Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 161140
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
640 AM CDT Sat Aug 16 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 320 AM CDT SAT AUG 16 2014

Isolated showers and thunderstorms continue to move across east
central Kansas at this hour, bringing with them locally heavy
rainfall as they pass. Evening sounding indicated PW values over two
inches in the column, with some improvement in wind shear and cape
above 850mb.  Shortwave trof sliding SE in the upper flow across far
NE Kansas aiding in generating convection there, while broader
sheered out vorticity trailing westward in the trof continues to
initiate isolated activity to the west. Dense fog has formed across
some of the north central counties, which lie north of the surface
boundary where winds are calm and over areas that had better
rainfall yesterday.

For today, expect shortwave to continue sliding southward and to
bring a slight chance for showers and storms through the day before
diminishing northwest to southeast by the early evening hours.
Little in the way of severe storm parameters however a quick heavy
downpour is possible given PW values.  Highs in the far NE should be
in the lower 80s with highs in the lower 90s far southwest.  Winds
light and out of the north for the most part. Lows tonight in the
60s as slightly cooler drier air pushes southward.  Fog this morning
should dissipate by mid morning.

.LONG TERM...(Sunday through Friday)
Issued at 320 AM CDT SAT AUG 16 2014

On Sunday the region should experience subsidence behind the
shortwave trough moving into the mid MS valley. This trough will
drive the front into southeast KS where it will stall out. Have
therefore lowered the pops across far eastern KS since most of the
activity should be well east. On Sunday night the models are
suggesting a weak wave moving over the region aiding in the
development of elevated showers and thunderstorms. A stronger wave
moving over the northern plains and upper Midwest will force another
front through the area during the day Monday. The ECMWF is much
faster with the front suggesting that precip should clear out by
Monday night. The GEM and GFS are much slower with the front and
keep precip going through the overnight hours. The area should get a
break during the day Tuesday, but that will be short lived as the
models bring another weak wave along the northern periphery of the
upper ridge. The ECMWF is then advertising a front moving through
Thursday night and Friday, so have kept slight chances around for
most of the area. Although there is low confidence in the pops after
Saturday night since most of the precip is dependent on the track of
these weak shortwaves and timing of the possible fronts.

Beyond Tuesday a deepening longwave trough over the west coast will
allow the upper ridge to build across the center of the country.
This means that summertime heat will return with daytime highs in
the 90s and lower 100s, which could last into the weekend. Have
increased the highs late next week since climatology is in the upper
80s and influences some of the guidance.

&&

.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 623 AM CDT SAT AUG 16 2014

Given trajectory of cloud deck and proximity to the surface trof,
opted to keep MHK with IFR cigs through at least 16z. Think
TOP/FOE will have enough influence from south to southwest winds
to keep cigs in higher categories. Would expect spotty isolated
showers for a few more hours and will carry VCSH for this.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 9 AM CDT this morning FOR KSZ008>010-
020.

&&

$$

SHORT TERM...67
LONG TERM...Sanders
AVIATION...67






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