Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 202350 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 650 PM EST Mon Feb 20 2017 .SYNOPSIS... A warm and well above normal temperature pattern will continue through Friday. A weak frontal boundary will approach on Tuesday and wash out over the region Tuesday night. An unsettled pattern will be present Thursday through Friday night. A strong cold front will move through Friday night. && .NEAR TERM /THROUGH TUESDAY/... High pressure will be situated east of the area overnight allowing for southerly flow to continue through the overnight hours. In addition cloud cover will be on the increase as a weak frontal boundary approaches. The southerly flow and increase in clouds will allow for continued above normal temperatures. Precipitation is expected to hold off through the night. The increase in cloud cover overnight should help limit fog development. && .SHORT TERM /TUESDAY NIGHT/... Well above normal temperatures will continue through the short term. A weak frontal boundary will approach the region Tuesday and wash out over the area Tuesday night. Models continue to disagree on precipitation coverage for the short term. The pattern indicates that there will be two light areas of precipitation one that moves into northwestern portions of the forecast area and another that moves across the south and into central portions of the forecast area. Due to the expected precipitation coverage limited precipitation chances to the chance or likely categories. As the front washes out Tuesday night some patchy fog will be possible. Added patchy fog mention to the forecast. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... An upper level low will break off from the main flow and head towards Florida on Wednesday with 850 mb temperatures around 10 degrees C. By Thursday the inversion around 800 mb will start to erode with a slight cooling in 850 temperatures. As the inversion begins to weaken surface based instability will grow. Both the ECMWF and GFS also show weak PVA moving over the area Thursday afternoon into evening. Forecast soundings on the GFS show MU CAPE values averaging ~600 J/kg while ML CAPE values are around 300 J/kg. There is some dry air in forecast soundings which could help to limit updraft growth but still think thunderstorms will be possible in the afternoon. Previous model runs also had a stalled front across the area Thursday afternoon but the latest GFS and ECMWF have the front closer to the Ohio/ Michigan border. Friday an upper level low will eject out of the midwest and head east. ILN will be in the warm sector Friday with southwesterly flow firmly established in the low levels. GFS forecast soundings have a CAP forming around 800 mb Friday morning and holding firm until Friday evening. Friday afternoon into evening the cold front will be pushing into Indiana and approach the CWA border Friday night. As the front approaches the CAP will erode with forecast soundings completely saturating briefly. ML CAPE is forecasted to be around 700 J/kg with SFC- 1 km shear values around 35 kts. The LLJ will also be strong with 50 kts forecasted at 850 mb. Due to the mentioned above SPC has the area outlooked for Day 5. Looking at the mean flow orientation (relative to the boundary) and magnitude a linear feature looks to form along the front and push east. Saturday morning the cold front will clear the CWA by 8 am with the upper level low over northern Michigan. As the low deepens the pressure gradient will continue to tighten. This mean winds could be gusty Saturday with GFS forecast soundings showing gusts of 30 to 35 kts possible (via momentum transfer). Sunday surface high pressure will move south of the region with 850 mb temperatures forecasted to be around 6 degrees C below zero. This will help push high temperatures for Saturday and Sunday back down into the 40s or near normal for this time of year. Monday the upper level trough amplitude will begin to modulate with another upper level system approaching the western United States. The GFS and ECMWF differ here with the GFS holding a baroclinic zone across the CWA while the ECMWF lifts a warm front through the CWA. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Mid and high level cloudiness will continue to stream across the region through the overnight hours. Weakening short wave energy will push east across the region Tuesday into Tuesday night. Persistent southwesterly low level flow will allow us to gradually moisten up the lower levels through the day on Tuesday. The combination of this and the approaching trough will allow for scattered showers to develop, primarily through the late afternoon hours. Expect cigs to remain mainly VFR until lowering into MVFR and possibly even IFR heading into Tuesday night. OUTLOOK...MVFR ceilings are possible into Wednesday. Thunderstorms are possible Thursday and Friday. && .CLIMATE... Record High Temperatures Date CVG CMH DAY Tue 2/21 70(1930) 71(1997) 68(1930) Wed 2/22 71(1922) 70(1930) 69(1922) Thu 2/23 72(1985/1996) 66(1906/1985) 68(1985) Fri 2/24 72(1930) 72(1961) 67(1930/1961) && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Novak NEAR TERM...Novak SHORT TERM...Novak LONG TERM...Haines AVIATION...JGL CLIMATE...

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