National Weather Service
Area Forecast Discussion

1019 PM EDT Sat Sep 21 2019
SYNOPSIS
Southerly flow over the Ohio Valley will persist through the weekend, offering increased moisture and continued warm temperatures. A few showers are expected through this afternoon, then the chance for showers and thunderstorms will increase Sunday night ahead of a cold front that will cross the region early Monday. The threat for storms will decrease Monday, as surface high pressure begins to build into the region.



NEAR TERM
THROUGH SUNDAY
Skies have gone mostly clear across the area this evening. In continued southwesterly flow, we may see some increase in mid and high level clouds at times through the night. Lows tonight will be in the low to mid 60s.



SHORT TERM
SUNDAY NIGHT
Mid level ridge starts to move away on Sunday as a trough swings east in the Upper Midwest/Upper Mississippi Valley. Sunday will be another very warm day with temperatures in the mid 80s. Gradient tightens up a bit as well, with midday and afternoon wind gusts possibly 25 to 30 mph. Sunday should be dry, then as a cold front approaches from the northwest Sunday night, clouds will increase during the evening and showers and perhaps a few thunderstorms are expected to move into western portion of the CWA, generally after midnight. Convection will spread through much of the CWA through sunrise Monday.



LONG TERM
MONDAY THROUGH SATURDAY
Model consensus remains in good agreement showing a fairly quick progression of the much-anticipated cold front southeast through the ILN FA Monday morning, yielding progressively drier conditions from late morning onward from northwest to southeast. Even with this said, do expect a gradual weakening trend of one or more initially cohesive bands of showers and isolated thunder as the activity pushes further to the south/east -- owing to a gradual loss of focused forcing. This will result in mainly dry and clearing conditions by mid/late afternoon -- even in the east. And with the arrival of the aforementioned drier air will come seasonably cool overnight lows Monday night and Tuesday night with highs generally in the mid to upper 70s both days.

The cold front will allow for cooler and drier air to infiltrate the Ohio Valley from Monday afternoon through at least midweek -- with near normal to slightly above normal temperatures during the first part of next week. This will occur coincident with surface high pressure briefly building into the region followed by a secondary weak frontal passage Wednesday night into early Thursday morning. While certainly this FROPA could deliver another round of scattered showers to the area -- as of right now, it does appear that the forcing and moisture availability will be rather meager. This would tend to suggest for the front to progress through the area with just some chance PoPs at best before drier conditions once again return by Thursday afternoon.

Beyond Thursday, longer range guidance remains in remarkable agreement showing potent quasi-zonal mid/upper level flow transitioning to anomalously expansive and strong ridging initially across the southeastern U.S. late in the workweek before overspreading pretty much all of the Tennessee/Ohio Valleys by next weekend. While there are some natural discrepancies that exist in longer range solutions -- specifically as they relate to exact positioning and timing of ridge development -- there remains above normal confidence in another period of very warm temperatures setting up by the end of the long term period. The persistence of several deterministic and ensemble solutions showing this highly- amplified pattern lends itself to high confidence in above to even much-above temperatures to close out the month next weekend into the following week. In fact, EPS mean H5 heights approaching 2 standard deviations are being advertised across the Tennessee Valley about 7 days from now, with H8 temps 8C+ above normal. This type of pattern -- should it evolve in such a manner -- would suggest the potential for record or near record temperatures to close out the month. Of course, the specifics of the pattern which will ultimately dictate the sensible weather locally will still be coming into better focus in the coming days. So certainly this pattern and the eventual evolution will be watched closely in the coming week.



AVIATION
02Z SUNDAY THROUGH THURSDAY
Scattered showers and isolated thunderstorms across central Ohio should continue to weaken/move east of KCMH/KLCK over the next hour. Otherwise, any lingering cu should dissipate through mid evening leaving just some occasional mid and high level clouds at times through the overnight hours. Some river valley fog will be possible late tonight and this could lead to a period of IFR vsbys at KLUK. Dry conditions and VFR conditions are expected during the day on Sunday with any pcpn associated with an approaching frontal boundary holding off until later Sunday night.



OUTLOOK

Thunderstorms possible on Sunday night into Monday.



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