Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 241027 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 627 AM EDT Mon Apr 24 2017 .SYNOPSIS... An area of upper level low pressure will continue moving slowly east across the deep south today, as drier air remains in place over the Ohio Valley. A mid-level ridge will gradually build into the area by the middle of the week, allowing for increasing temperatures and generally dry conditions. As a cold front moves into the region on Thursday, chances for precipitation will increase. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... The 00Z KILN sounding sampled an extremely dry air mass between 850mb and 500mb. IR/WV satellite imagery depicts an interesting flow pattern through the mid-levels, in between the upper low over the deep south and a ridge off the east coast. There is a significant feed of moisture running northward between these features from Florida into eastern Kentucky, abruptly ceasing northward progress and spreading WSW and ENE at the col in the mid-level flow. Thus, the dry air mass just north of the mid- level wind shift -- and over Wilmington -- remains steadily in place for now. Interestingly, in both the high and low levels, flow moving into the middle Ohio Valley is gradually becoming more cyclonic and advective. Some patchy cirrus has already begun to move into the area, and an area of more notable low-level moisture (characterized by dewpoints in the upper 40s to near 50) is just nudging up against the southeastern ILN CWA border. Surface winds are expected to veer from NE to E throughout the day today, with a shift in flow at 850mb-700mb also allowing for an increase in moisture just off the surface today as well. The story has changed very little with regards to precipitation chances today, as the dry air will keep most of the CWA firmly dry all day -- and mostly clear in the low and mid levels at least to start the day. However, a 20-PoP has been maintained through the afternoon in the southeastern sections of the forecast area, closest to where the low level moisture is forecast to increase. By afternoon, there may be enough moisture spreading northwestward to allow for some scattered cumulus / stratocumulus development, necessitating an increase in sky cover during the second half of the day. This is unlikely to affect the far northwestern CWA, which (under generally clear skies) may again see the warmest temperatures of anywhere in the forecast area. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... By this evening, any chance for light rain will be coming to an end, setting up a dry forecast for the rest of the short term period. However, with wind flow aligning to southeasterly from 700mb to near the surface, an increase in mid and low level moisture will continue, prompting a continued increase in sky cover through the overnight and into Tuesday morning. Things change again on Tuesday morning, as an increased amount of warming at 5kft-10kft will likely lead to decreasing RH and a scattering of the cloud deck, eventually mixing into a cumulus field by afternoon. With ridging building in aloft and a switch to SSE flow at the surface, the pattern will set up for a more significant increase in temperatures -- reaching the middle to upper 70s across the ILN CWA. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Our region will be between a departing upper level low to our east and a s/wv and associated cold front to our west on Wednesday. Dry weather is expected along with locally breezy southerly winds. Temperatures should warm into the lower 80s, which is much above normal for late April. Embedded s/wv will rotate northeast from the southern plains to the Great Lakes region Wednesday night into Thursday. As this occurs, aforementioned cold front will push east across the Great Lakes and Ohio Valley. This will provide for a chance of showers and thunderstorms. Temperatures will cool into the 70s given clouds and the threat for precipitation. By Thursday night, cold front should settle off to our east/southeast, allowing for weak high pressure to move in. For the period Friday into Saturday, there continues to be differences in the timing of a warm front to push through our region. Some models keep the forecast area dry on Friday while return moist flow on others bring at least a chance of showers or thunderstorms back by Friday afternoon. Have kept low PoPs on Friday, pushing south to north through the day. Best chance for showers and thunderstorms still appears slated for Friday night into Saturday morning as a low level jet provides the necessary moist convergence to trigger showers and storms. Temperatures will remain above normal through the period. Mid level flow is still expected to amplify Saturday night into Sunday as an upper level low digs east across the southern Plains, then northeast toward the middle Mississippi River Valley. This should eventually push the warm front north into the southern Great Lakes. Chances for showers/storms appears low at this time frame since the area will be warm sectored. Best chance for showers and thunderstorms should come Sunday night or Monday as an associated cold front eventually pushes into the Great Lakes and Ohio Valley. Highs on Sunday will be warm, ranging from the lower 80s northwest, to perhaps the upper 80s southeast. Again, these readings are much above normal for late April. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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VFR conditions are expected through the day today. There will be a gradual increase in mid and high clouds through the period at all TAF sites, and there have also been some VFR low clouds (around 5kft) in the Cincinnati area. Overnight and into early Tuesday morning, low clouds will continue to increase, and some MVFR ceilings will be possible -- mainly for KCVG/KLUK/KILN/KDAY. However, these ceilings should scatter out by mid-morning on Tuesday. Winds will remain out of the northeast today at around 10 knots, gradually shifting to the east by tonight into Tuesday. OUTLOOK...MVFR ceilings will be possible on Thursday along with a chance of thunderstorms.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Hatzos SHORT TERM...Hatzos LONG TERM...Hickman AVIATION...Hatzos

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