000
FXUS63 KTOP 020438
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1138 PM CDT Fri Aug 1 2014

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Saturday)
Issued at 332 PM CDT FRI AUG 1 2014

Latest water vapor loops shows a shortwave axis moving over
Missouri with subsidence over eastern Kansas at 19Z. Surface trough
and low extended from northeast to southwest Kansas. Scattered
clouds have developed in layer around 750-700mb and forecast
soundings from the RUC show clouds dissolving by 02Z. Winds expected
to become easterly this evening as the surface low and trough moves
into southeast Kansas. Some isentropic lift develops after 06Z
tonight with low condensation pressure deficits over east central
Kansas. NAM has best lift over southeast Kansas after 09Z on the
305K isentropic surface. Have kept in some partly cloudy skies in
east central Kansas later tonight and into early Saturday morning.
There is little in the way of upper support, but could see some
isolated very light showers or sprinkles develop in the isentropic
lift and models have shown over the last few runs. Lows tonight will
range from the lower to mid 60s.

Saturday, the northwest upper flow continues with heights rising
slightly through the day. Expect highs to be a few degrees warmer
out toward central Kansas and similar to today. Some small chances
of showers are possible on Saturday with weak embedded waves and
some weak isentropic lift especially in the morning. With nothing
showing up upstream in water vapor will keep the dry forecast going.
Models show a 700 mb wave over north central Nebraska Saturday
afternoon. The NAM develops some showers and isolated thunderstorms
across central and parts of east central Kansas in a zone of
700-500mb frontogenesis in the afternoon. Slight warming aloft may
inhibit any precipitation from forming and will increase pops but
remain less than 15 percent attm.

.LONG TERM...(Saturday Night through Friday)
Issued at 332 PM CDT FRI AUG 1 2014

A board upper level ridge across the west-central conus will
gradually build east across the southern plains by mid week.

Weak upper level troughs embedded in northwesterly flow aloft may
provide enough ascent when combined with weak isentropic lift at
night for isolated showers Saturday Night through Sunday night. At
this time I will only carry 10 to 14 pops due to the uncertainty on
areal coverage and timing. Highs on Sunday will be in the upper 80s
to lower 90s. lows will be in the 60s.

It looks dry Monday through Tuesday as the upper level ridge
builds eastward into the southern plains. Highs will be in the lower
to mid 90s. lows will be in the upper 60s to lower 70s.

Tuesday Night through Thursday, A series of upper level troughs will
round the upper level ridge axis across the northern and central
plains. A cold front will also push southward into eastern KS on
Wednesday and may stall out across the CWA through Thursday. The
combination of ascent ahead of the upper level troughs and surface
convergence along the surface cold front will provide the CWA with
chances for showers and thunderstorms. Highs will gradually cool
into the mid 80s to lower 90s, with overnight lows in the mid 60s
to lower 70s.

&&

.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1137 PM CDT FRI AUG 1 2014

Will continue VFR through the period with light SE winds. Stray
showers continue overnight and a slightly better chance for
isolated thunder tomorrow afternoon leads to VCTS in all TAF
sites.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...53
LONG TERM...Gargan
AVIATION...67