Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 212336 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 736 PM EDT Wed Jun 21 2017 .SYNOPSIS... A weak front will remain stretched across the region today and then lift north tonight. Tropical moisture will spread into the area from the south on Thursday with a cold front dropping in from the northwest Friday afternoon and night. Below normal temperatures will ensue over the weekend into early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Some widely scattered showers and thunderstorms have started to form this afternoon as a weak boundary remains across the area. These isolated showers and thunderstorms will likely continue this afternoon into early evening and be mainly diurnal driven. This makes sense as forecast instability starts to wane this evening. Late this evening into Thursday morning a warm front will lift north with southwest flow washing across the region. Low temperatures will only fall into the upper 60s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... During the day Thursday Tropical Storm Cindy will head north through LA/ TX. A shortwave will also push north up ahead of the tropical storm and around the subtropical ridge. Thursday morning into early Thursday afternoon will probably remain dry out ahead of the shortwave. Later Thursday afternoon forecast soundings start to destabilize with PWATs slowly ticking up. By Thursday evening ML CAPE values on the GFS approach ~500 J/kg with PWATs almost up to 2.00" (near or at the daily PWAT max). The main concern will be the late Thursday through Friday morning period as a frontogenetic band moves out ahead of Cindy and interacting with high PWATs. Overall the pattern looks to have similarities to a predecessor rainfall event (PRE). As Friday morning evolves a potent upper level longwave trough axis approaches from the west with the ILN forecast area moving into a RRQ. The shortwave trough axis also extends from the Minnesota/ Canada border towards the Gulf Coast with ILN being east of the axis. A cold front will extend from northern Michigan southwest towards northern Illinois. The CMC has an axis of heavy rainfall extending from southern Illinois towards our northwestern zones. The ECMWF has this axis across our central zones. The GFS and NAM have this heavy rain axis across our southern zones. Given the signals above have added the mention of heavy rain into the forecast. Also have extended the heavy rain mention to all zones of the HWO given the uncertainty. This uncertainty is also highlighted in SREF plume runs which shows a wide range of possible solutions of eventual rainfall totals (or placement of the eventual band). && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Tropical moisture advects northeast ahead of the remnants of T.S. Cindy with precipitable water values increasing to 2.3 inches over the Ohio Valley. This tropical moisture will interact with a southward advancing frontal boundary to produce widespread showers and thunderstorms and the potential for heavy rain over ILN/s southern counties. Due to this moisture rich environment with favorable frontogenetic forcing will mention heavy rain in the weather grids. Fridays temperatures will be a little below normal with highs around 80s. Model solutions in a little better agreement with main remnants of T.S. Cindy staying south of ILN/s area and pcpn ending early Saturday. Will diminish pops from northwest to south late Friday night into Saturday. Temperatures to remain a little below normal with Fridays highs ranging from the upper 70s northwest to the lower 80s southeast. Mid level trof to develop over the Great Lakes with westerly flow over the Ohio Valley. ECMWF solution sharper with this trof and therefore offers a wetter solution. Will follow a blend of GFS and Canadian, limiting any mention of pcpn to a slight chance of a shower or thunderstorm to the far north Sunday afternoon. Cool temperatures to continue with Sundays highs in the mid/upper 70s. With the mid level trof lagging 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. Surface high pressure to build across the Ohio Valley keeping the region dry and cool Tuesday. Expect Tuesdays highs in the mid/upper 70s. Return moisture on the back side of surface high pressure will lead to a chance of thunderstorms Wednesday afternoon across the north. Expect Wednesdays highs to be around 80. && .AVIATION /00Z THURSDAY THROUGH MONDAY/...
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Conditions are likely to remain VFR tonight as a frontal boundary lifts northeast across the region. Isolated showers that have developed in the vicinity of TAF sites should dissipate this evening with loss of daytime heating. This will leave SCT to BKN mid and high clouds through the overnight hours. Expect VFR to continue through the day Thursday in a humid but weakly forced environment. Showers may occur in the vicinity of all sites late in the forecast ahead of a massive system approaching from the southwest. At CVG near the end of their 30 hour TAF, forcing and moisture will increase significantly as a cold front from the west begins to interact with remnants of TS Cindy. Look for showers with VCTS and MVFR ceilings to come into the picture after 00Z Friday. OUTLOOK...Thunderstorms possible Thursday night into Saturday morning. MVFR ceilings possible Thursday night into Friday night. Low level wind shear will also be possible early Friday morning.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Haines NEAR TERM...Haines SHORT TERM...Haines LONG TERM...AR AVIATION...Coniglio is the U.S. government's official web portal to all federal, state and local government web resources and services.