Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 270936 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 436 AM EST Mon Feb 27 2017 .SYNOPSIS...
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A weak upper level disturbance will result in a chance of showers today. A warm front will lift north across the region on Tuesday, leading to mild temperatures and a chance for showers and thunderstorms. A cold front will sag slowly southeast across the region Tuesday night into Wednesday. This will bring a continuation of widespread showers and thunderstorms through mid week.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A weak mid level short wave currently over the mid Mississippi Valley will push quickly east across the upper Ohio Valley through this afternoon. Ahead of this, a 30-40 knot 850 mb jet will shift northeast across the Tennessee Valley and nose up into the upper Ohio Valley through this morning before weakening and shifting off to the east this afternoon. This will be accompanied by some weak lower level isentropic lift as noted on the 290K surfaces, continuing to spread into southern portions of our fa this morning before shifting north into northern portions of our fa through this afternoon. This should allow for pcpn to develop across southwest portions of our fa through daybreak and then overspread at least the rest of our southern fa through the mid to late morning hours. With the better low level convergence remaining across southern portions of our fa, there is some model uncertainty as to how far north the pcpn will make it. Several of the higher res models are trying show some spotty weakening showers pushing all the way up across most of the rest of our area through this afternoon. Will therefore linger at least some low chance pops up across northern portions of our fa into this afternoon. Highs today will be in the upper 40s to lower 50s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
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A warm front will approach from the southwest overnight and then lift northeast across our area through Tuesday morning. This will be accompanied by strengthening southwesterly low and mid level flow on Tuesday with a 40-50 knot 850 jet nosing into western portions of our fa toward daybreak and then overspreading the rest of our area during the mid to late morning hours. In increasing low level convergence and isentropic lift, expect to see shower development spread into southwest/western portions of our area late tonight and then become more numerous across the remainder of our area as we progress through the morning on Tuesday. As we get more into the warm sector and start to see some destabilization, some embedded thunder will also be possible. This activity should then push off to our east through the afternoon hours on Tuesday. In developing low level WAA, expect highs on Tuesday mainly in the 60s. Short wave energy will move out of central Rockies and into the Great Lakes region Tuesday night into Wednesday. As it does, a cold front stretching from the Great Lakes into the mid Mississippi Valley will sag slowly southeast into our area Tuesday night into Wednesday, with waves of low pressure riding northeast along the front. There continues to be some model timing and placement issues with the front as it moves through our area on Wednesday, with the 00Z GFS and CMC generally faster than the 00Z ECMWF and NAM. Nonetheless, in broad and strong southwesterly flow ahead of this, strong moisture transport will develop across the region Tuesday night with PWs pushing up into the 1.25 to possibly 1.5 inch range. This will also help pull some better instabilities northeast into at least western portions of our fa later Tuesday night into Wednesday morning. This will allow for more widespread showers and thunderstorms to develop/spread into our area Tuesday night and push down across our area heading into Wednesday. Very strong wind fields will result in impressive lower and deep shear values and hodographs. The biggest question will be the amount of instability but it does looks like there should be at least enough to combine with the strong dynamics to result in a decent severe threat Tuesday night into Wednesday. Given the high PWs and possibility for some training storms, heavy rain will also be a concern. GEFS plumes are ranging from 1 to 2 inches of rain across our area and we could end up with localized higher amounts than this. Six hour FFG values are running around 2 inches so we may very well end up with some flooding concerns as well Tuesday night into Wednesday. Temperatures will likely be non diurnal both Tuesday night and Wednesday and will be dependent on the exact timing of the front. Will keep temperatures pretty steady Tuesday night given the good southerly flow and then start to drop them off across at least the northwest heading into Wednesday afternoon.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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A weak clipper type system will drop down out of Canada Wednesday night and pivot east across the Great Lakes Thursday into Thursday night. This will lead to a chance of showers for Thursday afternoon into Thursday night, with the highest pops across our northeast, closest to the better forcing. Depending on the timing, we may be cold enough for a brief mix across our northwest on Thursday. However, thermal fields off the forecast soundings suggest the pcpn should be mainly liquid during the day on Thursday, before possibly changing over to some snow from the north Thursday night before ending. Weak mid and upper level ridging will develop through the end of the week. A weak short wave may drop down across the Great Lakes on Saturday but it looks like any pcpn associated with this should remain well off to our north. In developing WAA, temperatures will moderate through the weekend with readings pushing well above normal once again.
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&& .AVIATION /08Z MONDAY THROUGH FRIDAY/... Light returns are showing up on radar stretching from southern Illinois and western Kentucky eastward into far southern Ohio/eastern Kentucky. Just based on surface obs though, it does not appear that much of this is reaching the ground so far. As a result, will just have some mid level clouds across the area at the start of the TAF period. The low level jet is forecast to gradually strengthen as we progress through the pre dawn hours. This should allow for the pcpn to fill in some more and start to reach the ground as the lower levels begin to saturate. As a result, expect the best chance for rain to be at the southern TAF sites through the mid to late morning hours. Will therefore carry a prevailing -shra at KCVG and KLUK for a period and just have a vcsh later today at the remaining TAF sites. Cigs should drop down into MVFR category later this morning and then continue through much of the afternoon before lifting back to VFR this evening. OUTLOOK...MVFR ceilings and visibilities likely Tuesday into Wednesday along with a chance of thunderstorms. MVFR ceilings may linger into Wednesday night and be possible again Thursday night. Wind gusts to 30 kts will be possible Wednesday afternoon and evening. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...JGL AVIATION...JGL

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