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

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FXUS63 KEAX 262327

527 PM CST Wed Nov 26 2014

Issued at 255 PM CST WED NOV 26 2014

A strong clipper system is tracking through the region with most of
the forecast area entering the backside of the trough. The low-level
circulation associated with the upper shortwave has remained nearly
stationary and has only drifted slightly southward throughout the
day, with snow occurring across Iowa. As this area begins to move
southeast through the evening/overnight light snow may spread back
into northern/northeastern Missouri. But there should also be a
general weakening trend as the support from the upper trough
moves away. So for now, will keep a mention for a chance of snow
through about midnight in our far northeastern counties. With the
intensity weakening, not thinking that any additional snow amounts
will occur.

After this system moves out, the weather trends to being quiet for
the weekend with a substantial warmup expected for Friday and
Saturday. Winds will become southerly/southwesterly Friday, with
strong warm advection aloft. This trend will persist into Saturday
and as a result highs should be able to climb into the 50s on Friday
and the lower 60s on Saturday. To add some perspective on this
warmup, the normal high temperature for Friday and Saturday is 47
and 46 respectively. So we will be looking a temperatures at least
15 degrees above normal to start the weekend. Sunday is a little
trickier. Models are in good agreement moving a strong cold front
through the area sometime during the day. But there is a fair amount
of difference with the timing and this will have a huge impact on
temperatures given the strong cold advection behind the front and
the warm air in place ahead the front. By midday, all the models
have the front through far northwestern Missouri, so confidence is
fairly high that temperatures in that portion of the forecast area
will be in the 30s. But the rest of the forecast area is quite
variable with the GFS faster than both the ECMWF and the GEM. If the
front is slower like the ECMWF and the GEM depict, portions of the
forecast area could see the mid to upper 60s. If the GFS verifies,
then highs would be set early in the day with temperatures steady or
falling through the afternoon. Regardless, models have continued to
trend drier and now it looks like it should be a dry frontal passage.

This colder air should be relatively short-lived as the cold high
pressure center moves over the Great Lakes region. By early Tuesday,
as the high continues to shift east, winds in the local area will
turn to the south and a decent recovery is expected for Tuesday
afternoon with highs getting close to normal levels. From there,
models begin to diverge significantly with the ECMWF and the GFS
nearly out of phase in a relatively flattened upper-level pattern.
In the lower levels, the ECMWF moves a cool surface high pressure
over the region, whereas the GFS stretches a baroclinic zone across
the area with a surface front draped over northern Missouri. The end
result is at least a 25 degree difference in the surface
temperatures between the two models and a very low confidence
forecast for Wednesday into Thursday.


.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 527 PM CST WED NOV 26 2014

Main concern for aviators for the 00Z TAF will be MVFR cigs thru the
first half of the period. Cigs right about 2kft this evening will
sink overnight and remain MVFR thru 11Z-12Z. NAM bufr soundings keep
MVFR cigs at the terminals thru 19Z-20Z tomorrow however that seems
bullish considering the back edge of MVFR cigs is not far to the west
and high pressure will be building into the region tomorrow morning.
Otrw...expect sct-bkn mid-lvl clouds tomorrow morning before giving
way to just sct high clouds tomorow afternoon. Winds will remain out
of the NW around 10kts tonight before dmshg overnight. Winds may even
remain gusty for the first hour of the TAF period so have included a
TEMPO grp to account for that. High pressure will build into the area
tomorrow morning and winds will become lgt and vrb before picking up
from the SE btn 5-10kts tomorrow afternoon.




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