469 FXUS63 KEAX 180859 AFDEAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 359 AM CDT Wed Jun 18 2014 .DISCUSSION... Issued at 358 AM CDT WED JUN 18 2014 Wednesday should start out without the complication of Tuesday with respect to the surging outflow that likely contributed to the lessor heat index values than was anticipated. Skies look to be mostly clear across the area, and good southerly flow is in place across the area as all observing sites are S/SW around 15 gusting to 25. A fairly moist atmosphere is already in place over the forecast area as lower 70 degree dewpoints are present in almost all observing stations. Despite mixing this afternoon to around 850 mb, expect this moist atmosphere to remain in place through the afternoon and evening hours. With mostly clear skies allowing for good insolation, as well as the decent mixing, it's conceivable that the forecast area could see temperatures reach the upper 80s to lower 90s. These temperatures in combination with the humid conditions will bring heat index values into the upper 90s to lower 100s. Rain does not look very possible on Wednesday as the lower to mid atmosphere looks to be rather capped off with a warm nose around 700 mb. That in combination with no real focus for ascent will preclude any mention of precipitation, at least through the afternoon and early evening hours. By late tonight deep convection could be ongoing across eastern Nebraska and western Iowa. This batch of convection could drop south/southeast in the form of a late evening/overnight MCS, and perhaps clip the northern most counties of Missouri. High instability and deep shear of around 30 to 40 kts could help the MCS maintain its strength as it pushes to the southeast. The hazards with this complex will likely be heavy rain, as well as some gusty winds, and perhaps some small hail. The better chance for thunderstorm activity will likely arrive through the day on Thursday as the trough over the northern Plains takes on a negative tilt and ejects northeastward. The influence of that trough will likely allow for some mid level ascent, aiding in the formation of more widespread convection on Thursday afternoon. While instability will be quite large, given the very moist atmosphere, the wind profile over the forecast area will likely not be conducive to organizing very many updrafts enough to cause any high-impact severe weather. While heavy rain, as well as gusty winds and maybe some small hail will be likely with these storms, it's unlikely that large hail or any damaging winds will be widespread occurrences. A weak frontal boundary should slide through the area for Friday, which should shunt the best chances for rain south/southeast of the forecast area for Friday. The cooler air will also help to bring temperatures back down into the middle to upper 80s through the end of the week and into this weekend. Precipitation chances through the weekend become tougher to nail down as a mid level ridge forms over the central and southern Plains. However, most of Missouri will find itself under some decent flow at 500 mb, out of the northwest. With this better mid level flow over head it will keep alive chances for overnight MCS activity to move through the forecast area. Kept chance PoPs though the forecast period, as that flow remains over the area through at least mid week. Latest ECMWF hints at the mid level ridge over the plains being taken over by a strong mid level trough, which may help to enhance chances at showers and thunderstorms for early next week. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 107 AM CDT WED JUN 18 2014 Gusty winds will be present across the area through the overnight hours. Gusts will come and go as the night progresses as some decopling has occurred in the lowest layer of the atmosphere. Once daytime mixing commences on Wednesday morning gusts will be more prevailing through the daytime hours. Showers and thunderstorms could move into the terminals very late in the forecast period, but will likely introduce those shower chances in the next forecast issuance at 12z. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ DISCUSSION...Leighton AVIATION...Leighton