Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 181717 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 1217 PM EST Sat Feb 18 2017 .SYNOPSIS... A few rain showers will possible this afternoon and this evening across southern Ohio and northern Kentucky, as an upper level disturbance tracks through the Tennessee valley. Temperatures are expected to be 20 to 25 degrees above normal, today through Tuesday, with the next chance for rain showers Tuesday with the approach of a front. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Low pressure can be seen on water vapor this morning rotating over Arkansas with only a weak surface reflection. Latest KILN sounding revealed 850 mb temperatures at 10 degrees C with a PWAT of 0.27". The upper level low will push east this afternoon with the highest chance of precipitation across our far southern zones. The best lift from the low will remain south with only a deformation band/ weak WAA across the southern zones. PWATs on the GFS/ NAM all appear to aggressive with values for KILN above what the 12z sounding showed. Also, 850 mb temperatures of 10 degrees C will allow surface temperatures to quickly rise into the 60s today. Clouds will move in from the south though which should help us from completely realizing that 850 mb temperature. Prev Discussion-> In warm sector mid level ridge to flatten some and slide off to the east. Meanwhile, southern mid/upr level low over the southern Plains to to open up some and track east into the Tennessee Valley. Mid/high level clouds will increase through the day ahead of this system. Model solution differences exist regarding how far north the rain showers will make it. GFS/ECMWF solns differ on timing some but both bring northern periphery of pcpn associated with 700 mb deformation zone into northern Ky and far southern Ohio. NAM soln is an outlier and is further south. Will side with consensus of GFS/ECMWF solns which have better continuity, bringing chance pops of rain showers into the far south this aftn into this evening. Expect highs to be around 20 degrees above normal, generally in the lower 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Mid/upper level trough to track east through the TN Valley this evening with rain showers across the southeast counties coming to an end. Weak surface ridge across the region with weak front dropping into northern Ohio. In weak flow pattern, low clouds look to linger tonight especially across the southeast. Lows will be mild, with readings above normal highs. Expect lows from the lower 40s north to the upper 40s south. Sharp full latitude mid level ridge to build into the MS Valley and western Great Lakes Sunday as weak surface ridge slides east. Lingering morning clouds, especially across the southeast will give way to increasing sunshine in the afternoon. Warm high temperatures to be 20 to 25 degrees above normal, ranging from the lower 60s north to the mid/upper 60s south. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... For Sunday night and Monday, surface high will be centered to the northeast, with the axis of a high amplitude upper ridge crossing the ILN area. This regime of scant moisture and forcing points to a warm and dry period to start the long term. Next system to produce precip will be a front extending from the polar regions into the tropics. This front has been very consistently represented on models for several days, raising confidence that showers will be moving in Tuesday afternoon through Tuesday night. Weak temperature gradient and lack of cold air aloft should keep thunderstorms from developing. High pressure and a dry airmass are forecast to return Wednesday. For Thursday, some increase in moisture along a developing warm front may produce a few showers. Showers will be likely and thunderstorms possible Friday along a strong cold front swinging in from the west. Geopotential surfaces that will be well above normal for February, coupled with a southerly surface flow carrying warmer air, will produce temperatures that are far above normal. Highs in the 60s each day will contrast with normal highs in the lower to middle 40s. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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All TAF sites are currently VFR with mid and high clouds increasing across northern Kentucky. Weak returns are appearing on the radar this afternoon and will likely remain near and southeast of interstate 71. This is thanks to weak isentropic upglide and a weak 700 mb deformation band. High res models also in general support this with better coverage south and east. By 6z Sunday morning any precipitation that does form will be starting to exit the region. Sunday morning a weak frontal boundary will sag and stall just north of KDAY. Not surprisingly right ahead and along the front high res models are restricting visibilities and ceilings. The SREF probabilities also support this. Later Sunday morning lower PWAT air will filter into the northern zones (GFS PWATs < 0.5") and help to clear some of the low clouds out (esp. towards CMH/LCK). Further towards the south and west the lower PWAT air will not ever make it. Due to this some high res models never clear out KCVG/ KLUK and keep them MVFR. Overall think this is overdone. Most likely KCVG/KLUK will eventually breakout Sunday afternoon. OUTLOOK...MVFR ceilings are possible Tuesday and Thursday.
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&& .CLIMATE... Record High Temperatures Date CVG CMH DAY Sat 2/18 68(1948) 63(1948/1994/2011) 64(1948) Sun 2/19 74(1939) 70(1939) 70(1939) Mon 2/20 72(1891/2016) 68(1891/2016) 69(2016) Tue 2/21 70(1930) 71(1997) 68(1930) && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Haines/AR NEAR TERM...Haines/AR SHORT TERM...AR LONG TERM...Coniglio AVIATION...Haines CLIMATE...

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