convection could help some areas, but likely not all. The tropics will get busier as we progress further into the hurricane season, but the tracks will dictate if we see any precipitation from these. As we move more into the seasonal aspect of the outlook, we are transitioning from neutral to La Nina ENSO conditions which would commonly increase our chances for late fall into winter rain. ....................................................................... VISIT OUR WATER RESOURCES WEBSITE AT http://www.weather.gov/ohrfc/WRO IN ADDITION TO A 30-DAY STREAMFLOW OUTLOOK...YOU CAN ALSO OBTAIN A 60- AND 90-DAY OUTLOOK AT THE WEBSITE