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

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FXUS63 KEAX 160531

National Weather Service Kansas City/Pleasant Hill MO
1131 PM CST Wed Nov 15 2017

Issued at 218 PM CST WED NOV 15 2017

High pressure moving across the area tonight will keep things
clear/mostly clear and quiet overnight. The one potential concern
would be fog, given the light winds and clear skies. But a
significantly drier air mass will likely prevent much, if not all,
fog formation. The one exception may be in sheltered, low lying
areas in northern to northeastern MO. But really think that the air
mass will be too dry for fog formation.

Flow quickly turns southerly tomorrow and we should warm back up
close to normal with highs in the low to mid 50s. The next chance
for any precipitation should arrive Thursday night as moisture
starts to return to the region. This may initially be in the form of
drizzle due to a strong inversion above the saturated layer. But as
cold air aloft advects over the region, this inversion will erode,
saturation will deepen, and there may even be enough instability
build to lead to a few thunderstorms Friday evening. No severe
weather is expected with this activity as instability looks weak,
but enough there may be a few storms.

Model spread really starts to increase next week, and there is over
a 20 degree spread in surface temperatures for the middle of the
week and beyond. Looking at hemispheric 500 mb plots, this seems
to be a result of a difference in the handling of a low over the
eastern Pacific. The GFS deepens and cuts this low off between
Hawaii and Alaska. This dipping of the flow so far west allows for
chunk of cold air to slam south into the middle to eastern
portions of the CONUS. In contrast, the ECMWF keeps a more open
wave and progresses the wave further east. But there is stronger
ridging over the western half of the CONUS that blocks this cold
air from surging south through the middle of the country. The
Canadian model is about in the middle of these two so forecast is
closer to this solution.


.Aviation...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1130 PM CST WED NOV 15 2017

VFR conditions are expected to prevail for this forecast period. A
surface high is working its way toward the area, moving to the
southeast right now. The high will pass over northern MO near
dawn, making winds light or calm. STJ may see MVFR visibilities,
but the odds are looking less and less likely as this seems to be
a pretty dry airmass. Nonetheless, have kept the tempo though as
the MO River temp will be about 20 deg warmer than the air
temperature and winds could go calm. As the high continues to move
east, winds will veer to the southeast by this afternoon. The
return to southerly flow will bring moisture and at least MVFR
ceilings back into the area shortly after the end of this TAF




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