Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 221800 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 200 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 PM THIS EVENING/... A widespread cirrus shield has pushed into our central and southern zones this morning with temperatures being held back slightly. This afternoon the ILN forecast area will be in between a mid-level ridge across the eastern United States and an upper level trough axis across southern Canada. At the same time Tropical Depression Cindy will be approaching from the south. A broad shield of precipitation is currently located in Tennessee and will move into the ILN forecast area this evening. The main concern for the forecast package this afternoon will be early Friday morning with a band of precipitation forecasted to form out in front of Cindy. Latest run of the 12z NAM has a band of 1" to 3" forming and running along a Wayne (IN) to Champaign county Ohio line Friday morning and continuing into Friday afternoon. This will likely require a flood watch. Will wait for 12z CAMs before making final decision on watch. Prev Discussion-> Extensive high clouds will be present across the area. Looks like they should be thin enough in the north for temperatures to still rise into the upper 80s. Further south expect them to be thicker and/or thicken earlier. In addition, some showers and thunderstorms may start spreading in late in the day ahead of mid level impulse. South winds may become a bit gusty. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Mid level impulse will move northeast during the evening. Instability is forecast to be decreasing, but still expect an area of showers and embedded thunderstorms to track across the region, especially the southern and eastern counties. This area of precipitation will also be the leading edge of the tropical air mass with precipitable water over 2 inches. Strong, persistent moisture transport into the region combined with good upper support in the right rear quadrant of an upper jet will result in abundant vertical motion and widespread showers with embedded thunderstorms starting late tonight and continuing through most of the day Friday. There will be a frontogenetical axis that will maximize vertical motion and create a band that will likely have heavy rainfall. Still some disagreement in 00Z models where this corridor sets up which provided enough uncertainty to hold off on a flash flood watch. At this stage, the best forecast is for the highest rainfall totals to extend from Ripley County to Fairfield County with the greatest rainfall occurring between 09Z and 18Z. The band will become more progressive in the afternoon as the front pushes southeast. Temperatures will remain warm tonight with lows around 70, but readings will not rise much during the day except for perhaps in the far southeast counties where there may be a window in the morning for temperatures to warm before more widespread precipitation makes it there. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Plenty of lingering tropical moisture in the way of PW values still in the 95th percentile in the southern and southeast forecast area in especially the 00-06z period Friday evening. Still some distinction between the actual TS remains and the ese advancing frontal boundary in terms of 2 areas of greatest ascent/forcing combining with ample moisture. Continued mention of heavy rain in the southeast forecast area, where lingering warm cloud depths near 4k ft and se counties on the edge of area of favorable moisture transport and continued ascent with the continued frontogenetic forcing until the frontal boundary finally pushes the most efficient moisture further east of forecast area. A fairly tight back edge gradient and clearing skies for Saturday after 12z with slightly below normal temperatures as the broader upper level trough axis begins to swing through and weak surface high pressure builds into the central MS valley and lower Ohio Valley. As the mid level trough sharpens up a bit on Sunday, precipitation potential mainly across northern forecast area where some limited moisture rides along the northern fringe of the aforementioned surface high. A slightly more pronounced mid level trough and associated shortwave passes north of the area again late Monday into Monday evening, so another period of scattered showers and isolated thunderstorms. For later in the week, decent agreement between the GFS/GFS Ensemble and ECMWF of a deepening this mid level trough positioned over the eastern Great Lakes and keeping the region under broader NW flow and therefor below normal temperatures through the remainder of the period, with daytime highs in the mid 70s increasing to near 80 by the end of the period. && .AVIATION /18Z 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... OH...Flash Flood Watch from late tonight through late Friday night for OHZ042>046-051>056-060>065-070>074-077>082-088. KY...Flash Flood Watch from late tonight through late Friday night for KYZ089>100. IN...Flash Flood Watch from late tonight through late Friday night for INZ050-058-059-066-073>075-080. && $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM... LONG TERM...JDR AVIATION...Haines is the U.S. government's official web portal to all federal, state and local government web resources and services.