textproduct: Wilmington

WHAT HAS CHANGED

Flood watch issued for southern parts of the area.

KEY MESSAGES

1) Widespread showers and scattered thunderstorms will spread across the region today and continue into Saturday, with the potential for locally heavy rain.

DISCUSSION

KEY MESSAGE 1) Initial short wave moving into central Kentucky will lift across the region today. A second short wave in western Arkansas will move northeast and cross the area tonight into Saturday.

Showers will continue to spread northwards, making into west central Ohio during the mid afternoon. The Gulf will be wide open allowing a modest low level jet to transport deep moisture into the region with precipitable water in the vicinity of 1.8 inches. The warm cloud depth will be greater than 3.5 km allowing for more efficient warm rain processes. Instability will be rather limited, although some embedded thunder may occur with the better chances in southern areas.

Low pressure associated with the second impulse will move into the area during the latter part of the night and continue on up to around Lake Erie on Saturday. An arching warm front extending out from the low will lift across the region tonight. As it passes, widespread precipitation will end with just some spotty light showers in the warm sector for the rest of the night into early Saturday. However, additional showers and storms will develop with the diurnal cycle as some destabilization occurs ahead of surface trough trailing the low.

Most guidance continues with the theme of a swath of heavier rainfall along and south/east of I-71. Most of that zone will get at least one inch with both REFS and HEFS indicating that narrow stripes of up to 3 inches will be possible. It should be noted that there is at least some potential for a secondary heavier axis near the I-75 corridor in Ohio if cells can become concentrated where the warm front takes on a more southwest-northeast orientation immediate ahead of the low. The probability of this occurring is less than 30 percent.

Most of northern Kentucky and parts of nearby southeast Indiana and southern Ohio have moister soils from recent rainfall. Thus it seemed prudent to issue a flood watch for the potential of flash flooding this afternoon into the overnight. The northeast extent of the watch is a bit of a question. Highland, Ross, and Hocking counties have not had as much recent rain and thus drier soil. But there are some flashier areas in these counties, so they have been included. There was also some consideration of extending the watch into central Ohio. If guidance trends continue to indicate that the heaviest rain may impact that part of the area, then an expansion of the watch may be needed.

With a very moist profile limiting instability, the potential for severe weather looks low. There remains a narrow window late in the day, when instability will be maximized, where the warm front will be near the far southern part of the area. Low level wind profiles near the warm front are concerning, so cannot completely rule out rotating storms if any pockets of sufficient instability are manifested. There is very little shear on Saturday, so the potential for any stronger, organized storms looks very low.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Ceilings will be lowering through the early part of the TAF period, eventually falling to IFR area wide. Showers will spread across the terminals after 14Z resulting in visibility restrictions, initially MVFR but then dropping to IFR as well. Ceilings may drop to LIFR immediately ahead of an approaching warm front after 00Z. Once the warm front lifts across the region, winds will veer to the southeast and eventually south. Ceilings will get back IFR with MVFR visibilities and only spotty lingering showers.

OUTLOOK...MVFR to IFR ceilings and visibilities will persist into Saturday morning with MVFR ceilings possibly lingering into Sunday morning.

ILN WATCHES/WARNINGS/ADVISORIES

OH...Flood Watch from noon EDT today through late tonight for OHZ073-074- 078>082-088. KY...Flood Watch from noon EDT today through late tonight for KYZ089>100. IN...Flood Watch from noon EDT today through late tonight for INZ075-080.