Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 131051
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
451 AM CST SAT FEB 13 2016

...AVIATION UPDATE...

.SHORT TERM...(Today and Tonight)
Issued at 258 AM CST SAT FEB 13 2016

Northwest flow continued over the central and northern plains with
the 08Z water vapor showing a shortwave moving across WA and OR. At
the surface, observations showed a cold ridge of high pressure
centered along the SD and MN state line moving towards northern IA.
Very dry air was also associated with the surface ridge. There have
been a few weak radar returns move across the area, but are likely
not reaching the ground due to the dry air in low levels.

For today, the weather should remain cold with mostly cloudy skies
as the surface ridge continues to track to the southeast. While
models do not show much cold air or warm air advection today, an
easterly component to surface winds don`t favor much of a warm up.
Additionally forecast soundings tend to favor at least mostly cloudy
skies through the day so think insolation will be limited. With this
in mind, have highs ranging from the mid 20s over northeast KS to
the mid 30s across central KS. I`m not expecting much in the way of
sensible weather as models show little in the way of large scale
forcing until later tonight.

The shortwave over the Pacific northwest is expected to move across
the central plains overnight and all the operational models appear
to be in reasonable agreement with this. The general consensus
however is for the better forcing to pass along or just north of the
NEB and KS state line with the deep layer moisture remaining just
out of the forecast area to the east and south. A good warm air
advection pattern is progged to develop overnight as the wave passes
and isentropic surfaces are showing good upglide through the depth
of the low clouds. Since deep moisture is limited, the dendritic
growth zone never really saturates. So the predominant precip type
looks to be freezing drizzle. There may be a chance for a brief
period of snow along the NEB state line due to the proximity of the
shortwave passing. Otherwise models continue to trend towards very
light precip if any at all. Have kept slight chance POPs across
eastern KS after midnight where the isentropic upglide is likely to
persist longer giving the drizzle a longer window to accumulate.
Outside of that it appears to be mainly a trace event with the
potential for a very light glaze developing. The prev shift had
included a mention of freezing fog across north central KS. However
forecast soundings from the NAM and GFS suggest there will remain
decent mixing of the boundary layer even with surface winds
diminishing somewhat with the surface trough. Additionally stratus
is likely to have developed well in advance of the surface boundary
preventing any radiational cooling. Therefore think chances for fog
are to low to keep a mention in the forecast. With the cloud cover
and low level warm air advection pattern, Lows are expected to be in
the lower to mid 20s.

.LONG TERM...(Sunday through Friday)
Issued at 258 AM CST SAT FEB 13 2016

Late Sunday morning the isentropic responsible for the possibility
of freezing drizzle across portions of eastern KS will gradually
weaken. The shortwave tracking over the central US will not have any
connection to an arctic air mass so the boundary layer should mix
well behind this wave. Temperatures near freezing around sunrise
will quickly increase as warmer mid level air moves in from the
west. So if any roads manage to become icy from the freezing drizzle
they will improve during the late morning. The highs for Sunday are
forecasted to range from mid 40s to lower 50s. Quickly behind the
departing wave another wave is forecasted to track over the area
Sunday night. Temperatures will be warm enough to support rain, but
very limited moisture return in the lower levels it may be tough to
get measurable precipitation. The last of this series of shortwaves
will arrive on Monday night and could clip far northeast bringing
the chance for rain. Low temperatures that night will drop maybe as
low as the mid 30s, but the mid level temperatures are quite warm
and should support mostly rain. Beyond that an upper ridge builds
across the central US ahead of a decent shortwave set to arrive
sometime late week. Temperatures should warm way above normal
through the week so expect highs to reach the upper 60s to lower 70s
by Thursday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 451 AM CST SAT FEB 13 2016

Think VFR conditions will prevail through the evening due to dry
low level air advecting in with the surface ridge. However am a
little uncertain whether CIGS will remain over the terminals all
day. Satellite trends suggest we may clear out while model progs
show a mid deck hanging in. Will follow the satellite trends for
now. There may be some MVFR conditions develop late in the
forecast period with -FZDZ possible. Confidence in this occurring
is not quite high enough to mention just yet.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Wolters
LONG TERM...Sanders
AVIATION...Wolters


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