Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 110823
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
323 AM CDT Fri Aug 11 2017

.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Fri Aug 11 2017

Isolated showers and storms continue at 08Z this morning across much
of the forecast area. Weak isentropic lift within the 305K-310K
layer along with weak embedded wave was contributing to the
precipitation. Further south a MCS was ongoing across south central
Kansas into western Oklahoma. Regional radar loop shows the presence
of an MCV over northwest Oklahoma. This feature is forecast to moves
eastward through the morning across northern Oklahoma and southern
Kansas into the early afternoon. Will maintain small chances for
showers and isolated storms through the morning mainly south of
Interstate 70, closer to I-35. Extensive cirrus shield will
gradually diminish through the from northwest to southeast through
the day with clouds lingering across east central Kansas through
much of the day. Surface high building into northeast Kansas will
bring drier air into the cwa through the day. Temperatures today are
expected to be in the lower 80s. Tonight, the surface high will move
eastward through the night with return flow setting up along across
the western high Plains. Winds will be light from the northeast to
east across the area tonight with skies mostly clear to start with
an increase overnight with cloud debris increasing after midnight
from the high plains convection. There may be some shallow ground
fog in some low lying areas forming toward midnight across northeast
and east central Kansas. Lows tonight should range from the upper
50s to lower 60s.

.LONG TERM...(Saturday through Thursday)
Issued at 321 AM CDT Fri Aug 11 2017

By Saturday morning, a broad mid-level trough will remain centered
over the Great Lakes region with surface high pressure focused just
northeast of the CWA.  The northwesterly flow aloft on Saturday will
become more westerly late weekend into early next week, with models
continuing to show scattered precipitation chances as a result of
several disturbances developing within this mid-level pattern.  On
Saturday, models show two weak embedded waves:  one in western NE
and the second near the Texas/Oklahoma panhandles.  Precipitation
from these waves should stay west of the CWA through much of the
daytime hours. By Saturday night, showers and thunderstorms from
both waves may skim across portions of the forecast area and
continue through Sunday. While models show around 30kts of 0-6km
bulk shear with ~1000 J/kg of MUCAPE Sunday afternoon, lift and
forcing over the area look to be pretty weak so that may hinder the
development of stronger storms. Model discrepancies in the mid-level
pattern are apparent by Monday as the GFS shows a well-defined
shortwave tracking over the region, bringing additional
precipitation chances. In contrast, the ECMWF/Canadian models either
do not depict the wave or show the wave as being much weaker
compared to the GFS.  Due to this model uncertainty, have kept
slight to low-end chance PoPs in for Monday, but have a dry forecast
going for Monday night.

By Monday night into Tuesday, the mid-level trough that will have
been anchored over the Great Lakes region for several days will
finally shift into the northeastern U.S. with a weak mid-level ridge
briefly building in behind it across the central U.S.  This ridge
will become less defined through the day on Tuesday as a mid-level
trough over the Pacific Northwest progresses further east with an
embedded shortwave sliding into Kansas Tuesday into Wednesday.
However, there are model discrepancies with the timing of this
shortwave, with the ECMWF bringing it into the CWA Tuesday/Tuesday
night and the GFS/Canadian generally bringing the wave into the area
on Wednesday.  As a result of these timing differences, have only
slight chance PoPs for Tuesday with increasing PoPs into Wednesday.
This pattern through mid-week will keep a frontal boundary stalled
out across Oklahoma, however models show this boundary lifting
northward into the area as a warm front by Thursday, bringing
additional showers and thunderstorms.

As for temperatures, conditions will remain below the seasonal
normals this weekend into early next week with highs in the low 80s
and lows in the low/mid 60s.  Surface low pressure over Colorado
will start advancing into western Kansas mid-week, resulting in more
southerly flow and warm-air advection into the forecast area by
Wednesday and Thursday.  As a result, high temperatures by Thursday
may rise into the mid/upper 80s and possibly near 90 degrees.


&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday)
Issued at 1112 PM CDT Thu Aug 10 2017

04Z satellite shows mid clouds stretching back to northwest KS and
the models persist in keeping these clouds over much of the area
through the night. Meanwhile low level dry air should continue
advecting south. So chances for fog continue to look small. Some
shower activity continues to persist across east central KS and I
expect this to continue to slowly shift south through the night as
the 850MB front pushes south. So VFR conditions are forecast to
continue Through Friday.


&&

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

$$

SHORT TERM...53
LONG TERM...Hennecke
AVIATION...Wolters



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