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

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FXUS63 KEAX 210851

351 AM CDT Tue Apr 21 2015

Issued at 351 AM CDT TUE APR 21 2015

The primary concern for today will be the potential for a few light
rain showers to develop along a weak boundary/convergence zone,
especially south of I-70 this aftn as some weak instability builds
near the boundary in an area of 40+ sfc dewpoints. A few isolated
thunderstorms are possible across very far southern portions of the
forecast area where MUCAPE values may reach 500 J/kg, but this still
modest instability should keep any thunderstorms fairly weak, and
expected rainfall totals light.

Temperatures this afternoon will reach the mid to possibly upper 60s
due to mixing of increasing 850 hPa temperatures, and a slightly
more westerly direction to winds this afternoon.

A cold front will sweep through the region from late this evening
through the early overnight hours, ushering in colder temperatures
and very briefly gusty northwest winds. Although winds will begin to
diminish behind the initial frontal passage, non-zero boundary layer
mixing overnight should decrease the possibility of widespread frost
development, even despite 2 m temperatures dropping into the mid 30s
across northern MO and far northeast KS. Have mentioned patchy frost
in areas where the low temperature is expected to meet or drop below
35 degrees, but do not feel that the potential for frost is high
enough to warrant an advisory at this time.

The cold front will stall near or just south of the CWA border early
Wednesday morning and will linger through the afternoon before
continuing its southward drift as surface high pressure begins to
edge into northern MO. Kept very low-end PoPs for our far southern
counties during the daylight hours Wednesday, but expect most shower
activity to remain primarily south of the CWA. High temps will be
significantly cooler on the north side of the front, topping out
only in the mid to upper 50s Wednesday afternoon. Also lowered
temperatures a bit below guidance for Wednesday night/Thursday
morning due to the surface high building in, and will need to watch
the potential for frost development once again in northeast MO where
light winds and the coldest temperatures aloft will occur during a
more favorable part of the late overnight/early morning.

Model trends have been to shift Friday`s system farther south than
guidance suggested yesterday, decreasing the potential for strong
storms in our forecast area. Shear will still be quite high Friday
afternoon and evening, but with the surface low tracking from
central KS across the MO Ozarks, the warm front won`t even move into
the vicinity of the forecast area, keeping surface-based instability
nil. Models still indicate widespread elevated convection north of
the warm front as the parent shortwave trough tracks across the CWA
Friday evening through Friday night, so have kept PoPs likely from
late Friday afternoon through Saturday morning. Timing looks similar
to that in previous forecasts, so still expect precipitation to
clear out during the afternoon or evening hours Saturday, preventing
a complete washout of a weekend across the region.

Additional showers are possible late Sunday evening into Monday as a
shortwave trough treks eastward across the central Plains, but model
agreement is considerably lower with this feature, and have kept
PoPs low and high temperatures minimally impacted.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1123 PM CDT MON APR 20 2015

VFR conditions will continue as surface high pressure to the south
continues to push eastward. A few mid-level clouds will pass over the
area tonight as NW flow aloft continues to bring a scattered layer
through the area. Otherwise, westerly winds will pick up Tuesday
afternoon, gusting to 20 kts until sunset.




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