Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 291742
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1242 PM CDT SAT AUG 29 2015

.UPDATE...
ISSUED AT 1032 AM CDT SAT AUG 29 2015

Upstream 12Z raob at Omaha indicate a 500-700 ft stratus deck
advecting south and southeast towards northeast Kansas. Current
indications from the latest RAP and HRRR forecast soundings
suggest the low level saturation at 2500 ft to persist through
late afternoon so have adjusted to mostly cloudy skies through
most of the day. Also lowered highs about 5-7 degrees to the upper
70s and lower 80s. Will continue to monitor trends, especially
over north central areas where earlier clearing will quickly warm
temps.

&&

...Update to aviation forecast discussion...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT SAT AUG 29 2015

Early this morning an upper level trough extended from the northern
Great Lakes...southwest across northern MO into eastern KS. The
surface cold front was moving southeast of the CWA. A broad upper
level ridge was located across the west central US.

The upper trough will shear apart with the more amplified northern
branch moving east across the Great Lakes States. The southern
section of the H5 trough will dig south across northeast OK through
the day. The model forecast soundings show wrap around low-level
moisture will advect southeast across northeast and east central KS
this morning. The low clouds should increase towards sunrise across
the eastern half of the CWA. I cannot rule out a few sprinkles but
the stronger ascent for rain showers and thunderstorms will be east
and south of the CWA. The clouds will gradually erode from west to
east across northeast and east central KS through the late morning
and early afternoon hours. Skies will remain clear across the
western counties of the CWA and patchy fog may develop before
sunrise but should mix out by 8 AM. Most areas will become mostly
sunny during the mid afternoon hours, though a few more clouds may
continue across the southeast counties through the afternoon hours.
Highs will be in the lower 80s across most of the CWA. The western
counties will receive more insolation and may reach into the mid 80s
for afternoon highs.

Tonight...The H5 trough digging south-southwest across east central
OK will cause a sfc and 850mb low to develop across central and
eastern OK. Some of the numerical models develop weak isentropic
lift across southeast KS and western MO. The extreme southeast
counties may see a few isolated showers but at this time I will keep
14 pops across the southeast counties of the CWA. Once again some
patchy fog may develop across north central KS by
sunrise...especially if skies remain clear through the night.
Overnight lows will drop to around 60 degrees across the western
counties of the CWA with lower to mid 60s across east central KS.

.LONG TERM...(Sunday THROUGH Friday)
ISSUED AT 231 AM CDT SAT AUG 29 2015

Remnants of upper trough moving through the area tonight will
weaken and leave a vort max in the vicinity of southern MO that
remains nearly stationary through Monday. This feature will
result in scattered clouds and a few showers that could extend
into extreme east central and southeast KS during this time. While
isolated showers aren`t out of the question in our far
southeastern forecast area south of I35, chances are low enough
that I did not include in any products at this time.

Other than the influence of the aforementioned vort max, an upper
ridge axis will extend from the southern Rockies into the Upper
Midwest early next week. From Tuesday through Wednesday, a
shortwave trough will move from the central Rockies to the Upper
Midwest, flattening the ridge axis and producing lift out ahead of
it. Main dynamics and lift with this system will be focused to
our north, but medium range models continue to have continuity in
producing QPF down into northeast KS with the best chance Tuesday
night.

After that, upper ridge builds back in which should keep the
eastern third of KS dry through the rest of the work week.
Pattern is favorable for temperatures to average several degrees
above normal for late August with highs near 90 for most of the
week and lows in the 65 to 70 degree range.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Sunday AFTERNOON)
ISSUED AT 1235 PM CDT SAT AUG 29 2015

Persistent MVFR cigs will remain pivoted around a 850 mb front
this afternoon, while dry air coming from the northeast attempts
to scatter cloud deck by 00Z tonight. Best chances for this
occurring is over KMHK. Otherwise expect the MVFR stratus to
remain in place overnight with some guidance indicating fog
developing underneath the frontal inversion. This unusual scenario
for this time of year leads to uncertainty in how low visibilitieswill
be based on what occurs with the stratus this afternoon. For now,
have introduced IFR 10Z to 15Z for low stratus and fog at all
sites. May need to monitor trends to adjust timing, but believe
the MVFR stratus will linger through at least 18Z Sunday.

&&

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

$$

UPDATE...Bowen
SHORT TERM...Gargan
LONG TERM...GDP
AVIATION...Bowen


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