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fxus63 keax 181104 

Area forecast discussion
National Weather Service Kansas City/Pleasant Hill MO
604 am CDT Wed Sep 18 2019

issued at 319 am CDT Wednesday Sep 18 2019

Early this morning, a weak front was located from northwestern KS,
through central NE, and into southeastern South Dakota. This front was slowly
moving southeastward. The main change to the forecast for today was
to slow down the arrival of any pops in northwestern MO due to the
slow movement of the front. This afternoon, in the eastern third of
the forecast area, it looks like there is at least a slight chance
for afternoon showers and storms. Forecast soundings in that area,
while showing steep low-level lapse rates, have just enough cinh
that, in absence of any forcing, should prevent any development.
Additionally, the 00z/18 sounding from sgf, and to a lesser extent
on the oun sounding, showed some mid-level warm air. Convection
allowing models do develop some showers/ storms and given the very
muggy conditions, can't rule out completely an isolated shower or
storm. Thursday afternoon looks similar but there may be a little
deeper moisture in the area. This may lead to a small chance for
showers and storms across the area.

A major concern with this forecast continues to be the potential
for heavy rain Saturday into Sunday. Precipitable water values on
the models are trending upward to around 2" early Sunday morning.
Based on sounding climatology, this is above the Max value and
more than half an inch above the 90th percentile. With moisture
contribution continuing to show up through deep layers of the
atmosphere, and upper-level contributions from the Pacific, this
extremely moist environment looks very possible. Then throw in a
slow moving frontal boundary, upper level diffluence, and low-
level flow along the boundary leading slow movement and/or
training, it looks like some areas will see very heavy rainfall
with potential for flash flooding. There are still timing/location
discrepancies in the models but the trend has been to be in or
close to the forecast area. This results in fairly low pops given
the high quantitative precipitation forecast. As models come into better agreement with the timing
and location of the front, precipitation chances will increase
and we'll be better able to place areas of higher quantitative precipitation forecast with more
confidence. But for now, the synoptic pattern favors heavy rain
and flash flooding potential Saturday into Sunday.


Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 604 am CDT Wednesday Sep 18 2019

VFR conditions are expected through the forecast. A few high level
clouds will move across the area today. A few diurnal cumulus are
also expected this afternoon.


Eax watches/warnings/advisories...

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