Area Forecast Discussion
Issued by NWS Wilmington, OH

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364 FXUS61 KILN 251044 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 644 AM EDT MON JUL 25 2016 .SYNOPSIS... Showers and thunderstorms will be observed in the hot and humid air mass which is in place, ahead of cold front which will move through the region this afternoon. This front will stall out across Kentucky, bringing a continued threat for storms across southern portions of the region Tuesday and Wednesday. The front is expected to lift north as warm front, as a wave of low pressure tracks through the Great Lakes late in the week. This will bring the threat for widespread thunderstorms Thursday night and Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Upper level ridge stretches east from the central plains into the Ohio Valley with band of westerlies across the upper Mississippi valley and Great Lakes. Progressive shortwave trof to pivot east through the Great Lakes flattening the northern portion of the ridge. This will allow a surface cold front to drop southeast though the Ohio Valley this afternoon. Numerical models continue to have a difficult time pin pointing storms in weakly forced, unstable airmass in the warm sector. Ongoing MCS tracking east across Indiana is weakening. However, outflow boundary well ahead of this feature has lead to new convection over se Indiana where blyr capes values of 2000-2500 j/kg exist. Expect a few storms to continue to fire along this outflow boundary and then become more numerous in coverage later today with blyr capes of 3000-3500 j/kg expected across southern Ohio/northern Ky ahead of the approaching cold front. Have high chance pops jump up to likely across the south this afternoon in this favorable environment. In this environment where strong instby is expected a few storms may become severe with damaging winds being the primary threat. Will continue to mention this threat in the HWO product. Heat again will be a factor today across the south where highs are expected to be in the lower 90s. These hot temperatures combined with dewpoints in the lower and middle 70s will result in heat indices of 100 to 104 degrees. Therefore, will continue previous heat headlines. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... Surface cold front to push south of the Ohio river and stall out south of the Ohio river tonight. Storms will end from the north across all but the far south overnight. Temperatures will be a little cooler with lows from the mid 60s north to the lower 70s south. Surface cold front to stall out east-west just south of the Ohio river at the south end of the mid level westerlies. This front will be the focus for diurnal storm development Tuesday. Will mention this potential along and south of the Ohio river. Further north, drier air should inhibit thunderstorm development. Highs on Tuesday will be slightly cooler and generally in the mid and upper 80s. Weak surface high pressure to build acrs the Great Lakes with a continued threat of showers and thunderstorms along and south of the Ohio river Wednesday. Have limited mention to slight chance. Generally expect highs in the upper 80s Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Boundary will lift north as a warm front late Wednesday night into Thursday. This will allow precipitable water values to increase northward, placing the CWA back in a very moist environment for Thursday. Models show a shortwave approaching late Thursday or Thursday night. Timing is still somewhat in question, but there is decent consensus on the track which will bring it across the Ohio Valley. Therefore, begin to increase pops for Thursday afternoon and will continue chance pops into Thursday night for possible influence from shortwave. Additional shortwaves may affect the Ohio Valley Friday through Saturday. Details associated with the shortwaves (such as track/timing/strength) are in question and will need to be resolved with time. But the potential for shortwaves combined with a warm moist air mass means that chance pops for convection will continue through at least Saturday. Eventually, a cold front may move through and this could occur late Saturday into Sunday but confidence is low on the timing of the frontal passage. Temperatures are forecast to favor near average to slightly above average values through the long term. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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Cold front lies across Illinois, moving toward Ohio. Thunderstorms that developed in the very humid airmass along and ahead of the front have now dissipated west of TAF sites. VFR conditions are forecast to persist through the early part of the TAF period. Thunderstorms are expected to develop in the vicinity of TAF sites this afternoon as forcing increases near the approaching front, while instability rises toward daytime maxima. The chance for thunderstorms will then linger into evening as the front makes its way toward the Ohio River. Will issue amendments to better indicate timing and effects of thunderstorms closer to their time of occurrence. Look for improving conditions late in the forecast as instability drops off with loss of daytime heating. Winds will generally out of the west with speeds close to 10 knots during the afternoon. BR may reduce visibility at ILN and LUK late in the forecast. CVG should see VFR and light northwest winds after 12Z Tuesday. OUTLOOK...Thunderstorms possible Thursday.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...Heat Advisory until 8 PM EDT this evening for OHZ073-074- 078>082-088. Excessive Heat Warning until 8 PM EDT this evening for OHZ077. KY...Heat Advisory until 8 PM EDT this evening for KYZ089>100. IN...Heat Advisory until 8 PM EDT this evening for INZ075-080. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...AR LONG TERM...BPP AVIATION...Coniglio

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