Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 241132

632 AM CDT Thu Apr 24 2014

Issued at 343 AM CDT THU APR 24 2014

Today/Tonight...As of early this morning, a surface warm front
stretched across the northern forecast area, delineating
temperatures in the lower 50s from the middle to upper 60s south of
the boundary. This front was also serving for some weak isentropic
ascent, with light showers developing over northern Missouri and
southern Iowa. To the west, a cold front was located over central
Kansas, with a quickly-moving outflow boundary preceding the cold
front. The outflow boundary has been efficient at generating
scattered convection just behind the leading edge of outflow during
the past several hours. The overall activity will continue to push
eastward through the remainder of the morning and afternoon hours.
Trends with this system have been for a slower progression, and
likewise expect chances for precipitation to hold on through mid to
late afternoon in many areas, although coverage should become more
spotty later in the event. Current upper trough axis is located over
far eastern Colorado and is taking on a negative tilt. Strongest
upper diffluence is approaching current activity and with strong
dynamics to overspread the region over the next 6 hours, should see
widespread precipitation continue, with perhaps a gradual increase in
coverage. As for thunderstorms, mesoanalysis and short-term guidance
continue to call for meager instability (MUCAPE < 500 J/kg) along and
ahead of this activity. Not only should this eliminate the severe
weather potential, but limit overall thunderstorm coverage across the
forecast area. Therefore, expect light to moderate rainfall, with the
best chance of thunder along the leading and southwestern edge of the
convective activity. Many areas may receive up to one-half inch of
precipitation, with locally higher amounts in areas with thunderstorms.
Rain will end from west to east during the afternoon and early
evening hours. As for temperatures, highs today will be cooler with
abundant cloud cover and precipitation, with readings topping in the
middle to upper 60s. Cool readings will prevail tonight as skies
clear, with lows in the middle 40s.

Friday through Sunday...Temperatures will remain warm as little cold
air advection will be present upon the departing upper system.
Afternoon temperatures will reach the 70s to lower 80s both Friday
and Saturday. Another highly-amplified upper trough will move into
the western US on Friday, and emerge into the Plains during the
weekend. There remains some model spread with regards to the
synoptic placement of key features, especially Sunday. Initial
chances for thunderstorms, elevated in nature, are possible
beginning Saturday morning upon the nose of warm air/moisture
advection. There should be a lull in the activity once this
convection shifts eastward and the CWA establishes a moistening warm
sector. As the trough moves into the Plains Saturday night into
Sunday, strong upper ascent and an approaching pacific cold
front/lee trough will lead to increasing chances of thunderstorms.
One of the more important features the models differ on position is
the cold front/lee trough on Sunday. The GFS places this boundary
over eastern Kansas by Sunday afternoon, with the Euro further west
over central Kansas. Considering strong pressure falls with this
large upper system, would not be surprised to see a slower
progression of the surface front. This may be important as
convective initiation along the front may occur further west,
potentially keeping the high-end severe weather to the west of the
forecast area. However, with this dynamic system, it is too early to
rule out the potential for warm sector development ahead of the
front and/or intensification of any left over activity from Saturday
night. Deep layer shear is likely to be supportive of organized
convection, although the low-level shear and overall instability
vary greatly among model members, along with the actual timing of
convection, owing to modest uncertainty at this stage to gage the
anticipated storm mode and subsequent severe weather threat. Long
story short, it is a little too early to dive into the specifics of
Sunday/Sunday night`s severe weather potential.

Monday and beyond...The surface low pressure will occlude over
Nebraska on Monday, with the broad stacked upper system left to
gradually drift eastward as it evolves. Models generally agree with
this upper pattern, which will spell much cooler and continued wet
weather for Monday through mid-week. Depending on the speed of the
surface front, there is a chance for the warm sector to remain in
the forecast area on Monday, potentially allowing for redevelopment
of thunderstorms with good lapse rates. Severe weather would be
possible if the slower solution were to verify. Otherwise, expect
well below normal temperatures Tuesday and Wednesday, with highs in
the 50s and lows in the upper 30s to lower 40s.


.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 623 AM CDT THU APR 24 2014

VFR conditions currently in place should remain the prevailing flight
category through much of the period. However, there is a chance
conditions may temporarily be reduced to MVFR during the heaviest
precipitation, most likely during the 12-16Z time frame. Surface wind
speeds may briefly become gusty and variable in direction. Scattered
showers will remain possible after 17Z, but coverage and intensity
should be less. Skies will clear during the early evening.




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