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

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FXUS63 KEAX 271721

National Weather Service Kansas City/Pleasant Hill MO
1221 PM CDT Thu Apr 27 2017

Issued at 353 AM CDT THU APR 27 2017

Satellite imagery shows a trough, that brought the rain Tuesday
night through Wednesday, swinging through eastern Missouri early
this morning; taking the lingering rain with it. This is all
occurring within a larger flow pattern which has pushed the
prevailing westerlies down across the southern Plains, allowing
cooler temperatures to prevail. In fact, the current trough exiting
eastern Missouri shoved a cold front all the way down to the Gulf
Coast. However, looking back to the west, of note for the next 24
hours is a subtle trough zipping across the Great Basin in the
prevailing westerlies; best seen in the models as a 700mb shortwave

Today through Friday...Quick note for the morning hours today,
cloud cover is not eroding across northwest Missouri as expected,
so have trimmed the eastern counties out of the Frost Advisory.
Moving our focus back to the west, the 700mb trough will move east
into the Plains States today and tonight and will be the main
diver for tonight`s activity, especially as it pivots northeast
Friday morning as the prevailing westerlies tilt towards a
southwest flow as a larger trough digs into the Desert Southwest.
There is a broad consensus in the model solutions that this will
induce strong warm air advection by late tonight into Friday
morning across our section of eastern Kansas and northern
Missouri, making more rain likely tonight into Friday. Given the
time of night (late) that activity is expected move north, there
wont be much, if any, instability available for this system to
work with. So, while we are expecting rain tonight, it looks
likely that it will be mostly showers with a few embedded
thunderstorms with no chance of severe weather with rainfall
totals likely ranging between a quarter and half an inch. And,
while this wont beget flooding tonight or Friday, it will help set
the stage for potential flooding come this weekend when more rain

Otherwise, expect temperatures to rebound a little today
--highs around 60 degrees--, though we will have to wait till
Friday to see a significant increase in temperatures as southerly
winds return to the region. Though even then, areas near the Iowa
border may wallow in the 50s Friday while central Missouri climbs
into the low 70s thanks to lingering rain and differential cloud
cover up north.

This looking wet. As the 700mb shortwave moves past us,
the digging trough out west will help induce a meridional flow from
the Gulf Coast north into the Central Plains. As the trough then
moves into the Plains this weekend model consensus indicates that a
frontal boundary will develop and stall across southern Missouri,
resulting in an inverted surface trough from Texas northeast into
southern and eastern Missouri. As a result, expectations are that
available moisture and instability will get pumped north from the
Gulf, resulting in heavy rain and thunderstorm activity focused
across southern Missouri. The question is, how far north of the
boundary do the storms spread, which will have significant
ramifications on the rainfall accumulation we have in our area.
Given the significant rainfall expected, areas of southern and
eastern Missouri will be under a Flash Flood Watch through the
weekend; but given the questions on how far north the torrential
rains will get, we will locally hold off on issuing a Flash Flood
Watch for now, providing the following shifts the opportunity to
narrow down and focus where any watch might be needed for the
weekend. Otherwise, temperatures do look to remain cool through
the weekend as our area will be on the cool side of the front that
should be wallowing across southern Missouri, likely meaning we
wont see widespread temperatures in the 60s till next work week,
and limiting the potential for any kind of severe weather for the
northern half of Missouri through the weekend.


.Aviation...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1215 PM CDT THU APR 27 2017

While VFR conditions will prevail for the remainder of the
afternoon, increasing ceilings along with rain chances enter into
the terminal areas by this evening, perhaps lowering visbys as
well. By the pre-dawn hours on Friday, at least IFR ceilings will
likely be in the area, impacting aviation interests through at
least midday tomorrow. Look for the better rain chances to
directly impact the terminals during the early to mid-morning time
frame on Friday.




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