Area Forecast Discussion
Issued by NWS Wilmington, OH

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889 FXUS61 KILN 222005 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 405 PM EDT Thu Jun 22 2017 .SYNOPSIS... Moisture from Cindy will overspread the region today. A cold front will drop southeast across the area Friday afternoon and evening, with heavy rainfall possible ahead of this front. Temperatures will drop below normal through the weekend and into early next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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A band of mostly showers has continued to push north today with the northern extent now approaching the CWA border. This is in response to a shortwave that is slowly pushing north and moving up and around a mid-level ridge. As the shortwave approaches the area, it will begin to pull east around the ridge pulling the rain east as well. This shield of rain also delineates a very moist tropical air mass in response to Cindy. PWATs with this air mass are at or above 2.00". A PWAT of 2.00" is close to record values for this time of year. After this band of precipitation clears the CWA there will likely be a brief break. Early Friday morning an upper level low over Southern Manitoba will begin to swing southeast. Another upper level low will dive south across eastern Saskatchewan. As this happens the upper level longwave trough axis will amplify. Upper level diffluence will rapidly increase starting around 3 AM thanks to ILN being in between the subtropical ridge and upper level trough axis to the north. As this occurs a band of showers and thunderstorms will start to fill in. There has been some disagreement on where exactly this band will likely form, but the latest ECMWF has no also pulled the band north following suite with the NAM and CMC. This placement would put the band from a Wayne county (IN) to a Union county (OH) line. The GFS has a line that closely follows I- 71. PWATs on both the NAM and GFS are around 2.10" at this time (near max values). Given the strong vertical lift and near max moisture values have kept PoPs categorical.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
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Friday morning looks wet as the upper level trough axis continues to amplify with a strengthening RRQ approaching from the west. Overall this event has the symptoms of a PRE. As the tropical cyclone approaches a band of precipitation will form Friday morning and be driven frontogenetically (as seen on GFS fgen vectors). The event also is not directly from Cindy but indirectly. The ILN forecast area is in a RRQ and the fgen band looks to help to strengthen the upper level jet. The ILN forecast area is also north and left of the forecast track for Cindy (and north and west of a low level theta-e ridge axis). Run accumulated precipitation on the GFS, ECMWF, NAM and CMC show widespread totals of one to three inches with isolated totals of three to four inches. Give the strong upper level divergence/ diffluence, near max PWAT values, and vorticity advection have gone ahead and issued a Flash Flood Watch for the entire CWA except Auglaize, Hardin, and Mercer counties. WPC also has the area in a day 2 moderate risk for excessive rainfall. Friday afternoon the band of heavier precipitation will slowly sag southeastwards as the upper level trough approaches from the northwest. The remnants of Cindy will also push east across Kentucky at this time. This means heavy rain will likely continue through the day Friday. Late Friday evening the remnants of Cindy will skirt just south of our southern zones with rain slowly coming to an end early Saturday morning.
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&& .LONG TERM /SATURDAY THROUGH THURSDAY/...
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Mid level trof to develop over the Great Lakes with westerly flow over the Ohio Valley. Surface high pressure to begin nosing into the Ohio Valley Saturday. Expect pcpn to stay north of the area with cool highs in the mid/upper 70s Saturday. Shortwave pivoting through the mean trof over the Great Lakes may lead to few showers but expect this pcpn to stay north of ILN/s FA. Cool temperatures to continue with Sundays highs in the mid/upper 70s. With another s/w and the mean mid level trof across the Great Lakes can not rule out an afternoon shower mainly across the north Monday. Will limit these pops to slight chance. Temperatures look to be about 10 degrees below normal with highs on Monday in the lower and middle 70s. Models solns sharpen up mid level trof over the eastern Great Lakes which may lead to a few showers or thunderstorms over the northeastern counties. Rather cool readings to continue Tuesday with highs generally in the mid 70s. Surface high pressure slide east with southerly low level developing on its back side at midweek. Expect dry conditions with a warming trend. Temperatures will be closer to normal with highs on Wednesday in the lower 80s. Warm front to develop over the Great Lakes with southerly flow increasing. Temperatures will continue to moderate with highs Thursday in the lower and middle 80s. The ECMWF and Canadian solns bringing a progressive system through the Great Lakes Thursday, while the GFS holds off pcpn. With an increase in moisture have allowed for a slight chance of a thunderstorm but confidence is not high in this chance.
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&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/... Currently all TAF sites VFR this afternoon with a shield of precipitation approaching from the south. This shield of showers are in association with an upper level disturbance that is forecasted to push north and then east around a ridge of high pressure off the coast of Georgia. Latest guidance continues to show the shield of showers weakening as they move north. Brief restrictions of MVFR will be possible. A band of showers and thunderstorms will then form Friday morning starting around 9z and slowly sag southeast. Inside this band, restrictions down to LIFR will be possible in the heaviest cells. The band of precipitation will then slowly sag southeast during the afternoon keeping most of the TAF sites IFR/ MVFR through the day Friday until the end of the TAF issuance. Not until Saturday morning will TAF sites recover. OUTLOOK...Intermittent MVFR ceilings possible Saturday through Tuesday. && .ILN WATCHES/WARNINGS/ADVISORIES...
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OH...Flash Flood Watch from 2 AM EDT Friday through late Friday night for OHZ042>046-051>056-060>065-070>074-077>082-088. KY...Flash Flood Watch from 2 AM EDT Friday through late Friday night for KYZ089>100. IN...Flash Flood Watch from 2 AM EDT Friday through late Friday night for INZ050-058-059-066-073>075-080.
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&& $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM...Haines LONG TERM...AR AVIATION...Haines

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